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Sample records for rice blast fungal

  1. Identification of rice blast fungal elicitor-responsive genes by differential display analysis.

    PubMed

    Kim, C Y; Lee, S H; Park, H C; Bae, C G; Cheong, Y H; Choi, Y J; Han, C; Lee, S Y; Lim, C O; Cho, M J

    2000-04-01

    In order to study molecular interactions that occur between rice and rice blast fungus upon infection, we isolated fungal elicitor-responsive genes from rice (Oryza sativa cv. Milyang 117) suspension-cultured cells treated with fungal elicitor prepared from the rice blast fungus (Magnaporthe grisea) employing a method that combined mRNA differential display and cDNA library screening. Data base searches with the isolated cDNA clones revealed that the OsERG1 and OsERG2 cDNAs share significant similarities with the mammalian Ca2+-dependent lipid binding (C2) domains. The OsCPX1 cDNA is highly homologous to peroxidases. The OsHin1 cDNA exhibits homology to the tobacco hin1 gene, whose expression is induced by avirulent pathogens. The OsLPL1 and OsMEK1 cDNAs share homologies with lysophospholipases and serine/threonine mitogen-activated protein (MAP) kinase kinases, respectively. The OsWRKY1 and OsEREBP1 cDNAs are homologous to transcription factors, such as the WRKY protein family and the AP2/EREBP family, respectively. Transcripts of the OsERG1, OsHin1, and OsMEK1 genes were specifically elevated only in response to the avirulent race KJ301 of the rice blast fungus. Our study yielded a number of elicitor-responsive genes that will not only provide molecular probes, but also contribute to our understanding of host defense mechanisms against the rice blast fungus.

  2. Increase of Fungal Pathogenicity and Role of Plant Glutamine in Nitrogen-Induced Susceptibility (NIS) To Rice Blast

    PubMed Central

    Huang, Huichuan; Nguyen Thi Thu, Thuy; He, Xiahong; Gravot, Antoine; Bernillon, Stéphane; Ballini, Elsa; Morel, Jean-Benoit

    2017-01-01

    Highlight  Modifications in glutamine synthetase OsGS1-2 expression and fungal pathogenicity underlie nitrogen-induced susceptibility to rice blast. Understanding why nitrogen fertilization increase the impact of many plant diseases is of major importance. The interaction between Magnaporthe oryzae and rice was used as a model for analyzing the molecular mechanisms underlying Nitrogen-Induced Susceptibility (NIS). We show that our experimental system in which nitrogen supply strongly affects rice blast susceptibility only slightly affects plant growth. In order to get insights into the mechanisms of NIS, we conducted a dual RNA-seq experiment on rice infected tissues under two nitrogen fertilization regimes. On the one hand, we show that enhanced susceptibility was visible despite an over-induction of defense gene expression by infection under high nitrogen regime. On the other hand, the fungus expressed to high levels effectors and pathogenicity-related genes in plants under high nitrogen regime. We propose that in plants supplied with elevated nitrogen fertilization, the observed enhanced induction of plant defense is over-passed by an increase in the expression of the fungal pathogenicity program, thus leading to enhanced susceptibility. Moreover, some rice genes implicated in nitrogen recycling were highly induced during NIS. We further demonstrate that the OsGS1-2 glutamine synthetase gene enhances plant resistance to M. oryzae and abolishes NIS and pinpoint glutamine as a potential key nutrient during NIS. PMID:28293247

  3. Increase of Fungal Pathogenicity and Role of Plant Glutamine in Nitrogen-Induced Susceptibility (NIS) To Rice Blast.

    PubMed

    Huang, Huichuan; Nguyen Thi Thu, Thuy; He, Xiahong; Gravot, Antoine; Bernillon, Stéphane; Ballini, Elsa; Morel, Jean-Benoit

    2017-01-01

    Highlight  Modifications in glutamine synthetase OsGS1-2 expression and fungal pathogenicity underlie nitrogen-induced susceptibility to rice blast. Understanding why nitrogen fertilization increase the impact of many plant diseases is of major importance. The interaction between Magnaporthe oryzae and rice was used as a model for analyzing the molecular mechanisms underlying Nitrogen-Induced Susceptibility (NIS). We show that our experimental system in which nitrogen supply strongly affects rice blast susceptibility only slightly affects plant growth. In order to get insights into the mechanisms of NIS, we conducted a dual RNA-seq experiment on rice infected tissues under two nitrogen fertilization regimes. On the one hand, we show that enhanced susceptibility was visible despite an over-induction of defense gene expression by infection under high nitrogen regime. On the other hand, the fungus expressed to high levels effectors and pathogenicity-related genes in plants under high nitrogen regime. We propose that in plants supplied with elevated nitrogen fertilization, the observed enhanced induction of plant defense is over-passed by an increase in the expression of the fungal pathogenicity program, thus leading to enhanced susceptibility. Moreover, some rice genes implicated in nitrogen recycling were highly induced during NIS. We further demonstrate that the OsGS1-2 glutamine synthetase gene enhances plant resistance to M. oryzae and abolishes NIS and pinpoint glutamine as a potential key nutrient during NIS.

  4. Identification of blast resistance genes for managing rice blast disease

    USDA-ARS?s Scientific Manuscript database

    Rice blast, caused by the fungal pathogen Magnaporthe oryzae, is one of the most devastating diseases worldwide. In the present study, an international set of monogenic differentials carrying 24 major blast resistance (R) genes (Pia, Pib, Pii, Pik, Pik-h, Pik-m, Pik-p, Pik-s, Pish, Pit, Pita, Pita2,...

  5. Genetic transformation of the fungal pathogen responsible for rice blast disease

    PubMed Central

    Parsons, Kenneth A.; Chumley, Forrest G.; Valent, Barbara

    1987-01-01

    The analysis of complex genetic determinants that control the ability of a fungus to colonize its host has been impaired by the lack of sophisticated genetic tools for characterizing important pathogens. We have developed a system for the genetic transformation of Magnaporthe grisea, the causal agent of rice blast disease, to overcome this limitation. A M. grisea arginine auxotroph was shown to contain a mutation (arg3-12) that abolishes ornithine carbamoyltransferase activity. M. grisea strains that contain arg3-12 were used as recipients in transformation experiments with plasmid pMA2, which carries the ArgB+ gene from Aspergillus nidulans. Stable prototrophic transformants arose at a frequency of about 35 per microgram of plasmid DNA. Integration of single or multiple plasmid copies occurred at a single site in the genome of each transformant; rearrangements were often created during integration. When M. grisea genomic segments were incorporated into pMA2, the presence of any one of five different M. grisea segments did not greatly affect the efficiency of transformation. Integration via homologous recombination occurred when the donor plasmid was linearized by cleaving at a unique restriction site within the M. grisea segment. Images PMID:16593854

  6. Identification of rice blast resistance genes using international monogenic differentials

    USDA-ARS?s Scientific Manuscript database

    Rice blast disease, caused by the fungal pathogen Magnaporthe oryzae, is one of the most devastating diseases of rice that severely affects crop production in Jilin Province, Northeast China, where temperate japonica rice is primarily grown. In the present study, 44 representative local blast isolat...

  7. Current advances on genetic resistance to rice blast disease

    USDA-ARS?s Scientific Manuscript database

    Rice blast disease caused by the fungal pathogen Magnaporthe oryzae is one of the most threatening fungal diseases resulting in significant annual crop losses worldwide. Blast disease has been effectively managed by a combination of resistant (R) gene deployment, application of fungicides, and suita...

  8. The β-1,3-glucanosyltransferases (Gels) affect the structure of the rice blast fungal cell wall during appressorium-mediated plant infection.

    PubMed

    Samalova, Marketa; Mélida, Hugo; Vilaplana, Francisco; Bulone, Vincent; Soanes, Darren M; Talbot, Nicholas J; Gurr, Sarah J

    2017-03-01

    The fungal wall is pivotal for cell shape and function, and in interfacial protection during host infection and environmental challenge. Here, we provide the first description of the carbohydrate composition and structure of the cell wall of the rice blast fungus Magnaporthe oryzae. We focus on the family of glucan elongation proteins (Gels) and characterize five putative β-1,3-glucan glucanosyltransferases that each carry the Glycoside Hydrolase 72 signature. We generated targeted deletion mutants of all Gel isoforms, that is, the GH72(+) , which carry a putative carbohydrate-binding module, and the GH72(-) Gels, without this motif. We reveal that M. oryzae GH72(+) GELs are expressed in spores and during both infective and vegetative growth, but each individual Gel enzymes are dispensable for pathogenicity. Further, we demonstrated that a Δgel1Δgel3Δgel4 null mutant has a modified cell wall in which 1,3-glucans have a higher degree of polymerization and are less branched than the wild-type strain. The mutant showed significant differences in global patterns of gene expression, a hyper-branching phenotype and no sporulation, and thus was unable to cause rice blast lesions (except via wounded tissues). We conclude that Gel proteins play significant roles in structural modification of the fungal cell wall during appressorium-mediated plant infection.

  9. Natural rice rhizospheric microbes suppress rice blast infections

    PubMed Central

    2014-01-01

    Background The natural interactions between plant roots and their rhizospheric microbiome are vital to plant fitness, modulating both growth promotion and disease suppression. In rice (Oryza sativa), a globally important food crop, as much as 30% of yields are lost due to blast disease caused by fungal pathogen Magnaporthe oryzae. Capitalizing on the abilities of naturally occurring rice soil bacteria to reduce M. oryzae infections could provide a sustainable solution to reduce the amount of crops lost to blast disease. Results Naturally occurring root-associated rhizospheric bacteria were isolated from California field grown rice plants (M-104), eleven of which were taxonomically identified by16S rRNA gene sequencing and fatty acid methyl ester (FAME) analysis. Bacterial isolates were tested for biocontrol activity against the devastating foliar rice fungal pathogen, M. oryzae pathovar 70–15. In vitro, a Pseudomonas isolate, EA105, displayed antibiosis through reducing appressoria formation by nearly 90% as well as directly inhibiting fungal growth by 76%. Although hydrogen cyanide (HCN) is a volatile commonly produced by biocontrol pseudomonads, the activity of EA105 seems to be independent of its HCN production. During in planta experiments, EA105 reduced the number of blast lesions formed by 33% and Pantoea agglomerans isolate, EA106 by 46%. Our data also show both EA105 and EA106 trigger jasmonic acid (JA) and ethylene (ET) dependent induced systemic resistance (ISR) response in rice. Conclusions Out of 11 bacteria isolated from rice soil, pseudomonad EA105 most effectively inhibited the growth and appressoria formation of M. oryzae through a mechanism that is independent of cyanide production. In addition to direct antagonism, EA105 also appears to trigger ISR in rice plants through a mechanism that is dependent on JA and ET signaling, ultimately resulting in fewer blast lesions. The application of native bacteria as biocontrol agents in combination with

  10. Transcriptomics of the Rice Blast Fungus Magnaporthe oryzae in Response to the Bacterial Antagonist Lysobacter enzymogenes Reveals Candidate Fungal Defense Response Genes

    PubMed Central

    Mathioni, Sandra M.; Patel, Nrupali; Riddick, Bianca; Sweigard, James A.; Czymmek, Kirk J.; Caplan, Jeffrey L.; Kunjeti, Sridhara G.; Kunjeti, Saritha; Raman, Vidhyavathi; Hillman, Bradley I.; Kobayashi, Donald Y.; Donofrio, Nicole M.

    2013-01-01

    Plants and animals have evolved a first line of defense response to pathogens called innate or basal immunity. While basal defenses in these organisms are well studied, there is almost a complete lack of understanding of such systems in fungal species, and more specifically, how they are able to detect and mount a defense response upon pathogen attack. Hence, the goal of the present study was to understand how fungi respond to biotic stress by assessing the transcriptional profile of the rice blast pathogen, Magnaporthe oryzae, when challenged with the bacterial antagonist Lysobacter enzymogenes. Based on microscopic observations of interactions between M. oryzae and wild-type L. enzymogenes strain C3, we selected early and intermediate stages represented by time-points of 3 and 9 hours post-inoculation, respectively, to evaluate the fungal transcriptome using RNA-seq. For comparative purposes, we also challenged the fungus with L. enzymogenes mutant strain DCA, previously demonstrated to be devoid of antifungal activity. A comparison of transcriptional data from fungal interactions with the wild-type bacterial strain C3 and the mutant strain DCA revealed 463 fungal genes that were down-regulated during attack by C3; of these genes, 100 were also found to be up-regulated during the interaction with DCA. Functional categorization of genes in this suite included those with roles in carbohydrate metabolism, cellular transport and stress response. One gene in this suite belongs to the CFEM-domain class of fungal proteins. Another CFEM class protein called PTH11 has been previously characterized, and we found that a deletion in this gene caused advanced lesion development by C3 compared to its growth on the wild-type fungus. We discuss the characterization of this suite of 100 genes with respect to their role in the fungal defense response. PMID:24098512

  11. Sorting nexin (MoVps17) is required for fungal development and plant infection by regulating endosome dynamics in the rice blast fungus.

    PubMed

    Zheng, Huawei; Guo, Zhongkun; Xi, Yang; Yuan, Mingyue; Lin, Yahong; Wu, Congxian; Abubakar, Yakubu Saddeeq; Dou, Xianying; Li, Guangpu; Wang, Zonghua; Zheng, Wenhui; Zhou, Jie

    2017-08-24

    Vps17 is a sorting nexin (SNX) and a component of the retromer, a protein complex mediating retrograde vesicle transport between endosomes and the trans-Golgi network. However, its role in the development and pathogenicity of filamentous fungi such as the rice blast fungus (Magnaporthe oryzae) remains unclear. We investigate the functional relationship between the SNX and the cargo-selective complex (CSC) of the fungal retromer by genetic analysis, live cell imaging and immunological assay. Our data show that the MoVps17 null mutation causes defects in growth, development and pathogenicity in M. oryzae. MoVps17 is localized to endosomes depending on the activity of phosphatidylinositol 3-kinase (PI3K), a key enzyme for fungal development and infection. Both PX and BAR domains of MoVps17 are essential for its endosomal localization and function. Furthermore, our yeast two-hybrid assays show that MoVps17 and MoVps5 can interact. Lastly, live cell imaging suggests that MoVps17 can regulate early endosome fusion and budding as well as endocytosis. Taken together, our results suggest that MoVps17 specifically functions as a retromer component with CSC and also plays a distinct role in the regulation of endosome dynamics during fungal development and plant infection. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  12. Preformed expression of defense is a hallmark of partial resistance to rice blast fungal pathogen Magnaporthe oryzae

    PubMed Central

    2010-01-01

    Background Partial resistance to plant pathogens is extensively used in breeding programs since it could contribute to resistance durability. Partial resistance often builds up during plant development and confers quantitative and usually broad-spectrum resistance. However, very little is known on the mechanisms underlying partial resistance. Partial resistance is often explained by poorly effective induction of plant defense systems. By exploring rice natural diversity, we asked whether expression of defense systems before infection could explain partial resistance towards the major fungal pathogen Magnaporthe oryzae. The constitutive expression of 21 defense-related genes belonging to the defense system was monitored in 23 randomly sampled rice cultivars for which partial resistance was measured. Results We identified a strong correlation between the expression of defense-related genes before infection and partial resistance. Only a weak correlation was found between the induction of defense genes and partial resistance. Increasing constitutive expression of defense-related genes also correlated with the establishment of partial resistance during plant development. Some rice genetic sub-groups displayed a particular pattern of constitutive expression, suggesting a strong natural polymorphism for constitutive expression of defense. Constitutive levels of hormones like salicylic acid and ethylene cannot explain constitutive expression of defense. We could identify an area of the genome that contributes to explain both preformed defense and partial resistance. Conclusion These results indicate that constitutive expression of defense-related genes is likely responsible for a large part of partial resistance in rice. The finding of this preformed defense system should help guide future breeding programs and open the possibility to identify the molecular mechanisms behind partial resistance. PMID:20849575

  13. A novel role for catalase B in the maintenance of fungal cell-wall integrity during host invasion in the rice blast fungus Magnaporthe grisea.

    PubMed

    Skamnioti, Pari; Henderson, Catherine; Zhang, Ziguo; Robinson, Zena; Gurr, Sarah Jane

    2007-05-01

    Asexual spores of the rice blast fungus germinate to produce a specialized and melanized infection structure, the appressorium, which is pivotal to successful plant penetration. To investigate whether Magnaporthe grisea counteracts the toxic burst of H2O2 localized beneath the site of attempted invasion, we examined the temporal expression of five candidate antioxidant genes. Of these, the putatively secreted large subunit catalase CATB gene was 600-fold up-regulated in vivo, coincident with penetration, and moderately up-regulated in vitro, in response to exogenous H2O2. Targeted gene replacement of CATB led to compromised pathogen fitness; the catB mutant displayed paler pigmentation and accelerated hyphal growth but lower biomass, poorer sporulation, fragile conidia and appressoria, and impaired melanization. The catB mutant was severely less pathogenic than Guy 11 on barley and rice, and its infectivity was further reduced on exposure to H2O2. The wild-type phenotype was restored by the reintroduction of CATB into the catB mutant We found no evidence to support a role for CATB in detoxification of the host-derived H2O2 at the site of penetration. Instead, we demonstrated that CATB plays a part in strengthening the fungal wall, a role of particular importance during forceful entry into the host.

  14. The germin-like protein OsGLP2-1 enhances resistance to fungal blast and bacterial blight in rice.

    PubMed

    Liu, Qing; Yang, Jianyuan; Yan, Shijuan; Zhang, Shaohong; Zhao, Junliang; Wang, Wenjuan; Yang, Tifeng; Wang, Xiaofei; Mao, Xingxue; Dong, Jingfang; Zhu, Xiaoyuan; Liu, Bin

    2016-11-01

    This is the first report that GLP gene (OsGLP2-1) is involved in panicle blast and bacterial blight resistance in rice. In addition to its resistance to blast and bacterial blight, OsGLP2-1 has also been reported to co-localize with a QTLs for sheath blight resistance in rice. These suggest that the disease resistance provided by OsGLP2-1 is quantitative and broad spectrum. Its good resistance to these major diseases in rice makes it to be a promising target in rice breeding. Rice (Oryza sativa) blast caused by Magnaporthe oryzae and bacterial blight caused by Xanthomonas oryzae pv. oryzae are the two most destructive rice diseases worldwide. Germin-like protein (GLP) gene family is one of the important defense gene families which have been reported to be involved in disease resistance in plants. Although GLP proteins have been demonstrated to positively regulate leaf blast resistance in rice, their involvement in resistance to panicle blast and bacterial blight, has not been reported. In this study, we reported that one of the rice GLP genes, OsGLP2-1, was significantly induced by blast fungus. Overexpression of OsGLP2-1 quantitatively enhanced resistance to leaf blast, panicle blast and bacterial blight. The temporal and spatial expression analysis revealed that OsGLP2-1is highly expressed in leaves and panicles and sub-localized in the cell wall. Compared with empty vector transformed (control) plants, the OsGLP2-1 overexpressing plants exhibited higher levels of H2O2 both before and after pathogen inoculation. Moreover, OsGLP2-1 was significantly induced by jasmonic acid (JA). Overexpression of OsGLP2-1 induced three well-characterized defense-related genes which are associated in JA-dependent pathway after pathogen infection. Higher endogenous level of JA was also identified in OsGLP2-1 overexpressing plants than in control plants both before and after pathogen inoculation. Together, these results suggest that OsGLP2-1 functions as a positive regulator to

  15. Functional characterization of electron-transferring flavoprotein and its dehydrogenase required for fungal development and plant infection by the rice blast fungus

    PubMed Central

    Li, Ya; Zhu, Jindong; Hu, Jiexiong; Meng, Xiuli; Zhang, Qi; Zhu, Kunpeng; Chen, Xiaomin; Chen, Xuehang; Li, Guangpu; Wang, Zonghua; Lu, Guodong

    2016-01-01

    Electron-transferring flavoprotein (ETF) and its dehydrogenase (ETFDH) are highly conserved electron carriers which mainly function in mitochondrial fatty acid β oxidation. Here, we report the identification and characterization of ETF α and β subunit encoding genes (ETFA and ETFB) and ETFDH encoding gene (ETFDH) in the rice blast fungus Magnaporthe oryzae. It was demonstrated that, by impacting fatty acid metabolism, ETF and ETFDH mutations led to severe growth and conidiation defects, which could be largely rescued by exogenous acetate or carbonate. Furthermore, although conidium germination and appressorium formation appeared to be normal in ETF and ETFDH mutants, most appressoria failed to penetrate the host epidermis due to low turgor pressure. The few appressoria that succeeded in penetration were severely restricted in invasive growth and consequently failed to cause disease. Moreover, ETF mutant etfb− induced ROS accumulation in infected host cells and exogenous antioxidant GSH accelerated mutant invading growth without increasing the penetration rate. In addition, mutant etfb− displayed elevated lipid body accumulation and reduced ATP synthesis. Taken together, ETF and ETFDH play an important role in fungal development and plant infection in M. oryzae by regulation of fatty acid metabolism, turgor establishment and induction of host ROS accumulation. PMID:27113712

  16. Registration of four rice germplasm lines with improved resistance to sheath blight and blast diseases

    USDA-ARS?s Scientific Manuscript database

    Rice sheath blight (ShB) and blast caused by the fungal pathogens Rhizoctonia solani and Magnaporthe oryzae, respectively, are the two most serious diseases of rice worldwide. Four rice (Oryza sativa L.) germplasm lines designated as LJRIL103 (PI 660982), LJRIL158 (PI 660983), LJRIL186 (PI 660984),...

  17. Sequence variation at the rice blast resistance gene Pi-km locus: Implications for the development of allele specific markers

    USDA-ARS?s Scientific Manuscript database

    The recently cloned blast resistance (R) gene Pi-km protects rice crops against specific races of the fungal pathogen Magnaporthe oryzae in a gene-for-gene manner. The use of blast R genes remains the most cost-effective method for an integrated disease management strategy. To facilitate rice breed...

  18. New Marker Development for the Rice Blast Resistance Gene Pi-km

    USDA-ARS?s Scientific Manuscript database

    The blast resistance (R) gene Pi-km protects rice against specific races of the fungal pathogen Magnaporthe oryzae. The use of blast R genes remains the most cost-effective method of disease control. To facilitate the breeding process, we developed a Pi-km specific molecular marker. For this purp...

  19. Storage stability of flour-blasted brown rice

    USDA-ARS?s Scientific Manuscript database

    Brown rice was blasted with rice flour rather than sand in a sand blaster to make microscopic nicks and cuts so that water can easily penetrate into the brown rice endosperm and cook the rice in a shorter time. The flour-blasted American Basmati brown rice, long grain brown rice, and parboiled long...

  20. Blast resistance in rice: a review of conventional breeding to molecular approaches.

    PubMed

    Miah, G; Rafii, M Y; Ismail, M R; Puteh, A B; Rahim, H A; Asfaliza, R; Latif, M A

    2013-03-01

    Blast disease caused by the fungal pathogen Magnaporthe oryzae is the most severe diseases of rice. Using classical plant breeding techniques, breeders have developed a number of blast resistant cultivars adapted to different rice growing regions worldwide. However, the rice industry remains threatened by blast disease due to the instability of blast fungus. Recent advances in rice genomics provide additional tools for plant breeders to improve rice production systems that would be environmentally friendly. This article outlines the application of conventional breeding, tissue culture and DNA-based markers that are used for accelerating the development of blast resistant rice cultivars. The best way for controlling the disease is to incorporate both qualitative and quantitative genes in resistant variety. Through conventional and molecular breeding many blast-resistant varieties have been developed. Conventional breeding for disease resistance is tedious, time consuming and mostly dependent on environment as compare to molecular breeding particularly marker assisted selection, which is easier, highly efficient and precise. For effective management of blast disease, breeding work should be focused on utilizing the broad spectrum of resistance genes and pyramiding genes and quantitative trait loci. Marker assisted selection provides potential solution to some of the problems that conventional breeding cannot resolve. In recent years, blast resistant genes have introgressed into Luhui 17, G46B, Zhenshan 97B, Jin 23B, CO39, IR50, Pusa1602 and Pusa1603 lines through marker assisted selection. Introduction of exotic genes for resistance induced the occurrence of new races of blast fungus, therefore breeding work should be concentrated in local resistance genes. This review focuses on the conventional breeding to the latest molecular progress in blast disease resistance in rice. This update information will be helpful guidance for rice breeders to develop durable blast

  1. Wheat puroindolines enhance fungal disease resistance in transgenic rice.

    PubMed

    Krishnamurthy, K; Balconi, C; Sherwood, J E; Giroux, M J

    2001-10-01

    Antimicrobial peptides play a role in the immune systems of animals and plants by limiting pathogen infection and growth. The puroindolines, endosperm-specific proteins involved in wheat seed hardness, are small proteins reported to have in vitro antimicrobial properties. Rice, the most widely used cereal crop worldwide, normally does not contain puroindolines. Transgenic rice plants that constitutively express the puroindoline genes pinA and/or pinB throughout the plants were produced. PIN extracts of leaves from the transgenic plants reduced in vitro growth of Magnaporthe grisea and Rhizoctonia solani, two major fungal pathogens of rice, by 35 to 50%. Transgenic rice expressing pinA and/or pinB showed significantly increased tolerance to M. grisea (rice blast), with a 29 to 54% reduction in symptoms, and R. solani (sheath blight), with an 11 to 22% reduction in symptoms. Puroindolines are effective in vivo in antifungal proteins and could be valuable new tools in the control of a wide range of fungal pathogens of crop plants.

  2. Killing Two Birds with One Stone: Natural Rice Rhizospheric Microbes Reduce Arsenic Uptake and Blast Infections in Rice.

    PubMed

    Lakshmanan, Venkatachalam; Cottone, Jonathon; Bais, Harsh P

    2016-01-01

    Our recent work has shown that a rice thizospheric natural isolate, a Pantoea sp (hereafter EA106) attenuates Arsenic (As) uptake in rice. In parallel, yet another natural rice rhizospheric isolate, a Pseudomonas chlororaphis (hereafter EA105), was shown to inhibit rice blast pathogen Magnaporthe oryzae. Considering the above, we envisaged to evaluate the importance of mixed stress regime in rice plants subjected to both As toxicity and blast infections. Plants subjected to As regime showed increased susceptibility to blast infections compared to As-untreated plants. Rice blast pathogen M. oryzae showed significant resistance against As toxicity compared to other non-host fungal pathogens. Interestingly, plants treated with EA106 showed reduced susceptibility against blast infections in plants pre-treated with As. This data also corresponded with lower As uptake in plants primed with EA106. In addition, we also evaluated the expression of defense related genes in host plants subjected to As treatment. The data showed that plants primed with EA106 upregulated defense-related genes with or without As treatment. The data shows the first evidence of how rice plants cope with mixed stress regimes. Our work highlights the importance of natural association of plant microbiome which determines the efficacy of benign microbes to promote the development of beneficial traits in plants.

  3. Killing Two Birds with One Stone: Natural Rice Rhizospheric Microbes Reduce Arsenic Uptake and Blast Infections in Rice

    PubMed Central

    Lakshmanan, Venkatachalam; Cottone, Jonathon; Bais, Harsh P.

    2016-01-01

    Our recent work has shown that a rice thizospheric natural isolate, a Pantoea sp (hereafter EA106) attenuates Arsenic (As) uptake in rice. In parallel, yet another natural rice rhizospheric isolate, a Pseudomonas chlororaphis (hereafter EA105), was shown to inhibit rice blast pathogen Magnaporthe oryzae. Considering the above, we envisaged to evaluate the importance of mixed stress regime in rice plants subjected to both As toxicity and blast infections. Plants subjected to As regime showed increased susceptibility to blast infections compared to As-untreated plants. Rice blast pathogen M. oryzae showed significant resistance against As toxicity compared to other non-host fungal pathogens. Interestingly, plants treated with EA106 showed reduced susceptibility against blast infections in plants pre-treated with As. This data also corresponded with lower As uptake in plants primed with EA106. In addition, we also evaluated the expression of defense related genes in host plants subjected to As treatment. The data showed that plants primed with EA106 upregulated defense-related genes with or without As treatment. The data shows the first evidence of how rice plants cope with mixed stress regimes. Our work highlights the importance of natural association of plant microbiome which determines the efficacy of benign microbes to promote the development of beneficial traits in plants. PMID:27790229

  4. [Recent advances in understanding the innate immune mechanisms and developing new disease resistance breeding strategies against the rice blast fungus Magnaporthe oryzae in rice].

    PubMed

    He, Feng; Zhang, Hao; Liu, Jinling; Wang, Zhilong; Wang, Guoliang

    2014-08-01

    Rice blast, caused by the fungal pathogen Magnaporthe oryzae, is one of the most destructive diseases in rice. Utilization of resistant cultivars is the most effective and economic strategy against the disease. Recently, rice blast has become an advanced model system for elucidating the molecular mechanisms of plant-fungal interactions. Significant progress has been made in the molecular biology, genomics and proteomics of the rice-M. oryzae interaction and host resistance in the last few years. In this review, we summarize the recent advances in understanding the molecular basis of PAMP-triggered immunity (PTI) and effector-triggered immunity (ETI) in rice against M. oryzae, and propose the new strategies for blast resistance molecular breeding. We also discuss the new challenges for future investigations.

  5. New insight for two major rice blast R genes: Pi-ta and Pi-km

    USDA-ARS?s Scientific Manuscript database

    In rice breeding programs across the world, the introgression of major resistance (R) genes remains the most cost-effective method to control blast epidemics caused by the fungal pathogen Magnaporthe oryzae. During the last two years, we have examined two loci, on chromosome 12 and 11, which harbor ...

  6. Global efforts in managing rice blast disease

    USDA-ARS?s Scientific Manuscript database

    Rice blast disease caused by the fungus Magnaporthe oryzae is a major destructive disease threatening global food security. Resistance (R) genes to M. oryzae are effective in preventing infections by strains of M. oryzae carry the corresponding avirulence (AVR) genes. Effectiveness of genetic resist...

  7. Insights into molecular mechanism of blast resistance in weedy rice

    USDA-ARS?s Scientific Manuscript database

    Weedy rice is a serious pest in direct-seeded rice fields in the U.S. and worldwide. Under suitable conditions, weedy rice can reduce crop yields up to 70%. However, weedy rice may carry novel disease resistance genes. Rice blast disease caused by the fungus Magnaporthe oryzae is a major disease wo...

  8. Rice OsVAMP714, a membrane-trafficking protein localized to the chloroplast and vacuolar membrane, is involved in resistance to rice blast disease.

    PubMed

    Sugano, Shoji; Hayashi, Nagao; Kawagoe, Yasushi; Mochizuki, Susumu; Inoue, Haruhiko; Mori, Masaki; Nishizawa, Yoko; Jiang, Chang-Jie; Matsui, Minami; Takatsuji, Hiroshi

    2016-05-01

    Membrane trafficking plays pivotal roles in many cellular processes including plant immunity. Here, we report the characterization of OsVAMP714, an intracellular SNARE protein, focusing on its role in resistance to rice blast disease caused by the fungal pathogen Magnaporthe oryzae. Disease resistance tests using OsVAMP714 knockdown and overexpressing rice plants demonstrated the involvement of OsVAMP714 in blast resistance. The overexpression of OsVAMP7111, whose product is highly homologous to OsVAMP714, did not enhance blast resistance to rice, implying a potential specificity of OsVAMP714 to blast resistance. OsVAMP714 was localized to the chloroplast in mesophyll cells and to the cellular periphery in epidermal cells of transgenic rice plant leaves. We showed that chloroplast localization is critical for the normal OsVAMP714 functioning in blast resistance by analyzing the rice plants overexpressing OsVAMP714 mutants whose products did not localize in the chloroplast. We also found that OsVAMP714 was located in the vacuolar membrane surrounding the invasive hyphae of M. oryzae. Furthermore, we showed that OsVAMP714 overexpression promotes leaf sheath elongation and that the first 19 amino acids, which are highly conserved between animal and plant VAMP7 proteins, are crucial for normal rice plant growths. Our studies imply that the OsVAMP714-mediated trafficking pathway plays an important role in rice blast resistance as well as in the vegetative growth of rice.

  9. Overexpression of BSR1 confers broad-spectrum resistance against two bacterial diseases and two major fungal diseases in rice

    PubMed Central

    Maeda, Satoru; Hayashi, Nagao; Sasaya, Takahide; Mori, Masaki

    2016-01-01

    Broad-spectrum disease resistance against two or more types of pathogen species is desirable for crop improvement. In rice, Xanthomonas oryzae pv. oryzae (Xoo), the causal bacteria of rice leaf blight, and Magnaporthe oryzae, the fungal pathogen causing rice blast, are two of the most devastating pathogens. We identified the rice BROAD-SPECTRUM RESISTANCE 1 (BSR1) gene for a BIK1-like receptor-like cytoplasmic kinase using the FOX hunting system, and demonstrated that BSR1-overexpressing (OX) rice showed strong resistance to the bacterial pathogen, Xoo and the fungal pathogen, M. oryzae. Here, we report that BSR1-OX rice showed extended resistance against two other different races of Xoo, and to at least one other race of M. oryzae. In addition, the rice showed resistance to another bacterial species, Burkholderia glumae, which causes bacterial seedling rot and bacterial grain rot, and to Cochliobolus miyabeanus, another fungal species causing brown spot. Furthermore, BSR1-OX rice showed slight resistance to rice stripe disease, a major viral disease caused by rice stripe virus. Thus, we demonstrated that BSR1-OX rice shows remarkable broad-spectrum resistance to at least two major bacterial species and two major fungal species, and slight resistance to one viral pathogen. PMID:27436950

  10. Overexpression of BSR1 confers broad-spectrum resistance against two bacterial diseases and two major fungal diseases in rice.

    PubMed

    Maeda, Satoru; Hayashi, Nagao; Sasaya, Takahide; Mori, Masaki

    2016-06-01

    Broad-spectrum disease resistance against two or more types of pathogen species is desirable for crop improvement. In rice, Xanthomonas oryzae pv. oryzae (Xoo), the causal bacteria of rice leaf blight, and Magnaporthe oryzae, the fungal pathogen causing rice blast, are two of the most devastating pathogens. We identified the rice BROAD-SPECTRUM RESISTANCE 1 (BSR1) gene for a BIK1-like receptor-like cytoplasmic kinase using the FOX hunting system, and demonstrated that BSR1-overexpressing (OX) rice showed strong resistance to the bacterial pathogen, Xoo and the fungal pathogen, M. oryzae. Here, we report that BSR1-OX rice showed extended resistance against two other different races of Xoo, and to at least one other race of M. oryzae. In addition, the rice showed resistance to another bacterial species, Burkholderia glumae, which causes bacterial seedling rot and bacterial grain rot, and to Cochliobolus miyabeanus, another fungal species causing brown spot. Furthermore, BSR1-OX rice showed slight resistance to rice stripe disease, a major viral disease caused by rice stripe virus. Thus, we demonstrated that BSR1-OX rice shows remarkable broad-spectrum resistance to at least two major bacterial species and two major fungal species, and slight resistance to one viral pathogen.

  11. Rice blast research: improving our arsenal and using it

    USDA-ARS?s Scientific Manuscript database

    Rice blast disease is a constant threat to U.S. rice production, and there have been sporadic outbreaks of the disease for many decades. However, the U.S. southern rice growing area has been fortunate because the pathogen population has been relatively stable compared to other rice producing areas i...

  12. Screening and association mapping of rice blast disease resistance using a diverse collection of rice germplasm

    USDA-ARS?s Scientific Manuscript database

    Rice blast, caused by the fungus Magnaporthe oryzae B. Couch, is a very serious disease in rice (Oryza sativa L.) worldwide. Incorporation of new blast resistance genes into breeding lines is an important objective of many rice breeding programs. A diverse collection of 409 O. sativa accessions des...

  13. Rice WRKY45 plays important roles in fungal and bacterial disease resistance.

    PubMed

    Shimono, Masaki; Koga, Hironori; Akagi, Aya; Hayashi, Nagao; Goto, Shingo; Sawada, Miyuki; Kurihara, Takayuki; Matsushita, Akane; Sugano, Shoji; Jiang, Chang-Jie; Kaku, Hisatoshi; Inoue, Haruhiko; Takatsuji, Hiroshi

    2012-01-01

    Plant 'activators', such as benzothiadiazole (BTH), protect plants from various diseases by priming the plant salicylic acid (SA) signalling pathway. We have reported previously that a transcription factor identified in rice, WRKY45 (OsWRKY45), plays a pivotal role in BTH-induced disease resistance by mediating SA signalling. Here, we report further functional characterization of WRKY45. Different plant activators vary in their action points, either downstream (BTH and tiadinil) or upstream (probenazole) of SA. Rice resistance to Magnaporthe grisea, induced by both types of plant activator, was markedly reduced in WRKY45-knockdown (WRKY45-kd) rice, indicating a universal role for WRKY45 in chemical-induced resistance. Fungal invasion into rice cells was blocked at most attempted invasion sites (pre-invasive defence) in WRKY45-overexpressing (WRKY45-ox) rice. Hydrogen peroxide accumulated within the cell wall underneath invading fungus appressoria or between the cell wall and the cytoplasm, implying a possible role for H(2)O(2) in pre-invasive defence. Moreover, a hypersensitive reaction-like reaction was observed in rice cells, in which fungal growth was inhibited after invasion (post-invasive defence). The two levels of defence mechanism appear to correspond to Type I and II nonhost resistances. The leaf blast resistance of WRKY45-ox rice plants was much higher than that of other known blast-resistant varieties. WRKY45-ox plants also showed strong panicle blast resistance. BTH-induced resistance to Xanthomonas oryzae pv. oryzae was compromised in WRKY45-kd rice, whereas WRKY45-ox plants were highly resistant to this pathogen. However, WRKY45-ox plants were susceptible to Rhizoctonia solani. These results indicate the versatility and limitations of the application of this gene.

  14. Molecular progress on the mapping and cloning of functional genes for blast disease in rice (Oryza sativa L.): current status and future considerations.

    PubMed

    Ashkani, S; Rafii, M Y; Shabanimofrad, M; Ghasemzadeh, A; Ravanfar, S A; Latif, M A

    2016-01-01

    Rice blast disease, which is caused by the fungal pathogen Magnaporthe oryzae, is a recurring problem in all rice-growing regions of the world. The use of resistance (R) genes in rice improvement breeding programmes has been considered to be one of the best options for crop protection and blast management. Alternatively, quantitative resistance conferred by quantitative trait loci (QTLs) is also a valuable resource for the improvement of rice disease resistance. In the past, intensive efforts have been made to identify major R-genes as well as QTLs for blast disease using molecular techniques. A review of bibliographic references shows over 100 blast resistance genes and a larger number of QTLs (∼500) that were mapped to the rice genome. Of the blast resistance genes, identified in different genotypes of rice, ∼22 have been cloned and characterized at the molecular level. In this review, we have summarized the reported rice blast resistance genes and QTLs for utilization in future molecular breeding programmes to introgress high-degree resistance or to pyramid R-genes in commercial cultivars that are susceptible to M. oryzae. The goal of this review is to provide an overview of the significant studies in order to update our understanding of the molecular progress on rice and M. oryzae. This information will assist rice breeders to improve the resistance to rice blast using marker-assisted selection which continues to be a priority for rice-breeding programmes.

  15. Genetic analysis of durable resistance to Magnaporthe oryzae in the rice accession Gigante Vercelli identified two blast resistance loci.

    PubMed

    Urso, Simona; Desiderio, Francesca; Biselli, Chiara; Bagnaresi, Paolo; Crispino, Laura; Piffanelli, Pietro; Abbruscato, Pamela; Assenza, Federica; Guarnieri, Giada; Cattivelli, Luigi; Valè, Giampiero

    2016-02-01

    Rice cultivars exhibiting durable resistance to blast, the most important rice fungal disease provoking up to 30 % of rice losses, are very rare and searching for sources of such a resistance represents a priority for rice-breeding programs. To this aim we analyzed Gigante Vercelli (GV) and Vialone Nano (VN), two temperate japonica rice cultivars in Italy displaying contrasting response to blast, with GV showing a durable and broad-spectrum resistance, whereas VN being highly susceptible. An SSR-based genetic map developed using a GV × VN population segregating for blast resistance identified two blast resistance loci, localized to the long arm of chromosomes 1 and 4 explaining more than 78 % of the observed phenotypic variation for blast resistance. The pyramiding of two blast resistance QTLs was therefore involved in the observed durable resistance in GV. Mapping data were integrated with information obtained from RNA-seq expression profiling of all classes of resistance protein genes (resistance gene analogs, RGAs) and with the map position of known cloned or mapped blast resistance genes to search candidates for the GV resistant response. A co-localization of RGAs with the LOD peak or the marker interval of the chromosome 1 QTL was highlighted and a valuable tool for selecting the resistance gene during breeding programs was developed. Comparative analysis with known blast resistance genes revealed co-positional relationships between the chromosome 1 QTL with the Pi35/Pish blast resistance alleles and showed that the chromosome 4 QTL represents a newly identified blast resistance gene. The present genetic analysis has therefore allowed the identification of two blast resistance loci in the durable blast-resistant rice cultivar GV and tools for molecular selection of these resistance genes.

  16. Genetic analysis and identification of SSR markers associated with rice blast disease in a BC2F1 backcross population.

    PubMed

    Hasan, N; Rafii, M Y; Abdul Rahim, H; Nusaibah, S A; Mazlan, N; Abdullah, S

    2017-01-23

    Rice (Oryza sativa L.) blast disease is one of the most destructive rice diseases in the world. The fungal pathogen, Magnaporthe oryzae, is the causal agent of rice blast disease. Development of resistant cultivars is the most preferred method to achieve sustainable rice production. However, the effectiveness of resistant cultivars is hindered by the genetic plasticity of the pathogen genome. Therefore, information on genetic resistance and virulence stability are vital to increase our understanding of the molecular basis of blast disease resistance. The present study set out to elucidate the resistance pattern and identify potential simple sequence repeat markers linked with rice blast disease. A backcross population (BC2F1), derived from crossing MR264 and Pongsu Seribu 2 (PS2), was developed using marker-assisted backcross breeding. Twelve microsatellite markers carrying the blast resistance gene clearly demonstrated a polymorphic pattern between both parental lines. Among these, two markers, RM206 and RM5961, located on chromosome 11 exhibited the expected 1:1 testcross ratio in the BC2F1 population. The 195 BC2F1 plants inoculated against M. oryzae pathotype P7.2 showed a significantly different distribution in the backcrossed generation and followed Mendelian segregation based on a single-gene model. This indicates that blast resistance in PS2 is governed by a single dominant gene, which is linked to RM206 and RM5961 on chromosome 11. The findings presented in this study could be useful for future blast resistance studies in rice breeding programs.

  17. Chloroplast-expressed MSI-99 in tobacco improves disease resistance and displays inhibitory effect against rice blast fungus.

    PubMed

    Wang, Yun-Peng; Wei, Zheng-Yi; Zhang, Yu-Ying; Lin, Chun-Jing; Zhong, Xiao-Fang; Wang, Yue-Lin; Ma, Jing-Yong; Ma, Jian; Xing, Shao-Chen

    2015-03-02

    Rice blast is a major destructive fungal disease that poses a serious threat to rice production and the improvement of blast resistance is critical to rice breeding. The antimicrobial peptide MSI-99 has been suggested as an antimicrobial peptide conferring resistance to bacterial and fungal diseases. Here, a vector harboring the MSI-99 gene was constructed and introduced into the tobacco chloroplast genome via particle bombardment. Transformed plants were obtained and verified to be homoplastomic by PCR and Southern hybridization. In planta assays demonstrated that the transgenic tobacco plants displayed an enhanced resistance to the fungal disease. The evaluation of the antimicrobial activity revealed that the crude protein extracts from the transgenic plants manifested an antimicrobial activity against E. coli, even after incubation at 120 °C for 20 min, indicating significant heat stability of MSI-99. More importantly, the MSI-99-containing protein extracts were firstly proved in vitro and in vivo to display significant suppressive effects on two rice blast isolates. These findings provide a strong basis for the development of new biopesticides to combat rice blast.

  18. Identification of rice blast resistance genes in the elite hybrid rice restorer line Yahui2115.

    PubMed

    Shi, Jun; Li, Deqiang; Li, Yan; Li, Xiaoyan; Guo, Xiaoyi; Luo, Yiwan; Lu, Yuangen; Zhang, Qin; Xu, Yongju; Fan, Jing; Huang, Fu; Wang, Wenming

    2015-03-01

    Rice blast, caused by the ascomycete fungus Magnaporthe oryzae, is one of the most serious rice diseases worldwide. We previously developed an elite hybrid rice restorer line with high resistance to rice blast, Yahui2115 (YH2115). To identify the blast resistance genes in YH2115, we first performed expression profiling on previously reported blast resistance genes and disease assay on monogenic lines, and we found that Pi2, Pi9, and Pikm were the most likely resistance candidates in YH2115. Furthermore, RNA interference and linkage analysis demonstrated that silencing of Pi2 reduced the blast resistance of YH2115 and a Pi2 linkage marker was closely associated with blast resistance in an F2 population generated from YH2115. These data suggest that the broad-spectrum blast resistance gene Pi2 contributes greatly to the blast resistance of YH2115. Thus, YH2115 could be used as a new germplasm to facilitate rice blast resistance breeding in hybrid rice breeding programs.

  19. Gene pyramiding enhances durable blast disease resistance in rice.

    PubMed

    Fukuoka, Shuichi; Saka, Norikuni; Mizukami, Yuko; Koga, Hironori; Yamanouchi, Utako; Yoshioka, Yosuke; Hayashi, Nagao; Ebana, Kaworu; Mizobuchi, Ritsuko; Yano, Masahiro

    2015-01-14

    Effective control of blast, a devastating fungal disease of rice, would increase and stabilize worldwide food production. Resistance mediated by quantitative trait loci (QTLs), which usually have smaller individual effects than R-genes but confer broad-spectrum or non-race-specific resistance, is a promising alternative to less durable race-specific resistance for crop improvement, yet evidence that validates the impact of QTL combinations (pyramids) on the durability of plant disease resistance has been lacking. Here, we developed near-isogenic experimental lines representing all possible combinations of four QTL alleles from a durably resistant cultivar. These lines enabled us to evaluate the QTLs singly and in combination in a homogeneous genetic background. We present evidence that pyramiding QTL alleles, each controlling a different response to M. oryzae, confers strong, non-race-specific, environmentally stable resistance to blast disease. Our results suggest that this robust defence system provides durable resistance, thus avoiding an evolutionary "arms race" between a crop and its pathogen.

  20. Crucial Roles of Abscisic Acid Biogenesis in Virulence of Rice Blast Fungus Magnaporthe oryzae

    PubMed Central

    Spence, Carla A.; Lakshmanan, Venkatachalam; Donofrio, Nicole; Bais, Harsh P.

    2015-01-01

    Rice suffers dramatic yield losses due to blast pathogen Magnaporthe oryzae. Pseudomonas chlororaphis EA105, a bacterium that was isolated from the rice rhizosphere, inhibits M. oryzae. It was shown previously that pre-treatment of rice with EA105 reduced the size of blast lesions through jasmonic acid (JA)- and ethylene (ETH)-mediated ISR. Abscisic acid (ABA) acts antagonistically toward salicylic acid (SA), JA, and ETH signaling, to impede plant defense responses. EA105 may be reducing the virulence of M. oryzae by preventing the pathogen from up-regulating the key ABA biosynthetic gene NCED3 in rice roots, as well as a β-glucosidase likely involved in activating conjugated inactive forms of ABA. However, changes in total ABA concentrations were not apparent, provoking the question of whether ABA concentration is an indicator of ABA signaling and response. In the rice-M. oryzae interaction, ABA plays a dual role in disease severity by increasing plant susceptibility and accelerating pathogenesis in the fungus itself. ABA is biosynthesized by M. oryzae. Further, exogenous ABA increased spore germination and appressoria formation, distinct from other plant growth regulators. EA105, which inhibits appressoria formation, counteracted the virulence-promoting effects of ABA on M. oryzae. The role of endogenous fungal ABA in blast disease was confirmed through the inability of a knockout mutant impaired in ABA biosynthesis to form lesions on rice. Therefore, it appears that EA105 is invoking multiple strategies in its protection of rice from blast including direct mechanisms as well as those mediated through plant signaling. ABA is a molecule that is likely implicated in both tactics. PMID:26648962

  1. Molecular evolution of the Pi-ta gene resistant to rice blast in wild rice (Oryza rufipogon).

    PubMed

    Huang, Chun-Lin; Hwang, Shih-Ying; Chiang, Yu-Chung; Lin, Tsan-Piao

    2008-07-01

    Rice blast disease resistance to the fungal pathogen Magnaporthe grisea is triggered by a physical interaction between the protein products of the host R (resistance) gene, Pi-ta, and the pathogen Avr (avirulence) gene, AVR-pita. The genotype variation and resistant/susceptible phenotype at the Pi-ta locus of wild rice (Oryza rufipogon), the ancestor of cultivated rice (O. sativa), was surveyed in 36 locations worldwide to study the molecular evolution and functional adaptation of the Pi-ta gene. The low nucleotide polymorphism of the Pi-ta gene of O. rufipogon was similar to that of O. sativa, but greatly differed from what has been reported for other O. rufipogon genes. The haplotypes can be subdivided into two divergent haplogroups named H1 and H2. H1 is derived from H2, with nearly no variation and at a low frequency. H2 is common and is the ancestral form. The leucine-rich repeat (LRR) domain has a high pi(non)/pi(syn) ratio, and the low polymorphism of the Pi-ta gene might have primarily been caused by recurrent selective sweep and constraint by other putative physiological functions. Meanwhile, we provide data to show that the amino acid Ala-918 of H1 in the LRR domain has a close relationship with the resistant phenotype. H1 might have recently arisen during rice domestication and may be associated with the scenario of a blast pathogen-host shift from Italian millet to rice.

  2. The wheat durable, multipathogen resistance gene Lr34 confers partial blast resistance in rice.

    PubMed

    Krattinger, Simon G; Sucher, Justine; Selter, Liselotte L; Chauhan, Harsh; Zhou, Bo; Tang, Mingzhi; Upadhyaya, Narayana M; Mieulet, Delphine; Guiderdoni, Emmanuel; Weidenbach, Denise; Schaffrath, Ulrich; Lagudah, Evans S; Keller, Beat

    2016-05-01

    The wheat gene Lr34 confers durable and partial field resistance against the obligate biotrophic, pathogenic rust fungi and powdery mildew in adult wheat plants. The resistant Lr34 allele evolved after wheat domestication through two gain-of-function mutations in an ATP-binding cassette transporter gene. An Lr34-like fungal disease resistance with a similar broad-spectrum specificity and durability has not been described in other cereals. Here, we transformed the resistant Lr34 allele into the japonica rice cultivar Nipponbare. Transgenic rice plants expressing Lr34 showed increased resistance against multiple isolates of the hemibiotrophic pathogen Magnaporthe oryzae, the causal agent of rice blast disease. Host cell invasion during the biotrophic growth phase of rice blast was delayed in Lr34-expressing rice plants, resulting in smaller necrotic lesions on leaves. Lines with Lr34 also developed a typical, senescence-based leaf tip necrosis (LTN) phenotype. Development of LTN during early seedling growth had a negative impact on formation of axillary shoots and spikelets in some transgenic lines. One transgenic line developed LTN only at adult plant stage which was correlated with lower Lr34 expression levels at seedling stage. This line showed normal tiller formation and more importantly, disease resistance in this particular line was not compromised. Interestingly, Lr34 in rice is effective against a hemibiotrophic pathogen with a lifestyle and infection strategy that is different from obligate biotrophic rusts and mildew fungi. Lr34 might therefore be used as a source in rice breeding to improve broad-spectrum disease resistance against the most devastating fungal disease of rice.

  3. Single spore isolation and morphological characterization of local Malaysian isolates of rice blast fungus Magnoporthe grisea

    NASA Astrophysics Data System (ADS)

    Mishra, Ankitta; Ratnam, Wickneswari; Bhuiyan, Md Atiqur Rahman; Ponaya, Ariane; Jena, Khisord K.

    2015-09-01

    Rice blast is a destructive disease, caused by the fungal pathogen Magnaporthe grisea. It causes considerable damage to rice and leads to crop loss in rice growing regions worldwide. Although fungicides can be used to control rice blast, they generate additional cost in rice production and contamination of environment and food. Therefore, the use of resistant varieties is thought to be one of the most economically and environmentally efficient ways of crop protection from the disease. Six new local Malaysian isolates of M. grisea were isolated using single spore isolation method. Five isolates were from infected leaf samples collected from Kompleks Latihan MADA, Kedah and one was from Kelantan. These isolates were identified using morphological characteristics and microscopic studies and later confirmed by ITSequences. These isolates were induced to sporulate and used for greenhouse screening on two differential rice varieties: Mahsuri (susceptible) and Pongsu Seribu 2 (resistant). Among the 6 isolates, isolate number 3 was found to be the most virulent showing high sporulation while isolate number 4 was very slow growing, and the least virulent.

  4. Development of strategies to manage rice blast disease in the USA

    USDA-ARS?s Scientific Manuscript database

    Rice blast disease has been a serious threat to stable rice production in the southern USA. Blast disease has been causing yield losses for decades. Severity of blast epidemics has been always influenced by a combination of the following three factors: 1) rice cultivars deployed with different comb...

  5. Characterization of molecular identity and pathogenicity of rice blast fungus in Hunan province of China

    USDA-ARS?s Scientific Manuscript database

    Characterization of molecular identity and pathogenicity of the rice blast fungus benefits the deployment of effective blast resistance (R) genes. In order to identify blast resistance genes in rice producing areas where most of the hybrid rice is grown in Hunan province, 182 M. oryzae strains were ...

  6. Evidence for biotrophic lifestyle and biocontrol potential of dark septate endophyte Harpophora oryzae to rice blast disease.

    PubMed

    Su, Zhen-Zhu; Mao, Li-Juan; Li, Na; Feng, Xiao-Xiao; Yuan, Zhi-Lin; Wang, Li-Wei; Lin, Fu-Cheng; Zhang, Chu-Long

    2013-01-01

    The mutualism pattern of the dark septate endophyte (DSE) Harpophora oryzae in rice roots and its biocontrol potential in rice blast disease caused by Magnaporthe oryzae were investigated. Fluorescent protein-expressing H. oryzae was used to monitor the colonization pattern. Hyphae invaded from the epidermis to the inner cortex, but not into the root stele. Fungal colonization increased with root tissue maturation, showing no colonization in the meristematic zone, slight colonization in the elongation zone, and heavy colonization in the differentiation zone. H. oryzae adopted a biotrophic lifestyle in roots accompanied by programmed cell death. Real-time PCR facilitated the accurate quantification of fungal growth and the respective plant response. The biocontrol potential of H. oryzae was visualized by inoculation with eGFP-tagged M. oryzae in rice. H. oryzae protected rice from M. oryzae root invasion by the accumulation of H2O2 and elevated antioxidative capacity. H. oryzae also induced systemic resistance against rice blast. This systemic resistance was mediated by the OsWRKY45-dependent salicylic acid (SA) signaling pathway, as indicated by the strongly upregulated expression of OsWRKY45. The colonization pattern of H. oryzae was consistent with the typical characteristics of DSEs. H. oryzae enhanced local resistance by reactive oxygen species (ROS) and high antioxidative level and induced OsWRKY45-dependent SA-mediated systemic resistance against rice blast.

  7. Improving of Rice Blast Resistances in Japonica by Pyramiding Major R Genes.

    PubMed

    Xiao, Ning; Wu, Yunyu; Pan, Cunhong; Yu, Ling; Chen, Yu; Liu, Guangqing; Li, Yuhong; Zhang, Xiaoxiang; Wang, Zhiping; Dai, Zhengyuan; Liang, Chengzhi; Li, Aihong

    2016-01-01

    Rice blast, caused by the fungal pathogen Magnaporthe oryzae, is a major constraint to rice production worldwide. In this study, we developed monogenic near-isogenic lines (NILs) NIL (Pi9), NIL (Pizt) , and NIL (Pi54) carrying genes Pi9, Pizt, and Pi54, respectively, by marker assisted backcross breeding using 07GY31 as the japonica genetic background with good agronomic traits. Polygene pyramid lines (PPLs) PPL (Pi9+Pi54) combining Pi9 with Pi54, and PPL (Pizt+Pi54) combining Pizt with Pi54 were then developed using corresponding NILs with genetic background recovery rates of more than 97%. Compared to 07GY31, the above NILs and PPLs exhibited significantly enhanced resistance frequencies (RFs) for both leaf and panicle blasts. RFs of both PPLs for leaf blast were somewhat higher than those of their own parental NILs, respectively, and PPL (Pizt)(+)(Pi54) exhibited higher RF for panicle blast than NIL (Pizt) and NIL (Pi54) (P < 0.001), hinting an additive effect on the resistance. However, PPL (Pi9+Pi54) exhibited lower RF for panicle blast than NIL (Pi9) (P < 0.001), failing to realize an additive effect. PPL (Pizt)(+)(Pi54) showed higher resistant level for panicle blast and better additive effects on the resistance than PPL (Pi9+Pi54). It was suggested that major R genes interacted with each other in a way more complex than additive effect in determining panicle blast resistance levels. Genotyping by sequencing analysis and extreme-phenotype genome-wide association study further confirmed the above results. Moreover, data showed that pyramiding multiple resistance genes did not affect the performance of basic agronomic traits. So the way to enhance levels of leaf and panicle blast resistances for rice breeding in this study is effective and may serve as a reference for breeders. Key Message: Resistant levels of rice blast is resulted from different combinations of major R genes, PPL (Pizt)(+)(Pi54) showed higher resistant level and better additive effects on

  8. Improving of Rice Blast Resistances in Japonica by Pyramiding Major R Genes

    PubMed Central

    Xiao, Ning; Wu, Yunyu; Pan, Cunhong; Yu, Ling; Chen, Yu; Liu, Guangqing; Li, Yuhong; Zhang, Xiaoxiang; Wang, Zhiping; Dai, Zhengyuan; Liang, Chengzhi; Li, Aihong

    2017-01-01

    Rice blast, caused by the fungal pathogen Magnaporthe oryzae, is a major constraint to rice production worldwide. In this study, we developed monogenic near-isogenic lines (NILs) NILPi9, NILPizt, and NILPi54 carrying genes Pi9, Pizt, and Pi54, respectively, by marker assisted backcross breeding using 07GY31 as the japonica genetic background with good agronomic traits. Polygene pyramid lines (PPLs) PPLPi9+Pi54 combining Pi9 with Pi54, and PPLPizt+Pi54 combining Pizt with Pi54 were then developed using corresponding NILs with genetic background recovery rates of more than 97%. Compared to 07GY31, the above NILs and PPLs exhibited significantly enhanced resistance frequencies (RFs) for both leaf and panicle blasts. RFs of both PPLs for leaf blast were somewhat higher than those of their own parental NILs, respectively, and PPLPizt+Pi54 exhibited higher RF for panicle blast than NILPizt and NILPi54 (P < 0.001), hinting an additive effect on the resistance. However, PPLPi9+Pi54 exhibited lower RF for panicle blast than NILPi9 (P < 0.001), failing to realize an additive effect. PPLPizt+Pi54 showed higher resistant level for panicle blast and better additive effects on the resistance than PPLPi9+Pi54. It was suggested that major R genes interacted with each other in a way more complex than additive effect in determining panicle blast resistance levels. Genotyping by sequencing analysis and extreme-phenotype genome-wide association study further confirmed the above results. Moreover, data showed that pyramiding multiple resistance genes did not affect the performance of basic agronomic traits. So the way to enhance levels of leaf and panicle blast resistances for rice breeding in this study is effective and may serve as a reference for breeders. Key Message: Resistant levels of rice blast is resulted from different combinations of major R genes, PPLPizt+Pi54 showed higher resistant level and better additive effects on the panicle blast resistance than PPLPi9+Pi54. PMID

  9. Genotyping-by-Sequencing-Based Genetic Analysis of African Rice Cultivars and Association Mapping of Blast Resistance Genes Against Magnaporthe oryzae Populations in Africa.

    PubMed

    Mgonja, Emmanuel M; Park, Chan Ho; Kang, Houxiang; Balimponya, Elias G; Opiyo, Stephen; Bellizzi, Maria; Mutiga, Samuel K; Rotich, Felix; Ganeshan, Veena Devi; Mabagala, Robert; Sneller, Clay; Correll, Jim; Zhou, Bo; Talbot, Nicholas J; Mitchell, Thomas K; Wang, Guo-Liang

    2017-09-01

    Understanding the genetic diversity of rice germplasm is important for the sustainable use of genetic materials in rice breeding and production. Africa is rich in rice genetic resources that can be utilized to boost rice productivity on the continent. A major constraint to rice production in Africa is rice blast, caused by the hemibiotrophic fungal pathogen Magnaporthe oryzae. In this report, we present the results of a genotyping-by-sequencing (GBS)-based diversity analysis of 190 African rice cultivars and an association mapping of blast resistance (R) genes and quantitative trait loci (QTLs). The 190 African cultivars were clustered into three groups based on the 184K single nucleotide polymorphisms generated by GBS. We inoculated the rice cultivars with six African M. oryzae isolates. Association mapping identified 25 genomic regions associated with blast resistance (RABRs) in the rice genome. Moreover, PCR analysis indicated that RABR_23 is associated with the Pi-ta gene on chromosome 12. Our study demonstrates that the combination of GBS-based genetic diversity population analysis and association mapping is effective in identifying rice blast R genes/QTLs that contribute to resistance against African populations of M. oryzae. The identified markers linked to the RABRs and 14 highly resistant cultivars in this study will be useful for rice breeding in Africa.

  10. Multiple rice microRNAs are involved in immunity against the blast fungus Magnaporthe oryzae.

    PubMed

    Li, Yan; Lu, Yuan-Gen; Shi, Yi; Wu, Liang; Xu, Yong-Ju; Huang, Fu; Guo, Xiao-Yi; Zhang, Yong; Fan, Jing; Zhao, Ji-Qun; Zhang, Hong-Yu; Xu, Pei-Zhou; Zhou, Jian-Min; Wu, Xian-Jun; Wang, Ping-Rong; Wang, Wen-Ming

    2014-02-01

    MicroRNAs (miRNAs) are indispensable regulators for development and defense in eukaryotes. However, the miRNA species have not been explored for rice (Oryza sativa) immunity against the blast fungus Magnaporthe oryzae, the most devastating fungal pathogen in rice production worldwide. Here, by deep sequencing small RNA libraries from susceptible and resistant lines in normal conditions and upon M. oryzae infection, we identified a group of known rice miRNAs that were differentially expressed upon M. oryzae infection. They were further classified into three classes based on their expression patterns in the susceptible japonica line Lijiangxin Tuan Hegu and in the resistant line International Rice Blast Line Pyricularia-Kanto51-m-Tsuyuake that contains a single resistance gene locus, Pyricularia-Kanto 51-m (Pikm), within the Lijiangxin Tuan Hegu background. RNA-blot assay of nine of them confirmed sequencing results. Real-time reverse transcription-polymerase chain reaction assay showed that the expression of some target genes was negatively correlated with the expression of miRNAs. Moreover, transgenic rice plants overexpressing miR160a and miR398b displayed enhanced resistance to M. oryzae, as demonstrated by decreased fungal growth, increased hydrogen peroxide accumulation at the infection site, and up-regulated expression of defense-related genes. Taken together, our data indicate that miRNAs are involved in rice immunity against M. oryzae and that overexpression of miR160a or miR398b can enhance rice resistance to the disease.

  11. Panicle blast 1 (Pb1) resistance is dependent on at least four QTLs in the rice genome.

    PubMed

    Inoue, Haruhiko; Nakamura, Mitsuru; Mizubayashi, Tatsumi; Takahashi, Akira; Sugano, Shoji; Fukuoka, Shuuichi; Hayashi, Nagao

    2017-12-01

    Rice blast is the most serious disease afflicting rice and there is an urgent need for the use of disease resistance (R) genes in blast tolerance breeding programs. Pb1 is classified as a quantitative resistance gene and it does not have fungal specificity. Pb1-mediated resistance develops in the latter stages of growth. However, some cultivars, such as Kanto209 (K209), cultivar name Satojiman, despite possessing Pb1, do not exert resistance to rice blast during the reproductive stage. We found that the expression of WRKY45 gene downstream of Pb1 was weakly induced by rice blast inoculation at the full heading stage in K209. Genetic analysis using the SNP-based Golden Gate assay of K209 crossing with Koshihikari Aichi SBL (KASBL) found at least four regions related to the resistance in the rice genome (Chr8, Chr9, Chr7, Chr11). Mapping of QTL related to Chr7 confirmed the existence of factors that were required for the resistance of Pb1 in the 22 to 23 Mbp region of the rice genome. We clarified how the K209 cultivar is vulnerable to the blast disease despite possessing Pb1 and found the DNA marker responsible for the quantitative resistance of Pb1. We identified the QTL loci required for Pb1-mediated resistance to rice panicle blast. Pb1 was negatively dependent on at least three QTLs, 7, 9 and 11, and positively dependent on one, QTL 8, in the K209 genome. This finding paves the way for creating a line to select optimal QTLs in order to make use of Pb1-mediated resistance more effectively.

  12. Geographically Distinct and Domain-Specific Sequence Variations in the Alleles of Rice Blast Resistance Gene Pib

    PubMed Central

    Vasudevan, Kumar; Vera Cruz, Casiana M.; Gruissem, Wilhelm; Bhullar, Navreet K.

    2016-01-01

    Rice blast is caused by Magnaporthe oryzae, which is the most destructive fungal pathogen affecting rice growing regions worldwide. The rice blast resistance gene Pib confers broad-spectrum resistance against Southeast Asian M. oryzae races. We investigated the allelic diversity of Pib in rice germplasm originating from 12 major rice growing countries. Twenty-five new Pib alleles were identified that have unique single nucleotide polymorphisms (SNPs), insertions and/or deletions, in addition to the polymorphic nucleotides that are shared between the different alleles. These partially or completely shared polymorphic nucleotides indicate frequent sequence exchange events between the Pib alleles. In some of the new Pib alleles, nucleotide diversity is high in the LRR domain, whereas, in others it is distributed among the NB-ARC and LRR domains. Most of the polymorphic amino acids in LRR and NB-ARC2 domains are predicted as solvent-exposed. Several of the alleles and the unique SNPs are country specific, suggesting a diversifying selection of alleles in various geographical locations in response to the locally prevalent M. oryzae population. Together, the new Pib alleles are an important genetic resource for rice blast resistance breeding programs and provide new information on rice-M. oryzae interactions at the molecular level. PMID:27446145

  13. Geographically Distinct and Domain-Specific Sequence Variations in the Alleles of Rice Blast Resistance Gene Pib.

    PubMed

    Vasudevan, Kumar; Vera Cruz, Casiana M; Gruissem, Wilhelm; Bhullar, Navreet K

    2016-01-01

    Rice blast is caused by Magnaporthe oryzae, which is the most destructive fungal pathogen affecting rice growing regions worldwide. The rice blast resistance gene Pib confers broad-spectrum resistance against Southeast Asian M. oryzae races. We investigated the allelic diversity of Pib in rice germplasm originating from 12 major rice growing countries. Twenty-five new Pib alleles were identified that have unique single nucleotide polymorphisms (SNPs), insertions and/or deletions, in addition to the polymorphic nucleotides that are shared between the different alleles. These partially or completely shared polymorphic nucleotides indicate frequent sequence exchange events between the Pib alleles. In some of the new Pib alleles, nucleotide diversity is high in the LRR domain, whereas, in others it is distributed among the NB-ARC and LRR domains. Most of the polymorphic amino acids in LRR and NB-ARC2 domains are predicted as solvent-exposed. Several of the alleles and the unique SNPs are country specific, suggesting a diversifying selection of alleles in various geographical locations in response to the locally prevalent M. oryzae population. Together, the new Pib alleles are an important genetic resource for rice blast resistance breeding programs and provide new information on rice-M. oryzae interactions at the molecular level.

  14. Characterization of rice blast resistance gene Pi61(t) in rice germplasm

    USDA-ARS?s Scientific Manuscript database

    Identification of resistance (R) genes to races of Magnaporthe oryzae in rice germplasm is essential for the development of rice cultivars with long lasting blast resistance. In the present study, one major quantitative trait locus, qPi93-3, was fine mapped using a recombinant inbred line (RIL), F8 ...

  15. Current progress on genetic interactions of rice with rice blast and sheath blight fungi

    USDA-ARS?s Scientific Manuscript database

    Analysis of genetic interactions between rice and its pathogenic fungi Magnaporthe oryzae and Rhizoctonia solani should lead to a better understanding of molecular mechanisms of host resistance, and the improvement of strategies to manage rice blast and sheath blight diseases. Presently dozens of ri...

  16. Identification of broad spectrum rice blast resistance genes with IRRI Rice monogenic lines

    USDA-ARS?s Scientific Manuscript database

    Rice blast disease, caused by the fungus Magnaporthe oryzae, is the most destructive rice disease worldwide. This disease is managed with a combination of the use of resistant cultivars, application of fungicides, and improved cultural practices. Among them, the use of resistant cultivars is the mos...

  17. Several wall-associated kinases participate positively and negatively in basal defense against rice blast fungus.

    PubMed

    Delteil, Amandine; Gobbato, Enrico; Cayrol, Bastien; Estevan, Joan; Michel-Romiti, Corinne; Dievart, Anne; Kroj, Thomas; Morel, J-B

    2016-01-16

    Receptor-like kinases are well-known to play key roles in disease resistance. Among them, the Wall-associated kinases (WAKs) have been shown to be positive regulators of fungal disease resistance in several plant species. WAK genes are often transcriptionally regulated during infection but the pathways involved in this regulation are not known. In rice, the OsWAK gene family is significantly amplified compared to Arabidopsis. The possibility that several WAKs participate in different ways to basal defense has not been addressed. Moreover, the direct requirement of rice OSWAK genes in regulating defense has not been explored. Here we show using rice (Oryza sativa) loss-of-function mutants of four selected OsWAK genes, that individual OsWAKs are required for quantitative resistance to the rice blast fungus, Magnaporthe oryzae. While OsWAK14, OsWAK91 and OsWAK92 positively regulate quantitative resistance, OsWAK112d is a negative regulator of blast resistance. In addition, we show that the very early transcriptional regulation of the rice OsWAK genes is triggered by chitin and is partially under the control of the chitin receptor CEBiP. Finally, we show that OsWAK91 is required for H2O2 production and sufficient to enhance defense gene expression during infection. We conclude that the rice OsWAK genes studied are part of basal defense response, potentially mediated by chitin from fungal cell walls. This work also shows that some OsWAKs, like OsWAK112d, may act as negative regulators of disease resistance.

  18. Sequence analysis and expression pattern of MGTA1 gene in rice blast pathogen Magnaporthe grisea *

    PubMed Central

    Wang, Jiao-yu; Liu, Xiao-hong; Lu, Jian-ping; Lin, Fu-cheng

    2005-01-01

    MGTA1, a putative fungal Zn(II)2Cys6 transcriptional activator-encoding gene, was isolated from rice blast pathogen Magnaporthe grisea, which is homologous to CLTA1 from Colletotrichum lindemuthianum with 51% identity at protein level. MGTA1 cassette contains a 2370 bp open reading frame, consisting of 6 exons, coding a 790 amino acid peptide. MGTA1 gene exists as a single copy in genomes of 7 strains of M. grisea, and is expressed in tip hyphae, conidia, and mature appressoria of strain Guy11. PMID:16052717

  19. Transcriptomic analyses of space-induced rice mutants with enhanced susceptibility to rice blast

    NASA Astrophysics Data System (ADS)

    Cheng, Zhenlong; Liu, Ming; Zhang, Meng; Hang, Xiaoming; Lei, Cailin; Sun, Yeqing

    Mutagenic factors of the space environment influence organisms in different aspects. To elucidate the transcriptomic effects of space flight, a space flight-induced rice mutant, 972-4, and its on-ground control, 972ck, were inoculated with rice blast pathogens. Compared to the control, the mutant exhibited reduced resistance to the rice blast pathogen CH45. Microarray technique was employed to analyze affected genes and revealed that 481 genes were expressed at higher levels in the mutant strain and 188 genes were expressed at higher levels in the control strain under normal growth conditions, indicating that transcriptomic changes of rice seeds are induced by the space environment. After inoculation with the rice blast pathogen CH45, however, 2680 genes were differentially expressed in 972ck and 1863 genes were differentially expressed in 972-4. In addition, disease evaluation indicated that the control strain 972ck is more resistant to the rice blast pathogen CH45 than mutant strain 972-4. In addition, genes in both strains that were co-regulated after blast inoculation account for only 36.8% and 53.3% of the genes expressed in 972ck and 972-4, respectively. A large percentage of blast-regulated genes were not consistently expressed in 972-4 and 972ck, and the mutant and control strains exhibit different gene expression patterns after blast inoculation. Interestingly, 84 genes constitutively expressed higher in 972ck were up-regulated by blast inoculation, and 105 genes that were expressed at constitutively higher levels in 972-4 were down-regulated by blast inoculation. Of the differentially expressed, 7 encoded genes associated with pathogen resistance. Taken together, our results suggest that gene expression patterns are different between a space flight-induced rice mutant and its on-ground control, and the differential expression of resistance genes may be a potential mechanism that modulates the resistance of 972-4 to rice blast. Our results also suggest

  20. Fungal diversity of rice straw for meju fermentation.

    PubMed

    Kim, Dae-Ho; Kim, Seon-Hwa; Kwon, Soon-Wo; Lee, Jong-Kyu; Hong, Seung-Beom

    2013-12-01

    Rice straw is closely associated with meju fermentation and it is generally known that the rice straw provides meju with many kinds of microorganisms. In order to elucidate the origin of meju fungi, the fungal diversity of rice straw was examined. Rice straw was collected from 12 Jang factories where meju are produced, and were incubated under nine different conditions by altering the media (MEA, DRBC, and DG18), and temperature (15°C, 25°C, and 35°C). In total, 937 strains were isolated and identified as belonging to 39 genera and 103 species. Among these, Aspergillus, Cladosporium, Eurotium, Fusarium, and Penicillium were the dominant genera. Fusarium asiaticum (56.3%), Cladosporium cladosporioides (48.6%), Aspergillus tubingensis (37.5%), A. oryzae (31.9%), Eurotium repens (27.1%), and E. chevalieri (25.0%) were frequently isolated from the rice straw obtained from many factories. Twelve genera and 40 species of fungi that were isolated in the rice straw in this study were also isolated from meju. Specifically, A. oryzae, C. cladosporioides, E. chevalieri, E. repens, F. asiaticum, and Penicillium polonicum (11.8%), which are abundant species in meju, were also isolated frequently from rice straw. C. cladosporioides, F. asiaticum, and P. polonicum, which are abundant in the low temperature fermentation process of meju fermentation, were frequently isolated from rice straw incubated at 15°C and 25°C, whereas A. oryzae, E. repens, and E. chevalieri, which are abundant in the high temperature fermentation process of meju fermentation, were frequently isolated from rice straw incubated at 25°C and 35°C. This suggests that the mycobiota of rice straw has a large influence in the mycobiota of meju. The influence of fungi on the rice straw as feed and silage for livestock, and as plant pathogens for rice, are discussed as well.

  1. Evolutionary dynamics and structure of the rice blast resistance locus Pi-ta in wild, cultivated, and US weedy rice

    USDA-ARS?s Scientific Manuscript database

    The Pi-ta gene in rice has been used to control rice blast pathogen, Magnaporthe oryza, in rice growing areas worldwide for decades. To understand the evolutionary process and natural selection of Pi-ta during rice domestication, we first examined sequences of the genomic region of Pi-ta in geograph...

  2. Analysis of rice blast resistance gene Pi-z in rice germplasm using pathogenicity assays and DNA markers

    USDA-ARS?s Scientific Manuscript database

    The Pi-z(t) gene in rice confers resistance to a wide range of races of the rice blast fungus, Magnaporthe oryzae. The objective of this study was to characterize Pi-z(t) in 117 rice germplasm accessions using DNA markers and pathogenicity assays. The existence of Pi-z(t) in rice germplasm was detec...

  3. A New Recessive Gene Conferring Resistance Against Rice Blast.

    PubMed

    Liang, Zhijian; Wang, Ling; Pan, Qinghua

    2016-12-01

    Rice blast (causative pathogen Magnaporthe oryzae) represents a major biotic constraint over rice production. While numerous genes for resistance have been found in both japonica and indica germplasm, as yet the diversity harbored by aus germplasm has not been widely exploited. The blast resistance present in the aus type cultivar AS20-1 was shown, via an analysis of segregation in the F2 generation bred from a cross with the highly blast susceptible cultivar Aichi Asahi, to be due to the action of a single recessive gene, denoted pi66(t). The presence of pi66(t) gave an intermediate level control to plants infected with the blast pathogen isolate EHL0635. A bulked segregant analysis indicated that four microsatellite loci (SSRs) mapping to chromosome 3 were probably linked to pi66(t). Localized mapping using chromosome 3-based SSRs and Indels defined a genetic window for pi66(t), flanked by the markers F04-j2 and M19-i12, which physically equals to 27.7 and 49.0 kb, respectively, in the reference genomes of cultivars Nipponbare and 93-11. This physical interval does not harbor any major gene currently associated with disease resistance. pi66(t) is one of just three recessive genes controlling rice blast, and is the first major gene for resistance to be mapped to chromosome 3.

  4. Natural variation of rice blast resistance gene Pi-d2

    USDA-ARS?s Scientific Manuscript database

    Studying natural variation of rice resistance (R) genes in cultivated and wild rice relatives can predict resistance stability to rice blast fungus. In the present study, the protein coding regions of rice R gene Pi-d2 in 35 rice accessions of subgroups, aus (AUS), indica (IND), temperate japonica (...

  5. Fungal Biomass Protein Production from Trichoderma harzianum Using Rice Polishing

    PubMed Central

    Mustafa, Ghulam; Arshad, Muhammad

    2017-01-01

    Industrially important enzymes and microbial biomass proteins have been produced from fungi for more than 50 years. High levels of crude protein as much as 45% are present in fungal biomass with balanced essential amino acids. The aim of this study was to access the potential of Trichoderma harzianum to produce fungal biomass protein from rice polishings. Maximum biomass yield was obtained at 5% (w/v) rice polishings after 72 h of incubation at 28°C at pH 4. Carbon and nitrogen ratio of 20 : 1 gave significantly higher production of fungal biomass protein. The FBP in the 75 L fermenter contained 49.50% crude protein, 32.00% true protein, 19.45% crude fiber, 9.62% ash, 11.5% cellulose content, and 0.325% RNA content. The profile of amino acids of final FBP exhibited that all essential amino acids were present in great quantities. The FBP produced by this fungus has been shown to be of good nutritional value for supplementation to poultry. The results presented in this study have practical implications in that the fungus T. harzianum could be used successfully to produce fungal biomass protein using rice polishings. PMID:28367444

  6. Fungal Biomass Protein Production from Trichoderma harzianum Using Rice Polishing.

    PubMed

    Ahmed, Sibtain; Mustafa, Ghulam; Arshad, Muhammad; Rajoka, Muhammad Ibrahim

    2017-01-01

    Industrially important enzymes and microbial biomass proteins have been produced from fungi for more than 50 years. High levels of crude protein as much as 45% are present in fungal biomass with balanced essential amino acids. The aim of this study was to access the potential of Trichoderma harzianum to produce fungal biomass protein from rice polishings. Maximum biomass yield was obtained at 5% (w/v) rice polishings after 72 h of incubation at 28°C at pH 4. Carbon and nitrogen ratio of 20 : 1 gave significantly higher production of fungal biomass protein. The FBP in the 75 L fermenter contained 49.50% crude protein, 32.00% true protein, 19.45% crude fiber, 9.62% ash, 11.5% cellulose content, and 0.325% RNA content. The profile of amino acids of final FBP exhibited that all essential amino acids were present in great quantities. The FBP produced by this fungus has been shown to be of good nutritional value for supplementation to poultry. The results presented in this study have practical implications in that the fungus T. harzianum could be used successfully to produce fungal biomass protein using rice polishings.

  7. Chitin-deacetylase activity induces appressorium differentiation in the rice blast fungus Magnaporthe oryzae.

    PubMed

    Kuroki, Misa; Okauchi, Kana; Yoshida, Sho; Ohno, Yuko; Murata, Sayaka; Nakajima, Yuichi; Nozaka, Akihito; Tanaka, Nobukiyo; Nakajima, Masahiro; Taguchi, Hayao; Saitoh, Ken-Ichiro; Teraoka, Tohru; Narukawa, Megumi; Kamakura, Takashi

    2017-08-29

    The rice blast fungus Magnaporthe oryzae differentiates a specialized infection structure called an appressorium to invade rice cells. In this report, we show that CBP1, which encodes a chitin-deacetylase, is involved in the induction phase of appressorium differentiation. We demonstrate that the enzymatic activity of Cbp1 is critical for appressorium formation. M. oryzae has six CDA homologues in addition to Cbp1, but none of these are indispensable for appressorium formation. We observed chitosan localization at the fungal cell wall using OGA(488). This observation suggests that Cbp1-catalysed conversion of chitin into chitosan occurs at the cell wall of germ tubes during appressorium differentiation by M. oryzae. Taken together, our results provide evidence that the chitin deacetylase activity of Cbp1 is necessary for appressorium formation.

  8. QTL Analysis for Resistance to Blast Disease in U.S. Weedy Rice.

    PubMed

    Liu, Yan; Qi, Xinshuai; Gealy, Dave R; Olsen, Kenneth M; Caicedo, Ana L; Jia, Yulin

    2015-07-01

    Understanding the genetic architecture of adaptation is of great importance in evolutionary biology. U.S. weedy rice is well adapted to the local conditions in U.S. rice fields. Rice blast disease is one of the most destructive diseases of cultivated rice worldwide. However, information about resistance to blast in weedy rice is limited. Here, we evaluated the disease reactions of 60 U.S. weedy rice accessions with 14 blast races, and investigated the quantitative trait loci (QTL) associated with blast resistance in two major ecotypes of U.S. weedy rice. Our results revealed that U.S. weedy rice exhibited a broad resistance spectrum. Using genotyping by sequencing, we identified 28 resistance QTL in two U.S. weedy rice ecotypes. The resistance QTL with relatively large and small effects suggest that U.S. weedy rice groups have adapted to blast disease using two methods, both major resistance (R) genes and QTL. Three genomic loci shared by some of the resistance QTL indicated that these loci may contribute to no-race-specific resistance in weedy rice. Comparing with known blast disease R genes, we found that the R genes at these resistance QTL are novel, suggesting that U.S. weedy rice is a potential source of novel blast R genes for resistant breeding.

  9. Economic and Environmental Impact of Rice Blast Pathogen (Magnaporthe oryzae) Alleviation in the United States

    PubMed Central

    2016-01-01

    Rice blast (Magnaporthe oryzae) is a key concern in combating global food insecurity given the disease is responsible for approximately 30% of rice production losses globally—the equivalent of feeding 60 million people. These losses increase the global rice price and reduce consumer welfare and food security. Rice is the staple crop for more than half the world’s population so any reduction in rice blast would have substantial beneficial effects on consumer livelihoods. In 2012, researchers in the US began analyzing the feasibility of creating blast-resistant rice through cisgenic breeding. Correspondingly, our study evaluates the changes in producer, consumer, and environmental welfare, if all the rice produced in the Mid-South of the US were blast resistant through a process like cisgenics, using both international trade and environmental assessment modeling. Our results show that US rice producers would gain 69.34 million dollars annually and increase the rice supply to feed an additional one million consumers globally by eliminating blast from production in the Mid-South. These results suggest that blast alleviation could be even more significant in increasing global food security given that the US is a small rice producer by global standards and likely experiences lower losses from blast than other rice-producing countries because of its ongoing investment in production technology and management. Furthermore, results from our detailed life cycle assessment (LCA) show that producing blast-resistant rice has lower environmental (fossil fuel depletion, ecotoxicity, carcinogenics, eutrophication, acidification, global warming potential, and ozone depletion) impacts per unit of rice than non-blast resistant rice production. Our findings suggest that any reduction in blast via breeding will have significantly positive impacts on reducing global food insecurity through increased supply, as well as decreased price and environmental impacts in production. PMID

  10. Economic and Environmental Impact of Rice Blast Pathogen (Magnaporthe oryzae) Alleviation in the United States.

    PubMed

    Nalley, Lawton; Tsiboe, Francis; Durand-Morat, Alvaro; Shew, Aaron; Thoma, Greg

    2016-01-01

    Rice blast (Magnaporthe oryzae) is a key concern in combating global food insecurity given the disease is responsible for approximately 30% of rice production losses globally-the equivalent of feeding 60 million people. These losses increase the global rice price and reduce consumer welfare and food security. Rice is the staple crop for more than half the world's population so any reduction in rice blast would have substantial beneficial effects on consumer livelihoods. In 2012, researchers in the US began analyzing the feasibility of creating blast-resistant rice through cisgenic breeding. Correspondingly, our study evaluates the changes in producer, consumer, and environmental welfare, if all the rice produced in the Mid-South of the US were blast resistant through a process like cisgenics, using both international trade and environmental assessment modeling. Our results show that US rice producers would gain 69.34 million dollars annually and increase the rice supply to feed an additional one million consumers globally by eliminating blast from production in the Mid-South. These results suggest that blast alleviation could be even more significant in increasing global food security given that the US is a small rice producer by global standards and likely experiences lower losses from blast than other rice-producing countries because of its ongoing investment in production technology and management. Furthermore, results from our detailed life cycle assessment (LCA) show that producing blast-resistant rice has lower environmental (fossil fuel depletion, ecotoxicity, carcinogenics, eutrophication, acidification, global warming potential, and ozone depletion) impacts per unit of rice than non-blast resistant rice production. Our findings suggest that any reduction in blast via breeding will have significantly positive impacts on reducing global food insecurity through increased supply, as well as decreased price and environmental impacts in production.

  11. Gene Ontology annotation of the rice blast fungus, Magnaporthe oryzae

    PubMed Central

    Meng, Shaowu; Brown, Douglas E; Ebbole, Daniel J; Torto-Alalibo, Trudy; Oh, Yeon Yee; Deng, Jixin; Mitchell, Thomas K; Dean, Ralph A

    2009-01-01

    Background Magnaporthe oryzae, the causal agent of blast disease of rice, is the most destructive disease of rice worldwide. The genome of this fungal pathogen has been sequenced and an automated annotation has recently been updated to Version 6 . However, a comprehensive manual curation remains to be performed. Gene Ontology (GO) annotation is a valuable means of assigning functional information using standardized vocabulary. We report an overview of the GO annotation for Version 5 of M. oryzae genome assembly. Methods A similarity-based (i.e., computational) GO annotation with manual review was conducted, which was then integrated with a literature-based GO annotation with computational assistance. For similarity-based GO annotation a stringent reciprocal best hits method was used to identify similarity between predicted proteins of M. oryzae and GO proteins from multiple organisms with published associations to GO terms. Significant alignment pairs were manually reviewed. Functional assignments were further cross-validated with manually reviewed data, conserved domains, or data determined by wet lab experiments. Additionally, biological appropriateness of the functional assignments was manually checked. Results In total, 6,286 proteins received GO term assignment via the homology-based annotation, including 2,870 hypothetical proteins. Literature-based experimental evidence, such as microarray, MPSS, T-DNA insertion mutation, or gene knockout mutation, resulted in 2,810 proteins being annotated with GO terms. Of these, 1,673 proteins were annotated with new terms developed for Plant-Associated Microbe Gene Ontology (PAMGO). In addition, 67 experiment-determined secreted proteins were annotated with PAMGO terms. Integration of the two data sets resulted in 7,412 proteins (57%) being annotated with 1,957 distinct and specific GO terms. Unannotated proteins were assigned to the 3 root terms. The Version 5 GO annotation is publically queryable via the GO site

  12. OsGF14e positively regulates panicle blast resistance in rice.

    PubMed

    Liu, Qing; Yang, Jianyuan; Zhang, Shaohong; Zhao, Junliang; Feng, Aiqing; Yang, Tifeng; Wang, Xiaofei; Mao, Xingxue; Dong, Jingfang; Zhu, Xiaoyuan; Leung, Hei; Leach, Jan E; Liu, Bin

    2016-02-26

    Though GF14e has been reported to negatively regulate bacterial blight and sheath blight resistance in rice, its effect on panicle blast, the most destructive disease in rice is still unknown. In the present study, we identified that GF14e was highly expressed in panicles and was induced in panicles infected by blast pathogen. Overexpression of GF14e enhances resistance to panicle blast whereas silencing GF14e results in increased susceptibility to panicle blast, suggesting that GF14e plays a positive role in quantitative panicle blast resistance in rice. Our results also demonstrate that GF14e is regulated by WRKY71 and GF14e-mediated panicle blast resistance is related to activation of SA-dependent pathway and suppression of JA-dependent pathway. The functional confirmation of GF14e in panicle blast resistance makes it to be a promising target in molecular rice breeding.

  13. Cytokinin Production by the Rice Blast Fungus Is a Pivotal Requirement for Full Virulence

    PubMed Central

    Chanclud, Emilie; Kisiala, Anna; Emery, Neil R. J; Chalvon, Véronique; Ducasse, Aurélie; Romiti-Michel, Corinne; Gravot, Antoine; Kroj, Thomas; Morel, Jean-Benoit

    2016-01-01

    Plants produce cytokinin (CK) hormones for controlling key developmental processes like source/sink distribution, cell division or programmed cell-death. Some plant pathogens have been shown to produce CKs but the function of this mimicry production by non-tumor inducing pathogens, has yet to be established. Here we identify a gene required for CK biosynthesis, CKS1, in the rice blast fungus Magnaporthe oryzae. The fungal-secreted CKs are likely perceived by the plant during infection since the transcriptional regulation of rice CK-responsive genes is altered in plants infected by the mutants in which CKS1 gene was deleted. Although cks1 mutants showed normal in vitro growth and development, they were severely affected for in planta growth and virulence. Moreover, we showed that the cks1 mutant triggered enhanced induction of plant defenses as manifested by an elevated oxidative burst and expression of defense-related markers. In addition, the contents of sugars and key amino acids for fungal growth were altered in and around the infection site by the cks1 mutant in a different manner than by the control strain. These results suggest that fungal-derived CKs are key effectors required for dampening host defenses and affecting sugar and amino acid distribution in and around the infection site. PMID:26900703

  14. Current advance methods for the identification of blast resistance genes in rice.

    PubMed

    Tanweer, Fatah A; Rafii, Mohd Y; Sijam, Kamaruzaman; Rahim, Harun A; Ahmed, Fahim; Latif, Mohammad A

    2015-05-01

    Rice blast caused by Magnaporthe oryzae is one of the most devastating diseases of rice around the world and crop losses due to blast are considerably high. Many blast resistant rice varieties have been developed by classical plant breeding and adopted by farmers in various rice-growing countries. However, the variability in the pathogenicity of the blast fungus according to environment made blast disease a major concern for farmers, which remains a threat to the rice industry. With the utilization of molecular techniques, plant breeders have improved rice production systems and minimized yield losses. In this article, we have summarized the current advanced molecular techniques used for controlling blast disease. With the advent of new technologies like marker-assisted selection, molecular mapping, map-based cloning, marker-assisted backcrossing and allele mining, breeders have identified more than 100 Pi loci and 350 QTL in rice genome responsible for blast disease. These Pi genes and QTLs can be introgressed into a blast-susceptible cultivar through marker-assisted backcross breeding. These molecular techniques provide timesaving, environment friendly and labour-cost-saving ways to control blast disease. The knowledge of host-plant interactions in the frame of blast disease will lead to develop resistant varieties in the future.

  15. Roles of Peroxisomes in the Rice Blast Fungus

    PubMed Central

    Liu, Caiyun

    2016-01-01

    The rice blast fungus, Magnaporthe oryzae, is a model plant pathogenic fungus and is a severe threat to global rice production. Over the past two decades, it has been found that the peroxisomes play indispensable roles during M. oryzae infection. Given the importance of the peroxisomes for virulence, we review recent advances of the peroxisomes roles during M. oryzae infection processes. We firstly introduce the molecular mechanisms and life cycles of the peroxisomes. And then, metabolic functions related to the peroxisomes are also discussed. Finally, we provide an overview of the relationship between peroxisomes and pathogenicity. PMID:27610388

  16. Analysis of rice blast resistance genes from domesticated and weedy species of rice

    USDA-ARS?s Scientific Manuscript database

    Blast disease of rice caused by Magnaporthe oryzae is the most serious crop disease worldwide. The fungus is known to be highly adaptive to host environments and resistance (R) genes often do not last for an extended period of time after their deployment. In the USA, a dozen genetically diverse blas...

  17. Genome-wide association of rice blast disease resistance and yield-related components of rice

    USDA-ARS?s Scientific Manuscript database

    Robust disease resistance may require an expenditure of energy that may limit crop yield potential. In the present study, a subset of a USDA rice core collection consisting of 151 accessions was selected using a major blast resistance (R) gene Pi-ta marker, and was genotyped with 156 simple sequence...

  18. Development of genetic and molecular toolboxes to control both rice blast and sheath blight

    USDA-ARS?s Scientific Manuscript database

    Rice blast and sheath blight diseases are the two major constraints for stable rice production in the Southern USA. New genetic and molecular tool boxes have been developed at the USDA-ARS Dale Bumpers National Rice Research Center. Resistance (major and minor) genes from rice have been identified...

  19. QTLs analysis for resistance to blast disease in US weedy rice

    USDA-ARS?s Scientific Manuscript database

    Understanding the genetic architecture of adaptation is of great importance in evolutionary biology. US weedy rice is well-adapted to the local conditions in US rice fields. Rice blast disease is one of the most destructive diseases of cultivated rice worldwide. However, information about resistance...

  20. Host-Induced Gene Silencing of Rice Blast Fungus Magnaporthe oryzae Pathogenicity Genes Mediated by the Brome Mosaic Virus.

    PubMed

    Zhu, Lin; Zhu, Jian; Liu, Zhixue; Wang, Zhengyi; Zhou, Cheng; Wang, Hong

    2017-09-26

    Magnaportheoryzae is a devastating plant pathogen, which has a detrimental impact on rice production worldwide. Despite its agronomical importance, some newly-emerging pathotypes often overcome race-specific disease resistance rapidly. It is thus desirable to develop a novel strategy for the long-lasting resistance of rice plants to ever-changing fungal pathogens. Brome mosaic virus (BMV)-induced RNA interference (RNAi) has emerged as a useful tool to study host-resistance genes for rice blast protection. Planta-generated silencing of targeted genes inside biotrophic pathogens can be achieved by expression of M.oryzae-derived gene fragments in the BMV-mediated gene silencing system, a technique termed host-induced gene silencing (HIGS). In this study, the effectiveness of BMV-mediated HIGS in M.oryzae was examined by targeting three predicted pathogenicity genes, MoABC1,MoMAC1 and MoPMK1. Systemic generation of fungal gene-specific small interfering RNA (siRNA) molecules induced by inoculation of BMV viral vectors inhibited disease development and reduced the transcription of targeted fungal genes after subsequent M.oryzae inoculation. Combined introduction of fungal gene sequences in sense and antisense orientation mediated by the BMV silencing vectors significantly enhanced the efficiency of this host-generated trans-specific RNAi, implying that these fungal genes played crucial roles in pathogenicity. Collectively, our results indicated that BMV-HIGS system was a great strategy for protecting host plants against the invasion of pathogenic fungi.

  1. Confirming and identifying new loci for rice blast disease resistance using magnaporthe oryzae field isolates in the US

    USDA-ARS?s Scientific Manuscript database

    Quantitative trait loci (QTL) in rice play important roles in controlling rice blast disease. In the present study, 10 field isolates of the races IA1, IB1, IB17, and IC1 of U.S. rice blast fungus Magnaporthe oryzae collected in 1996 and 2009 were used to identify blast resistance QTL with a recombi...

  2. OsGF14b Positively Regulates Panicle Blast Resistance but Negatively Regulates Leaf Blast Resistance in Rice.

    PubMed

    Liu, Qing; Yang, Jianyuan; Zhang, Shaohong; Zhao, Junliang; Feng, Aiqing; Yang, Tifeng; Wang, Xiaofei; Mao, Xinxue; Dong, Jingfang; Zhu, Xiaoyuan; Leung, Hei; Leach, Jan E; Liu, Bin

    2016-01-01

    Although 14-3-3 proteins have been reported to be involved in responses to biotic stresses in plants, their functions in rice blast, the most destructive disease in rice, are largely unknown. Only GF14e has been confirmed to negatively regulate leaf blast. We report that GF14b is highly expressed in seedlings and panicles during blast infection. Rice plants overexpressing GF14b show enhanced resistance to panicle blast but are susceptible to leaf blast. In contrast, GF14b-silenced plants show increased susceptibility to panicle blast but enhanced resistance to leaf blast. Yeast one-hybrid assays demonstrate that WRKY71 binds to the promoter of GF14b and modulates its expression. Overexpression of GF14b induces expression of jasmonic acid (JA) synthesis-related genes but suppresses expression of salicylic acid (SA) synthesis-related genes. In contrast, suppressed GF14b expression causes decreased expression of JA synthesis-related genes but activation of SA synthesis-related genes. These results suggest that GF14b positively regulates panicle blast resistance but negatively regulates leaf blast resistance, and that GF14b-mediated disease resistance is associated with the JA- and SA-dependent pathway. The different functions for 14-3-3 proteins in leaf and panicle blast provide new evidence that leaf and panicle blast resistance are controlled by different mechanisms.

  3. Comparative Analysis of the Genomes of Two Field Isolates of the Rice Blast Fungus Magnaporthe oryzae

    PubMed Central

    Li, Zhigang; Hu, Songnian; Yao, Nan; Dean, Ralph A.; Zhao, Wensheng; Shen, Mi; Zhang, Haiwang; Li, Chao; Liu, Liyuan; Cao, Lei; Xu, Xiaowen; Xing, Yunfei; Hsiang, Tom; Zhang, Ziding; Xu, Jin-Rong; Peng, You-Liang

    2012-01-01

    Rice blast caused by Magnaporthe oryzae is one of the most destructive diseases of rice worldwide. The fungal pathogen is notorious for its ability to overcome host resistance. To better understand its genetic variation in nature, we sequenced the genomes of two field isolates, Y34 and P131. In comparison with the previously sequenced laboratory strain 70-15, both field isolates had a similar genome size but slightly more genes. Sequences from the field isolates were used to improve genome assembly and gene prediction of 70-15. Although the overall genome structure is similar, a number of gene families that are likely involved in plant-fungal interactions are expanded in the field isolates. Genome-wide analysis on asynonymous to synonymous nucleotide substitution rates revealed that many infection-related genes underwent diversifying selection. The field isolates also have hundreds of isolate-specific genes and a number of isolate-specific gene duplication events. Functional characterization of randomly selected isolate-specific genes revealed that they play diverse roles, some of which affect virulence. Furthermore, each genome contains thousands of loci of transposon-like elements, but less than 30% of them are conserved among different isolates, suggesting active transposition events in M. oryzae. A total of approximately 200 genes were disrupted in these three strains by transposable elements. Interestingly, transposon-like elements tend to be associated with isolate-specific or duplicated sequences. Overall, our results indicate that gain or loss of unique genes, DNA duplication, gene family expansion, and frequent translocation of transposon-like elements are important factors in genome variation of the rice blast fungus. PMID:22876203

  4. Multiple Rice MicroRNAs Are Involved in Immunity against the Blast Fungus Magnaporthe oryzae1[C][W][OPEN

    PubMed Central

    Li, Yan; Lu, Yuan-Gen; Shi, Yi; Wu, Liang; Xu, Yong-Ju; Huang, Fu; Guo, Xiao-Yi; Zhang, Yong; Fan, Jing; Zhao, Ji-Qun; Zhang, Hong-Yu; Xu, Pei-Zhou; Zhou, Jian-Min; Wu, Xian-Jun; Wang, Ping-Rong; Wang, Wen-Ming

    2014-01-01

    MicroRNAs (miRNAs) are indispensable regulators for development and defense in eukaryotes. However, the miRNA species have not been explored for rice (Oryza sativa) immunity against the blast fungus Magnaporthe oryzae, the most devastating fungal pathogen in rice production worldwide. Here, by deep sequencing small RNA libraries from susceptible and resistant lines in normal conditions and upon M. oryzae infection, we identified a group of known rice miRNAs that were differentially expressed upon M. oryzae infection. They were further classified into three classes based on their expression patterns in the susceptible japonica line Lijiangxin Tuan Hegu and in the resistant line International Rice Blast Line Pyricularia-Kanto51-m-Tsuyuake that contains a single resistance gene locus, Pyricularia-Kanto 51-m (Pikm), within the Lijiangxin Tuan Hegu background. RNA-blot assay of nine of them confirmed sequencing results. Real-time reverse transcription-polymerase chain reaction assay showed that the expression of some target genes was negatively correlated with the expression of miRNAs. Moreover, transgenic rice plants overexpressing miR160a and miR398b displayed enhanced resistance to M. oryzae, as demonstrated by decreased fungal growth, increased hydrogen peroxide accumulation at the infection site, and up-regulated expression of defense-related genes. Taken together, our data indicate that miRNAs are involved in rice immunity against M. oryzae and that overexpression of miR160a or miR398b can enhance rice resistance to the disease. PMID:24335508

  5. Characterization of genetic diversity of rice blast fungus in Arkansas field isolates

    USDA-ARS?s Scientific Manuscript database

    The rice blast resistance gene Pita has been deployed for preventing blast disease in the southern US for the past two decades. To date, at least eleven rice cultivars, Katy, Drew, Madison, Kaybonnet, Banks, Ahrent, Spring, Cybonnet, Catahoula, CL111, and Templeton carrying Pi-ta were developed by ...

  6. Large scale germplasm screening for identification of novel rice blast resistance sources

    PubMed Central

    Vasudevan, Kumar; Vera Cruz, Casiana M.; Gruissem, Wilhelm; Bhullar, Navreet K.

    2014-01-01

    Rice is a major cereal crop that contributes significantly to global food security. Biotic stresses, including the rice blast fungus, cause severe yield losses that significantly impair rice production worldwide. The rapid genetic evolution of the fungus often overcomes the resistance conferred by major genes after a few years of intensive agricultural use. Therefore, resistance breeding requires continuous efforts of enriching the reservoir of resistance genes/alleles to effectively tackle the disease. Seed banks represent a rich stock of genetic diversity, however, they are still under-explored for identifying novel genes and/or their functional alleles. We conducted a large-scale screen for new rice blast resistance sources in 4246 geographically diverse rice accessions originating from 13 major rice-growing countries. The accessions were selected from a total collection of over 120,000 accessions based on their annotated rice blast resistance information in the International Rice Genebank. A two-step resistance screening protocol was used involving natural infection in a rice uniform blast nursery and subsequent artificial infections with five single rice blast isolates. The nursery-resistant accessions showed varied disease responses when infected with single isolates, suggesting the presence of diverse resistance genes/alleles in this accession collection. In addition, 289 accessions showed broad-spectrum resistance against all five single rice blast isolates. The selected resistant accessions were genotyped for the presence of the Pi2 resistance gene, thereby identifying potential accessions for isolation of allelic variants of this blast resistance gene. Together, the accession collection with broad spectrum and isolate specific blast resistance represent the core material for isolation of previously unknown blast resistance genes and/or their allelic variants that can be deployed in rice breeding programs. PMID:25324853

  7. Cyanide, a Coproduct of Plant Hormone Ethylene Biosynthesis, Contributes to the Resistance of Rice to Blast Fungus1[W][OA

    PubMed Central

    Seo, Shigemi; Mitsuhara, Ichiro; Feng, Jiao; Iwai, Takayoshi; Hasegawa, Morifumi; Ohashi, Yuko

    2011-01-01

    Rice (Oryza sativa) plants carrying the Pi-i resistance gene to blast fungus Magnaporthe oryzae restrict invaded fungus in infected tissue via hypersensitive reaction or response (HR), which is accompanied by rapid ethylene production and formation of small HR lesions. Ethylene biosynthesis has been implicated to be important for blast resistance; however, the individual roles of ethylene and cyanide, which are produced from the precursor 1-aminocyclopropane-1-carboxylic acid, remain unevaluated. In this study, we found that Pi-i-mediated resistance was compromised in transgenic rice lines, in which ethylene biosynthetic enzyme genes were silenced and then ethylene production was inhibited. The compromised resistance in transgenic lines was recovered by exogenously applying cyanide but not ethephon, an ethylene-releasing chemical in plant tissue. In a susceptible rice cultivar, treatment with cyanide or 1-aminocyclopropane-1-carboxylic acid induced the resistance to blast fungus in a dose-dependent manner, while ethephon did not have the effect. Cyanide inhibited the growth of blast fungus in vitro and in planta, and application of flavonoids, secondary metabolites that exist ubiquitously in the plant kingdom, enhanced the cyanide-induced inhibition of fungal growth. These results suggested that cyanide, whose production is triggered by HR in infected tissue, contributes to the resistance in rice plants via restriction of fungal growth. PMID:21075959

  8. Effector-Mediated Suppression of Chitin-Triggered Immunity by Magnaporthe oryzae Is Necessary for Rice Blast Disease[C][W

    PubMed Central

    Mentlak, Thomas A.; Kombrink, Anja; Shinya, Tomonori; Ryder, Lauren S.; Otomo, Ippei; Saitoh, Hiromasa; Terauchi, Ryohei; Nishizawa, Yoko; Shibuya, Naoto; Thomma, Bart P.H.J.; Talbot, Nicholas J.

    2012-01-01

    Plants use pattern recognition receptors to defend themselves from microbial pathogens. These receptors recognize pathogen-associated molecular patterns (PAMPs) and activate signaling pathways that lead to immunity. In rice (Oryza sativa), the chitin elicitor binding protein (CEBiP) recognizes chitin oligosaccharides released from the cell walls of fungal pathogens. Here, we show that the rice blast fungus Magnaporthe oryzae overcomes this first line of plant defense by secreting an effector protein, Secreted LysM Protein1 (Slp1), during invasion of new rice cells. We demonstrate that Slp1 accumulates at the interface between the fungal cell wall and the rice plasma membrane, can bind to chitin, and is able to suppress chitin-induced plant immune responses, including generation of reactive oxygen species and plant defense gene expression. Furthermore, we show that Slp1 competes with CEBiP for binding of chitin oligosaccharides. Slp1 is required by M. oryzae for full virulence and exerts a significant effect on tissue invasion and disease lesion expansion. By contrast, gene silencing of CEBiP in rice allows M. oryzae to cause rice blast disease in the absence of Slp1. We propose that Slp1 sequesters chitin oligosaccharides to prevent PAMP-triggered immunity in rice, thereby facilitating rapid spread of the fungus within host tissue. PMID:22267486

  9. Experimental evolution reveals genome-wide spectrum and dynamics of mutations in the rice blast fungus, Magnaporthe oryzae.

    PubMed

    Jeon, Junhyun; Choi, Jaeyoung; Lee, Gir-Won; Dean, Ralph A; Lee, Yong-Hwan

    2013-01-01

    Knowledge on mutation processes is central to interpreting genetic analysis data as well as understanding the underlying nature of almost all evolutionary phenomena. However, studies on genome-wide mutational spectrum and dynamics in fungal pathogens are scarce, hindering our understanding of their evolution and biology. Here, we explored changes in the phenotypes and genome sequences of the rice blast fungus Magnaporthe oryzae during the forced in vitro evolution by weekly transfer of cultures on artificial media. Through combination of experimental evolution with high throughput sequencing technology, we found that mutations accumulate rapidly prior to visible phenotypic changes and that both genetic drift and selection seem to contribute to shaping mutational landscape, suggesting the buffering capacity of fungal genome against mutations. Inference of mutational effects on phenotypes through the use of T-DNA insertion mutants suggested that at least some of the DNA sequence mutations are likely associated with the observed phenotypic changes. Furthermore, our data suggest oxidative damages and UV as major sources of mutation during subcultures. Taken together, our work revealed important properties of original source of variation in the genome of the rice blast fungus. We believe that these results provide not only insights into stability of pathogenicity and genome evolution in plant pathogenic fungi but also a model in which evolution of fungal pathogens in natura can be comparatively investigated.

  10. First report of multiple races of the rice blast fungus Magnaporthe oryzae in Puerto Rico

    USDA-ARS?s Scientific Manuscript database

    The rice nursery located in the Lajas Valley, in the southwestern corner of Puerto Rico has been used by US rice breeders for the past 43 years to produce one to two extra generations per year. In April, 2015, blast disease lesions were observed on rice breeding lines belonging to the USDA ARS DB NR...

  11. Monitoring fungal growth on brown rice grains using rapid and non-destructive hyperspectral imaging.

    PubMed

    Siripatrawan, U; Makino, Y

    2015-04-16

    This research aimed to develop a rapid, non-destructive, and accurate method based on hyperspectral imaging (HSI) for monitoring spoilage fungal growth on stored brown rice. Brown rice was inoculated with a non-pathogenic strain of Aspergillus oryzae and stored at 30 °C and 85% RH. Growth of A. oryzae on rice was monitored using viable colony counts, expressed as colony forming units per gram (CFU/g). The fungal development was observed using scanning electron microscopy. The HSI system was used to acquire reflectance images of the samples covering the visible and near-infrared (NIR) wavelength range of 400-1000 nm. Unsupervised self-organizing map (SOM) was used to visualize data classification of different levels of fungal infection. Partial least squares (PLS) regression was used to predict fungal growth on rice grains from the HSI reflectance spectra. The HSI spectral signals decreased with increasing colony counts, while conserving similar spectral pattern during the fungal growth. When integrated with SOM, the proposed HSI method could be used to classify rice samples with different levels of fungal infection without sample manipulation. Moreover, HSI was able to rapidly identify infected rice although the samples showed no symptoms of fungal infection. Based on PLS regression, the coefficient of determination was 0.97 and root mean square error of prediction was 0.39 log (CFU/g), demonstrating that the HSI technique was effective for prediction of fungal infection in rice grains. The ability of HSI to detect fungal infection at early stage would help to prevent contaminated rice grains from entering the food chain. This research provides scientific information on the rapid, non-destructive, and effective fungal detection system for rice grains. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. The WRKY45-2 WRKY13 WRKY42 transcriptional regulatory cascade is required for rice resistance to fungal pathogen.

    PubMed

    Cheng, Hongtao; Liu, Hongbo; Deng, Yong; Xiao, Jinghua; Li, Xianghua; Wang, Shiping

    2015-03-01

    Blast caused by fungal Magnaporthe oryzae is a devastating disease of rice (Oryza sativa) worldwide, and this fungus also infects barley (Hordeum vulgare). At least 11 rice WRKY transcription factors have been reported to regulate rice response to M. oryzae either positively or negatively. However, the relationships of these WRKYs in the rice defense signaling pathway against M. oryzae are unknown. Previous studies have revealed that rice WRKY13 (as a transcriptional repressor) and WRKY45-2 enhance resistance to M. oryzae. Here, we show that rice WRKY42, functioning as a transcriptional repressor, suppresses resistance to M. oryzae. WRKY42-RNA interference (RNAi) and WRKY42-overexpressing (oe) plants showed increased resistance and susceptibility to M. oryzae, accompanied by increased or reduced jasmonic acid (JA) content, respectively, compared with wild-type plants. JA pretreatment enhanced the resistance of WRKY42-oe plants to M. oryzae. WRKY13 directly suppressed WRKY42. WRKY45-2, functioning as a transcriptional activator, directly activated WRKY13. In addition, WRKY13 directly suppressed WRKY45-2 by feedback regulation. The WRKY13-RNAi WRKY45-2-oe and WRKY13-oe WRKY42-oe double transgenic lines showed increased susceptibility to M. oryzae compared with WRKY45-2-oe and WRKY13-oe plants, respectively. These results suggest that the three WRKYs form a sequential transcriptional regulatory cascade. WRKY42 may negatively regulate rice response to M. oryzae by suppressing JA signaling-related genes, and WRKY45-2 transcriptionally activates WRKY13, whose encoding protein in turn transcriptionally suppresses WRKY42 to regulate rice resistance to M. oryzae.

  13. Characterization of resistance genes to rice blast fungus Magnaporthe oryzae in a “Green Revolution” rice variety

    USDA-ARS?s Scientific Manuscript database

    The indica rice variety Dee Geo Woo Gen (DGWG) was the source of the semi-dwarf gene (SD1) which played an important role in the Green Revolution. In the present study, resistance (R) genes to the U.S. race (isolate) IB54 of Magnaporthe oryzae, causal agent of rice blast disease, was investigated. T...

  14. Registration of 42 blast resistant medium grain rice genetic stocks with suitable agronomic, yield, milling yield, and grain characteristics

    USDA-ARS?s Scientific Manuscript database

    Rice blast disease caused by the filamentous ascomycete fungus Magnaporthe oryzae Cav. [Magnaporthe grisea (Herbert) Barr.] is one of the most threatening rice diseases in the southern United States. In the present study, 42 rice (Oryza sativa L.) blast resistant genetic stocks (GSOR102501 to 201542...

  15. Site-directed mutagenesis of the cytochrome b gene and development of diagnostic methods for identifying QoI resistance of rice blast fungus.

    PubMed

    Wei, Chuan-Zhao; Katoh, Hiroshi; Nishimura, Kumiko; Ishii, Hideo

    2009-12-01

    It is possible that a single nucleotide polymorphism (SNP) (G143A mutation) in the cytochrome b gene could confer resistance to quinone outside inhibiting (QoI) fungicides (strobilurins) in rice blast fungus because this mutation caused a high level of resistance to fungicides such as azoxystrobin in Pyricularia grisea Sacc. and other fungal plant pathogens. The aim of this study was to survey Magnaporthe oryzae B Couch sp. nov. isolates in Japan for resistance to QoIs, and to try to develop molecular detection methods for QoI resistance. A survey on the QoI resistance among M. oryzae isolates from rice was conducted in Japan. A total of 813 single-spore isolates of M. oryzae were tested for their sensitivity to azoxystrobin using a mycelial growth test on PDA. QoI fungicide resistance was not found among these isolates. The introduction of G143A mutation into a plasmid containing the cytochrome b gene sequence of rice blast fungus was achieved by site-directed mutagenesis. Molecular diagnostic methods were developed for identifying QoI resistance in rice blast fungus using the plasmid construct. As the management of rice blast disease is often dependent on chemicals, the rational design of control programmes requires a proper understanding of the fungicide resistance phenomenon in field populations of the pathogen. Mutation of the cytochrome b gene of rice blast fungus would be specifically detected from diseased leaves and seeds using the molecular methods developed in this study. (c) 2009 Society of Chemical Industry.

  16. A Lipoxygenase Pathway Is Activated in Rice after Infection with the Rice Blast Fungus Magnaporthe grisea.

    PubMed

    Ohta, H; Shida, K; Peng, Y L; Furusawa, I; Shishiyama, J; Aibara, S; Morita, Y

    1991-09-01

    Lipoxygenase (LOX) and lipid hydroperoxide-decomposing activity (LHDA) markedly increased in the fifth leaves of rice (Oryza sativa cv Aichiasahi) after infection with the rice blast fungus, Magnaporthe grisea. The increases in the enzyme activities were significantly higher in response to infection with an incompatible strain (race 131) compared with infection with a compatible strain (race 007) of the fungus. Using ion-exchange chromatography, we isolated three LOX activities (leaf LOX-1, -2, -3) from both uninoculated and infected leaves. The activity of leaf LOX-3, in particular, increased in the incompatible race-infected leaves. The leaf LOX-3 had a pH optimum of 5.0 and produced preferentially 13-l-hydroperoxy-9,11 (Z,E)-octadecadienoic acid (13-HPODD) from linoleic acid. 13-HPODD and 13-l-hydroxy-9,11 (Z,E)-octadecadienoic acid, one of the reaction products from 13-HPODD by LHDA, were highly inhibitory to the germination of conidia of the fungus. The present study provides correlative evidence for important roles of LOX and LHDA in the resistance response of rice against the blast fungus.

  17. Cloning of novel rice blast resistance genes from two rapidly evolving NBS-LRR gene families in rice.

    PubMed

    Guo, Changjiang; Sun, Xiaoguang; Chen, Xiao; Yang, Sihai; Li, Jing; Wang, Long; Zhang, Xiaohui

    2016-01-01

    Most rice blast resistance genes (R-genes) encode proteins with nucleotide-binding site (NBS) and leucine-rich repeat (LRR) domains. Our previous study has shown that more rice blast R-genes can be cloned in rapidly evolving NBS-LRR gene families. In the present study, two rapidly evolving R-gene families in rice were selected for cloning a subset of genes from their paralogs in three resistant rice lines. A total of eight functional blast R-genes were identified among nine NBS-LRR genes, and some of these showed resistance to three or more blast strains. Evolutionary analysis indicated that high nucleotide diversity of coding regions served as important parameters in the determination of gene resistance. We also observed that amino-acid variants (nonsynonymous mutations, insertions, or deletions) in essential motifs of the NBS domain contribute to the blast resistance capacity of NBS-LRR genes. These results suggested that the NBS regions might also play an important role in resistance specificity determination. On the other hand, different splicing patterns of introns were commonly observed in R-genes. The results of the present study contribute to improving the effectiveness of R-gene identification by using evolutionary analysis method and acquisition of novel blast resistance genes.

  18. Molecular Screening of Blast Resistance Genes in Rice using SSR Markers.

    PubMed

    Singh, A K; Singh, P K; Arya, Madhuri; Singh, N K; Singh, U S

    2015-03-01

    Rice Blast is the most devastating disease causing major yield losses in every year worldwide. It had been proved that using resistant rice varieties would be the most effective way to control this disease. Molecular screening and genetic diversities of major rice blast resistance genes were determined in 192 rice germplasm accessions using simple sequence repeat (SSR) markers. The genetic frequencies of the 10 major rice blast resistance genes varied from 19.79% to 54.69%. Seven accessions IC337593, IC346002, IC346004, IC346813, IC356117, IC356422 and IC383441 had maximum eight blast resistance gene, while FR13B, Hourakani, Kala Rata 1-24, Lemont, Brown Gora, IR87756-20-2-2-3, IC282418, IC356419, PKSLGR-1 and PKSLGR-39 had seven blast resistance genes. Twenty accessions possessed six genes, 36 accessions had five genes, 41 accessions had four genes, 38 accessions had three genes, 26 accessions had two genes, 13 accessions had single R gene and only one accession IC438644 does not possess any one blast resistant gene. Out of 192 accessions only 17 accessions harboured 7 to 8 blast resistance genes.

  19. The role of glycerol in the pathogenic lifestyle of the rice blast fungus Magnaporthe oryzae.

    PubMed

    Foster, Andrew J; Ryder, Lauren S; Kershaw, Michael J; Talbot, Nicholas J

    2017-03-01

    The rice blast fungus Magnaporthe oryzae elaborates a specialized cell called an appressorium, which is used to breach the tough outer cuticle of a rice leaf, enabling the fungus entry to host plant cells. The appressorium generates enormous turgor by accumulating glycerol to very high concentrations within the cell. Glycerol accumulation and melanization of the appressorium cell wall collectively drive turgor-mediated penetration of the rice leaf. In this review, we discuss the potential metabolic sources of glycerol in the rice blast fungus and how appressorium turgor is focused as physical force at the base of the infection cell, leading to the formation of a rigid penetration peg. We review recent studies of M. oryzae and other relevant appressorium-forming fungi which shed light on how glycerol is synthesized and how appressorium turgor is regulated. Finally, we provide some questions to guide avenues of future research that will be important in fully understanding the role of glycerol in rice blast disease.

  20. Screening for resistance against Pseudomonas syringae in rice-FOX Arabidopsis lines identified a putative receptor-like cytoplasmic kinase gene that confers resistance to major bacterial and fungal pathogens in Arabidopsis and rice.

    PubMed

    Dubouzet, Joseph G; Maeda, Satoru; Sugano, Shoji; Ohtake, Miki; Hayashi, Nagao; Ichikawa, Takanari; Kondou, Youichi; Kuroda, Hirofumi; Horii, Yoko; Matsui, Minami; Oda, Kenji; Hirochika, Hirohiko; Takatsuji, Hiroshi; Mori, Masaki

    2011-05-01

    Approximately 20,000 of the rice-FOX Arabidopsis transgenic lines, which overexpress 13,000 rice full-length cDNAs at random in Arabidopsis, were screened for bacterial disease resistance by dip inoculation with Pseudomonas syringae pv. tomato DC3000 (Pst DC3000). The identities of the overexpressed genes were determined in 72 lines that showed consistent resistance after three independent screens. Pst DC3000 resistance was verified for 19 genes by characterizing other independent Arabidopsis lines for the same genes in the original rice-FOX hunting population or obtained by reintroducing the genes into ecotype Columbia by floral dip transformation. Thirteen lines of these 72 selections were also resistant to the fungal pathogen Colletotrichum higginsianum. Eight genes that conferred resistance to Pst DC3000 in Arabidopsis have been introduced into rice for overexpression, and transformants were evaluated for resistance to the rice bacterial pathogen, Xanthomonas oryzae pv. oryzae. One of the transgenic rice lines was highly resistant to Xanthomonas oryzae pv. oryzae. Interestingly, this line also showed remarkably high resistance to Magnaporthe grisea, the fungal pathogen causing rice blast, which is the most devastating rice disease in many countries. The causal rice gene, encoding a putative receptor-like cytoplasmic kinase, was therefore designated as BROAD-SPECTRUM RESISTANCE 1. Our results demonstrate the utility of the rice-FOX Arabidopsis lines as a tool for the identification of genes involved in plant defence and suggest the presence of a defence mechanism common between monocots and dicots. © 2010 The Authors. Plant Biotechnology Journal © 2010 Society for Experimental Biology, Association of Applied Biologists and Blackwell Publishing Ltd.

  1. NADPH oxidases regulate septin-mediated cytoskeletal remodeling during plant infection by the rice blast fungus

    PubMed Central

    Ryder, Lauren S.; Dagdas, Yasin F.; Mentlak, Thomas A.; Kershaw, Michael J.; Thornton, Christopher R.; Schuster, Martin; Chen, Jisheng; Wang, Zonghua; Talbot, Nicholas J.

    2013-01-01

    The rice blast fungus Magnaporthe oryzae infects plants with a specialized cell called an appressorium, which uses turgor to drive a rigid penetration peg through the rice leaf cuticle. Here, we show that NADPH oxidases (Nox) are necessary for septin-mediated reorientation of the F-actin cytoskeleton to facilitate cuticle rupture and plant cell invasion. We report that the Nox2–NoxR complex spatially organizes a heteroligomeric septin ring at the appressorium pore, required for assembly of a toroidal F-actin network at the point of penetration peg emergence. Maintenance of the cortical F-actin network during plant infection independently requires Nox1, a second NADPH oxidase, which is necessary for penetration hypha elongation. Organization of F-actin in appressoria is disrupted by application of antioxidants, whereas latrunculin-mediated depolymerization of appressorial F-actin is competitively inhibited by reactive oxygen species, providing evidence that regulated synthesis of reactive oxygen species by fungal NADPH oxidases directly controls septin and F-actin dynamics. PMID:23382235

  2. Calcium-dependent protein kinase OsCPK10 mediates both drought tolerance and blast disease resistance in rice plants.

    PubMed

    Bundó, Mireia; Coca, María

    2017-05-17

    Plant growth and productivity is negatively affected by different stresses. Most stresses trigger calcium signals that initiate acclimation responses in plants. The multigene family of plant calcium-dependent protein kinases (CPKs) functions in multiple stress responses by transducing calcium signals into phosphorylation events. This work reports that the OsCPK10 isoform positively mediates tolerance to different stresses in rice plants by enhancing their antioxidant capacity and protecting them from reactive oxygen species (ROS) damage, with the uncontrolled generation of ROS being a common feature of these stresses. Here, we show that the constitutive accumulation of an HA-tagged OsCPK10 full-length protein enhances the hydrogen peroxide detoxifying capacity of rice plants during desiccation. This is achived by modulating the accumulation of catalase proteins, which reduces the extent of lipid peroxidation and protects the integrity of cell membranes, resulting in drought tolerance. OsCPK10HA accumulation also confers blast disease resistance by interfering with fungal necrotrophic growth via a reduction in the accumulation of hydrogen peroxide. Furthermore, we show by bimolecular complementation assays that OsCPK10 is a plasma membrane protein that physically interacts in vivo with catalase A. OsCPK10 therefore appears to be a good molecular target to improve tolerance to abiotic stresses as well as to blast disease, which limit rice crop productivity. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  3. Possible Contribution of Blast Spores to the Oxidative Burst in the Infection Droplet on Rice Leaf

    USDA-ARS?s Scientific Manuscript database

    The infection-induced overproduction of reactive oxygen species (ROS) in resistant plants is usually ascribed to the host. Here we tested the possible contribution of the parasite, the rice blast fungus to ROS production. Droplets of spore suspensions or water were kept on rice leaves or on plastic....

  4. Analysis of the effectiveness of the rice blast resistance gene Pi-ta

    USDA-ARS?s Scientific Manuscript database

    The casual agent of rice blast, Magnaporthe oryzae, continues to remain a serious threat for rice production and in general for the world food supply. The most economically and environmentally viable strategy to control this pathogen is the development of cultivars which possess major resistance gen...

  5. Dynamic changes in the rice blast population in the USA over six decades

    USDA-ARS?s Scientific Manuscript database

    Rice blast disease caused by Magnaporthe oryzae is one of the most destructive diseases of rice. Field isolates of M. oryzae rapidly adapt to the hosts and climate. Tracking the genetic and pathogenic variability of the field isolates is essential to understand how M. oryzae interacts with hosts an...

  6. Statistical inference of selection and divergence of rice blast resistance gene Pi-ta

    USDA-ARS?s Scientific Manuscript database

    The resistance gene Pi-ta has been effectively used to control rice blast disease worldwide. A few recent studies have described the possible evolution of Pi-ta in cultivated and weedy rice. However, evolutionary statistics used for the studies are too limited to precisely understand selection and d...

  7. Population structure analysis and association mapping of blast resistance in indica rice (Oryza sativa L.) landraces.

    PubMed

    Wu, Y Y; He, J B; Li, A H; Fang, N Y; He, W W; Dang, L L; Zeng, G Y; Huang, J; Bao, Y M; Zhang, H S

    2016-08-12

    Rice blast caused by Magnaporthe oryzae is one of the most devastating rice diseases worldwide. To understand the genetic diversity of indica landrace accessions and identify simple sequence repeat (SSR) markers that are associated with blast resistance, a population of 276 indica landraces from across the world was constructed. This population was then used to evaluate the blast-resistance phenotype through artificial inoculation under controlled conditions in 2012 and 2013. The genetic diversity and association of the population with resistance were analyzed by examining the phenotype for 160 SSR markers distributed on 12 rice chromosomes. The 276 accessions were classified into seven groups using model- and distance-based cluster analyses. Associations between SSR markers and blast resistance showed that 26 SSR markers were significantly associated with blast resistance in 2012 and 2013 (P < 0.01) and that the phenotypic variation ranged from 2.68 to 13.11%. Nineteen of the markers associated with blast resistance were located in regions where genes or quantitative trait loci (QTLs) have been previously reported, and seven were newly identified in this study. These results indicate that marker-trait association has potential advantages over classical linkage analysis and QTL mapping, and that these markers could be used for marker-assisted selection in rice blast-resistance-breeding programs.

  8. Phenotypic screening and molecular analysis of blast resistance in fragrant rice for marker assisted selection.

    PubMed

    Khan, Mohammad Ashik Iqbal; Sen, Partha Pratim; Bhuiyan, Rejwan; Kabir, Enamul; Chowdhury, Abul Kashem; Fukuta, Yoshimichi; Ali, Ansar; Latif, Mohammad Abdul

    2014-05-01

    Experiments were conducted to identify blast-resistant fragrant genotypes for the development of a durable blast-resistant rice variety during years 2012-2013. The results indicate that out of 140 test materials including 114 fragrant germplasms, 25 differential varieties (DVs) harbouring 23 blast-resistant genes, only 16 fragrant rice germplasms showed comparatively better performance against a virulent isolate of blast disease. The reaction pattern of single-spore isolate of Magnaporthe oryzae to differential varieties showed that Pish, Pi9, Pita-2 and Pita are the effective blast-resistant genes against the tested blast isolates in Bangladesh. The DNA markers profiles of selected 16 rice germplasms indicated that genotype Chinigura contained Pish, Pi9 and Pita genes; on the other hand, both BRRI dhan50 and Bawaibhog contained Pish and Pita genes in their genetic background. Genotypes Jirakatari, BR5, and Gopalbhog possessed Pish gene, while Uknimodhu, Deshikatari, Radhunipagol, Kalijira (3), Chinikanai each contained the Pita gene only. There are some materials that did not contain any target gene(s) in their genetic background, but proved resistant in pathogenicity tests. This information provided valuable genetic information for breeders to develop durable blast-resistant fragrant or aromatic rice varieties in Bangladesh.

  9. The Potential of Streptomyces as Biocontrol Agents against the Rice Blast Fungus, Magnaporthe oryzae (Pyricularia oryzae)

    PubMed Central

    Law, Jodi Woan-Fei; Ser, Hooi-Leng; Khan, Tahir M.; Chuah, Lay-Hong; Pusparajah, Priyia; Chan, Kok-Gan; Goh, Bey-Hing; Lee, Learn-Han

    2017-01-01

    Rice is a staple food source for more than three billion people worldwide. However, rice is vulnerable to diseases, the most destructive among them being rice blast, which is caused by the fungus Magnaporthe oryzae (anamorph Pyricularia oryzae). This fungus attacks rice plants at all stages of development, causing annual losses of approximately 10–30% in various rice producing regions. Synthetic fungicides are often able to effectively control plant diseases, but some fungicides result in serious environmental and health problems. Therefore, there is growing interest in discovering and developing new, improved fungicides based on natural products as well as introducing alternative measures such as biocontrol agents to manage plant diseases. Streptomyces bacteria appear to be promising biocontrol agents against a wide range of phytopathogenic fungi, which is not surprising given their ability to produce various bioactive compounds. This review provides insight into the biocontrol potential of Streptomyces against the rice blast fungus, M. oryzae. The ability of various Streptomyces spp. to act as biocontrol agents of rice blast disease has been studied by researchers under both laboratory and greenhouse/growth chamber conditions. Laboratory studies have shown that Streptomyces exhibit inhibitory activity against M. oryzae. In greenhouse studies, infected rice seedlings treated with Streptomyces resulted in up to 88.3% disease reduction of rice blast. Studies clearly show that Streptomyces spp. have the potential to be used as highly effective biocontrol agents against rice blast disease; however, the efficacy of any biocontrol agent may be affected by several factors including environmental conditions and methods of application. In order to fully exploit their potential, further studies on the isolation, formulation and application methods of Streptomyces along with field experiments are required to establish them as effective biocontrol agents. PMID:28144236

  10. The Potential of Streptomyces as Biocontrol Agents against the Rice Blast Fungus, Magnaporthe oryzae (Pyricularia oryzae).

    PubMed

    Law, Jodi Woan-Fei; Ser, Hooi-Leng; Khan, Tahir M; Chuah, Lay-Hong; Pusparajah, Priyia; Chan, Kok-Gan; Goh, Bey-Hing; Lee, Learn-Han

    2017-01-01

    Rice is a staple food source for more than three billion people worldwide. However, rice is vulnerable to diseases, the most destructive among them being rice blast, which is caused by the fungus Magnaporthe oryzae (anamorph Pyricularia oryzae). This fungus attacks rice plants at all stages of development, causing annual losses of approximately 10-30% in various rice producing regions. Synthetic fungicides are often able to effectively control plant diseases, but some fungicides result in serious environmental and health problems. Therefore, there is growing interest in discovering and developing new, improved fungicides based on natural products as well as introducing alternative measures such as biocontrol agents to manage plant diseases. Streptomyces bacteria appear to be promising biocontrol agents against a wide range of phytopathogenic fungi, which is not surprising given their ability to produce various bioactive compounds. This review provides insight into the biocontrol potential of Streptomyces against the rice blast fungus, M. oryzae. The ability of various Streptomyces spp. to act as biocontrol agents of rice blast disease has been studied by researchers under both laboratory and greenhouse/growth chamber conditions. Laboratory studies have shown that Streptomyces exhibit inhibitory activity against M. oryzae. In greenhouse studies, infected rice seedlings treated with Streptomyces resulted in up to 88.3% disease reduction of rice blast. Studies clearly show that Streptomyces spp. have the potential to be used as highly effective biocontrol agents against rice blast disease; however, the efficacy of any biocontrol agent may be affected by several factors including environmental conditions and methods of application. In order to fully exploit their potential, further studies on the isolation, formulation and application methods of Streptomyces along with field experiments are required to establish them as effective biocontrol agents.

  11. Characterization and Fine Mapping of a Blast Resistant Gene Pi-jnw1 from the japonica Rice Landrace Jiangnanwan.

    PubMed

    Wang, Ruisen; Fang, Nengyan; Guan, Changhong; He, Wanwan; Bao, Yongmei; Zhang, Hongsheng

    2016-01-01

    Rice blast is a destructive disease caused by Magnaporthe oryzae, and it has a large impact on rice production worldwide. Compared with leaf blast resistance, our understanding of panicle blast resistance is limited. The japonica landrace Jiangnanwan from Taihu Lake region in China shows highly resistance to panicle and leaf blast. In this study, three generations (F2:5, F2:6, F2:7) consisting of 221 RILs (recombination inbreeding lines), developed from the cross of Jiangnanwan and Suyunuo, a susceptible-blast japonica variety, were evaluated for panicle blast resistance in the fields and leaf blast resistance in greenhouse in Nanjing in 2013, 2014 and 2015. A blast resistance gene Pi-jnw1 referring to panicle blast resistance and leaf blast resistance was identified in the three generations and located in the region of RM27273 and RM27381 in chromosome 11. The RIL18 line harboring Pi-jnw1 was selected to be backcrossed with Suyunuo to develop BC2F2 populations. According to the genotyping of 1,150 BC2F2 individuals and panicle blast and leaf blast resistance evaluation of 47 recombinants between RM27150 and RM27381, Pi-jnw1 was finally mapped to the 282 kb region between markers W28 and BS39. This study revealed that Jiangnanwan harboring a panicle blast and leaf blast resistance gene Pi-jnw1 could be a genetic source for breeding new rice cultivars with panicle blast resistance.

  12. Characterization and Fine Mapping of a Blast Resistant Gene Pi-jnw1 from the japonica Rice Landrace Jiangnanwan

    PubMed Central

    Wang, Ruisen; Fang, Nengyan; Guan, Changhong; He, Wanwan; Bao, Yongmei; Zhang, Hongsheng

    2016-01-01

    Rice blast is a destructive disease caused by Magnaporthe oryzae, and it has a large impact on rice production worldwide. Compared with leaf blast resistance, our understanding of panicle blast resistance is limited. The japonica landrace Jiangnanwan from Taihu Lake region in China shows highly resistance to panicle and leaf blast. In this study, three generations (F2:5, F2:6, F2:7) consisting of 221 RILs (recombination inbreeding lines), developed from the cross of Jiangnanwan and Suyunuo, a susceptible-blast japonica variety, were evaluated for panicle blast resistance in the fields and leaf blast resistance in greenhouse in Nanjing in 2013, 2014 and 2015. A blast resistance gene Pi-jnw1 referring to panicle blast resistance and leaf blast resistance was identified in the three generations and located in the region of RM27273 and RM27381 in chromosome 11. The RIL18 line harboring Pi-jnw1 was selected to be backcrossed with Suyunuo to develop BC2F2 populations. According to the genotyping of 1,150 BC2F2 individuals and panicle blast and leaf blast resistance evaluation of 47 recombinants between RM27150 and RM27381, Pi-jnw1 was finally mapped to the 282 kb region between markers W28 and BS39. This study revealed that Jiangnanwan harboring a panicle blast and leaf blast resistance gene Pi-jnw1 could be a genetic source for breeding new rice cultivars with panicle blast resistance. PMID:28036378

  13. Below-Ground Attack by the Root Knot Nematode Meloidogyne graminicola Predisposes Rice to Blast Disease.

    PubMed

    Kyndt, Tina; Zemene, Henok Yimer; Haeck, Ashley; Singh, Richard; De Vleesschauwer, David; Denil, Simon; De Meyer, Tim; Höfte, Monica; Demeestere, Kristof; Gheysen, Godelieve

    2017-03-01

    Magnaporthe oryzae (rice blast) and the root-knot nematode Meloidogyne graminicola are causing two of the most important pathogenic diseases jeopardizing rice production. Here, we show that root-knot nematode infestation on rice roots leads to important above-ground changes in plant immunity gene expression, which is correlated with significantly enhanced susceptibility to blast disease. A detailed metabolic analysis of oxidative stress responses and hormonal balances demonstrates that the above-ground tissues have a disturbed oxidative stress level, with accumulation of H2O2, as well as hormonal disturbances. Moreover, double infection experiments on an oxidative stress mutant and an auxin-deficient rice line indicate that the accumulation of auxin in the above-ground tissue is at least partly responsible for the blast-promoting effect of root-knot nematode infection.

  14. Identification of novel alleles of the rice blast resistance gene Pi54

    NASA Astrophysics Data System (ADS)

    Vasudevan, Kumar; Gruissem, Wilhelm; Bhullar, Navreet K.

    2015-10-01

    Rice blast is one of the most devastating rice diseases and continuous resistance breeding is required to control the disease. The rice blast resistance gene Pi54 initially identified in an Indian cultivar confers broad-spectrum resistance in India. We explored the allelic diversity of the Pi54 gene among 885 Indian rice genotypes that were found resistant in our screening against field mixture of naturally existing M. oryzae strains as well as against five unique strains. These genotypes are also annotated as rice blast resistant in the International Rice Genebank database. Sequence-based allele mining was used to amplify and clone the Pi54 allelic variants. Nine new alleles of Pi54 were identified based on the nucleotide sequence comparison to the Pi54 reference sequence as well as to already known Pi54 alleles. DNA sequence analysis of the newly identified Pi54 alleles revealed several single polymorphic sites, three double deletions and an eight base pair deletion. A SNP-rich region was found between a tyrosine kinase phosphorylation site and the nucleotide binding site (NBS) domain. Together, the newly identified Pi54 alleles expand the allelic series and are candidates for rice blast resistance breeding programs.

  15. Identification of novel alleles of the rice blast resistance gene Pi54.

    PubMed

    Vasudevan, Kumar; Gruissem, Wilhelm; Bhullar, Navreet K

    2015-10-26

    Rice blast is one of the most devastating rice diseases and continuous resistance breeding is required to control the disease. The rice blast resistance gene Pi54 initially identified in an Indian cultivar confers broad-spectrum resistance in India. We explored the allelic diversity of the Pi54 gene among 885 Indian rice genotypes that were found resistant in our screening against field mixture of naturally existing M. oryzae strains as well as against five unique strains. These genotypes are also annotated as rice blast resistant in the International Rice Genebank database. Sequence-based allele mining was used to amplify and clone the Pi54 allelic variants. Nine new alleles of Pi54 were identified based on the nucleotide sequence comparison to the Pi54 reference sequence as well as to already known Pi54 alleles. DNA sequence analysis of the newly identified Pi54 alleles revealed several single polymorphic sites, three double deletions and an eight base pair deletion. A SNP-rich region was found between a tyrosine kinase phosphorylation site and the nucleotide binding site (NBS) domain. Together, the newly identified Pi54 alleles expand the allelic series and are candidates for rice blast resistance breeding programs.

  16. Molecular Breeding Strategy and Challenges Towards Improvement of Blast Disease Resistance in Rice Crop.

    PubMed

    Ashkani, Sadegh; Rafii, Mohd Y; Shabanimofrad, Mahmoodreza; Miah, Gous; Sahebi, Mahbod; Azizi, Parisa; Tanweer, Fatah A; Akhtar, Mohd Sayeed; Nasehi, Abbas

    2015-01-01

    Rice is a staple and most important security food crop consumed by almost half of the world's population. More rice production is needed due to the rapid population growth in the world. Rice blast caused by the fungus, Magnaporthe oryzae is one of the most destructive diseases of this crop in different part of the world. Breakdown of blast resistance is the major cause of yield instability in several rice growing areas. There is a need to develop strategies providing long-lasting disease resistance against a broad spectrum of pathogens, giving protection for a long time over a broad geographic area, promising for sustainable rice production in the future. So far, molecular breeding approaches involving DNA markers, such as QTL mapping, marker-aided selection, gene pyramiding, allele mining and genetic transformation have been used to develop new resistant rice cultivars. Such techniques now are used as a low-cost, high-throughput alternative to conventional methods allowing rapid introgression of disease resistance genes into susceptible varieties as well as the incorporation of multiple genes into individual lines for more durable blast resistance. The paper briefly reviewed the progress of studies on this aspect to provide the interest information for rice disease resistance breeding. This review includes examples of how advanced molecular method have been used in breeding programs for improving blast resistance. New information and knowledge gained from previous research on the recent strategy and challenges towards improvement of blast disease such as pyramiding disease resistance gene for creating new rice varieties with high resistance against multiple diseases will undoubtedly provide new insights into the rice disease control.

  17. Molecular Breeding Strategy and Challenges Towards Improvement of Blast Disease Resistance in Rice Crop

    PubMed Central

    Ashkani, Sadegh; Rafii, Mohd Y.; Shabanimofrad, Mahmoodreza; Miah, Gous; Sahebi, Mahbod; Azizi, Parisa; Tanweer, Fatah A.; Akhtar, Mohd Sayeed; Nasehi, Abbas

    2015-01-01

    Rice is a staple and most important security food crop consumed by almost half of the world’s population. More rice production is needed due to the rapid population growth in the world. Rice blast caused by the fungus, Magnaporthe oryzae is one of the most destructive diseases of this crop in different part of the world. Breakdown of blast resistance is the major cause of yield instability in several rice growing areas. There is a need to develop strategies providing long-lasting disease resistance against a broad spectrum of pathogens, giving protection for a long time over a broad geographic area, promising for sustainable rice production in the future. So far, molecular breeding approaches involving DNA markers, such as QTL mapping, marker-aided selection, gene pyramiding, allele mining and genetic transformation have been used to develop new resistant rice cultivars. Such techniques now are used as a low-cost, high-throughput alternative to conventional methods allowing rapid introgression of disease resistance genes into susceptible varieties as well as the incorporation of multiple genes into individual lines for more durable blast resistance. The paper briefly reviewed the progress of studies on this aspect to provide the interest information for rice disease resistance breeding. This review includes examples of how advanced molecular method have been used in breeding programs for improving blast resistance. New information and knowledge gained from previous research on the recent strategy and challenges towards improvement of blast disease such as pyramiding disease resistance gene for creating new rice varieties with high resistance against multiple diseases will undoubtedly provide new insights into the rice disease control. PMID:26635817

  18. Marker development for rice blast resistance gene Pi66(t) and application in USDA rice mini-core collection

    USDA-ARS?s Scientific Manuscript database

    Molecular markers are useful for the identification of critical genes controlling agricultural traits of interest in crop germplasm and for the utilization of these genes in crop improvement using marker assisted selection (MAS). The improvement of blast disease resistance of rice varieties is one o...

  19. Analysis of Magnaporthe oryzae Genome Reveals a Fungal Effector, Which Is Able to Induce Resistance Response in Transgenic Rice Line Containing Resistance Gene, Pi54

    PubMed Central

    Ray, Soham; Singh, Pankaj K.; Gupta, Deepak K.; Mahato, Ajay K.; Sarkar, Chiranjib; Rathour, Rajeev; Singh, Nagendra K.; Sharma, Tilak R.

    2016-01-01

    Rice blast caused by Magnaporthe oryzae is one of the most important diseases of rice. Pi54, a rice gene that imparts resistance to M. oryzae isolates prevalent in India, was already cloned but its avirulent counterpart in the pathogen was not known. After decoding the whole genome of an avirulent isolate of M. oryzae, we predicted 11440 protein coding genes and then identified four candidate effector proteins which are exclusively expressed in the infectious structure, appresoria. In silico protein modeling followed by interaction analysis between Pi54 protein model and selected four candidate effector proteins models revealed that Mo-01947_9 protein model encoded by a gene located at chromosome 4 of M. oryzae, interacted best at the Leucine Rich Repeat domain of Pi54 protein model. Yeast-two-hybrid analysis showed that Mo-01947_9 protein physically interacts with Pi54 protein. Nicotiana benthamiana leaf infiltration assay confirmed induction of hypersensitive response in the presence of Pi54 gene in a heterologous system. Genetic complementation test also proved that Mo-01947_9 protein induces avirulence response in the pathogen in presence of Pi54 gene. Here, we report identification and cloning of a new fungal effector gene which interacts with blast resistance gene Pi54 in rice. PMID:27551285

  20. Analysis of Magnaporthe oryzae Genome Reveals a Fungal Effector, Which Is Able to Induce Resistance Response in Transgenic Rice Line Containing Resistance Gene, Pi54.

    PubMed

    Ray, Soham; Singh, Pankaj K; Gupta, Deepak K; Mahato, Ajay K; Sarkar, Chiranjib; Rathour, Rajeev; Singh, Nagendra K; Sharma, Tilak R

    2016-01-01

    Rice blast caused by Magnaporthe oryzae is one of the most important diseases of rice. Pi54, a rice gene that imparts resistance to M. oryzae isolates prevalent in India, was already cloned but its avirulent counterpart in the pathogen was not known. After decoding the whole genome of an avirulent isolate of M. oryzae, we predicted 11440 protein coding genes and then identified four candidate effector proteins which are exclusively expressed in the infectious structure, appresoria. In silico protein modeling followed by interaction analysis between Pi54 protein model and selected four candidate effector proteins models revealed that Mo-01947_9 protein model encoded by a gene located at chromosome 4 of M. oryzae, interacted best at the Leucine Rich Repeat domain of Pi54 protein model. Yeast-two-hybrid analysis showed that Mo-01947_9 protein physically interacts with Pi54 protein. Nicotiana benthamiana leaf infiltration assay confirmed induction of hypersensitive response in the presence of Pi54 gene in a heterologous system. Genetic complementation test also proved that Mo-01947_9 protein induces avirulence response in the pathogen in presence of Pi54 gene. Here, we report identification and cloning of a new fungal effector gene which interacts with blast resistance gene Pi54 in rice.

  1. Neck blast disease influences grain yield and quality traits of aromatic rice.

    PubMed

    Khan, Mohammad Ashik Iqbal; Bhuiyan, Md Rejwan; Hossain, Md Shahadat; Sen, Partha Pratim; Ara, Anjuman; Siddique, Md Abubakar; Ali, Md Ansar

    2014-11-01

    A critical investigation was conducted to find out the effect of neck blast disease on yield-contributing characters, and seed quality traits of aromatic rice in Bangladesh. Both healthy and neck-blast-infected panicles of three aromatic rice cultivars (high-yielding and local) were collected and investigated at Plant Pathology Division, Bangladesh Rice Research Institute (BRRI), Gazipur, Bangladesh. All of the tested varieties were highly susceptible to neck blast disease under natural conditions, though no leaf blast symptoms appear on leaves. Neck blast disease increased grain sterility percentages, reduced grain size, yield and quality traits of seeds. The degrees of yield and seed quality reduction depended on disease severity and variety's genetic make-up. Unfilled grains were the main source of seed-borne pathogen, especially for blast in the seed lot. Transmission of blast pathogen from neck (panicle base) to seed was very poor. These findings are important, especially concerning the seed certification programme in which seed lots are certified on the basis of field inspection. Finally, controlled experiments are needed to draw more critical conclusions. Copyright © 2014 Académie des sciences. Published by Elsevier SAS. All rights reserved.

  2. Draft Genome Sequence of Rice Isolate Pseudomonas chlororaphis EA105

    PubMed Central

    McCully, Lucy M.; Bitzer, Adam S.; Spence, Carla A.; Bais, Harsh P.

    2014-01-01

    Pseudomonas chlororaphis EA105, a strain isolated from rice rhizosphere, has shown antagonistic activities against a rice fungal pathogen, and could be important in defense against rice blast. We report the draft genome sequence of EA105, which is an estimated size of 6.6 Mb. PMID:25540352

  3. Protein kinase C is essential for viability of the rice blast fungus M agnaporthe oryzae

    PubMed Central

    Penn, Tina J.; Wood, Mark E.; Soanes, Darren M.; Csukai, Michael; Corran, Andrew John

    2015-01-01

    Summary Protein kinase C constitutes a family of serine–threonine kinases found in all eukaryotes and implicated in a wide range of cellular functions, including regulation of cell growth, cellular differentiation and immunity. Here, we present three independent lines of evidence which indicate that protein kinase C is essential for viability of M agnaporthe oryzae. First, all attempts to generate a target deletion of PKC 1, the single copy protein kinase C‐encoding gene, proved unsuccessful. Secondly, conditional gene silencing of PKC 1 by RNA interference led to severely reduced growth of the fungus, which was reversed by targeted deletion of the Dicer2‐encoding gene, MDL 2. Finally, selective kinase inhibition of protein kinase C by targeted allelic replacement with an analogue‐sensitive PKC 1AS allele led to specific loss of fungal viability in the presence of the PP1 inhibitor. Global transcriptional profiling following selective PKC inhibition identified significant changes in gene expression associated with cell wall re‐modelling, autophagy, signal transduction and secondary metabolism. When considered together, these results suggest protein kinase C is essential for growth and development of M . oryzae with extensive downstream targets in addition to the cell integrity pathway. Targeting protein kinase C signalling may therefore prove an effective means of controlling rice blast disease. PMID:26192090

  4. Molecular evolution of the rice blast resistance gene Pi-ta in invasive weedy rice in the USA.

    PubMed

    Lee, Seonghee; Jia, Yulin; Jia, Melissa; Gealy, David R; Olsen, Kenneth M; Caicedo, Ana L

    2011-01-01

    The Pi-ta gene in rice has been effectively used to control rice blast disease caused by Magnaporthe oryzae worldwide. Despite a number of studies that reported the Pi-ta gene in domesticated rice and wild species, little is known about how the Pi-ta gene has evolved in US weedy rice, a major weed of rice. To investigate the genome organization of the Pi-ta gene in weedy rice and its relationship to gene flow between cultivated and weedy rice in the US, we analyzed nucleotide sequence variation at the Pi-ta gene and its surrounding 2 Mb region in 156 weedy, domesticated and wild rice relatives. We found that the region at and around the Pi-ta gene shows very low genetic diversity in US weedy rice. The patterns of molecular diversity in weeds are more similar to cultivated rice (indica and aus), which have never been cultivated in the US, rather than the wild rice species, Oryza rufipogon. In addition, the resistant Pi-ta allele (Pi-ta) found in the majority of US weedy rice belongs to the weedy group strawhull awnless (SH), suggesting a single source of origin for Pi-ta. Weeds with Pi-ta were resistant to two M. oryzae races, IC17 and IB49, except for three accessions, suggesting that component(s) required for the Pi-ta mediated resistance may be missing in these accessions. Signatures of flanking sequences of the Pi-ta gene and SSR markers on chromosome 12 suggest that the susceptible pi-ta allele (pi-ta), not Pi-ta, has been introgressed from cultivated to weedy rice by out-crossing.

  5. Molecular Evolution of the Rice Blast Resistance Gene Pi-ta in Invasive Weedy Rice in the USA

    PubMed Central

    Lee, Seonghee; Jia, Yulin; Jia, Melissa; Gealy, David R.; Olsen, Kenneth M.; Caicedo, Ana L.

    2011-01-01

    The Pi-ta gene in rice has been effectively used to control rice blast disease caused by Magnaporthe oryzae worldwide. Despite a number of studies that reported the Pi-ta gene in domesticated rice and wild species, little is known about how the Pi-ta gene has evolved in US weedy rice, a major weed of rice. To investigate the genome organization of the Pi-ta gene in weedy rice and its relationship to gene flow between cultivated and weedy rice in the US, we analyzed nucleotide sequence variation at the Pi-ta gene and its surrounding 2 Mb region in 156 weedy, domesticated and wild rice relatives. We found that the region at and around the Pi-ta gene shows very low genetic diversity in US weedy rice. The patterns of molecular diversity in weeds are more similar to cultivated rice (indica and aus), which have never been cultivated in the US, rather than the wild rice species, Oryza rufipogon. In addition, the resistant Pi-ta allele (Pi-ta) found in the majority of US weedy rice belongs to the weedy group strawhull awnless (SH), suggesting a single source of origin for Pi-ta. Weeds with Pi-ta were resistant to two M. oryzae races, IC17 and IB49, except for three accessions, suggesting that component(s) required for the Pi-ta mediated resistance may be missing in these accessions. Signatures of flanking sequences of the Pi-ta gene and SSR markers on chromosome 12 suggest that the susceptible pi-ta allele (pi-ta), not Pi-ta, has been introgressed from cultivated to weedy rice by out-crossing. PMID:22043312

  6. Dynamic Changes in the Rice Blast Population in the United States Over Six Decades.

    PubMed

    Wang, Xueyan; Jia, Yulin; Wamishe, Yeshi; Jia, Melissa H; Valent, Barbara

    2017-10-01

    Rice blast disease caused by Magnaporthe oryzae is one of the most destructive diseases of rice. Field isolates of M. oryzae rapidly adapt to their hosts and climate. Tracking the genetic and pathogenic variability of field isolates is essential to understand how M. oryzae interacts with hosts and environments. In this study, a total of 1,022 United States field isolates collected from 1959 to 2015 were analyzed for pathogenicity toward eight international rice differentials. A subset of 457 isolates was genotyped with 10 polymorphic simple sequence repeat (SSR) markers. The average polymorphism information content value of markers was 0.55, suggesting that the SSR markers were highly informative to capture the population variances. Six genetic clusters were identified by both STRUCTURE and discriminant analysis of principal components methods. Overall, Nei's diversity of M. oryzae in the United States was 0.53, which is higher than previously reported in a world rice blast collection (0.19). The observed subdivision was associated with collection time periods but not with geographic origin of the isolates. Races such as IC-17, IE-1, and IB-49 have been identified across almost all collection periods and all clusters; races such as IA-1, IB-17, and IH-1 have a much higher frequency in certain periods and clusters. Both genomic and pathogenicity changes of United States blast isolates were associated with collection year, suggesting that hosts are a driving force for the genomic variability of rice blast fungus.

  7. Rapid evolution of avirulence genes in rice blast fungus Magnaporthe oryzae

    PubMed Central

    2014-01-01

    Background Rice blast fungus Magnaporthe oryzae is one of the most devastating pathogens in rice. Avirulence genes in this fungus share a gene-for-gene relationship with the resistance genes in its host rice. Although numerous studies have shown that rice blast R-genes are extremely diverse and evolve rapidly in their host populations, little is known about the evolutionary patterns of the Avr-genes in the pathogens. Results Here, six well-characterized Avr-genes and seven randomly selected non-Avr control genes were used to investigate the genetic variations in 62 rice blast strains from different parts of China. Frequent presence/absence polymorphisms, high levels of nucleotide variation (~10-fold higher than non-Avr genes), high non-synonymous to synonymous substitution ratios, and frequent shared non-synonymous substitution were observed in the Avr-genes of these diversified blast strains. In addition, most Avr-genes are closely associated with diverse repeated sequences, which may partially explain the frequent presence/absence polymorphisms in Avr-genes. Conclusion The frequent deletion and gain of Avr-genes and rapid non-synonymous variations might be the primary mechanisms underlying rapid adaptive evolution of pathogens toward virulence to their host plants, and these features can be used as the indicators for identifying additional Avr-genes. The high number of nucleotide polymorphisms among Avr-gene alleles could also be used to distinguish genetic groups among different strains. PMID:24725999

  8. Peroxisomal Alanine: Glyoxylate Aminotransferase AGT1 Is Indispensable for Appressorium Function of the Rice Blast Pathogen, Magnaporthe oryzae

    PubMed Central

    Bhadauria, Vijai; Banniza, Sabine; Vandenberg, Albert; Selvaraj, Gopalan; Wei, Yangdou

    2012-01-01

    The role of β-oxidation and the glyoxylate cycle in fungal pathogenesis is well documented. However, an ambiguity still remains over their interaction in peroxisomes to facilitate fungal pathogenicity and virulence. In this report, we characterize a gene encoding an alanine, glyoxylate aminotransferase 1 (AGT1) in Magnaporthe oryzae, the causative agent of rice blast disease, and demonstrate that AGT1 is required for pathogenicity of M. oryzae. Targeted deletion of AGT1 resulted in the failure of penetration via appressoria; therefore, mutants lacking the gene were unable to induce blast symptoms on the hosts rice and barley. This penetration failure may be associated with a disruption in lipid mobilization during conidial germination as turgor generation in the appressorium requires mobilization of lipid reserves from the conidium. Analysis of enhanced green fluorescent protein expression using the transcriptional and translational fusion with the AGT1 promoter and open reading frame, respectively, revealed that AGT1 expressed constitutively in all in vitro grown cell types and during in planta colonization, and localized in peroxisomes. Peroxisomal localization was further confirmed by colocalization with red fluorescent protein fused with the peroxisomal targeting signal 1. Surprisingly, conidia produced by the Δagt1 mutant were unable to form appressoria on artificial inductive surfaces, even after prolonged incubation. When supplemented with nicotinamide adenine dinucleotide (NAD+)+pyruvate, appressorium formation was restored on an artificial inductive surface. Taken together, our data indicate that AGT1-dependent pyruvate formation by transferring an amino group of alanine to glyoxylate, an intermediate of the glyoxylate cycle is required for lipid mobilization and utilization. This pyruvate can be converted to non-fermentable carbon sources, which may require reoxidation of NADH generated by the β-oxidation of fatty acids to NAD+ in peroxisomes

  9. Two independent S-phase checkpoints regulate appressorium-mediated plant infection by the rice blast fungus Magnaporthe oryzae

    PubMed Central

    Osés-Ruiz, Míriam; Sakulkoo, Wasin; Littlejohn, George R.; Martin-Urdiroz, Magdalena

    2017-01-01

    To cause rice blast disease, the fungal pathogen Magnaporthe oryzae develops a specialized infection structure called an appressorium. This dome-shaped, melanin-pigmented cell generates enormous turgor and applies physical force to rupture the rice leaf cuticle using a rigid penetration peg. Appressorium-mediated infection requires septin-dependent reorientation of the F-actin cytoskeleton at the base of the infection cell, which organizes polarity determinants necessary for plant cell invasion. Here, we show that plant infection by M. oryzae requires two independent S-phase cell-cycle checkpoints. Initial formation of appressoria on the rice leaf surface requires an S-phase checkpoint that acts through the DNA damage response (DDR) pathway, involving the Cds1 kinase. By contrast, appressorium repolarization involves a novel, DDR-independent S-phase checkpoint, triggered by appressorium turgor generation and melanization. This second checkpoint specifically regulates septin-dependent, NADPH oxidase-regulated F-actin dynamics to organize the appressorium pore and facilitate entry of the fungus into host tissue. PMID:28028232

  10. Investigating the impact of rice blast disease on the livelihood of the local farmers in greater Mwea region of Kenya.

    PubMed

    Kihoro, Joseph; Bosco, Njoroge J; Murage, Hunja; Ateka, Elijah; Makihara, Daigo

    2013-12-01

    Rice is the most important cereal crop in Kenya coming third after maize and wheat. It forms a very important diet for a majority of families in Kenya. The demand for rice in Kenya has seen a dramatic increase over the last few years while production has remained low. This is because rice production has been faced by serious constraints notably plant diseases of which the most devastating is rice blast. Rice blast is known to cause approximately 60% -100% yield losses. It is caused by an Ascomycete fungus called Magnaporthe Oryzae. The aim of this study was to investigate the impact of rice blast disease on the livelihood of the local farmers in Greater Mwea region and develop a rice blast disease distribution map using GIS approach. The study methodology employed a questionnaire survey which were subjected to sample population of households in the 7 sections with 70 blocks within Mwea region. The collected data was analysed using SAS Version 9.1. Descriptive statistics were used to summarize the household characteristics, the farm characteristics and the farmers' perceptions of rice blast disease. In the questionnaire, farmers' response on whether they had been affected by rice blast disease and the total production per acreage was used to develop an attribute table with GPS points. The GPS points were interpolated to create a geographical distribution map of rice blast disease. From the research findings almost all the farmers' had awareness and knowledge of rice blast disease, 98% of the farmers interviewed were aware of rice blast disease. Out of the 98% with knowledge and awareness 76% have been affected by the disease, while 24% have never been affected. Farmers attributed rice blast disease to a range of different causes, including excessive use of nitrogen fertilizer, water shortage, lack of proper drainage canal and due to climate change. Majority of the farmers interviewed (72%) did not engage themselves in any other socio-economic activity even after

  11. Fungal isolates and metabolites in locally processed rice from five agro-ecological zones of Nigeria.

    PubMed

    Abdus-Salaam, Rofiat; Atanda, Olusegun; Fanelli, Francesca; Sulyok, Micheal; Cozzi, Giuseppe; Bavaro, Simona; Krska, Rudolf; Logrieco, Antonio F; Ezekiel, Chibundu N; Salami, Waheed A

    2016-12-01

    This study reports the distribution of fungal isolates and fungal metabolites that naturally contaminate locally processed rice from five agro-ecological zones of Nigeria. The fungal species were isolated by the dilution plate technique and identified by appropriate diagnostics, while metabolites were determined by a liquid chromatographic tandem mass spectrometric method. Aspergillus and Penicillium species were the predominant isolates found in the rice samples while Fusarium spp. were not isolated. The mean fungal count differed significantly (p < 0.05) across the zones and ranged from 9.98 × 10(2) cfu g(-1) in the Southern Guinea Savannah to 96.97 × 10(2) cfu g(-1) in the Derived Savannah. For 16 fungal metabolites, selected from 63 positively identified fungal metabolites based on their concentration and spread across the zones, an occurrence map was constructed. The Northern Guinea Savannah recorded the highest contamination of fungal metabolites while the Sudan Savannah zone recorded the least.

  12. Self-assembly of MPG1, a hydrophobin protein from the rice blast fungus that forms functional amyloid coatings, occurs by a surface-driven mechanism

    PubMed Central

    Pham, Chi L. L.; Rey, Anthony; Lo, Victor; Soulès, Margaux; Ren, Qin; Meisl, Georg; Knowles, Tuomas P. J.; Kwan, Ann H.; Sunde, Margaret

    2016-01-01

    Rice blast is a devastating disease of rice caused by the fungus Magnaporthe oryzae and can result in loss of a third of the annual global rice harvest. Two hydrophobin proteins, MPG1 and MHP1, are highly expressed during rice blast infections. These hydrophobins have been suggested to facilitate fungal spore adhesion and to direct the action of the enzyme cutinase 2, resulting in penetration of the plant host. Therefore a mechanistic understanding of the self-assembly properties of these hydrophobins and their interaction with cutinase 2 is crucial for the development of novel antifungals. Here we report details of a study of the structure, assembly and interactions of these proteins. We demonstrate that, in vitro, MPG1 assembles spontaneously into amyloid structures while MHP1 forms a non-fibrillar film. The assembly of MPG1 only occurs at a hydrophobic:hydrophilic interface and can be modulated by MHP1 and other factors. We further show that MPG1 assemblies can much more effectively retain cutinase 2 activity on a surface after co-incubation and extensive washing compared with other protein coatings. The assembly and interactions of MPG1 and MHP1 at hydrophobic surfaces thereby provide the basis for a possible mechanism by which the fungus can develop appropriately at the infection interface. PMID:27142249

  13. The WRKY45-2 WRKY13 WRKY42 Transcriptional Regulatory Cascade Is Required for Rice Resistance to Fungal Pathogen1[OPEN

    PubMed Central

    Cheng, Hongtao; Liu, Hongbo; Deng, Yong; Xiao, Jinghua; Li, Xianghua; Wang, Shiping

    2015-01-01

    Blast caused by fungal Magnaporthe oryzae is a devastating disease of rice (Oryza sativa) worldwide, and this fungus also infects barley (Hordeum vulgare). At least 11 rice WRKY transcription factors have been reported to regulate rice response to M. oryzae either positively or negatively. However, the relationships of these WRKYs in the rice defense signaling pathway against M. oryzae are unknown. Previous studies have revealed that rice WRKY13 (as a transcriptional repressor) and WRKY45-2 enhance resistance to M. oryzae. Here, we show that rice WRKY42, functioning as a transcriptional repressor, suppresses resistance to M. oryzae. WRKY42-RNA interference (RNAi) and WRKY42-overexpressing (oe) plants showed increased resistance and susceptibility to M. oryzae, accompanied by increased or reduced jasmonic acid (JA) content, respectively, compared with wild-type plants. JA pretreatment enhanced the resistance of WRKY42-oe plants to M. oryzae. WRKY13 directly suppressed WRKY42. WRKY45-2, functioning as a transcriptional activator, directly activated WRKY13. In addition, WRKY13 directly suppressed WRKY45-2 by feedback regulation. The WRKY13-RNAi WRKY45-2-oe and WRKY13-oe WRKY42-oe double transgenic lines showed increased susceptibility to M. oryzae compared with WRKY45-2-oe and WRKY13-oe plants, respectively. These results suggest that the three WRKYs form a sequential transcriptional regulatory cascade. WRKY42 may negatively regulate rice response to M. oryzae by suppressing JA signaling-related genes, and WRKY45-2 transcriptionally activates WRKY13, whose encoding protein in turn transcriptionally suppresses WRKY42 to regulate rice resistance to M. oryzae. PMID:25624395

  14. Gene interactions and genetics of blast resistance and yield attributes in rice (Oryza sativa L.).

    PubMed

    Divya, B; Biswas, A; Robin, S; Rabindran, R; Joel, A John

    2014-08-01

    Blast disease caused by the pathogen Pyricularia oryzae is a serious threat to rice production. Six generations viz., P1, P2, F1, F2, B1 and B2 of a cross between blast susceptible high-yielding rice cultivar ADT 43 and resistant near isogenic line (NIL) CT13432-3R, carrying four blast resistance genes Pi1, Pi2, Pi33 and Pi54 in combination were used to study the nature and magnitude of gene action for disease resistance and yield attributes. The epistatic interaction model was found adequate to explain the gene action in most of the traits. The interaction was complementary for number of productive tillers, economic yield, lesion number, infected leaf area and potential disease incidence but duplicate epistasis was observed for the remaining traits. Among the genotypes tested under epiphytotic conditions, gene pyramided lines were highly resistant to blast compared to individuals with single genes indicating that the nonallelic genes have a complementary effect when present together. The information on genetics of various contributing traits of resistance will further aid plant breeders in choosing appropriate breeding strategy for blast resistance and yield enhancement in rice.

  15. Preillumination of rice blast conidia induces tolerance to subsequent oxidative stress

    USDA-ARS?s Scientific Manuscript database

    Many environmental factors, alone or combined, affect organisms by changing a pro-/antioxidant balance. Here we tested rice blast fungus (Magnaporthe oryzae) for possible cross-adaptations caused by relatively intense light and protecting from artificially formed reactive oxygen species (ROS) and RO...

  16. Rice resistance to blast caused by leaf surface moistening prior to inoculation

    USDA-ARS?s Scientific Manuscript database

    Effect of water droplets placed onto rice (Oryza sativa L.) leaves before inoculation with blast fungus Magnaporthe grisea (Hebert) Barr on disease severity and superoxide radical generation by the leaves was investigated. The leaves were inoculated by placement of spore suspension droplets. One da...

  17. Release of elicitors from rice blast spores under the action of reactive oxygen species

    USDA-ARS?s Scientific Manuscript database

    The effects of reactive oxygen species (ROS) on secretion of hypothesized elicitors from spores of rice blast causal fungus Magnaporthe grisea were studied. For spore exposure to exogenous ROS, they were germinated for 5 h in 50 µM H2O2 followed by addition of catalase E.C. 1.11.1.6 (to decompose pe...

  18. Identification of resistant germplasm containing novel resistance genes at or tightly linked to the Pi2/9 locus conferring broad-spectrum resistance against rice blast.

    PubMed

    Xiao, Gui; Borja, Frances Nikki; Mauleon, Ramil; Padilla, Jonas; Telebanco-Yanoria, Mary Jeanie; Yang, Jianxia; Lu, Guodong; Dionisio-Sese, Maribel; Zhou, Bo

    2017-12-01

    The rice Pi2/9 locus harbors multiple resistance (R) genes each controlling broad-spectrum resistance against diverse isolates of Magnaporthe oryzae, a fungal pathogen causing devastating blast disease to rice. Identification of more resistance germplasm containing novel R genes at or tightly linked to the Pi2/9 locus would promote breeding of resistance rice cultivars. In this study, we aim to identify resistant germplasm containing novel R genes at or tightly linked to the Pi2/9 locus using a molecular marker, designated as Pi2/9-RH (Pi2/9 resistant haplotype), developed from the 5' portion of the Pi2 sequence which was conserved only in the rice lines containing functional Pi2/9 alleles. DNA analysis using Pi2/9-RH identified 24 positive lines in 55 shortlisted landraces which showed resistance to 4 rice blast isolates. Analysis of partial sequences of the full-length cDNAs of Pi2/9 homologues resulted in the clustering of these 24 lines into 5 haplotypes each containing different Pi2/9 homologues which were designated as Pi2/9-A5, -A15, -A42, -A53, and -A54. Interestingly, Pi2/9-A5 and Pi2/9-A54 are identical to Piz-t and Pi2, respectively. To validate the association of other three novel Pi2/9 homologues with the blast resistance, monogenic lines at BC3F3 generation were generated by marker assisted backcrossing (MABC). Resistance assessment of the derived monogenic lines in both the greenhouse and the field hotspot indicated that they all controlled broad-spectrum resistance against rice blast. Moreover, genetic analysis revealed that the blast resistance of these three monogenic lines was co-segregated with Pi2/9-RH, suggesting that the Pi2/9 locus or tightly linked loci could be responsible for the resistance. The newly developed marker Pi2/9-RH could be used as a potentially diagnostic marker for the quick identification of resistant donors containing functional Pi2/9 alleles or unknown linked R genes. The three new monogenic lines containing the Pi2

  19. Differential accumulation of γ-aminobutyric acid in elicited cells of two rice cultivars showing contrasting sensitivity to the blast pathogen.

    PubMed

    Forlani, G; Bertazzini, M; Giberti, S

    2014-11-01

    Intracellular free amino acid pools were quantified in suspension cultured cells of a blast-sensitive and a blast-resistant rice genotype at increasing times after treatment with Magnaporthe oryzae cell wall hydrolysates. Besides some expected variations in free phenylalanine, a remarkable early increase of γ-aminobutyric acid (GABA) levels was evident in both cultivars. Glutamate decarboxylase activity and protein levels were unaffected. GABA homeostasis was recovered in the sensitive cultivar 48 h after the treatment. In contrast, a further GABA accumulation and a general increase of most amino acids was found at this later stage in the resistant genotype, which showed a larger decrease in cell viability as a consequence of elicitor addition. Data support a recently hypothesised role of GABA metabolism in the plant response to fungal pathogens. © 2014 German Botanical Society and The Royal Botanical Society of the Netherlands.

  20. Endophytic bacterial and fungal microbiota in sprouts, roots and stems of rice (Oryza sativa L.).

    PubMed

    Wang, Wenfeng; Zhai, Yanyan; Cao, Lixiang; Tan, Hongming; Zhang, Renduo

    2016-01-01

    The objective of this study was to elucidate the endophytic microbiota in rice sprouts, roots, and stems, and their transmission in the plant development. Prior to DNA extraction, roots and stems were treated with 36% formaldehyde and 0.1M NaOH solutions to remove epiphytic bacterial whole 16S rRNA genes. Bacterial and fungal taxa in the sprout, root, and stem samples were analyzed using Illumina-based sequencing of the V3-V4 hyper variable regions of bacterial 16S rRNA genes and the ITS2 regions of fungal rRNA genes, respectively. Results showed that more diverse bacterial OTUs were detected in roots than in stems, while more diverse fungal OTUs were detected in stems than in roots. Compared with the endophytic microbiota in sprouts, the bacterial OTUs increased in roots but decreased in stems, whereas the fungal OTUs in both stems and roots decreased. Sprout-borne bacterial genera Sphingomonas and Pseudomonus, and fungal genera Fusarium, Pestalotiopsis, and Penicillium were detected in stems and roots. The coexistence of these indigenous bacterial and fungal taxa in sprouts, roots, and stems indicated their transmission during the development from sprouts to mature plants. The results from this study should be useful to better understand the plant-microbe interactions and to select suitable microbial taxa for rice production. Copyright © 2016 Elsevier GmbH. All rights reserved.

  1. Pathogen effectors and plant immunity determine specialization of the blast fungus to rice subspecies

    PubMed Central

    Liao, Jingjing; Huang, Huichuan; Meusnier, Isabelle; Adreit, Henri; Ducasse, Aurélie; Bonnot, François; Pan, Lei; He, Xiahong; Kroj, Thomas; Fournier, Elisabeth; Tharreau, Didier; Gladieux, Pierre; Morel, Jean-Benoit

    2016-01-01

    Understanding how fungi specialize on their plant host is crucial for developing sustainable disease control. A traditional, centuries-old rice agro-system of the Yuanyang terraces was used as a model to show that virulence effectors of the rice blast fungus Magnaporthe oryzaeh play a key role in its specialization on locally grown indica or japonica local rice subspecies. Our results have indicated that major differences in several components of basal immunity and effector-triggered immunity of the japonica and indica rice varieties are associated with specialization of M. oryzae. These differences thus play a key role in determining M. oryzae host specificity and may limit the spread of the pathogen within the Yuanyang agro-system. Specifically, the AVR-Pia effector has been identified as a possible determinant of the specialization of M. oryzae to local japonica rice. DOI: http://dx.doi.org/10.7554/eLife.19377.001 PMID:28008850

  2. Expression of a fungal glucoamylase in transgenic rice seeds.

    PubMed

    Xu, Xiaoli; Huang, Jinming; Fang, Jun; Lin, Chaoyang; Cheng, Jiaan; Shen, Zhicheng

    2008-10-01

    Glucoamylase, which catalyses the hydrolysis of the alpha-1,4 glycosidic bonds of starch, is an important industrial enzyme used in starch enzymatic saccharification. In this study, a glucoamylase gene from Aspergillus awamori, under the control of the promoter of seed storage protein Gt1, was introduced into rice by Agrobacterium-mediated transformation. Significant glucoamylase activity was detected specifically in the seeds but not other tissues of the transgenic rice lines. The highest enzymatic activity was found in the transgenic line Bg17-2, which was estimated to have about 500 units per gram of seeds (one unit is defined as the amount of enzyme that produces 1 micromol of reducing sugar in 1 min at 60 degrees C using soluble starch as substrate). The optimum pH for the activity of the rice produced enzyme is 5.0-5.5, and the optimum temperature is around 60 degrees C. One part of this transgenic glucoamylase rice seed flour fully converted 25 parts of corn starch pre-liquefied by an alpha-amylase also produced by a transgenic rice into glucose in 16 h incubation. This study suggests that this hydrolysis enzyme may substitute commercial fermentation enzymes for industrial starch conversion.

  3. Multiple translocation of the AVR-Pita effector gene among chromosomes of the rice blast fungus Magnaporthe oryzae and related species.

    PubMed

    Chuma, Izumi; Isobe, Chihiro; Hotta, Yuma; Ibaragi, Kana; Futamata, Natsuru; Kusaba, Motoaki; Yoshida, Kentaro; Terauchi, Ryohei; Fujita, Yoshikatsu; Nakayashiki, Hitoshi; Valent, Barbara; Tosa, Yukio

    2011-07-01

    Magnaporthe oryzae is the causal agent of rice blast disease, a devastating problem worldwide. This fungus has caused breakdown of resistance conferred by newly developed commercial cultivars. To address how the rice blast fungus adapts itself to new resistance genes so quickly, we examined chromosomal locations of AVR-Pita, a subtelomeric gene family corresponding to the Pita resistance gene, in various isolates of M. oryzae (including wheat and millet pathogens) and its related species. We found that AVR-Pita (AVR-Pita1 and AVR-Pita2) is highly variable in its genome location, occurring in chromosomes 1, 3, 4, 5, 6, 7, and supernumerary chromosomes, particularly in rice-infecting isolates. When expressed in M. oryzae, most of the AVR-Pita homologs could elicit Pita-mediated resistance, even those from non-rice isolates. AVR-Pita was flanked by a retrotransposon, which presumably contributed to its multiple translocation across the genome. On the other hand, family member AVR-Pita3, which lacks avirulence activity, was stably located on chromosome 7 in a vast majority of isolates. These results suggest that the diversification in genome location of AVR-Pita in the rice isolates is a consequence of recognition by Pita in rice. We propose a model that the multiple translocation of AVR-Pita may be associated with its frequent loss and recovery mediated by its transfer among individuals in asexual populations. This model implies that the high mobility of AVR-Pita is a key mechanism accounting for the rapid adaptation toward Pita. Dynamic adaptation of some fungal plant pathogens may be achieved by deletion and recovery of avirulence genes using a population as a unit of adaptation.

  4. Multiple Translocation of the AVR-Pita Effector Gene among Chromosomes of the Rice Blast Fungus Magnaporthe oryzae and Related Species

    PubMed Central

    Chuma, Izumi; Isobe, Chihiro; Hotta, Yuma; Ibaragi, Kana; Futamata, Natsuru; Kusaba, Motoaki; Yoshida, Kentaro; Terauchi, Ryohei; Fujita, Yoshikatsu; Nakayashiki, Hitoshi; Valent, Barbara; Tosa, Yukio

    2011-01-01

    Magnaporthe oryzae is the causal agent of rice blast disease, a devastating problem worldwide. This fungus has caused breakdown of resistance conferred by newly developed commercial cultivars. To address how the rice blast fungus adapts itself to new resistance genes so quickly, we examined chromosomal locations of AVR-Pita, a subtelomeric gene family corresponding to the Pita resistance gene, in various isolates of M. oryzae (including wheat and millet pathogens) and its related species. We found that AVR-Pita (AVR-Pita1 and AVR-Pita2) is highly variable in its genome location, occurring in chromosomes 1, 3, 4, 5, 6, 7, and supernumerary chromosomes, particularly in rice-infecting isolates. When expressed in M. oryzae, most of the AVR-Pita homologs could elicit Pita-mediated resistance, even those from non-rice isolates. AVR-Pita was flanked by a retrotransposon, which presumably contributed to its multiple translocation across the genome. On the other hand, family member AVR-Pita3, which lacks avirulence activity, was stably located on chromosome 7 in a vast majority of isolates. These results suggest that the diversification in genome location of AVR-Pita in the rice isolates is a consequence of recognition by Pita in rice. We propose a model that the multiple translocation of AVR-Pita may be associated with its frequent loss and recovery mediated by its transfer among individuals in asexual populations. This model implies that the high mobility of AVR-Pita is a key mechanism accounting for the rapid adaptation toward Pita. Dynamic adaptation of some fungal plant pathogens may be achieved by deletion and recovery of avirulence genes using a population as a unit of adaptation. PMID:21829350

  5. Comparison of rice lines derived through anther culture and the pedigree method in relation to blast (Pyricularia grisea Sacc.) resistance.

    PubMed

    Martínez, C P; Victoria, F C; Amézquita, M C; Tulande, E; Lema, G; Zeigler, R S

    1996-04-01

    Crosses were made between Fanny (highly susceptible to blast) and 11 cultivars differing in blast resistance. Using the pedigree method (PM) segregating generations were evaluated and selected for blast resistance. Via anther culture (AC), doubled-haploids were obtained from F1 plants and from F2 blast-susceptible plants. Pedigree and anther culture-derived lines were planted together and evaluated for blast resistance under rainfed conditions at the Santa Rosa Experiment Station, Villavicencio, Colombia. The principal objective was to compare PM and AC in terms of their efficiency in producing rice lines resistant to blast. Results of a stratified analysis showed an association between method and blast resistance. Results of the logit-model analysis showed that AC produced a significantly (P=0.0001) higher proportion of lines with initial blast resistance (leaf- and neck-blast reaction ≤4) than did PM across all cross types. Stable blast resistance was assessed based on field performance over 3 years. AC was superior to PM in generating stable resistance for only some cross types. Consequently, with a few exceptions, AC can be used as effectively as PM to develop rice cultivars resistant to blast, with savings in time and labor. Additionally, blast-resistant lines were obtained either by the pedigree method or by anther culture from crosses between blast-susceptible cultivars (Fanny/CICA4 and Fanny/Colombial). This excludes somaclonal variation as a possible mechanism responsible for this resistance and suggests that a recombination of minor genes could have occurred and was fixed through either method. However, the stability of the resistance was greater in pedigree-derived lines. The implications of these findings for rice blast-resistance breeding are discussed.

  6. A six-gene phylogeny reveals the evolution of mode of infection in the rice blast fungus and allied species.

    PubMed

    Zhang, Ning; Zhao, Shuang; Shen, Qirong

    2011-01-01

    The family Magnaporthaceae contains devastating fungal cereal and grass pathogens, such as Magnaporthe oryzae (rice blast fungus, formerly known as M. grisea), M. poae (summer patch pathogen of turf grasses) and Gaeumannomyces graminis (take-all fungus of various cereals and grasses), which are popular model organisms in fungal biology and host-pathogen interaction studies. Despite their ecological and economic importance, the phylogenetic relationships among the constituent species remain ambiguous due to the lack of convincing morphological characters and paucity of molecular data for the majority of the non-model species in the family. In this study our multilocus phylogeny suggests that both Magnaporthe and Gaeumannomyces are polyphyletic genera. The phylogeny also provides insights into fungal biology and pathogenesis. Magnaporthe oryzae formed a basal clade, while M. poae and M. rhizophila formed another well supported clade with G. incrustans and G. graminis. The basal species infect both root and aerial parts of the plant host, while the aerial infection capacity seems to be lost in the taxa of the latter clade. The phylogeny is corroborated by evolution of the anamorphs and a cAMP-dependent protein kinase (CPKA) gene. Magnaporthe oryzae produces Pyricularia, while taxa in the latter clade all produce Phialophora-like anamorphs. CPKA is present in animals and many fungal lineages with various functions. In M. oryzae CPKA is essential for the formation of functional appressoria for leaf penetration. In root-infecting G. graminis var. tritici and M. poae however only non-functional CPKA homologous pseudogenes were found in their genomes. The study indicates that anamorphic and ecological features are more informative than the teleomorphic characters in defining monophyletic groups among these taxa.

  7. Rice WRKY45 plays a crucial role in benzothiadiazole-inducible blast resistance.

    PubMed

    Shimono, Masaki; Sugano, Shoji; Nakayama, Akira; Jiang, Chang-Jie; Ono, Kazuko; Toki, Seiichi; Takatsuji, Hiroshi

    2007-06-01

    Benzothiadiazole (BTH) is a so-called plant activator and protects plants from diseases by activating the salicylic acid (SA) signaling pathway. By microarray screening, we identified BTH- and SA-inducible WRKY transcription factor (TF) genes that were upregulated within 3 h after BTH treatment. Overexpression of one of them, WRKY45, in rice (Oryza sativa) markedly enhanced resistance to rice blast fungus. RNA interference-mediated knockdown of WRKY45 compromised BTH-inducible resistance to blast disease, indicating that it is essential for BTH-induced defense responses. In a transient expression system, WRKY45 activated reporter gene transcription through W-boxes. Epistasis analysis suggested that WRKY45 acts in the SA signaling pathway independently of NH1, a rice ortholog of Arabidopsis thaliana NPR1, which distinguishes WRKY45 from known Arabidopsis WRKY TFs. Two defense-related genes, encoding a glutathione S-transferase and a cytochrome P450, were found to be regulated downstream of WRKY45 but were not regulated by NH1, consistent with the apparent independence of the WRKY45- and NH1-dependent pathways. Defense gene expression in WRKY45-overexpressed rice plants varied with growth conditions, suggesting that some environmental factor(s) acts downstream of WRKY45 transcription. We propose a role for WRKY45 in BTH-induced and SA-mediated defense signaling in rice and its potential utility in improving disease resistance of rice, an importance food resource worldwide.

  8. Two Novel Transcriptional Regulators Are Essential for Infection-related Morphogenesis and Pathogenicity of the Rice Blast Fungus Magnaporthe oryzae

    PubMed Central

    Yan, Xia; Li, Ya; Yue, Xiaofeng; Wang, Congcong; Que, Yawei; Kong, Dandan; Ma, Zhonghua; Talbot, Nicholas J.; Wang, Zhengyi

    2011-01-01

    The cyclic AMP-dependent protein kinase A signaling pathway plays a major role in regulating plant infection by the rice blast fungus Magnaporthe oryzae. Here, we report the identification of two novel genes, MoSOM1 and MoCDTF1, which were discovered in an insertional mutagenesis screen for non-pathogenic mutants of M. oryzae. MoSOM1 or MoCDTF1 are both necessary for development of spores and appressoria by M. oryzae and play roles in cell wall differentiation, regulating melanin pigmentation and cell surface hydrophobicity during spore formation. MoSom1 strongly interacts with MoStu1 (Mstu1), an APSES transcription factor protein, and with MoCdtf1, while also interacting more weakly with the catalytic subunit of protein kinase A (CpkA) in yeast two hybrid assays. Furthermore, the expression levels of MoSOM1 and MoCDTF1 were significantly reduced in both Δmac1 and ΔcpkA mutants, consistent with regulation by the cAMP/PKA signaling pathway. MoSom1-GFP and MoCdtf1-GFP fusion proteins localized to the nucleus of fungal cells. Site-directed mutagenesis confirmed that nuclear localization signal sequences in MoSom1 and MoCdtf1 are essential for their sub-cellular localization and biological functions. Transcriptional profiling revealed major changes in gene expression associated with loss of MoSOM1 during infection-related development. We conclude that MoSom1 and MoCdtf1 functions downstream of the cAMP/PKA signaling pathway and are novel transcriptional regulators associated with cellular differentiation during plant infection by the rice blast fungus. PMID:22144889

  9. Peroxisomal fission is induced during appressorium formation and is required for full virulence of the rice blast fungus.

    PubMed

    Chen, Xiao-Lin; Shen, Mi; Yang, Jun; Xing, Yunfei; Chen, Deng; Li, Zhigang; Zhao, Wensheng; Zhang, Yan

    2017-02-01

    Peroxisomes are involved in various metabolic processes and are important for virulence in different pathogenic fungi. How peroxisomes rapidly emerge in the appressorium during fungal infection is poorly understood. Here, we describe a gene, PEF1, which can regulate peroxisome formation in the appressorium by controlling peroxisomal fission, and is required for plant infection in the rice blast fungus Magnaporthe oryzae. Targeted deletion of PEF1 resulted in a reduction in virulence and a delay in penetration and invasive growth in host cells. PEF1 was particularly expressed during appressorial development, and its encoding protein was co-localized with peroxisomes during appressorial development. Compared with the massive vesicle-shaped peroxisomes formed in the wild-type appressorium, the Δpef1 mutant could only form stringy linked immature peroxisomes, suggesting that PEF1 was involved in peroxisomal fission during appressorium formation. We also found that the Δpef1 mutant could not utilize fatty acids efficiently, which can improve significantly the expression level of PEF1 and induce peroxisomal fission. As expected, the Δpef1 mutant showed reduced intracellular production of reactive oxygen species (ROS) during appressorium formation and induced ROS accumulation in host cells during infection. Taken together, PEF1-mediated peroxisomal fission is important for fungal infection by controlling the number of peroxisomes in the appressorium.

  10. A genome-wide survey reveals abundant rice blast R genes in resistant cultivars.

    PubMed

    Zhang, Xiaohui; Yang, Sihai; Wang, Jiao; Jia, Yanxiao; Huang, Ju; Tan, Shengjun; Zhong, Yan; Wang, Ling; Gu, Longjiang; Chen, Jian-Qun; Pan, Qinghua; Bergelson, Joy; Tian, Dacheng

    2015-10-01

    Plant resistance genes (R genes) harbor tremendous allelic diversity, constituting a robust immune system effective against microbial pathogens. Nevertheless, few functional R genes have been identified for even the best-studied pathosystems. Does this limited repertoire reflect specificity, with most R genes having been defeated by former pests, or do plants harbor a rich diversity of functional R genes, the composite behavior of which is yet to be characterized? Here, we survey 332 NBS-LRR genes cloned from five resistant Oryza sativa (rice) cultivars for their ability to confer recognition of 12 rice blast isolates when transformed into susceptible cultivars. Our survey reveals that 48.5% of the 132 NBS-LRR loci tested contain functional rice blast R genes, with most R genes deriving from multi-copy clades containing especially diversified loci. Each R gene recognized, on average, 2.42 of the 12 isolates screened. The abundant R genes identified in resistant genomes provide extraordinary redundancy in the ability of host genotypes to recognize particular isolates. If the same is true for other pathogens, many extant NBS-LRR genes retain functionality. Our success at identifying rice blast R genes also validates a highly efficient cloning and screening strategy.

  11. A genome-wide survey reveals abundant rice blast R-genes in resistant cultivars

    PubMed Central

    Tan, Shengjun; Zhong, Yan; Wang, Ling; Gu, Longjiang; Chen, Jian-Qun; Pan, Qinghua; Bergelson, Joy; Tian, Dacheng

    2015-01-01

    Summary Plant resistance genes (R-genes) harbor tremendous allelic diversity, constituting a robust immune system effective against microbial pathogens. Nevertheless, few functional R-genes have been identified for even the best-studied pathosystems. Does this limited repertoire reflect specificity, with most R-genes having been defeated by former pests, or do plants harbor a rich diversity of functional R-genes whose composite behavior is yet to be characterized? Here, we survey 332 NBS-LRR genes cloned from 5 resistant rice cultivars for their ability to confer recognition of 12 rice blast isolates when transformed into susceptible cultivars. Our survey reveals that 48.5% of the 132 NBS-LRR loci tested contain functional rice blast R-genes, with most R-genes deriving from multi-copy clades containing especially diversified loci. Each R-gene recognized, on average, 2.42 of the 12 isolates screened. The abundant R-genes identified in resistant genomes provide extraordinary redundancy in the ability of host genotypes to recognize particular isolates. If the same is true for other pathogens, many extant NBS-LRR genes retain functionality. Our success at identifying rice blast R-genes also validates a highly efficient cloning and screening strategy. PMID:26248689

  12. Statistical inference of selection and divergence of the rice blast resistance gene Pi-ta.

    PubMed

    Amei, Amei; Lee, Seonghee; Mysore, Kirankumar S; Jia, Yulin

    2014-10-21

    The resistance gene Pi-ta has been effectively used to control rice blast disease, but some populations of cultivated and wild rice have evolved resistance. Insights into the evolutionary processes that led to this resistance during crop domestication may be inferred from the population history of domesticated and wild rice strains. In this study, we applied a recently developed statistical method, time-dependent Poisson random field model, to examine the evolution of the Pi-ta gene in cultivated and weedy rice. Our study suggests that the Pi-ta gene may have more recently introgressed into cultivated rice, indica and japonica, and U.S. weedy rice from the wild species, O. rufipogon. In addition, the Pi-ta gene is under positive selection in japonica, tropical japonica, U.S. cultivars and U.S. weedy rice. We also found that sequences of two domains of the Pi-ta gene, the nucleotide binding site and leucine-rich repeat domain, are highly conserved among all rice accessions examined. Our results provide a valuable analytical tool for understanding the evolution of disease resistance genes in crop plants.

  13. Fungal pretreatment of lignocellulose by Phanerochaete chrysosporium to produce ethanol from rice straw.

    PubMed

    Bak, Jin Seop; Ko, Ja Kyong; Choi, In-Geol; Park, Yong-Cheol; Seo, Jin-Ho; Kim, Kyoung Heon

    2009-10-15

    Phanerochaete chrysosporium is a wood-rot fungus that is capable of degrading lignin via its lignolytic system. In this study, an environmentally friendly fungal pretreatment process that produces less inhibitory substances than conventional methods was developed using P. chrysosporium and then evaluated by various analytical methods. To maximize the production of manganese peroxidase, which is the primary lignin-degrading enzyme, culture medium was optimized using response surface methodologies including the Plackett-Burman design and the Box-Behnken design. Fermentation of 100 g of rice straw feedstock containing 35.7 g of glucan (mainly in the form of cellulose) by cultivation with P. chrysosporium for 15 days in the media optimized by response surface methodology was resulted in a yield of 29.0 g of glucan that had an enzymatic digestibility of 64.9% of the theoretical maximum glucose yield. In addition, scanning electronic microscopy, confocal laser scanning microscopy, and X-ray diffractometry revealed significant microstructural changes, fungal growth, and a reduction of the crystallinity index in the pretreated rice straw, respectively. When the fungal-pretreated rice straw was used as a substrate for ethanol production in simultaneous saccharification and fermentation (SSF) for 24 h, the ethanol concentration, production yield and the productivity were 9.49 g/L, 58.2% of the theoretical maximum, and 0.40 g/L/h, respectively. Based on these experimental data, if 100 g of rice straw are subjected to fungal pretreatment and SSF, 9.9 g of ethanol can be produced after 96 h, which is 62.7% of the theoretical maximum ethanol yield.

  14. Understanding the coevolution of rice blast resistance gene Pi-ta and Magnaporthe oryzae avirulence gene AVR-Pita

    USDA-ARS?s Scientific Manuscript database

    Rice blast disease caused by the filamentous ascomycetous fungus Magnaporthe oryzae remains to be one of the most serious threats for food security globally. Using resistance (R) genes in integrated cultural practices has been the most powerful practice for rice crop protection. Genetic analysis s...

  15. Differential Gene Expression Reflects Morphological Characteristics and Physiological Processes in Rice Immunity against Blast Pathogen Magnaporthe oryzae.

    PubMed

    Azizi, Parisa; Rafii, Mohd Y; Mahmood, Maziah; Abdullah, Siti N A; Hanafi, Mohamed M; Nejat, Naghmeh; Latif, Muhammad A; Sahebi, Mahbod

    2015-01-01

    The rice blast fungus Magnaporthe oryzae is a serious pathogen that jeopardises the world's most important food-security crop. Ten common Malaysian rice varieties were examined for their morphological, physiological and genomic responses to this rice blast pathogen. qPCR quantification was used to assess the growth of the pathogen population in resistant and susceptible rice varieties. The chlorophyll content and photosynthesis were also measured to further understand the disruptive effects that M. oryzae has on infected plants of these varieties. Real-time PCR was used to explore the differential expression of eight blast resistance genes among the ten local varieties. Blast disease has destructive effects on the growth of rice, and the findings of our study provide evidence that the Pikh, Pi9, Pi21, and Osw45 genes are involved in defence responses in the leaves of Malaysian rice at 31 h after inoculation with M. oryzae pathotype P7.2. Both the chlorophyll content and photosynthesis were reduced, but the levels of Pikh gene expression remained constant in susceptible varieties, with a developed pathogen population and mild or severe symptoms. The Pi9, Pi21, and Osw45 genes, however, were simultaneously upregulated in infected rice plants. Therefore, the presence of the Pikh, Pi9, Pi21, and Osw45 genes in the germplasm is useful for improving the resistance of rice varieties.

  16. Differential Gene Expression Reflects Morphological Characteristics and Physiological Processes in Rice Immunity against Blast Pathogen Magnaporthe oryzae

    PubMed Central

    Mahmood, Maziah; Abdullah, Siti N. A.; Hanafi, Mohamed M.; Nejat, Naghmeh; Latif, Muhammad A.

    2015-01-01

    The rice blast fungus Magnaporthe oryzae is a serious pathogen that jeopardises the world’s most important food-security crop. Ten common Malaysian rice varieties were examined for their morphological, physiological and genomic responses to this rice blast pathogen. qPCR quantification was used to assess the growth of the pathogen population in resistant and susceptible rice varieties. The chlorophyll content and photosynthesis were also measured to further understand the disruptive effects that M. oryzae has on infected plants of these varieties. Real-time PCR was used to explore the differential expression of eight blast resistance genes among the ten local varieties. Blast disease has destructive effects on the growth of rice, and the findings of our study provide evidence that the Pikh, Pi9, Pi21, and Osw45 genes are involved in defence responses in the leaves of Malaysian rice at 31 h after inoculation with M. oryzae pathotype P7.2. Both the chlorophyll content and photosynthesis were reduced, but the levels of Pikh gene expression remained constant in susceptible varieties, with a developed pathogen population and mild or severe symptoms. The Pi9, Pi21, and Osw45 genes, however, were simultaneously upregulated in infected rice plants. Therefore, the presence of the Pikh, Pi9, Pi21, and Osw45 genes in the germplasm is useful for improving the resistance of rice varieties. PMID:26001124

  17. Proteins interacting with mitochondrial ATP-dependent Lon protease (MAP1) in Magnaporthe oryzae are involved in rice blast disease.

    PubMed

    Cui, Xiao; Wei, Yi; Wang, Yu-Han; Li, Jian; Wong, Fuk-Ling; Zheng, Ya-Jie; Yan, Hai; Liu, Shao-Shuai; Liu, Jin-Liang; Jia, Bao-Lei; Zhang, Shi-Hong

    2015-10-01

    The ATP-dependent Lon protease is involved in many physiological processes. In bacteria, Lon regulates pathogenesis and, in yeast, Lon protects mitochondia from oxidative damage. However, little is known about Lon in fungal phytopathogens. MAP1, a homologue of Lon in Magnaporthe oryzae, was recently identified to be important for stress resistance and pathogenesis. Here, we focus on a novel pathogenic pathway mediated by MAP1. Based on an interaction system between rice and a tandem affinity purification (TAP)-tagged MAP1 complementation strain, we identified 23 novel fungal proteins from infected leaves using a TAP approach with mass spectrometry, and confirmed that 14 of these proteins physically interact with MAP1 in vivo. Among these 14 proteins, 11 candidates, presumably localized to the mitochondria, were biochemically determined to be substrates of MAP1 hydrolysis. Deletion mutants were created and functionally analysed to further confirm the involvement of these proteins in pathogenesis. The results indicated that all mutants showed reduced conidiation and sensitivity to hydrogen peroxide. Appressorial formations were not affected, although conidia from certain mutants were morphologically altered. In addition, virulence was reduced in four mutants, enhanced (with lesions forming earlier) in two mutants and remained unchanged in one mutant. Together with the known virulence-related proteins alternative oxidase and enoyl-CoA hydratase, we propose that most of the Lon-interacting proteins are involved in the pathogenic regulation pathway mediated by MAP1 in M. oryzae. Perturbation of this pathway may represent an effective approach for the inhibition of rice blast disease. © 2015 BSPP AND JOHN WILEY & SONS LTD.

  18. Introgression of Blast Resistance Genes (Putative Pi-b and Pi-kh) into Elite Rice Cultivar MR219 through Marker-Assisted Selection.

    PubMed

    Tanweer, Fatah A; Rafii, Mohd Y; Sijam, Kamaruzaman; Rahim, Harun A; Ahmed, Fahim; Ashkani, Sadegh; Latif, Mohammad A

    2015-01-01

    Blast is the most common biotic stress leading to the reduction of rice yield in many rice-growing areas of the world, including Malaysia. Improvement of blast resistance of rice varieties cultivated in blast endemic areas is one of the most important objectives of rice breeding programs. In this study, the marker-assisted backcrossing strategy was applied to improve the blast resistance of the most popular Malaysian rice variety MR219 by introgressing blast resistance genes from the Pongsu Seribu 2 variety. Two blast resistance genes, Pi-b and Pi-kh, were pyramided into MR219. Foreground selection coupled with stringent phenotypic selection identified 15 plants homozygous for the Pi-b and Pi-kh genes, and background selection revealed more than 95% genome recovery of MR219 in advanced blast resistant lines. Phenotypic screening against blast disease indicated that advanced homozygous blast resistant lines were strongly resistant against pathotype P7.2 in the blast disease endemic areas. The morphological, yield, grain quality, and yield-contributing characteristics were significantly similar to those of MR219. The newly developed blast resistant improved lines will retain the high adoptability of MR219 by farmers. The present results will also play an important role in sustaining the rice production of Malaysia.

  19. Introgression of Blast Resistance Genes (Putative Pi-b and Pi-kh) into Elite Rice Cultivar MR219 through Marker-Assisted Selection

    PubMed Central

    Tanweer, Fatah A.; Rafii, Mohd Y.; Sijam, Kamaruzaman; Rahim, Harun A.; Ahmed, Fahim; Ashkani, Sadegh; Latif, Mohammad A.

    2015-01-01

    Blast is the most common biotic stress leading to the reduction of rice yield in many rice-growing areas of the world, including Malaysia. Improvement of blast resistance of rice varieties cultivated in blast endemic areas is one of the most important objectives of rice breeding programs. In this study, the marker-assisted backcrossing strategy was applied to improve the blast resistance of the most popular Malaysian rice variety MR219 by introgressing blast resistance genes from the Pongsu Seribu 2 variety. Two blast resistance genes, Pi-b and Pi-kh, were pyramided into MR219. Foreground selection coupled with stringent phenotypic selection identified 15 plants homozygous for the Pi-b and Pi-kh genes, and background selection revealed more than 95% genome recovery of MR219 in advanced blast resistant lines. Phenotypic screening against blast disease indicated that advanced homozygous blast resistant lines were strongly resistant against pathotype P7.2 in the blast disease endemic areas. The morphological, yield, grain quality, and yield-contributing characteristics were significantly similar to those of MR219. The newly developed blast resistant improved lines will retain the high adoptability of MR219 by farmers. The present results will also play an important role in sustaining the rice production of Malaysia. PMID:26734013

  20. Defence responses in rice plants in prior and simultaneous applications of Cladosporium sp. during leaf blast suppression.

    PubMed

    Chaibub, Amanda Abdallah; de Carvalho, Jacqueline Campos Borba; de Sousa Silva, Carlos; Collevatti, Rosane Garcia; Gonçalves, Fábio José; de Carvalho Barros Côrtes, Márcio Vinícius; de Filippi, Marta Cristina Corsi; de Faria, Fabrícia Paula; Lopes, Douglas Christian Borges; de Araújo, Leila Garcês

    2016-11-01

    An alternative method to control rice blast (Magnaporthe oryzae) is to include biological agent in the disease management strategy. The objective of this study was to assess the leaf blast-suppressing effects of rice phylloplane fungi. One Cladosporium sp. phylloplane fungus was shown to possess biocontrolling traits based on its morphological characteristics and an analysis of its 18S ribosomal DNA. Experiments aimed at determining the optimal time to apply the bioagent and the mechanisms involved in its rice blast-suppressing activities were performed under controlled greenhouse conditions. We used foliar spraying to apply the Cladosporium sp. 48 h prior to applying the pathogen, and we found that this increased the enzymatic activity. Furthermore, in vitro tests performed using isolate C24 showed that it possessed the ability to secrete endoxylanases and endoglucanases. When Cladosporium sp. was applied either prior to or simultaneous with the pathogen, we observed a significant increase in defence enzyme activity, and rice blast was suppressed by 84.0 and 78.6 %, respectively. However, some enzymes showed higher activity at 24 h while others did so at 48 h after the challenge inoculation. Cladosporium sp. is a biological agent that is capable of suppressing rice leaf blast by activating biochemical defence mechanisms in rice plants. It is highly adapted to natural field conditions and should be included in further studies aimed at developing strategies to support ecologically sustainable disease management and reduce environmental pollution by the judicious use of fungicidal sprays.

  1. Modern elite rice varieties of the 'Green Revolution' have retained a large introgression from wild rice around the Pi33 rice blast resistance locus.

    PubMed

    Ballini, Elsa; Berruyer, Romain; Morel, Jean-Benoît; Lebrun, Marc-Henri; Nottéghem, Jean-Loup; Tharreau, Didier

    2007-01-01

    During the breeding process of cultivated crops, resistance genes to pests and diseases are commonly introgressed from wild species. The size of these introgressions is predicted by theoretical models but has rarely been measured in cultivated varieties. By combining resistance tests with isogenic strains, genotyping and sequencing of different rice accessions, it was shown that, in the elite rice variety IR64, the resistance conferring allele of the rice blast resistance gene Pi33 was introgressed from the wild rice Oryza rufipogon (accession IRGC101508). Further characterization of this introgression revealed a large introgression at this locus in IR64 and the related variety IR36. The introgressed fragment represents approximately half of the short arm of rice chromosome 8. This is the first report of a large introgression in a cultivated variety of rice. Such a large introgression is likely to have been maintained during backcrossing only if a selection pressure was exerted on this genomic region. The possible traits that were selected are discussed.

  2. Identification of the rice blast resistance gene Pib in the National Small Grains Collection.

    PubMed

    Roychowdhury, M; Jia, Y; Jia, M H; Fjellstrom, R; Cartwright, R D

    2012-07-01

    The Pib gene in rice confers resistance to a wide range of races of the rice blast pathogen, Magnaporthe oryzae, including race IE1k that overcomes Pita, another broad-spectrum resistance gene. In this study, the presence of Pib was determined in 164 rice germplasm accessions from a core subset of the National Small Grains Collection utilizing DNA markers and pathogenicity assays. The presence of Pib was evaluated with two simple sequence repeat (SSR) markers and a dominant marker (Pib-dom) derived from the Pib gene sequence. Pathogenicity assays using two avirulent races (IE1k and IB1) and a virulent race (IB54) were performed to verify the resistance responses of accessions. Of the 164 accessions evaluated, 109 contained the Pib gene as determined using both SSR markers and pathogenicity assays, albeit different haplotypes were detected. The remaining 52 germplasm accessions were different in their responses to the blast races IB54, IE1k, and IB1, thus indicating the presence of R gene(s) other than Pib. The accessions characterized in this study could be used for marker-assisted breeding to improve blast resistance in indica and japonica cultivars worldwide.

  3. Avirulence (AVR) Gene-Based Diagnosis Complements Existing Pathogen Surveillance Tools for Effective Deployment of Resistance (R) Genes Against Rice Blast Disease.

    PubMed

    Selisana, S M; Yanoria, M J; Quime, B; Chaipanya, C; Lu, G; Opulencia, R; Wang, G-L; Mitchell, T; Correll, J; Talbot, N; Leung, H; Zhou, B

    2017-04-03

    Avirulence (AVR) genes in Magnaporthe oryzae, the fungal pathogen that causes the devastating rice blast disease, have been documented to be major targets subject to mutations to avoid recognition by resistance (R) genes. In this study, an AVR-gene-based diagnosis tool for determining the virulence spectrum of a rice blast pathogen population was developed and validated. A set of 77 single-spore field isolates was subjected to pathotype analysis using differential lines, each containing a single R gene, and classified into 20 virulent pathotypes, except for 4 isolates that lost pathogenicity. In all, 10 differential lines showed low frequency (<24%) of resistance whereas 8 lines showed a high frequency (>95%), inferring the effectiveness of R genes present in the respective differential lines. In addition, the haplotypes of seven AVR genes were determined by polymerase chain reaction amplification and sequencing, if applicable. The calculated frequency of different AVR genes displayed significant variations in the population. AVRPiz-t and AVR-Pii were detected in 100 and 84.9% of the isolates, respectively. Five AVR genes such as AVR-Pik-D (20.5%) and AVR-Pik-E (1.4%), AVRPiz-t (2.7%), AVR-Pita (0%), AVR-Pia (0%), and AVR1-CO39 (0%) displayed low or even zero frequency. The frequency of AVR genes correlated almost perfectly with the resistance frequency of the cognate R genes in differential lines, except for International Rice Research Institute-bred blast-resistant lines IRBLzt-T, IRBLta-K1, and IRBLkp-K60. Both genetic analysis and molecular marker validation revealed an additional R gene, most likely Pi19 or its allele, in these three differential lines. This can explain the spuriously higher resistance frequency of each target R gene based on conventional pathotyping. This study demonstrates that AVR-gene-based diagnosis provides a precise, R-gene-specific, and differential line-free assessment method that can be used for determining the virulence spectrum of

  4. Contribution of Ethylene Biosynthesis for Resistance to Blast Fungus Infection in Young Rice Plants1[OA

    PubMed Central

    Iwai, Takayoshi; Miyasaka, Atsushi; Seo, Shigemi; Ohashi, Yuko

    2006-01-01

    The role of ethylene (ET) in resistance to infection with blast fungus (Magnaporthe grisea) in rice (Oryza sativa) is poorly understood. To study it, we quantified ET levels after inoculation, using young rice plants at the four-leaf stage of rice cv Nipponbare (wild type) and its isogenic plant (IL7), which contains the Pi-i resistance gene to blast fungus race 003. Small necrotic lesions by hypersensitive reaction (HR) were formed at 42 to 72 h postinoculation (hpi) in resistant IL7 leaves, and whitish expanding lesions at 96 hpi in susceptible wild-type leaves. Notable was the enhanced ET emission at 48 hpi accompanied by increased 1-aminocyclopropane-1-carboxylic acid (ACC) levels and highly elevated ACC oxidase (ACO) activity in IL7 leaves, whereas only an enhanced ACC increase at 96 hpi in wild-type leaves. Among six ACC synthase (ACS) and seven ACO genes found in the rice genome, OsACS2 was transiently expressed at 48 hpi in IL7 and at 96 hpi in wild type, and OsACO7 was expressed at 48 hpi in IL7. Treatment with an inhibitor for ACS, aminooxyacetic acid, suppressed enhanced ET emission at 48 hpi in IL7, resulting in expanding lesions instead of HR lesions. Exogenously supplied ACC compromised the aminooxyacetic acid-induced breakdown of resistance in IL7, and treatment with 1-methylcyclopropene and silver thiosulfate, inhibitors of ET action, did not suppress resistance. These findings suggest the importance of ET biosynthesis and, consequently, the coproduct, cyanide, for HR-accompanied resistance to blast fungus in young rice plants and the contribution of induced OsACS2 and OsACO7 gene expression to it. PMID:17012402

  5. Global Gene Expression of Rice after Infections with Rice Blast and Sheath blight Pathogens

    USDA-ARS?s Scientific Manuscript database

    Rice (Oryza sativa) production worldwide has been challenged by increased new virulent pathogens. Over the years, genetic diversity needed for fighting diseases has been decreasing in cultivated rice around the globe. This presents a real challenge for rice crop protection. In an effort to develo...

  6. Antioxidative and Antimutagenic Activities of 70% Ethanolic Extracts from Four Fungal Mycelia-Fermented Specialty Rices

    PubMed Central

    Ra Yoon, Mi; Hyun Nam, Seok; Young Kang, Mi

    2008-01-01

    The health-promoting potential of 70% ethanolic extracts of 4 rice varieties fermented with Monascus ruber, Phellinus linteus, Cordyceps sinensis and Agaricus blazei was evaluated mainly focusing on their antioxidative and antimutagenic capacities based on the following parameters: phenolic compound and phytic acid content; inhibitory activity on lipid peroxidation; scavenging activity on DPPH radical; suppressing ability on mitomycin C-induced mutagenesis in E. coli cells; and protective effect on 4-nitroquinoline oxide-triggered DNA lesion in V79 hamster cells. The fermented rice extracts were superior in overall health-promoting parameters compared to the source material. The higher antimutagenic activity of the fermented rice extracts might be in part caused by a larger amount of antioxidant constituents such as phenolic compounds or phytic acid. Of the fungal species, Monascus ruber was found to impart a marked increase in both the antioxidative and antimutagenic abilities to the source material. The current study suggests a possibility that such fermented rice may contribute to the prevention of lifestyle-related diseases such as cancer through a daily intake of rice-based diets. PMID:18818745

  7. Secretome analysis of differentially induced proteins in rice suspension-cultured cells triggered by rice blast fungus and elicitor.

    PubMed

    Kim, Sun Tae; Kang, Young Hyun; Wang, Yiming; Wu, Jingni; Park, Zee Yong; Rakwal, Randeep; Agrawal, Ganesh Kumar; Lee, Sang Yeol; Kang, Kyu Young

    2009-03-01

    Secreted proteins were investigated in rice suspension-cultured cells treated with rice blast fungus Magnaporthe grisea and its elicitor using biochemical and 2-DE coupled with MS analyses followed by their in planta mRNA expression analysis. M. grisea and elicitor successfully interacted with suspension-cultured cells and prepared secreted proteins from these cultures were essentially intracellular proteins free. Comparative 2-D gel analyses identified 21 differential protein spots due to M. grisea and/or elicitor over control. MALDI-TOF-MS and microLC-ESI-MS/MS analyses of these protein spots revealed that most of assigned proteins were involved in defense such as nine chitinases, two germin A/oxalate oxidases, five domain unknown function 26 (DUF 26) secretory proteins, and beta-expansin. One chitin binding chitinase protein was isolated using chitin binding beads and strong enzymatic activity was identified in an in-gel assay. Interestingly, their protein abundance correlated well at transcript levels in elicitor-treated cultures as judged by semi-quantitative RT-PCR. Each identified differentially expressed protein group was compared at transcript levels in rice leaves inoculated with incompatible (KJ401) and compatible (KJ301) races of M. grisea. Time-course profiling revealed their inductions were stronger and earlier in incompatible than compatible interactions. Identified secreted proteins and their expression correlation at transcript level in suspension-cultured cells and also in planta suggest that suspension-cultured cells can be useful to investigate the secretome of rice blast-pathogen interactions.

  8. Understanding the co-evolution of the rice blast resistance gene Pi-ta and Magnaporthe oryzae avirulence gene AVR-Pita

    USDA-ARS?s Scientific Manuscript database

    Understanding the molecular basis of coevolutionary relationship between resistance genes in plants and the avirulence genes in the pathogen should benefit the development of methods to control plant diseases. Rice blast disease is one of the most damaging diseases worldwide. Rice blast disease has ...

  9. Allele Mining Strategies: Principles and Utilisation for Blast Resistance Genes in Rice (Oryza sativa L.).

    PubMed

    Ashkani, Sadegh; Yusop, Mohd Rafii; Shabanimofrad, Mahmoodreza; Azady, Amin; Ghasemzadeh, Ali; Azizi, Parisa; Latif, Mohammad Abdul

    2015-01-01

    Allele mining is a promising way to dissect naturally occurring allelic variants of candidate genes with essential agronomic qualities. With the identification, isolation and characterisation of blast resistance genes in rice, it is now possible to dissect the actual allelic variants of these genes within an array of rice cultivars via allele mining. Multiple alleles from the complex locus serve as a reservoir of variation to generate functional genes. The routine sequence exchange is one of the main mechanisms of R gene evolution and development. Allele mining for resistance genes can be an important method to identify additional resistance alleles and new haplotypes along with the development of allele-specific markers for use in marker-assisted selection. Allele mining can be visualised as a vital link between effective utilisation of genetic and genomic resources in genomics-driven modern plant breeding. This review studies the actual concepts and potential of mining approaches for the discovery of alleles and their utilisation for blast resistance genes in rice. The details provided here will be important to provide the rice breeder with a worthwhile introduction to allele mining and its methodology for breakthrough discovery of fresh alleles hidden in hereditary diversity, which is vital for crop improvement.

  10. [Genetic diversity of AVR-pita alleles of rice blast fungus Magnaporthe grisea].

    PubMed

    Ma, Bing Tian; Qu, Guang Lin; Shi, Jun; Chen, De Xi; Lin, Yu Fan; Huang, Wen Juan; Li, Shi Gui

    2008-12-01

    Rice blast, caused by fungus Magnaporthe grisea, is one of the most serious diseases of rice throughout the world and is also a classical system in which avirulence (AVR) genes in the pathogen show a functional correspondence with particular resistance (R) genes in rice. The interaction between AVR-pita gene in Magnaporthe grsiea and Pi-ta gene in rice is a classical gene-for-gene system. The genetic diversity of AVR-pita alleles was showed by 44 isolates from the fields in Sichuan and Chongqing. According to the published sequence of AVR-pita (GenBank Accession No. AF207841), the special primers were designed and a population analysis of AVR-pita occurrence in the field was conducted. The PCR negative isolates did not trigger host resistance responses and the disease might occur. The positive special PCR band in an isolate was not corresponding with its avirulence to the Pi-ta rice line. Among 11 sequenced A VR-pita alleles, six AVR-pita alleles encoded the same protein, four proteins differed from each other by one amino acid and one had nonsense mutation. The strategy of utilizing Pi-ta in rice breeding was also discussed.

  11. Glycogen Metabolic Genes Are Involved in Trehalose-6-Phosphate Synthase-Mediated Regulation of Pathogenicity by the Rice Blast Fungus Magnaporthe oryzae

    PubMed Central

    Wilson, Richard A.; Wang, Zheng-Yi; Kershaw, Michael J.; Talbot, Nicholas J.

    2013-01-01

    The filamentous fungus Magnaporthe oryzae is the causal agent of rice blast disease. Here we show that glycogen metabolic genes play an important role in plant infection by M. oryzae. Targeted deletion of AGL1 and GPH1, which encode amyloglucosidase and glycogen phosphorylase, respectively, prevented mobilisation of glycogen stores during appressorium development and caused a significant reduction in the ability of M. oryzae to cause rice blast disease. By contrast, targeted mutation of GSN1, which encodes glycogen synthase, significantly reduced the synthesis of intracellular glycogen, but had no effect on fungal pathogenicity. We found that loss of AGL1 and GPH1 led to a reduction in expression of TPS1 and TPS3, which encode components of the trehalose-6-phosphate synthase complex, that acts as a genetic switch in M. oryzae. Tps1 responds to glucose-6-phosphate levels and the balance of NADP/NADPH to regulate virulence-associated gene expression, in association with Nmr transcriptional inhibitors. We show that deletion of the NMR3 transcriptional inhibitor gene partially restores virulence to a Δagl1Δgph1 mutant, suggesting that glycogen metabolic genes are necessary for operation of the NADPH-dependent genetic switch in M. oryzae. PMID:24098112

  12. Glutamate synthase MoGlt1-mediated glutamate homeostasis is important for autophagy, virulence and conidiation in the rice blast fungus.

    PubMed

    Zhou, Wei; Shi, Wei; Xu, Xiao-Wen; Li, Zhi-Gang; Yin, Chang-Fa; Peng, Jun-Bo; Pan, Song; Chen, Xiao-Lin; Zhao, Wen-Sheng; Zhang, Yan; Yang, Jun; Peng, You-Liang

    2017-01-31

    Glutamate homeostasis plays vital roles in central nitrogen metabolism and coordinates several key metabolic functions. However, its functions in fungal pathogenesis and development have not been well investigated. In this study, we identified and characterized a glutamate synthase gene MoGLT1 in the rice blast fungus Magnaporthe oryzae that was important to glutamate homeostasis. MoGLT1 was constitutively expressed but had the highest expression level in appressoria. Deletion of MoGLT1 resulted in significant reductions in conidiation and virulence. The ΔMoglt1 mutants were defective in appressorial penetration and the differentiation and spreading of invasive hyphae in penetrated plant cells. Addition of exogenous glutamic acid partially rescued defects of the ΔMoglt1 mutants in conidiation and plant infection. Assays for MoAtg8 expression and localization showed that the ΔMoglt1 mutants were defective in autophagy. The ΔMoglt1 mutants were delayed in the mobilization of glycogens and lipid bodies from conidia to developing appressoria. Taken together, our results show that glutamate synthase MoGlt1-mediated glutamate homeostasis is important for pathogenesis and development in the rice blast fungus, possibly by regulating autophagy. This article is protected by copyright. All rights reserved.

  13. Isolation and evaluation of endophytic Streptomyces endus OsiSh-2 with potential application for biocontrol of rice blast disease.

    PubMed

    Xu, Ting; Li, Yan; Zeng, Xiadong; Yang, Xiaolu; Yang, Yuanzhu; Yuan, Shanshan; Hu, Xiaochun; Zeng, Jiarui; Wang, Zhenzhen; Liu, Qian; Liu, Yuqing; Liao, Hongdong; Tong, Chunyi; Liu, Xuanming; Zhu, Yonghua

    2017-03-01

    Biocontrol is a promising strategy in the control of rice blast disease. In the present study, we isolated and characterized a novel antagonist to the pathogen Magnaporthe oryzae from rice endophytic actinomycetes. Out of 482 endophytic actinomycetes isolated from rice blast infected and healthy rice, Streptomyces endus OsiSh-2 exhibited remarkable in vitro antagonistic activity. Scanning electron microscopy observations of M. oryzae treated by OsiSh-2 revealed significant morphological alterations in hyphae. In 2-year field tests, the spraying of OsiSh-2 spore solution (10(7)  spores mL(-1) ) is capable of reducing rice blast disease severity by 59.64%. In addition, a fermentation broth of OsiSh-2 and its cell-free filtrates could inhibit the growth of M. oryzae, suggesting the presence of active enzymes and secondary metabolites. OsiSh-2 tested positive for polyketide synthase-I and nonribosomal peptide synthetase genes and can produce cellulase, protease, gelatinase, siderophore, indole-3-acetic acid and 1-amino-cyclopropane-1-carboxylate deaminase. A preliminary separation indicated that the methanol extract of OsiSh-2 could suppress the growth of pathogens. The major active component was identified as nigericin. Endophytic S. endus OsiSh-2 has potential as a biocontrol agent against rice blast in agriculture. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  14. [Cloning and analyzing of rice blast resistance gene Pi-ta+ allele from Jinghong erect type of common wild rice (Oryza rufipogon Griff) in Yunnan].

    PubMed

    Geng, Xian-Sheng; Yang, Ming-Zhi; Huang, Xing-Qi; Cheng, Zai-Quan; Fu, Jian; Sun, Tao; Li, Jun

    2008-01-01

    A 4,672 bp DNA sequence including the whole coding region and partial non-coding region of rice blast resistance gene Pi-ta+ has been cloned from Jinghong erect type of common wild rice (Oryza rufipogon Griff) in Yunnan by polymerase chain reaction method. The coding region shares 99.86% and 98.78% identity with the corresponding regions of the reported cultivated rice Yashiro-mochi and Yuanjiang type of common wild rice respectively. There are 4 nucleotides difference in the coding region and 6 in intron of the cloned Pi-ta+ gene,compared with Pi-ta from Yashiro-mochi. Pi-ta+ gene in Jinghong erect type of common wild rice has been proved to be a rare existing Pi-ta+ allele, because there was a alanine rather than a serine at the position 918 within the predicted amino acid sequence of PITA. Pi-ta+ allele can cause disease resistance response to rice blast pathogens in plant cells. Differences in DNA sequence, deduced amino acid sequence and antibacterial spectrum may make the Pi-ta+ allele new resistant characteristics. Finding and cloning of Pi-ta+ allele from Jinghong erect type of common wild rice in Yunnan provides a basement for further utilization of the wild rice resources.

  15. A dsRNA mycovirus, Magnaporthe oryzae chrysovirus 1-B, suppresses vegetative growth and development of the rice blast fungus.

    PubMed

    Urayama, Syun-ichi; Sakoda, Hirofumi; Takai, Ryoko; Katoh, Yu; Minh Le, Tuong; Fukuhara, Toshiyuki; Arie, Tsutomu; Teraoka, Tohru; Moriyama, Hiromitsu

    2014-01-05

    A double-stranded RNA (dsRNA) mycovirus was found in isolate S-0412-II 2a of the rice blast fungus Magnaporthe oryzae. Sequence analysis of the five dsRNA segments (dsRNA1 through dsRNA5) revealed that this mycovirus is closely related to Magnaporthe oryzae chrysovirus 1-A (MoCV1-A), tentatively classified as a member of the Chrysoviridae; therefore, it was named Magnaporthe oryzae chrysovirus 1-B (MoCV1-B). Virus particles were spherical and composed of the ORF1, ORF3 and ORF4 proteins. MoCV1-B-infected isolate S-0412-II 2a showed a more severe impaired phenotype than the MoCV1-A-infected isolate. In a virus-cured isolate, normal growth was restored, implied that MoCV1-B could be involved in this observed phenotype. An unanticipated result was the occurrence of a fungal isolate lacking dsRNA5. The nonessential dsRNA5 had higher sequence identity (96%) with dsRNA5 of MoCV1-A than with the other dsRNA segments (71-79%), indicating that dsRNA5 could be a portable genomic element between MoCV1-A and MoCV1-B.

  16. An NADPH-dependent genetic switch regulates plant infection by the rice blast fungus.

    PubMed

    Wilson, Richard A; Gibson, Robert P; Quispe, Cristian F; Littlechild, Jennifer A; Talbot, Nicholas J

    2010-12-14

    To cause rice blast disease, the fungus Magnaporthe oryzae breaches the tough outer cuticle of the rice leaf by using specialized infection structures called appressoria. These cells allow the fungus to invade the host plant and proliferate rapidly within leaf tissue. Here, we show that a unique NADPH-dependent genetic switch regulates plant infection in response to the changing nutritional and redox conditions encountered by the pathogen. The biosynthetic enzyme trehalose-6-phosphate synthase (Tps1) integrates control of glucose-6-phosphate metabolism and nitrogen source utilization by regulating the oxidative pentose phosphate pathway, the generation of NADPH, and the activity of nitrate reductase. We report that Tps1 directly binds to NADPH and, thereby, regulates a set of related transcriptional corepressors, comprising three proteins, Nmr1, Nmr2, and Nmr3, which can each bind NADP. Targeted deletion of any of the Nmr-encoding genes partially suppresses the nonpathogenic phenotype of a Δtps1 mutant. Tps1-dependent Nmr corepressors control the expression of a set of virulence-associated genes that are derepressed during appressorium-mediated plant infection. When considered together, these results suggest that initiation of rice blast disease by M. oryzae requires a regulatory mechanism involving an NADPH sensor protein, Tps1, a set of NADP-dependent transcriptional corepressors, and the nonconsuming interconversion of NADPH and NADP acting as signal transducer.

  17. Marker-assisted introgression of broad-spectrum blast resistance genes into the cultivated MR219 rice variety.

    PubMed

    Miah, Gous; Rafii, Mohd Y; Ismail, Mohd R; Puteh, Adam B; Rahim, Harun A; Latif, Mohammad A

    2017-07-01

    The rice cultivar MR219 is famous for its better yield and long and fine grain quality; however, it is susceptible to blast disease. The main objective of this study was to introgress blast resistance genes into MR219 through marker-assisted selection (MAS). The rice cultivar MR219 was used as the recurrent parent, and Pongsu Seribu 1 was used as the donor. Marker-assisted foreground selection was performed using RM6836 and RM8225 to identify plants possessing blast resistance genes. Seventy microsatellite markers were used to estimate recurrent parent genome (RPG) recovery. Our analysis led to the development of 13 improved blast resistant lines with Piz, Pi2 and Pi9 broad-spectrum blast resistance genes and an MR219 genetic background. The RPG recovery of the selected improved lines was up to 97.70% with an average value of 95.98%. Selected improved lines showed a resistance response against the most virulent blast pathogen pathotype, P7.2. The selected improved lines did not express any negative effect on agronomic traits in comparison with MR219. The research findings of this study will be a conducive approach for the application of different molecular techniques that may result in accelerating the development of new disease-resistant rice varieties, which in turn will match rising demand and food security worldwide. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  18. Telomere-Targeted Retrotransposons in the Rice Blast Fungus Magnaporthe oryzae: Agents of Telomere Instability

    PubMed Central

    Starnes, John H.; Thornbury, David W.; Novikova, Olga S.; Rehmeyer, Cathryn J.; Farman, Mark L.

    2012-01-01

    The fungus Magnaporthe oryzae is a serious pathogen of rice and other grasses. Telomeric restriction fragments in Magnaporthe isolates that infect perennial ryegrass (prg) are hotspots for genomic rearrangement and undergo frequent, spontaneous alterations during fungal culture. The telomeres of rice-infecting isolates are very stable by comparison. Sequencing of chromosome ends from a number of prg-infecting isolates revealed two related non-LTR retrotransposons (M. oryzae Telomeric Retrotransposons or MoTeRs) inserted in the telomere repeats. This contrasts with rice pathogen telomeres that are uninterrupted by other sequences. Genetic evidence indicates that the MoTeR elements are responsible for the observed instability. MoTeRs represent a new family of telomere-targeted transposons whose members are found exclusively in fungi. PMID:22446319

  19. [Creation of Blast Disease-Resistant Rice Sorts with Modern DNA-Markers].

    PubMed

    Dubina, E V; Mukhina, Zh M; Kharitonov, E M; Shilovskiy, V N; Kharchenko, E S; Esaulova, L V; Korkina, N N; Maximenko, E P; Nikitina, I B

    2015-08-01

    Based on modern technologies of molecular DNA-markers, blast disease-resistance genes (Pi-ta, Pi-b, Pi-1, Pi-2, and Pi-33) were introgressed and pyramided into domestic rice varieties to give them long-term disease resistance. For that purpose, this case study uses SSR-markers closely linked to these genes, as well as intragenic markers of genes Pi-ta and Pi-b. Multiplex PCR systems were created for simultaneous identification of two resistance genes in the hybrid progeny for the following combinations: Pi-1 + Pi-2, Pi-ta + Pi-b, Pi-ta + Pi-33.

  20. WRKY76 is a rice transcriptional repressor playing opposite roles in blast disease resistance and cold stress tolerance.

    PubMed

    Yokotani, Naoki; Sato, Yuko; Tanabe, Shigeru; Chujo, Tetsuya; Shimizu, Takafumi; Okada, Kazunori; Yamane, Hisakazu; Shimono, Masaki; Sugano, Shoji; Takatsuji, Hiroshi; Kaku, Hisatoshi; Minami, Eiichi; Nishizawa, Yoko

    2013-11-01

    OsWRKY76 encodes a group IIa WRKY transcription factor of rice. The expression of OsWRKY76 was induced within 48h after inoculation with rice blast fungus (Magnaporthe oryzae), and by wounding, low temperature, benzothiadiazole, and abscisic acid. Green fluorescent protein-fused OsWRKY76 localized to the nuclei in rice epidermal cells. OsWRKY76 showed sequence-specific DNA binding to the W-box element in vitro and exhibited W-box-mediated transcriptional repressor activity in cultured rice cells. Overexpression of OsWRKY76 in rice plants resulted in drastically increased susceptibility to M. oryzae, but improved tolerance to cold stress. Microarray analysis revealed that overexpression of OsWRKY76 suppresses the induction of a specific set of PR genes and of genes involved in phytoalexin synthesis after inoculation with blast fungus, consistent with the observation that the levels of phytoalexins in the transgenic rice plants remained significantly lower than those in non-transformed control plants. Furthermore, overexpression of OsWRKY76 led to the increased expression of abiotic stress-associated genes such as peroxidase and lipid metabolism genes. These results strongly suggest that OsWRKY76 plays dual and opposing roles in blast disease resistance and cold tolerance.

  1. NBS-LRR Protein Pik-H4 Interacts with OsBIHD1 to Balance Rice Blast Resistance and Growth by Coordinating Ethylene-Brassinosteroid Pathway

    PubMed Central

    Liu, Hao; Dong, Shuangyu; Gu, Fengwei; Liu, Wei; Yang, Guili; Huang, Ming; Xiao, Wuming; Liu, Yongzhu; Guo, Tao; Wang, Hui; Chen, Zhiqiang; Wang, Jiafeng

    2017-01-01

    The regulation of innate immunity and plant growth, along with the trade-off between them, affects the defense and recovery mechanisms of the plant after it is attacked by pathogens. Although it is known that hormonal crosstalk plays a major role in regulating interaction of plant growth and PAMP-triggered immunity, the relationship between plant growth and effector-triggered immunity (ETI) remains unclear. In a large-scale yeast two-hybrid screening for Pik-H4-interacting proteins, a homeodomain transcription factor OsBIHD1 was identified, which is previously known to function in biotic and abiotic stress responses. The knockout of OsBIHD1 in rice lines carrying Pik-H4 largely compromised the resistance of the rice lines to Magnaporthe oryzae, the fungus that causes rice blast. While overexpression of OsBIHD1 resulted in enhanced expression of the pathogenesis-related (PR) and ethylene (ET) synthesis genes. Moreover, OsBIHD1 was also found to directly bind to the promoter region of ethylene-synthesis enzyme OsACO3. In addition, OsBIHD1 overexpression or deficiency provoked dwarfism and reduced brassinosteroid (BR) insensitivity through repressing the expression of several critical genes involved in BR biosynthesis and BR signaling. During M. oryzae infection, transcript levels of the crucial BR catabolic genes (CYP734A2, CYP734A4, and CYP734A6) were significantly up-regulated in OsBIHD1-OX plants. Furthermore, OsBIHD1 was found to be capable of binding to the sequence-specific cis-elements on the promoters of CYP734A2 to suppress the plant growth under fungal invasion. Our results collectively suggest a model that OsBIHD1 is required for Pik-H4-mediated blast resistance through modulating the trade-off between resistance and growth by coordinating brassinosteroid-ethylene pathway. PMID:28220140

  2. NBS-LRR Protein Pik-H4 Interacts with OsBIHD1 to Balance Rice Blast Resistance and Growth by Coordinating Ethylene-Brassinosteroid Pathway.

    PubMed

    Liu, Hao; Dong, Shuangyu; Gu, Fengwei; Liu, Wei; Yang, Guili; Huang, Ming; Xiao, Wuming; Liu, Yongzhu; Guo, Tao; Wang, Hui; Chen, Zhiqiang; Wang, Jiafeng

    2017-01-01

    The regulation of innate immunity and plant growth, along with the trade-off between them, affects the defense and recovery mechanisms of the plant after it is attacked by pathogens. Although it is known that hormonal crosstalk plays a major role in regulating interaction of plant growth and PAMP-triggered immunity, the relationship between plant growth and effector-triggered immunity (ETI) remains unclear. In a large-scale yeast two-hybrid screening for Pik-H4-interacting proteins, a homeodomain transcription factor OsBIHD1 was identified, which is previously known to function in biotic and abiotic stress responses. The knockout of OsBIHD1 in rice lines carrying Pik-H4 largely compromised the resistance of the rice lines to Magnaporthe oryzae, the fungus that causes rice blast. While overexpression of OsBIHD1 resulted in enhanced expression of the pathogenesis-related (PR) and ethylene (ET) synthesis genes. Moreover, OsBIHD1 was also found to directly bind to the promoter region of ethylene-synthesis enzyme OsACO3. In addition, OsBIHD1 overexpression or deficiency provoked dwarfism and reduced brassinosteroid (BR) insensitivity through repressing the expression of several critical genes involved in BR biosynthesis and BR signaling. During M. oryzae infection, transcript levels of the crucial BR catabolic genes (CYP734A2, CYP734A4, and CYP734A6) were significantly up-regulated in OsBIHD1-OX plants. Furthermore, OsBIHD1 was found to be capable of binding to the sequence-specific cis-elements on the promoters of CYP734A2 to suppress the plant growth under fungal invasion. Our results collectively suggest a model that OsBIHD1 is required for Pik-H4-mediated blast resistance through modulating the trade-off between resistance and growth by coordinating brassinosteroid-ethylene pathway.

  3. Two compounds from allelopathic rice accession and their inhibitory activity on weeds and fungal pathogens.

    PubMed

    Kong, Chuihua; Xu, Xiaohua; Zhou, Bin; Hu, Fei; Zhang, Chaoxian; Zhang, Maoxin

    2004-04-01

    A flavone (5,7,4'-trihydroxy-3',5'-dimethoxyflavone), a cyclohexenone (3-isopropyl-5-acetoxycyclohexene-2-one-1) and a liquid mixture of low polarity, containing long-chain and cyclic hydrocarbons, were isolated from leaves of allelopathic rice accession PI 312777 using column chromatography. Their structures and constituents were identified by means of HR-MS, NMR and GC/MS analyses, respectively. Bioassays showed that both the flavone and cyclohexenone significantly inhibited the growth of weeds Echinochloa crus-galli, Cyperus difformis and Cyperus iris, and the spore germination of fungal pathogens Pyricularia oryzae and Rhizoctonia solani at all tested concentrations. Moreover, the combination of the inactive mixture of low polarity and the active flavone or cyclohexenone significantly enhanced the inhibitory activities on weed growth. In addition, the two compounds and the mixture of low polarity from the leaves of PI312777 did not inhibit the rice growth at the same concentrations. It was also established that both compounds could be released into the soil, and was especially induced by E. crus-galli. The results suggest that 5,7,4'-trihydroxy-3',5'-dimethoxyflavone and 3-isopropyl- 5-acetoxycyclohexene-2-one-1 may act as allelochemicals participating in the defense of rice against weeds and pathogens.

  4. Unravelling the biosynthesis of pyriculol in the rice blast fungus Magnaporthe oryzae.

    PubMed

    Jacob, Stefan; Grötsch, Thomas; Foster, Andrew J; Schüffler, Anja; Rieger, Patrick H; Sandjo, Louis P; Liermann, Johannes C; Opatz, Till; Thines, Eckhard

    2017-04-01

    Pyriculol was isolated from the rice blast fungus Magnaporthe oryzae and found to induce lesion formation on rice leaves. These findings suggest that it could be involved in virulence. The gene MoPKS19 was identified to encode a polyketide synthase essential for the production of the polyketide pyriculol in the rice blast fungus M. oryzae. The transcript abundance of MoPKS19 correlates with the biosynthesis rate of pyriculol in a time-dependent manner. Furthermore, gene inactivation of MoPKS19 resulted in a mutant unable to produce pyriculol, pyriculariol and their dihydro derivatives. Inactivation of a putative oxidase-encoding gene MoC19OXR1, which was found to be located in the genome close to MoPKS19, resulted in a mutant exclusively producing dihydropyriculol and dihydropyriculariol. By contrast, overexpression of MoC19OXR1 resulted in a mutant strain only producing pyriculol. The MoPKS19 cluster, furthermore, comprises two transcription factors MoC19TRF1 and MoC19TRF2, which were both found individually to act as negative regulators repressing gene expression of MoPKS19. Additionally, extracts of ΔMopks19 and ΔMoC19oxr1 made from axenic cultures failed to induce lesions on rice leaves compared to extracts of the wild-type strain. Consequently, pyriculol and its isomer pyriculariol appear to be the only lesion-inducing secondary metabolites produced by M. oryzae wild-type (MoWT) under these culture conditions. Interestingly, the mutants unable to produce pyriculol and pyriculariol were as pathogenic as MoWT, demonstrating that pyriculol is not required for infection.

  5. Osa-miR169 Negatively Regulates Rice Immunity against the Blast Fungus Magnaporthe oryzae

    PubMed Central

    Li, Yan; Zhao, Sheng-Li; Li, Jin-Lu; Hu, Xiao-Hong; Wang, He; Cao, Xiao-Long; Xu, Yong-Ju; Zhao, Zhi-Xue; Xiao, Zhi-Yuan; Yang, Nan; Fan, Jing; Huang, Fu; Wang, Wen-Ming

    2017-01-01

    miR169 is a conserved microRNA (miRNA) family involved in plant development and stress-induced responses. However, how miR169 functions in rice immunity remains unclear. Here, we show that miR169 acts as a negative regulator in rice immunity against the blast fungus Magnaporthe oryzae by repressing the expression of nuclear factor Y-A (NF-YA) genes. The accumulation of miR169 was significantly increased in a susceptible accession but slightly fluctuated in a resistant accession upon M. oryzae infection. Consistently, the transgenic lines overexpressing miR169a became hyper-susceptible to different M. oryzae strains associated with reduced expression of defense-related genes and lack of hydrogen peroxide accumulation at the infection site. Consequently, the expression of its target genes, the NF-YA family members, was down-regulated by the overexpression of miR169a at either transcriptional or translational level. On the contrary, overexpression of a target mimicry that acts as a sponge to trap miR169a led to enhanced resistance to M. oryzae. In addition, three of miR169’s target genes were also differentially up-regulated in the resistant accession upon M. oryzae infection. Taken together, our data indicate that miR169 negatively regulates rice immunity against M. oryzae by differentially repressing its target genes and provide the potential to engineer rice blast resistance via a miRNA. PMID:28144248

  6. An S-(Hydroxymethyl)Glutathione Dehydrogenase Is Involved in Conidiation and Full Virulence in the Rice Blast Fungus Magnaporthe oryzae

    PubMed Central

    Zhang, Zhen; Wang, Jiaoyu; Chai, Rongyao; Qiu, Haiping; Jiang, Hua; Mao, Xueqin; Wang, Yanli; Liu, Fengquan; Sun, Guochang

    2015-01-01

    Magnaporthe oryzae is a hemibiotrophic fungal pathogen that causes rice blast disease. A compatible interaction requires overcoming plant defense responses to initiate colonization during the early infection process. Nitric oxide (NO) plays important roles in defense responses during host-pathogen interactions. Microbes generally protect themselves against NO-induced damage by using enzymes. Here, we characterized an S-(hydroxymethyl)- glutathione dehydrogenase gene in M. oryzae, MoSFA1, the homologs of which are involved in NO metabolism by specifically catalyzing the reduction of S-nitrosoglutathione (GSNO) in yeasts and plants. As expected from the activities of S-(hydroxymethyl)glutathione dehydrogenase in formaldehyde detoxification and GSNO reduction, MoSFA1 deletion mutants were lethal in formaldehyde containing medium, sensitive to exogenous NO and exhibited a higher level of S-nitrosothiols (SNOs) than that of the wild type. Notably, the mutants showed severe reduction of conidiation and appressoria turgor pressure, as well as significantly attenuated the virulence on rice cultivar CO-39. However, the virulence of MoSFA1 deletion mutants on wounded rice leaf was not affected. An infection assay on barley leaf further revealed that MoSFA1 deletion mutants exhibited a lower infection rate, and growth of infectious hyphae of the mutants was retarded not only in primary infected cells but also in expansion from cell to cell. Furthermore, barley leaf cell infected by MoSFA1 deletion mutants exhibited a stronger accumulation of H2O2 at 24 and 36 hpi. MoSFA1 deletion mutants displayed hypersensitivity to different oxidants, reduced activities of superoxide dismutases and peroxidases, and lower glutathione content in cells, compared with the wild type. These results imply that MoSFA1-mediated NO metabolism is important in redox homeostasis in response to development and host infection of M. oryzae. Taken together, this work identifies that MoSFA1 is required for

  7. An S-(hydroxymethyl)glutathione dehydrogenase is involved in conidiation and full virulence in the rice blast fungus Magnaporthe oryzae.

    PubMed

    Zhang, Zhen; Wang, Jiaoyu; Chai, Rongyao; Qiu, Haiping; Jiang, Hua; Mao, Xueqin; Wang, Yanli; Liu, Fengquan; Sun, Guochang

    2015-01-01

    Magnaporthe oryzae is a hemibiotrophic fungal pathogen that causes rice blast disease. A compatible interaction requires overcoming plant defense responses to initiate colonization during the early infection process. Nitric oxide (NO) plays important roles in defense responses during host-pathogen interactions. Microbes generally protect themselves against NO-induced damage by using enzymes. Here, we characterized an S-(hydroxymethyl)-glutathione dehydrogenase gene in M. oryzae, MoSFA1, the homologs of which are involved in NO metabolism by specifically catalyzing the reduction of S-nitrosoglutathione (GSNO) in yeasts and plants. As expected from the activities of S-(hydroxymethyl)glutathione dehydrogenase in formaldehyde detoxification and GSNO reduction, MoSFA1 deletion mutants were lethal in formaldehyde containing medium, sensitive to exogenous NO and exhibited a higher level of S-nitrosothiols (SNOs) than that of the wild type. Notably, the mutants showed severe reduction of conidiation and appressoria turgor pressure, as well as significantly attenuated the virulence on rice cultivar CO-39. However, the virulence of MoSFA1 deletion mutants on wounded rice leaf was not affected. An infection assay on barley leaf further revealed that MoSFA1 deletion mutants exhibited a lower infection rate, and growth of infectious hyphae of the mutants was retarded not only in primary infected cells but also in expansion from cell to cell. Furthermore, barley leaf cell infected by MoSFA1 deletion mutants exhibited a stronger accumulation of H2O2 at 24 and 36 hpi. MoSFA1 deletion mutants displayed hypersensitivity to different oxidants, reduced activities of superoxide dismutases and peroxidases, and lower glutathione content in cells, compared with the wild type. These results imply that MoSFA1-mediated NO metabolism is important in redox homeostasis in response to development and host infection of M. oryzae. Taken together, this work identifies that MoSFA1 is required for

  8. Systematic Analysis of Zn2Cys6 Transcription Factors Required for Development and Pathogenicity by High-Throughput Gene Knockout in the Rice Blast Fungus

    PubMed Central

    Huang, Pengyun; Lin, Fucheng

    2014-01-01

    Because of great challenges and workload in deleting genes on a large scale, the functions of most genes in pathogenic fungi are still unclear. In this study, we developed a high-throughput gene knockout system using a novel yeast-Escherichia-Agrobacterium shuttle vector, pKO1B, in the rice blast fungus Magnaporthe oryzae. Using this method, we deleted 104 fungal-specific Zn2Cys6 transcription factor (TF) genes in M. oryzae. We then analyzed the phenotypes of these mutants with regard to growth, asexual and infection-related development, pathogenesis, and 9 abiotic stresses. The resulting data provide new insights into how this rice pathogen of global significance regulates important traits in the infection cycle through Zn2Cys6TF genes. A large variation in biological functions of Zn2Cys6TF genes was observed under the conditions tested. Sixty-one of 104 Zn2Cys6 TF genes were found to be required for fungal development. In-depth analysis of TF genes revealed that TF genes involved in pathogenicity frequently tend to function in multiple development stages, and disclosed many highly conserved but unidentified functional TF genes of importance in the fungal kingdom. We further found that the virulence-required TF genes GPF1 and CNF2 have similar regulation mechanisms in the gene expression involved in pathogenicity. These experimental validations clearly demonstrated the value of a high-throughput gene knockout system in understanding the biological functions of genes on a genome scale in fungi, and provided a solid foundation for elucidating the gene expression network that regulates the development and pathogenicity of M. oryzae. PMID:25299517

  9. Karyotypic Variation within Clonal Lineages of the Rice Blast Fungus, Magnaporthe grisea

    PubMed Central

    Talbot, Nicholas J.; Salch, Yangkyo P.; Ma, Margery; Hamer, John E.

    1993-01-01

    We have analyzed the karyotype of the rice blast fungus, Magnaporthe grisea, by using pulsed-filed gel electrophoresis. We tested whether the electrophoretic karyotype of an isolate was related to its pathotype, as determined by infection assays, or its genetic lineage, as determined by DNA fingerprinting. Highly reproducible electrophoretic karyotypes were obtained for a collection of U.S. and Chinese isolates representing a diverse collection of pathotypes and genetic lineages. Chromosomes ranged in size from 3 to 10 Mb. Although chromosome number was largely invariant, chromosome length polymorphisms were frequent. Minichromosomes were also found, although their presence was not ubiquitous. They ranged in number from 1 to 3 and in size from 470 kb to 2.2 Mb. Karyotypes were sufficiently variable as to obscure the obvious relatedness of isolates on the basis of pathogenicity assays or genetic lineage analysis by DNA fingerprinting. We documented that the electrophoretic karyotype of an isolate can change after prolonged serial transfer in culture and that this change did not alter the isolate's pathotype. The mechanisms bringing about karyotype variability involve deletions, translocations, and more complex rearrangements. We conclude that karyotypic variability in the rice blast fungus is a reflection of the lack of sexuality in wild populations which leads to the maintenance of neutral genomic rearrangements in clones of the fungus. Images PMID:16348876

  10. Constitutive expression of McCHIT1-PAT enhances resistance to rice blast and herbicide, but does not affect grain yield in transgenic glutinous rice.

    PubMed

    Zeng, Xiao-Fang; Li, Lei; Li, Jian-Rong; Zhao, De-Gang

    2016-01-01

    To produce new rice blast- and herbicide-resistant transgenic rice lines, the McCHIT1 gene encoding the class I chitinase from Momordica charantia and the herbicide resistance gene PAT were introduced into Lailong (Oryza sativa L. ssp. Japonica), a glutinous local rice variety from Guizhou Province, People's Republic of China. Transgenic lines were identified by ß-glucuronidase (GUS) histochemical staining, PCR, and Southern blot analyses. Agronomic traits, resistance to rice blast and herbicide, chitinase activities, and transcript levels of McCHIT1 were assessed in the T2 progeny of three transgenic lines (L1, L8, and L10). The results showed that the introduction of McCHIT1-PAT into Lailong significantly enhanced herbicide and blast resistance. After infection with the blast fungus Magnaporthe oryzae, all of the T2 progeny exhibited less severe lesion symptoms than those of wild type. The disease indices were 100% for wild type, 65.66% for T2 transgenic line L1, 59.69% for T2 transgenic line L8, and 79.80% for T2 transgenic line L10. Transgenic lines expressing McCHIT1-PAT did not show a significant difference from wild type in terms of malondialdehyde (MDA) content, polyphenol oxidase (PPO) activity, and superoxide dismutase (SOD) activity in the leaves. However, after inoculation with M. oryzae, transgenic plants showed significantly higher SOD and PPO activities and lower MDA contents in leaves, compared with those in wild-type leaves. The transgenic and the wild-type plants did not show significant differences in grain yield parameters including plant height, panicles per plant, seeds per panicle, and 1000-grain weight. Therefore, the transgenic plants showed increased herbicide and blast resistance, with no yield penalty.

  11. Association between molecular markers and blast resistance in an advanced backcross population of rice.

    PubMed

    Wu, J-L; Sinha, P K; Variar, M; Zheng, K-L; Leach, J E; Courtois, B; Leung, H

    2004-04-01

    An advanced backcross population consisting of 80 BC(3)F(3) lines derived from rice vars. Vandana/ Moroberekan was analysed for blast resistance and genotyped with 50 candidate genes and 23 simple sequence repeat (SSR) markers. Six candidate defence response genes [thaumatin, three nucleotide-binding site-leucine-rich repeat sequences from maize and two resistance gene analogue (RGA) markers] and one SSR marker (RM21) were significantly associated with partial blast resistance in rice ( P=0.01). These markers accounted for phenotypic variation ranging from 9.6% to 29.4% and contributed to 76% of the total variation of percentage diseased leaf area (DLA) observed under natural infection. Four candidate genes (oxalate oxidase, 14-3-3 protein and two RGA markers) and four SSR markers (RM21, RM168, RM215 and RM250) were significantly associated with resistance to a single pathogen isolate, PO6-6. Among these, two markers were for DLA, five for lesion number and one for lesion size. These markers accounted for 9.1-28.7% of the phenotypic variation. A moderate correlation ( r=0.48, P<0.01) was found between the level of partial resistance measured in the greenhouse and that measured under natural conditions. Analysis of BC(3)F(4) progeny using genotypes of BC(3)F(3) confirmed the phenotypic contribution of these markers. Cluster analysis of DNA profiles showed that the BC(3) population was genetically similar (>85%) to the recurrent parent Vandana. Although no obvious relationship between DNA profiles and resistant phenotypes was observed, three lines (VM19, VM46 and VM76) in a cluster with high similarity to Vandana (89-96%) expressed a high level of partial blast resistance in the field. Analysis of disease progress in the field confirmed the performance of selected lines based on greenhouse and nursery analyses. The advanced backcross progeny with resistance phenotypes tagged by markers will be useful for accumulating blast resistance in upland rice.

  12. Stunted Growth Caused by Blast Disease in Rice Seedlings Is Associated with Changes in Phytohormone Signaling Pathways.

    PubMed

    Jiang, Chang-Jie; Liu, Xiao-Long; Liu, Xin-Qiong; Zhang, Hui; Yu, Ying-Jie; Liang, Zheng-Wei

    2017-01-01

    In response to pathogen attack, plants prioritize defense reactions generally at the expense of plant growth. In this work, we report that changes in phytohormone signaling pathways are associated with the stunted plant growth caused by blast disease in rice seedlings. Infection of rice seedlings with blast fungus Magnaporthe oryzae (race 007.0) at the four-leaf stage (three true leaves) resulted in considerable inhibition of the growth of the upper uninfected distal leaves; the length of leaf blade and leaf sheath of the sixth and seventh leaf was reduced by 27 and 82%, and 88 and 72%, respectively, compared to that in the uninoculated plant control. Interestingly, cutting off the blast-infected fourth leaf blade within 2 days post inoculation (dpi) significantly rescued the inhibition of leaf growth, implying that an inhibitory substance(s) and/or signal was generated in the blast-infected leaves (fourth leaf) and transmitted to the upper distal leaves (sixth and seventh) during the 2-dpi period that induced growth inhibition. Expression analysis of marker genes for phytohormone pathways revealed acute activation of the jasmonate (JA) and abscisic acid (ABA) signaling pathways, and repression of auxin, gibberellic acid (GA) and salicylic acid (SA) signaling pathways, in the sixth leaf. The genes related to cell wall expansion were also significantly downregulated. In the blast-infected fourth leaf, JA pathway was activated within 2 dpi, followed by activation of ABA pathway 3 dpi. Further, leaf inhibition caused by blast infection was partially rescued in the rice mutant line coleoptile photomorphogenesis 2 (cpm2), which is defective in the gene encoding allene oxide cyclase (OsAOC). These results indicate that the JA signaling pathway is at least partly involved in the growth inhibition processes. Collectively, our data suggest that, upon pathogen attack, rice seedlings prioritize defense reactions against the infecting pathogen by temporarily ceasing plant

  13. Characterization of rice blast resistance genes in rice germplasm with monogenic lines and pathogenicity assays

    USDA-ARS?s Scientific Manuscript database

    Resistance (R) genes have been effectively deployed in preventing rice crop losses due to the fungus Magnaporthe oryzae. In the present study, we studied the interaction between 24 monogenic lines carrying at least one major R gene, Pia, Pib, Pii, Pik, Pik-h, Pik-m, Pik-p, Pik-s, Pish, Pit, Pita, Pi...

  14. A rice fungal MAMP-responsive MAPK cascade regulates metabolic flow to antimicrobial metabolite synthesis

    PubMed Central

    Kishi-Kaboshi, Mitsuko; Okada, Kazunori; Kurimoto, Leona; Murakami, Shinya; Umezawa, Toshiaki; Shibuya, Naoto; Yamane, Hisakazu; Miyao, Akio; Takatsuji, Hiroshi; Takahashi, Akira; Hirochika, Hirohiko

    2010-01-01

    Plants recognize potential microbial pathogens through microbial-associated molecular patterns (MAMPs) and activate a series of defense responses, including cell death and the production of reactive oxygen species (ROS) and diverse anti-microbial secondary metabolites. Mitogen-activated protein kinase (MAPK) cascades are known to play a pivotal role in mediating MAMP signals; however, the signaling pathway from a MAPK cascade to the activation of defense responses is poorly understood. Here, we found in rice that the chitin elicitor, a fungal MAMP, activates two rice MAPKs (OsMPK3 and OsMPK6) and one MAPK kinase (OsMKK4). OsMPK6 was essential for the chitin elicitor-induced biosynthesis of diterpenoid phytoalexins. Conditional expression of the active form of OsMKK4 (OsMKK4DD) induced extensive alterations in gene expression, which implied dynamic changes of metabolic flow from glycolysis to secondary metabolite biosynthesis while suppressing basic cellular activities such as translation and cell division. OsMKK4DD also induced various defense responses, such as cell death, biosynthesis of diterpenoid phytoalexins and lignin but not generation of extracellular ROS. OsMKK4DD-induced cell death and expression of diterpenoid phytoalexin pathway genes, but not that of phenylpropanoid pathway genes, were dependent on OsMPK6. Collectively, the OsMKK4–OsMPK6 cascade plays a crucial role in reprogramming plant metabolism during MAMP-triggered defense responses. PMID:20525005

  15. A Review of Microsatellite Markers and Their Applications in Rice Breeding Programs to Improve Blast Disease Resistance

    PubMed Central

    Miah, Gous; Rafii, Mohd Y.; Ismail, Mohd R.; Puteh, Adam B.; Rahim, Harun A.; Islam, Kh. Nurul; Latif, Mohammad Abdul

    2013-01-01

    Over the last few decades, the use of molecular markers has played an increasing role in rice breeding and genetics. Of the different types of molecular markers, microsatellites have been utilized most extensively, because they can be readily amplified by PCR and the large amount of allelic variation at each locus. Microsatellites are also known as simple sequence repeats (SSR), and they are typically composed of 1–6 nucleotide repeats. These markers are abundant, distributed throughout the genome and are highly polymorphic compared with other genetic markers, as well as being species-specific and co-dominant. For these reasons, they have become increasingly important genetic markers in rice breeding programs. The evolution of new biotypes of pests and diseases as well as the pressures of climate change pose serious challenges to rice breeders, who would like to increase rice production by introducing resistance to multiple biotic and abiotic stresses. Recent advances in rice genomics have now made it possible to identify and map a number of genes through linkage to existing DNA markers. Among the more noteworthy examples of genes that have been tightly linked to molecular markers in rice are those that confer resistance or tolerance to blast. Therefore, in combination with conventional breeding approaches, marker-assisted selection (MAS) can be used to monitor the presence or lack of these genes in breeding populations. For example, marker-assisted backcross breeding has been used to integrate important genes with significant biological effects into a number of commonly grown rice varieties. The use of cost-effective, finely mapped microsatellite markers and MAS strategies should provide opportunities for breeders to develop high-yield, blast resistance rice cultivars. The aim of this review is to summarize the current knowledge concerning the linkage of microsatellite markers to rice blast resistance genes, as well as to explore the use of MAS in rice breeding

  16. Homeobox Transcription Factors Are Required for Conidiation and Appressorium Development in the Rice Blast Fungus Magnaporthe oryzae

    PubMed Central

    Kim, Seryun; Park, Sook-Young; Kim, Kyoung Su; Rho, Hee-Sool; Chi, Myoung-Hwan; Choi, Jaehyuk; Park, Jongsun; Kong, Sunghyung; Park, Jaejin; Goh, Jaeduk; Lee, Yong-Hwan

    2009-01-01

    The appropriate development of conidia and appressoria is critical in the disease cycle of many fungal pathogens, including Magnaporthe oryzae. A total of eight genes (MoHOX1 to MoHOX8) encoding putative homeobox transcription factors (TFs) were identified from the M. oryzae genome. Knockout mutants for each MoHOX gene were obtained via homology-dependent gene replacement. Two mutants, ΔMohox3 and ΔMohox5, exhibited no difference to wild-type in growth, conidiation, conidium size, conidial germination, appressorium formation, and pathogenicity. However, the ΔMohox1 showed a dramatic reduction in hyphal growth and increase in melanin pigmentation, compared to those in wild-type. ΔMohox4 and ΔMohox6 showed significantly reduced conidium size and hyphal growth, respectively. ΔMohox8 formed normal appressoria, but failed in pathogenicity, probably due to defects in the development of penetration peg and invasive growth. It is most notable that asexual reproduction was completely abolished in ΔMohox2, in which no conidia formed. ΔMohox2 was still pathogenic through hypha-driven appressoria in a manner similar to that of the wild-type. However, ΔMohox7 was unable to form appressoria either on conidial germ tubes, or at hyphal tips, being non-pathogenic. These factors indicate that M. oryzae is able to cause foliar disease via hyphal appressorium-mediated penetration, and MoHOX7 is mutually required to drive appressorium formation from hyphae and germ tubes. Transcriptional analyses suggest that the functioning of M. oryzae homeobox TFs is mediated through the regulation of gene expression and is affected by cAMP and Ca2+ signaling and/or MAPK pathways. The divergent roles of this gene set may help reveal how the genome and regulatory pathways evolved within the rice blast pathogen and close relatives. PMID:19997500

  17. Structure-function analyses of the Pth11 receptor reveal an important role for CFEM motif and redox regulation in rice blast.

    PubMed

    Kou, Yanjun; Tan, Yi Han; Ramanujam, Ravikrishna; Naqvi, Naweed I

    2017-04-01

    The interaction of Magnaporthe oryzae, the rice blast fungus, and rice begins when M. oryzae establishes contact with the host plant surface. On perception of appropriate surface signals, M. oryzae forms appressoria and initiates host invasion. Pth11, an important G-protein-coupled receptor necessary for appressorium formation in M. oryzae, contains seven transmembrane regions and a CFEM (common in several fungal extracellular membrane proteins) domain with the characteristic eight cysteine residues. We focused on gaining further insight into the role of the CFEM domain in the putative surface sensing/response function of Pth11. Increased/constitutive expression of CFEM resulted in precocious, albeit defective, appressoria formation in wild-type M. oryzae. The Pth11(C63A/C65A) mutant, probably with disrupted disulfide bonds in the CFEM, showed delayed appressorium formation and reduced virulence. Furthermore, the accumulation of reactive oxygen species (ROS) was found to be altered in the pth11Δ strain. Strikingly, antioxidant treatment induced appressorium formation in pth11Δ. The Gα subunit MagB and the mitogen-activated protein (MAP) kinase Pmk1 were required for the formation of antioxidant-induced appressoria. We conclude that the CFEM domain of Pth11 is required for proper development of the appressoria, appressoria-like structures and pathogenicity. Highly regulated ROS homeostasis is important for Pth11-mediated appressorium formation in M. oryzae.

  18. Structure-function analysis of a CVNH-LysM lectin expressed during plant infection by the rice blast fungus Magnaporthe oryzae.

    PubMed

    Koharudin, Leonardus M I; Viscomi, Arturo R; Montanini, Barbara; Kershaw, Michael J; Talbot, Nicholas J; Ottonello, Simone; Gronenborn, Angela M

    2011-05-11

    The rice blast fungus Magnaporthe oryzae's genome encodes a hypothetical protein (MGG_03307) containing a type III CVNH lectin, in which a LysM domain is inserted between individual repeats of a single CVNH domain. At present, no structural or ligand binding data are available for any type III CVNH and functional studies in natural source organisms are scarce. Here, we report NMR solution structure and functional data on MGG_03307. The structure of the CVNH/LysM module revealed that intact and functionally competent CVNH and LysM domains are present. Using NMR titrations, carbohydrate specificities for both domains were determined, and it was found that each domain behaves as an isolated unit without any interdomain communication. Furthermore, live-cell imaging revealed a predominant localization of MGG_03307 within the appressorium, the specialized fungal cell for gaining entry into rice tissue. Our results suggest that MGG_03307 plays a role in the early stages of plant infection. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. Structure-function analysis of a CVNH-LysM lectin expressed during plant infection by the rice blast fungus Magnaporthe oryzae

    PubMed Central

    Koharudin, Leonardus M.I.; Viscomi, Arturo R.; Montanini, Barbara; Kershaw, Michael J.; Talbot, Nicholas J.; Ottonello, Simone; Gronenborn, Angela M.

    2011-01-01

    Summary The rice blast fungus Magnaporthe oryzae’s genome encodes a hypothetical protein (MGG_03307) containing a type III CVNH lectin, in which a LysM domain is inserted between individual repeats of a single CVNH domain. At present, no structural or ligand binding data is available for any type III CVNH and functional studies in natural source organisms are scarce. Here, we report NMR solution structure and functional data on MGG_03307. The structure of the CVNH/LysM module revealed that intact and functionally competent CVNH and LysM domains are present. Using NMR titrations, carbohydrate specificities for both domains were determined, and it was found that each domain behaves as an isolated unit without any inter-domain communication. Furthermore, live-cell imaging revealed a predominant localization of MGG_03307 within the appressorium, the specialized fungal cell for gaining entry into rice tissue. Our results suggest that MGG_03307 plays a role in the early stages of plant infection. PMID:21565701

  20. Optimization of the HyPer sensor for robust real-time detection of hydrogen peroxide in the rice blast fungus.

    PubMed

    Huang, Kun; Caplan, Jeff; Sweigard, James A; Czymmek, Kirk J; Donofrio, Nicole M

    2017-02-01

    Reactive oxygen species (ROS) production and breakdown have been studied in detail in plant-pathogenic fungi, including the rice blast fungus, Magnaporthe oryzae; however, the examination of the dynamic process of ROS production in real time has proven to be challenging. We resynthesized an existing ROS sensor, called HyPer, to exhibit optimized codon bias for fungi, specifically Neurospora crassa, and used a combination of microscopy and plate reader assays to determine whether this construct could detect changes in fungal ROS during the plant infection process. Using confocal microscopy, we were able to visualize fluctuating ROS levels during the formation of an appressorium on an artificial hydrophobic surface, as well as during infection on host leaves. Using the plate reader, we were able to ascertain measurements of hydrogen peroxide (H2 O2 ) levels in conidia as detected by the MoHyPer sensor. Overall, by the optimization of codon usage for N. crassa and related fungal genomes, the MoHyPer sensor can be used as a robust, dynamic and powerful tool to both monitor and quantify H2 O2 dynamics in real time during important stages of the plant infection process.

  1. Tpc1 is an important Zn(II)2Cys6 transcriptional regulator required for polarized growth and virulence in the rice blast fungus.

    PubMed

    Galhano, Rita; Illana, Adriana; Ryder, Lauren S; Rodríguez-Romero, Julio; Demuez, Marie; Badaruddin, Muhammad; Martinez-Rocha, Ana Lilia; Soanes, Darren M; Studholme, David J; Talbot, Nicholas J; Sesma, Ane

    2017-07-01

    The establishment of polarity is a critical process in pathogenic fungi, mediating infection-related morphogenesis and host tissue invasion. Here, we report the identification of TPC1 (Transcription factor for Polarity Control 1), which regulates invasive polarized growth in the rice blast fungus Magnaporthe oryzae. TPC1 encodes a putative transcription factor of the fungal Zn(II)2Cys6 family, exclusive to filamentous fungi. Tpc1-deficient mutants show severe defects in conidiogenesis, infection-associated autophagy, glycogen and lipid metabolism, and plant tissue colonisation. By tracking actin-binding proteins, septin-5 and autophagosome components, we show that Tpc1 regulates cytoskeletal dynamics and infection-associated autophagy during appressorium-mediated plant penetration. We found that Tpc1 interacts with Mst12 and modulates its DNA-binding activity, while Tpc1 nuclear localisation also depends on the MAP kinase Pmk1, consistent with the involvement of Tpc1 in this signalling pathway, which is critical for appressorium development. Importantly, Tpc1 directly regulates NOXD expression, the p22phox subunit of the fungal NADPH oxidase complex via an interaction with Mst12. Tpc1 therefore controls spatial and temporal regulation of cortical F-actin through regulation of the NADPH oxidase complex during appressorium re-polarisation. Consequently, Tpc1 is a core developmental regulator in filamentous fungi, linking the regulated synthesis of reactive oxygen species and the Pmk1 pathway, with polarity control during host invasion.

  2. Tpc1 is an important Zn(II)2Cys6 transcriptional regulator required for polarized growth and virulence in the rice blast fungus

    PubMed Central

    Ryder, Lauren S.; Rodríguez-Romero, Julio; Badaruddin, Muhammad; Martinez-Rocha, Ana Lilia; Soanes, Darren M.; Studholme, David J.; Talbot, Nicholas J.

    2017-01-01

    The establishment of polarity is a critical process in pathogenic fungi, mediating infection-related morphogenesis and host tissue invasion. Here, we report the identification of TPC1 (Transcription factor for Polarity Control 1), which regulates invasive polarized growth in the rice blast fungus Magnaporthe oryzae. TPC1 encodes a putative transcription factor of the fungal Zn(II)2Cys6 family, exclusive to filamentous fungi. Tpc1-deficient mutants show severe defects in conidiogenesis, infection-associated autophagy, glycogen and lipid metabolism, and plant tissue colonisation. By tracking actin-binding proteins, septin-5 and autophagosome components, we show that Tpc1 regulates cytoskeletal dynamics and infection-associated autophagy during appressorium-mediated plant penetration. We found that Tpc1 interacts with Mst12 and modulates its DNA-binding activity, while Tpc1 nuclear localisation also depends on the MAP kinase Pmk1, consistent with the involvement of Tpc1 in this signalling pathway, which is critical for appressorium development. Importantly, Tpc1 directly regulates NOXD expression, the p22phox subunit of the fungal NADPH oxidase complex via an interaction with Mst12. Tpc1 therefore controls spatial and temporal regulation of cortical F-actin through regulation of the NADPH oxidase complex during appressorium re-polarisation. Consequently, Tpc1 is a core developmental regulator in filamentous fungi, linking the regulated synthesis of reactive oxygen species and the Pmk1 pathway, with polarity control during host invasion. PMID:28742127

  3. One of Three Pex11 Family Members Is Required for Peroxisomal Proliferation and Full Virulence of the Rice Blast Fungus Magnaporthe oryzae

    PubMed Central

    Wang, Jiaoyu; Li, Ling; Zhang, Zhen; Qiu, Haiping; Li, Dongmei; Fang, Yuan; Jiang, Hua; Chai, Rong Yao; Mao, Xueqin; Wang, Yanli; Sun, Guochang

    2015-01-01

    Peroxisomes play important roles in metabolisms of eukaryotes and infection of plant fungal pathogens. These organelles proliferate by de novo formation or division in response to environmental stimulation. Although the assembly of peroxisomes was documented in fungal pathogens, their division and its relationship to pathogenicity remain obscure. In present work, we analyzed the roles of three Pex11 family members in peroxisomal division and pathogenicity of the rice blast fungus Magnaporthe oryzae. Deletion of MoPEX11A led to fewer but enlarged peroxisomes, and impaired the separation of Woronin bodies from peroxisomes, while deletion of MoPEX11B or MoPEX11C put no evident impacts to peroxisomal profiles. MoPEX11A mutant exhibited typical peroxisome related defects, delayed conidial germination and appressoria formation, and decreased appressorial turgor and host penetration. As a result, the virulence of MoPEX11A mutant was greatly reduced. Deletion of MoPEX11B and MoPEX11C did not alter the virulence of the fungus. Further, double or triple deletions of the three genes were unable to enhance the virulence decrease in MoPEX11A mutant. Our data indicated that MoPEX11A is the main factor modulating peroxisomal division and is required for full virulence of the fungus. PMID:26218097

  4. Analysis of simple sequence repeat markers linked with blast disease resistance genes in a segregating population of rice (Oryza sativa).

    PubMed

    Ashkani, S; Rafii, M Y; Sariah, M; Siti Nor Akmar, A; Rusli, I; Abdul Rahim, H; Latif, M A

    2011-07-06

    Among 120 simple sequence repeat (SSR) markers, 23 polymorphic markers were used to identify the segregation ratio in 320 individuals of an F(2) rice population derived from Pongsu Seribu 2, a resistant variety, and Mahsuri, a susceptible rice cultivar. For phenotypic study, the most virulent blast (Magnaporthe oryzae) pathotype, P7.2, was used in screening of F(2) population in order to understand the inheritance of blast resistance as well as linkage with SSR markers. Only 11 markers showed a good fit to the expected segregation ratio (1:2:1) for the single gene model (d.f. = 1.0, P < 0.05) in chi-square (χ(2)) analyses. In the phenotypic data analysis, the F(2) population segregated in a 3:1 (R:S) ratio for resistant and susceptible plants, respectively. Therefore, resistance to blast pathotype P7.2 in Pongsu Seribu 2 is most likely controlled by a single nuclear gene. The plants from F(2) lines that showed resistance to blast pathotype P7.2 were linked to six alleles of SSR markers, RM168 (116 bp), RM8225 (221 bp), RM1233 (175 bp), RM6836 (240 bp), RM5961 (129 bp), and RM413 (79 bp). These diagnostic markers could be used in marker assisted selection programs to develop a durable blast resistant variety.

  5. Identification of positive and negative regulators of disease resistance to rice blast fungus using constitutive gene expression patterns.

    PubMed

    Grand, Xavier; Espinoza, Rocio; Michel, Corinne; Cros, Sandrine; Chalvon, Véronique; Jacobs, John; Morel, Jean-Benoit

    2012-09-01

    Elevated constitutive expression of components of the defence arsenal is associated with quantitative resistance to the rice blast fungus, a phenomenon called preformed defence. While the role of many disease regulators in inducible defence systems has been extensively studied, little attention has been paid so far to genes that regulate preformed defence. In this study, we show by microarray analysis across rice diversity that the preformed defence phenomenon impacts on a large number of defence-related genes without apparently affecting other biological processes. Using a guilt-by-association strategy, we identified two positive regulators that promote constitutive expression of known defence markers and partial resistance to rice blast. The HSF23 gene encodes for a putative member of the heat shock transcription factor family, while CaMBP encodes for a putative Calmodulin-binding protein. Both HSF23 and CaMBP strongly affect preformed defence and also plant growth. Additionally, we identified the OB-fold gene as a negative regulator of blast resistance, which could be involved in RNA stabilization. The OB-fold mutants do not suffer from obvious developmental defects. Taken together, our results prove that our strategy of combining analysis of gene expression diversity with guilt-by-association is a powerful way to identify disease resistance regulators in rice.

  6. Development and evaluation of near-isogenic lines for major blast resistance gene(s) in Basmati rice.

    PubMed

    Khanna, Apurva; Sharma, Vinay; Ellur, Ranjith K; Shikari, Asif B; Gopala Krishnan, S; Singh, U D; Prakash, G; Sharma, T R; Rathour, Rajeev; Variar, Mukund; Prashanthi, S K; Nagarajan, M; Vinod, K K; Bhowmick, Prolay K; Singh, N K; Prabhu, K V; Singh, B D; Singh, Ashok K

    2015-07-01

    A set of NILs carrying major blast resistance genes in a Basmati rice variety has been developed. Also, the efficacy of pyramids over monogenic NILs against rice blast pathogen Magnaporthe oryzae has been demonstrated. Productivity and quality of Basmati rice is severely affected by rice blast disease. Major genes and QTLs conferring resistance to blast have been reported only in non-Basmati rice germplasm. Here, we report incorporation of seven blast resistance genes from the donor lines DHMASQ164-2a (Pi54, Pi1, Pita), IRBLz5-CA (Pi2), IRBLb-B (Pib), IRBL5-M (Pi5) and IRBL9-W (Pi9) into the genetic background of an elite Basmati rice variety Pusa Basmati 1 (PB1). A total of 36 near-isogenic lines (NILs) comprising of 14 monogenic, 16 two-gene pyramids and six three-gene pyramids were developed through marker-assisted backcross breeding (MABB). Foreground, recombinant and background selection was used to identify the plants with target gene(s), minimize the linkage drag and increase the recurrent parent genome (RPG) recovery (93.5-98.6 %), respectively, in the NILs. Comparative analysis performed using 50,051 SNPs and 500 SSR markers revealed that the SNPs provided better insight into the RPG recovery. Most of the monogenic NILs showed comparable performance in yield and quality, concomitantly, Pusa1637-18-7-6-20 (Pi9), was significantly superior in yield and stable across four different environments as compared to recurrent parent (RP) PB1. Further, among the pyramids, Pusa1930-12-6 (Pi2+Pi5) showed significantly higher yield and Pusa1633-7-8-53-6-8 (Pi54+Pi1+Pita) was superior in cooking quality as compared to RP PB1. The NILs carrying gene Pi9 were found to be the most effective against the concoction of virulent races predominant in the hotspot locations for blast disease. Conversely, when analyzed under artificial inoculation, three-gene pyramids expressed enhanced resistance as compared to the two-gene and monogenic NILs.

  7. Function and Interaction of the Coupled Genes Responsible for Pik-h Encoded Rice Blast Resistance

    PubMed Central

    Yao, Nan; Lin, Fei; Liu, Zhe; Dong, Zhongqiu; Wang, Ling; Pan, Qinghua

    2014-01-01

    Pik-h, an allele of Pik, confers resistance against the rice blast pathogen Magnaporthe oryzae. Its positional cloning has shown that it comprises a pair of NBS-LRR genes, Pikh-1 and Pikh-2. While Pikh-1 appears to be constitutively transcribed, the transcript abundance of Pikh-2 responds to pathogen challenge. The Pikh-1 CC (coiled coil) domain interacts directly with both AvrPik-h and Pikh-2. Transient expression assays demonstrated that Pikh-2 mediates the initiation of the host defence response. Nucleocytoplasmic partitioning of both Pikh-1 and Pikh-2 is required for their functionalities. In a proposed mechanistic model of Pik-h resistance, it is suggested that Pikh-1 acts as an adaptor between AvrPik-h and Pikh-2, while Pikh-2 transduces the signal to trigger Pik-h-specific resistance. PMID:24896089

  8. Identification of rice sheath blight and blast quantitative trait loci in two different O. satival/O. nivara advanced backcross populations

    USDA-ARS?s Scientific Manuscript database

    Two accessions of the rice (Oryza sativa) wild ancestral species, O. nivara identified as being moderately resistant to sheath blight and leaf blast diseases, were used as donor parents to develop two advanced backcross populations with the U.S. rice cultivar, Bengal, as the recurrent parent. The O...

  9. Evidence for a transketolase-mediated metabolic checkpoint governing biotrophic growth in rice cells by the blast fungus Magnaporthe oryzae.

    PubMed

    Fernandez, Jessie; Marroquin-Guzman, Margarita; Wilson, Richard A

    2014-09-01

    The blast fungus Magnaporthe oryzae threatens global food security through the widespread destruction of cultivated rice. Foliar infection requires a specialized cell called an appressorium that generates turgor to force a thin penetration hypha through the rice cuticle and into the underlying epidermal cells, where the fungus grows for the first days of infection as a symptomless biotroph. Understanding what controls biotrophic growth could open new avenues for developing sustainable blast intervention programs. Here, using molecular genetics and live-cell imaging, we dismantled M. oryzae glucose-metabolizing pathways to reveal that the transketolase enzyme, encoded by TKL1, plays an essential role in facilitating host colonization during rice blast disease. In the absence of transketolase, Δtkl1 mutant strains formed functional appressoria that penetrated rice cuticles successfully and developed invasive hyphae (IH) in rice cells from primary hyphae. However, Δtkl1 could not undertake sustained biotrophic growth or cell-to-cell movement. Transcript data and observations using fluorescently labeled histone H1:RFP fusion proteins indicated Δtkl1 mutant strains were alive in host cells but were delayed in mitosis. Mitotic delay could be reversed and IH growth restored by the addition of exogenous ATP, a metabolite depleted in Δtkl1 mutant strains. We show that ATP might act via the TOR signaling pathway, and TOR is likely a downstream target of activation for TKL1. TKL1 is also involved in controlling the migration of appressorial nuclei into primary hyphae in host cells. When taken together, our results indicate transketolase has a novel role in mediating--via ATP and TOR signaling--an in planta-specific metabolic checkpoint that controls nuclear migration from appressoria into primary hyphae, prevents mitotic delay in early IH and promotes biotrophic growth. This work thus provides new information about the metabolic strategies employed by M. oryzae to enable

  10. Evidence for a Transketolase-Mediated Metabolic Checkpoint Governing Biotrophic Growth in Rice Cells by the Blast Fungus Magnaporthe oryzae

    PubMed Central

    Fernandez, Jessie; Marroquin-Guzman, Margarita; Wilson, Richard A.

    2014-01-01

    The blast fungus Magnaporthe oryzae threatens global food security through the widespread destruction of cultivated rice. Foliar infection requires a specialized cell called an appressorium that generates turgor to force a thin penetration hypha through the rice cuticle and into the underlying epidermal cells, where the fungus grows for the first days of infection as a symptomless biotroph. Understanding what controls biotrophic growth could open new avenues for developing sustainable blast intervention programs. Here, using molecular genetics and live-cell imaging, we dismantled M. oryzae glucose-metabolizing pathways to reveal that the transketolase enzyme, encoded by TKL1, plays an essential role in facilitating host colonization during rice blast disease. In the absence of transketolase, Δtkl1 mutant strains formed functional appressoria that penetrated rice cuticles successfully and developed invasive hyphae (IH) in rice cells from primary hyphae. However, Δtkl1 could not undertake sustained biotrophic growth or cell-to-cell movement. Transcript data and observations using fluorescently labeled histone H1:RFP fusion proteins indicated Δtkl1 mutant strains were alive in host cells but were delayed in mitosis. Mitotic delay could be reversed and IH growth restored by the addition of exogenous ATP, a metabolite depleted in Δtkl1 mutant strains. We show that ATP might act via the TOR signaling pathway, and TOR is likely a downstream target of activation for TKL1. TKL1 is also involved in controlling the migration of appressorial nuclei into primary hyphae in host cells. When taken together, our results indicate transketolase has a novel role in mediating - via ATP and TOR signaling - an in planta-specific metabolic checkpoint that controls nuclear migration from appressoria into primary hyphae, prevents mitotic delay in early IH and promotes biotrophic growth. This work thus provides new information about the metabolic strategies employed by M. oryzae to

  11. MicroRNA-mediated regulation of gene expression in the response of rice plants to fungal elicitors.

    PubMed

    Baldrich, Patricia; Campo, Sonia; Wu, Ming-Tsung; Liu, Tze-Tze; Hsing, Yue-Ie Caroline; San Segundo, Blanca

    2015-01-01

    MicroRNAs (miRNAs) are small non-coding RNAs that have important regulatory functions in plant growth, development, and response to abiotic stress. Increasing evidence also supports that plant miRNAs contribute to immune responses to pathogens. Here, we used deep sequencing of small RNA libraries for global identification of rice miRNAs that are regulated by fungal elicitors. We also describe 9 previously uncharacterized miRNAs in rice. Combined small RNA and degradome analyses revealed regulatory networks enriched in elicitor-regulated miRNAs supported by the identification of their corresponding target genes. Specifically, we identified an important number of miRNA/target gene pairs involved in small RNA pathways, including miRNA, heterochromatic and trans-acting siRNA pathways. We present evidence for miRNA/target gene pairs implicated in hormone signaling and cross-talk among hormone pathways having great potential in regulating rice immunity. Furthermore, we describe miRNA-mediated regulation of Conserved-Peptide upstream Open Reading Frame (CPuORF)-containing genes in rice, which suggests the existence of a novel regulatory network that integrates miRNA and CPuORF functions in plants. The knowledge gained in this study will help in understanding the underlying regulatory mechanisms of miRNAs in rice immunity and develop appropriate strategies for rice protection.

  12. PLS1, a gene encoding a tetraspanin-like protein, is required for penetration of rice leaf by the fungal pathogen Magnaporthe grisea.

    PubMed

    Clergeot, P H; Gourgues, M; Cots, J; Laurans, F; Latorse, M P; Pepin, R; Tharreau, D; Notteghem, J L; Lebrun, M H

    2001-06-05

    We describe in this study punchless, a nonpathogenic mutant from the rice blast fungus M. grisea, obtained by plasmid-mediated insertional mutagenesis. As do most fungal plant pathogens, M. grisea differentiates an infection structure specialized for host penetration called the appressorium. We show that punchless differentiates appressoria that fail to breach either the leaf epidermis or artificial membranes such as cellophane. Cytological analysis of punchless appressoria shows that they have a cellular structure, turgor, and glycogen content similar to those of wild type before penetration, but that they are unable to differentiate penetration pegs. The inactivated gene, PLS1, encodes a putative integral membrane protein of 225 aa (Pls1p). A functional Pls1p-green fluorescent protein fusion protein was detected only in appressoria and was localized in plasma membranes and vacuoles. Pls1p is structurally related to the tetraspanin family. In animals, these proteins are components of membrane signaling complexes controlling cell differentiation, motility, and adhesion. We conclude that PLS1 controls an appressorial function essential for the penetration of the fungus into host leaves.

  13. PLS1, a gene encoding a tetraspanin-like protein, is required for penetration of rice leaf by the fungal pathogen Magnaporthe grisea

    PubMed Central

    Clergeot, Pierre-Henri; Gourgues, Mathieu; Cots, Joaquim; Laurans, F.; Latorse, Marie-Pascale; Pépin, Régis; Tharreau, Didier; Notteghem, Jean-Loup; Lebrun, Marc-Henri

    2001-01-01

    We describe in this study punchless, a nonpathogenic mutant from the rice blast fungus M. grisea, obtained by plasmid-mediated insertional mutagenesis. As do most fungal plant pathogens, M. grisea differentiates an infection structure specialized for host penetration called the appressorium. We show that punchless differentiates appressoria that fail to breach either the leaf epidermis or artificial membranes such as cellophane. Cytological analysis of punchless appressoria shows that they have a cellular structure, turgor, and glycogen content similar to those of wild type before penetration, but that they are unable to differentiate penetration pegs. The inactivated gene, PLS1, encodes a putative integral membrane protein of 225 aa (Pls1p). A functional Pls1p-green fluorescent protein fusion protein was detected only in appressoria and was localized in plasma membranes and vacuoles. Pls1p is structurally related to the tetraspanin family. In animals, these proteins are components of membrane signaling complexes controlling cell differentiation, motility, and adhesion. We conclude that PLS1 controls an appressorial function essential for the penetration of the fungus into host leaves. PMID:11391010

  14. Combinations of fungal and milling pretreatments for enhancing rice straw biogas production during solid-state anaerobic digestion.

    PubMed

    Mustafa, Ahmed M; Poulsen, Tjalfe G; Xia, Yihua; Sheng, Kuichuan

    2017-01-01

    Rice straw was pretreated by different combinations of physical (milling) and biological (incubation with Pleurotus ostreatus fungus) treatment to improve its biodegradability and biogas production during solid-state anaerobic digestion (SS-AD). Effects of milling (⩽2mm) and incubation time (10, 20 and 30d), on lignin, cellulose, and hemicellulose degradation during fungal pretreatment and methane yield during digestion were assessed by comparison with untreated rice straw. Both incubation time and milling had significant impacts on both lignin removal during fungal pre-treatment and methane yield during digestion. A combination of fungal pretreatment at 30days followed by milling prior to anaerobic digestion resulted in 30.4% lignin removal, the highest selectivity value (the ratio between relative lignin removal and relative cellulose removal) of 4.22, and the highest methane yield of 258L/kgVS. This was equivalent to a 165% increase in methane yield from SS-AD compared to untreated rice straw. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Mutualistic fungal endophytes produce phytohormones and organic acids that promote japonica rice plant growth under prolonged heat stress*

    PubMed Central

    Waqas, Muhammad; Khan, Abdul Latif; Shahzad, Raheem; Ullah, Ihsan; Khan, Abdur Rahim; Lee, In-Jung

    2015-01-01

    This study identifies the potential role in heat-stress mitigation of phytohormones and other secondary metabolites produced by the endophytic fungus Paecilomyces formosus LWL1 in japonica rice cultivar Dongjin. The japonica rice was grown in controlled chamber conditions with and without P. formosus LWL1 under no stress (NS) and prolonged heat stress (HS) conditions. Endophytic association under NS and HS conditions significantly improved plant growth attributes, such as plant height, fresh weight, dry weight, and chlorophyll content. Furthermore, P. formosus LWL1 protected the rice plants from HS compared with controls, indicated by the lower endogenous level of stress-signaling compounds such as abscisic acid (25.71%) and jasmonic acid (34.57%) and the increase in total protein content (18.76%–33.22%). Such fungal endophytes may be helpful for sustainable crop production under high environmental temperatures. PMID:26642184

  16. Overexpression of Rice Wall-Associated Kinase 25 (OsWAK25) Alters Resistance to Bacterial and Fungal Pathogens

    PubMed Central

    Harkenrider, Mitch; Sharma, Rita; De Vleesschauwer, David; Tsao, Li; Zhang, Xuting; Chern, Mawsheng; Canlas, Patrick; Zuo, Shimin; Ronald, Pamela C.

    2016-01-01

    Wall-associated kinases comprise a sub-family of receptor-like kinases that function in plant growth and stress responses. Previous studies have shown that the rice wall-associated kinase, OsWAK25, interacts with a diverse set of proteins associated with both biotic and abiotic stress responses. Here, we show that wounding and BTH treatments induce OsWAK25 transcript expression in rice. We generated OsWAK25 overexpression lines and show that these lines exhibit a lesion mimic phenotype and enhanced expression of rice NH1 (NPR1 homolog 1), OsPAL2, PBZ1 and PR10. Furthermore, these lines show resistance to the hemibiotrophic pathogens, Xanthomonas oryzae pv. oryzae (Xoo) and Magnaporthe oryzae, yet display increased susceptibility to necrotrophic fungal pathogens, Rhizoctonia solani and Cochliobolus miyabeanus. PMID:26795719

  17. South-East Asia is the center of origin, diversity and dispersion of the rice blast fungus, Magnaporthe oryzae.

    PubMed

    Saleh, Dounia; Milazzo, Joëlle; Adreit, Henri; Fournier, Elisabeth; Tharreau, Didier

    2014-03-01

    • Inferring invasion routes and identifying reservoirs of diversity of plant pathogens are essential in proposing new strategies for their control. Magnaporthe oryzae, the fungus responsible for rice blast disease, has invaded all rice growing areas. Virulent genotypes regularly (re)emerge, causing rapid resistance breakdowns. However, the world-wide genetic subdivision of M. oryzae populations on rice and its past history of invasion have never been elucidated. • In order to investigate the centers of diversity, origin and migration of M. oryzae on rice, we analyzed the genetic diversity of 55 populations from 15 countries. • Three genetic clusters were identified world-wide. Asia was the center of diversity and the origin of most migrations to other continents. In Asia, two centers of diversity were revealed in the Himalayan foothills: South China-Laos-North Thailand, and western Nepal. Sexual reproduction persisted only in the South China-Laos-North Thailand region, which was identified as the putative center of origin of all M. oryzae populations on rice. • Our results suggest a scenario of early evolution of M. oryzae on rice that matches the past history of rice domestication. This study confirms that crop domestication may have considerable influence on the pestification process of natural enemies.

  18. South-East Asia is the center of origin, diversity and dispersion of the rice blast fungus, Magnaporthe oryzae

    PubMed Central

    Saleh, Dounia; Milazzo, Joëlle; Adreit, Henri; Fournier, Elisabeth; Tharreau, Didier

    2014-01-01

    Inferring invasion routes and identifying reservoirs of diversity of plant pathogens are essential in proposing new strategies for their control. Magnaporthe oryzae, the fungus responsible for rice blast disease, has invaded all rice growing areas. Virulent genotypes regularly (re)emerge, causing rapid resistance breakdowns. However, the world-wide genetic subdivision of M. oryzae populations on rice and its past history of invasion have never been elucidated. In order to investigate the centers of diversity, origin and migration of M. oryzae on rice, we analyzed the genetic diversity of 55 populations from 15 countries. Three genetic clusters were identified world-wide. Asia was the center of diversity and the origin of most migrations to other continents. In Asia, two centers of diversity were revealed in the Himalayan foothills: South China–Laos–North Thailand, and western Nepal. Sexual reproduction persisted only in the South China–Laos–North Thailand region, which was identified as the putative center of origin of all M. oryzae populations on rice. Our results suggest a scenario of early evolution of M. oryzae on rice that matches the past history of rice domestication. This study confirms that crop domestication may have considerable influence on the pestification process of natural enemies. PMID:24320224

  19. Co-transformation mediated stacking of blast resistance genes Pi54 and Pi54rh in rice provides broad spectrum resistance against Magnaporthe oryzae.

    PubMed

    Kumari, Mandeep; Rai, Amit Kumar; Devanna, B N; Singh, Pankaj Kumar; Kapoor, Ritu; Rajashekara, H; Prakash, G; Sharma, Vinay; Sharma, Tilak Raj

    2017-09-13

    This is the first report of stacking two major blast resistance genes in blast susceptible rice variety using co-transformation method to widen the resistance spectrum against different isolates of Magnaporthe oryzae. Single resistance (R-) gene mediated approach for the management of rice blast disease has met with frequent breakdown in resistance response. Besides providing the durable resistance, gene pyramiding or stacking also imparts broad spectrum resistance against plant pathogens, including rice blast. In the present study, we stacked two R-genes; Pi54 and Pi54rh having broad spectrum resistance against multiple isolates of Magnaporthe oryzae (M. oryzae). Both Pi54 and Pi54rh expressed under independent promoters were transferred into the blast susceptible japonica rice Taipei 309 (TP309) using particle gun bombardment method. Functional complementation analysis of stacked transgenic rice lines showed higher level of resistance to a set of highly virulent M. oryzae isolates collected from different rice growing regions. qRT-PCR analysis has shown M. oryzae induced expression of both the R-genes in stacked transgenic lines. The present study also demonstrated the effectiveness of the strategy for rapid single step gene stacking using co-transformation approach to engineer durable resistance against rice blast disease and also this is the first report in which two blast R-genes are stacked together using co-transformation approach. The two-gene-stacked transgenic line developed in this study can be used further to understand the molecular aspects of defense-related pathways vis-a-vis single R-gene containing transgenic lines.

  20. Synthesis and in vivo fungicidal activity of some new quinoline derivatives against rice blast.

    PubMed

    Liu, Xing-Hai; Fang, Yue-Ming; Xie, Feng; Zhang, Rui-Rui; Shen, Zhong-Hua; Tan, Chen-Xia; Weng, Jian-Quan; Xu, Tian-Ming; Huang, Hong-Ying

    2017-09-01

    Quinoline derivatives possess excellent fungicidal activity against rice blast, but quinoline derivatives have not been thoroughly explored as fungicides. In the process of designing new fungicides, the 1,1,1,2,3,3,3-heptafluoropropan-2-yl group was introduced in order to find new structure quinoline derivatives. Seventeen new quinoline derivatives containing 1,1,1,2,3,3,3-heptafluoropropan-2-yl moiety were designed and synthesised. In vivo fungicidal activities of these compounds were tested against rice blast. Some of the compounds provided effective control at 100 mg L(-1) , and a few compounds were effective at 10 mg L(-1) . Furthermore, a density functional theory study established the structure-activity relationships of the synthesised compounds. Quinoline derivatives, especially benzyl (2,3,8-trimethyl-6-(perfluoropropan-2-yl)quinolin-4-yl) carbonate, which possess good control effective against rice blast and cucumber powdery mildew, may become new lead compounds for the development of fungicides with further structure modification. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  1. Prediction of fungicidal activities of rice blast disease based on least-squares support vector machines and project pursuit regression.

    PubMed

    Du, Hongying; Wang, Jie; Hu, Zhide; Yao, Xiaojun; Zhang, Xiaoyun

    2008-11-26

    Three machine learning methods, genetic algorithm-multilinear regression (GA-MLR), least-squares support vector machine (LS-SVM), and project pursuit regression (PPR), were used to investigate the relationship between thiazoline derivatives and their fungicidal activities against the rice blast disease. The GA-MLR method was used to select the most appropriate molecular descriptors from a large set of descriptors, which were only calculated from molecular structures, and develop a linear quantitative structure-activity relationship (QSAR) model at the same time. On the basis of the selected descriptors, the other two more accurate models (LS-SVM and PPR) were built. Both the linear and nonlinear modes gave good prediction results, but the nonlinear models afforded better prediction ability, which meant that the LS-SVM and PPR methods could simulate the relationship between the structural descriptors and fungicidal activities more accurately. The results show that the nonlinear methods (LS-SVM and PPR) could be used as good modeling tools for the study of rice blast. Moreover, this study provides a new and simple but efficient approach, which should facilitate the design and development of new compounds to resist the rice blast disease.

  2. Origins of Host-Specific Populations of the Blast Pathogen Magnaporthe oryzae in Crop Domestication With Subsequent Expansion of Pandemic Clones on Rice and Weeds of Rice

    PubMed Central

    Couch, Brett C.; Fudal, Isabelle; Lebrun, Marc-Henri; Tharreau, Didier; Valent, Barbara; van Kim, Pham; Nottéghem, Jean-Loup; Kohn, Linda M.

    2005-01-01

    Rice, as a widely and intensively cultivated crop, should be a target for parasite host shifts and a source for shifts to co-occurring weeds. Magnaporthe oryzae, of the M. grisea species complex, is the most important fungal pathogen of rice, with a high degree of host specificity. On the basis of 10 loci from six of its seven linkage groups, 37 multilocus haplotypes among 497 isolates of M. oryzae from rice and other grasses were identified. Phylogenetic relationships among isolates from rice (Oryza sativa), millet (Setaria spp.), cutgrass (Leersia hexandra), and torpedo grass (Panicum repens) were predominantly tree like, consistent with a lack of recombination, but from other hosts were reticulate, consistent with recombination. The single origin of rice-infecting M. oryzae followed a host shift from a Setaria millet and was closely followed by additional shifts to weeds of rice, cutgrass, and torpedo grass. Two independent estimators of divergence time indicate that these host shifts predate the Green Revolution and could be associated with rice domestication. The rice-infecting lineage is characterized by high copy number of the transposable element MGR586 (Pot3) and, except in two haplotypes, by a loss of AVR-Co39. Both mating types have been retained in ancestral, well-distributed rice-infecting haplotypes 10 (mainly temperate) and 14 (mainly tropical), but only one mating type was recovered from several derived, geographically restricted haplotypes. There is evidence of a common origin of both ACE1 virulence genotypes in haplotype 14. Host-haplotype association is evidenced by low pathogenicity on hosts associated with other haplotypes. PMID:15802503

  3. Using Network Extracted Ontologies to Identify Novel Genes with Roles in Appressorium Development in the Rice Blast Fungus Magnaporthe oryzae

    PubMed Central

    Ames, Ryan M.

    2017-01-01

    Magnaporthe oryzae is the causal agent of rice blast disease, the most important infection of rice worldwide. Half the world’s population depends on rice for its primary caloric intake and, as such, rice blast poses a serious threat to food security. The stages of M. oryzae infection are well defined, with the formation of an appressorium, a cell type that allows penetration of the plant cuticle, particularly well studied. However, many of the key pathways and genes involved in this disease stage are yet to be identified. In this study, I have used network-extracted ontologies (NeXOs), hierarchical structures inferred from RNA-Seq data, to identify pathways involved in appressorium development, which in turn highlights novel genes with potential roles in this process. This study illustrates the use of NeXOs for pathway identification from large-scale genomics data and also identifies novel genes with potential roles in disease. The methods presented here will be useful to study disease processes in other pathogenic species and these data represent predictions of novel targets for intervention in M. oryzae. PMID:28106722

  4. Deciphering Cis-Regulatory Element Mediated Combinatorial Regulation in Rice under Blast Infected Condition

    PubMed Central

    Deb, Arindam; Kundu, Sudip

    2015-01-01

    Combinations of cis-regulatory elements (CREs) present at the promoters facilitate the binding of several transcription factors (TFs), thereby altering the consequent gene expressions. Due to the eminent complexity of the regulatory mechanism, the combinatorics of CRE-mediated transcriptional regulation has been elusive. In this work, we have developed a new methodology that quantifies the co-occurrence tendencies of CREs present in a set of promoter sequences; these co-occurrence scores are filtered in three consecutive steps to test their statistical significance; and the significantly co-occurring CRE pairs are presented as networks. These networks of co-occurring CREs are further transformed to derive higher order of regulatory combinatorics. We have further applied this methodology on the differentially up-regulated gene-sets of rice tissues under fungal (Magnaporthe) infected conditions to demonstrate how it helps to understand the CRE-mediated combinatorial gene regulation. Our analysis includes a wide spectrum of biologically important results. The CRE pairs having a strong tendency to co-occur often exhibit very similar joint distribution patterns at the promoters of rice. We couple the network approach with experimental results of plant gene regulation and defense mechanisms and find evidences of auto and cross regulation among TF families, cross-talk among multiple hormone signaling pathways, similarities and dissimilarities in regulatory combinatorics between different tissues, etc. Our analyses have pointed a highly distributed nature of the combinatorial gene regulation facilitating an efficient alteration in response to fungal attack. All together, our proposed methodology could be an important approach in understanding the combinatorial gene regulation. It can be further applied to unravel the tissue and/or condition specific combinatorial gene regulation in other eukaryotic systems with the availability of annotated genomic sequences and suitable

  5. An ATP-driven efflux pump is a novel pathogenicity factor in rice blast disease.

    PubMed Central

    Urban, M; Bhargava, T; Hamer, J E

    1999-01-01

    Cells tolerate exposure to cytotoxic compounds through the action of ATP-driven efflux pumps belonging to the ATP-binding cassette (ABC) superfamily of membrane transporters. Phytopathogenic fungi encounter toxic environments during plant invasion as a result of the plant defense response. Here we demonstrate the requirement for an ABC transporter during host infection by the fungal plant pathogen Magnaporthe grisea. The ABC1 gene was identified in an insertional mutagenesis screen for pathogenicity mutants. The ABC1 insertional mutant and a gene-replacement mutant arrest growth and die shortly after penetrating either rice or barley epidermal cells. The ABC1-encoded protein is similar to yeast ABC transporters implicated in multidrug resistance, and ABC1 gene transcripts are inducible by toxic drugs and a rice phytoalexin. However, abc1 mutants are not hypersensitive to antifungal compounds. The non-pathogenic, insertional mutation in ABC1 occurs in the promoter region and dramatically reduces transcript induction by metabolic poisons. These data strongly suggest that M.grisea requires the up-regulation of specific ABC transporters for pathogenesis; most likely to protect itself against plant defense mechanisms. PMID:9927411

  6. Suppression of the rice fatty-acid desaturase gene OsSSI2 enhances resistance to blast and leaf blight diseases in rice.

    PubMed

    Jiang, Chang-Jie; Shimono, Masaki; Maeda, Satoru; Inoue, Haruhiko; Mori, Masaki; Hasegawa, Morifumi; Sugano, Shoji; Takatsuji, Hiroshi

    2009-07-01

    Fatty acids and their derivatives play important signaling roles in plant defense responses. It has been shown that suppressing a gene for stearoyl acyl carrier protein fatty-acid desaturase (SACPD) enhances the resistance of Arabidopsis (SSI2) and soybean to multiple pathogens. In this study, we present functional analyses of a rice homolog of SSI2 (OsSSI2) in disease resistance of rice plants. A transposon insertion mutation (Osssi2-Tos17) and RNAi-mediated knockdown of OsSSI2 (OsSSI2-kd) reduced the oleic acid (18:1) level and increased that of stearic acid (18:0), indicating that OsSSI2 is responsible for fatty-acid desaturase activity. These plants displayed spontaneous lesion formation in leaf blades, retarded growth, slight increase in endogenous free salicylic acid (SA) levels, and SA/benzothiadiazole (BTH)-specific inducible genes, including WRKY45, a key regulator of SA/BTH-induced resistance, in rice. Moreover, the OsSSI2-kd plants showed markedly enhanced resistance to the blast fungus Magnaporthe grisea and leaf-blight bacteria Xanthomonas oryzae pv. oryzae. These results suggest that OsSSI2 is involved in the negative regulation of defense responses in rice, as are its Arabidopsis and soybean counterparts. Microarray analyses identified 406 genes that were differentially expressed (>or=2-fold) in OsSSI2-kd rice plants compared with wild-type rice and, of these, approximately 39% were BTH responsive. Taken together, our results suggest that induction of SA-responsive genes, including WRKY45, is likely responsible for enhanced disease resistance in OsSSI2-kd rice plants.

  7. Enhanced resistance to blast fungus in rice (Oryza sativa L.) by expressing the ribosome-inactivating protein α-momorcharin.

    PubMed

    Qian, Qian; Huang, Lin; Yi, Rong; Wang, Shuzhen; Ding, Yi

    2014-03-01

    Rice blast caused by Magnaporthe grisea is one of the three major diseases that seriously affect the rice production. Alpha-momorcharin (α-MC), a ribosome-inactivating protein (RIP) isolated from Momordica charantia seeds, has antifungal effects in vitro. In this study, the α-MC gene was constitutively expressed under the control of the 2×35S promoter in transgenic rice (Oryza sativa L.) using an Agrobacterium tumefaciens-mediated method. The nine transgenic plants were obtained and confirmed by PCR and RT-PCR, and the four (B2, B4, B7 and B9) of them whose copy numbers were 1, 2, 3 and 3, respectively, were shown to express the α-MC protein by Western blot. The molecular weight of α-MC in transgenic plants was approximately 38 kDa larger than the purified α-MC protein (28 kDa) in vitro. When the confirmed T1 generations were inoculated with a suspension of M. grisea spores for ten days, the lesions on leaves of transgenic plants were much lesser than those found on wild type (WT). According to the criteria of International Rice Research Institute standard, the mean values for morbidity and disease index numbers were 29.8% and 14.9%, respectively, which were lower than for WT. It is unclear whether RIPs could impact plant fitness and however our results suggest that the α-MC protein is an effective antifungal protein preventing rice blast in transgenic rice. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  8. Breeding for blast-disease-resistant and high-yield Thai jasmine rice (Oryza sativa L. cv. KDML 105) mutants using low-energy ion beams

    NASA Astrophysics Data System (ADS)

    Mahadtanapuk, S.; Teraarusiri, W.; Phanchaisri, B.; Yu, L. D.; Anuntalabhochai, S.

    2013-07-01

    Low-energy ion beam was applied on mutation induction for plant breeding of blast-disease-resistant Thai jasmine rice (Oryza sativa L. cv. KDML 105). Seeds of the wild-type rice were bombarded in vacuum by nitrogen ion beam at energy of 60-80 keV to a beam fluence range of 2 × 1016-2 × 1017 ions/cm2. The ion-bombarded rice seeds were grown in soil for 2 weeks as transplanted rice in plastic pots at 1 seedling/pot. The seedlings were then screened for blast resistance by Pyricularia grisea inoculation with 106 spores/ml concentrations. The blast-resistant rice mutant was planted up to F6 generation with the consistent phenotypic variation. The high percentage of the blast-disease-resistant rice was analyzed with DNA fingerprint. The HAT-RAPD (high annealing temperature-random amplified polymorphic DNA) marker revealed the modified polymorphism fragment presenting in the mutant compared with wild type (KDML 105). The cDNA fingerprints were investigated and the polymorphism fragment was subcloned into pGEM-T easy vector and then sequenced. The sequence of this fragment was compared with those already contained in the database, and the fragment was found to be related to the Spotted leaf protein 11 (Spl11).

  9. Fungal and bacterial metabolites associated with natural contamination of locally processed rice (Oryza sativa L.) in Nigeria.

    PubMed

    Rofiat, Abdus-Salaam; Fanelli, Francesca; Atanda, Olusegun; Sulyok, Michael; Cozzi, Giuseppe; Bavaro, Simona; Krska, Rudolf; Logrieco, Antonio F; Ezekiel, Chibundu N

    2015-01-01

    This study reports the fungal and bacterial metabolites associated with natural contamination of 38 composite samples of locally processed rice from five agro-ecological zones of Nigeria (AEZs). The samples were evaluated for the presence of microbial metabolites by LC-MS/MS. Among the identified metabolites, 63 fungal and 5 bacterial metabolites were measured at varying concentrations and occurrence levels. Fusarium toxins had the highest incidence of 79%, but occurred in low amounts with fumonisin B1 (FB1) having the highest percentage incidence of 39.5% and a mean of 18.5 µg/kg. Among the Aspergillus toxins, aflatoxins (AFs) occurred in 36.9% of the rice samples, with aflatoxin B1 (AFB1) having the highest occurrence level of 18.4% and a mean value of 5 µg/kg. About 12 metabolites had incidence levels > 50%, including beauvericin (BEA) and tryptophol, which had occurrence levels of 100%. Among the emerging toxins under evaluation by international organisations such as the European Food Safety Authority (EFSA) and the Food and Agriculture Organisation of the United Nations (FAO), citrinin, sterigmatocystin (STER) and beauvericin were detected with maximum values of 207, 125 and 131 μg/kg, respectively. This paper also reports the first documented evidence of the contamination of Nigerian rice by bacterial and Alternaria metabolites, nivalenol, kojic acid, STER, moniliformin, fusaric acid, fumonisin B3, citrinin, 3-nitropropionic acid, andrastin A, cytochalasins, emodin and physicon.

  10. Understanding Host-Pathogen Interactions with Expression Profiling of NILs Carrying Rice-Blast Resistance Pi9 Gene

    PubMed Central

    Jain, Priyanka; Singh, Pankaj K.; Kapoor, Ritu; Khanna, Apurva; Solanke, Amolkumar U.; Krishnan, S. Gopala; Singh, Ashok K.; Sharma, Vinay; Sharma, Tilak R.

    2017-01-01

    Magnaporthe oryzae infection causes rice blast, a destructive disease that is responsible for considerable decrease in rice yield. Development of resistant varieties via introgressing resistance genes with marker-assisted breeding can eliminate pesticide use and minimize crop losses. Here, resistant near-isogenic line (NIL) of Pusa Basmati-1(PB1) carrying broad spectrum rice blast resistance gene Pi9 was used to investigate Pi9-mediated resistance response. Infected and uninfected resistant NIL and susceptible control line were subjected to RNA-Seq. With the exception of one gene (Pi9), transcriptional signatures between the two lines were alike, reflecting basal similarities in their profiles. Resistant and susceptible lines possessed 1043 (727 up-regulated and 316 down-regulated) and 568 (341 up-regulated and 227 down-regulated) unique and significant differentially expressed loci (SDEL), respectively. Pathway analysis revealed higher transcriptional activation of kinases, WRKY, MYB, and ERF transcription factors, JA-ET hormones, chitinases, glycosyl hydrolases, lipid biosynthesis, pathogenesis and secondary metabolism related genes in resistant NIL than susceptible line. Singular enrichment analysis demonstrated that blast resistant NIL is significantly enriched with genes for primary and secondary metabolism, response to biotic stimulus and transcriptional regulation. The co-expression network showed proteins of genes in response to biotic stimulus interacted in a manner unique to resistant NIL upon M. oryzae infection. These data suggest that Pi9 modulates genome-wide transcriptional regulation in resistant NIL but not in susceptible PB1. We successfully used transcriptome profiling to understand the molecular basis of Pi9-mediated resistance mechanisms, identified potential candidate genes involved in early pathogen response and revealed the sophisticated transcriptional reprogramming during rice-M. oryzae interactions. PMID:28280498

  11. Understanding Host-Pathogen Interactions with Expression Profiling of NILs Carrying Rice-Blast Resistance Pi9 Gene.

    PubMed

    Jain, Priyanka; Singh, Pankaj K; Kapoor, Ritu; Khanna, Apurva; Solanke, Amolkumar U; Krishnan, S Gopala; Singh, Ashok K; Sharma, Vinay; Sharma, Tilak R

    2017-01-01

    Magnaporthe oryzae infection causes rice blast, a destructive disease that is responsible for considerable decrease in rice yield. Development of resistant varieties via introgressing resistance genes with marker-assisted breeding can eliminate pesticide use and minimize crop losses. Here, resistant near-isogenic line (NIL) of Pusa Basmati-1(PB1) carrying broad spectrum rice blast resistance gene Pi9 was used to investigate Pi9-mediated resistance response. Infected and uninfected resistant NIL and susceptible control line were subjected to RNA-Seq. With the exception of one gene (Pi9), transcriptional signatures between the two lines were alike, reflecting basal similarities in their profiles. Resistant and susceptible lines possessed 1043 (727 up-regulated and 316 down-regulated) and 568 (341 up-regulated and 227 down-regulated) unique and significant differentially expressed loci (SDEL), respectively. Pathway analysis revealed higher transcriptional activation of kinases, WRKY, MYB, and ERF transcription factors, JA-ET hormones, chitinases, glycosyl hydrolases, lipid biosynthesis, pathogenesis and secondary metabolism related genes in resistant NIL than susceptible line. Singular enrichment analysis demonstrated that blast resistant NIL is significantly enriched with genes for primary and secondary metabolism, response to biotic stimulus and transcriptional regulation. The co-expression network showed proteins of genes in response to biotic stimulus interacted in a manner unique to resistant NIL upon M. oryzae infection. These data suggest that Pi9 modulates genome-wide transcriptional regulation in resistant NIL but not in susceptible PB1. We successfully used transcriptome profiling to understand the molecular basis of Pi9-mediated resistance mechanisms, identified potential candidate genes involved in early pathogen response and revealed the sophisticated transcriptional reprogramming during rice-M. oryzae interactions.

  12. Validation of Reference Genes for Robust qRT-PCR Gene Expression Analysis in the Rice Blast Fungus Magnaporthe oryzae.

    PubMed

    Che Omar, Sarena; Bentley, Michael A; Morieri, Giulia; Preston, Gail M; Gurr, Sarah J

    2016-01-01

    The rice blast fungus causes significant annual harvest losses. It also serves as a genetically-tractable model to study fungal ingress. Whilst pathogenicity determinants have been unmasked and changes in global gene expression described, we know little about Magnaporthe oryzae cell wall remodelling. Our interests, in wall remodelling genes expressed during infection, vegetative growth and under exogenous wall stress, demand robust choice of reference genes for quantitative Real Time-PCR (qRT-PCR) data normalisation. We describe the expression stability of nine candidate reference genes profiled by qRT-PCR with cDNAs derived during asexual germling development, from sexual stage perithecia and from vegetative mycelium grown under various exogenous stressors. Our Minimum Information for Publication of qRT-PCR Experiments (MIQE) compliant analysis reveals a set of robust reference genes used to track changes in the expression of the cell wall remodelling gene MGG_Crh2 (MGG_00592). We ranked nine candidate reference genes by their expression stability (M) and report the best gene combination needed for reliable gene expression normalisation, when assayed in three tissue groups (Infective, Vegetative, and Global) frequently used in M. oryzae expression studies. We found that MGG_Actin (MGG_03982) and the 40S 27a ribosomal subunit MGG_40s (MGG_02872) proved to be robust reference genes for the Infection group and MGG_40s and MGG_Ef1 (Elongation Factor1-α) for both Vegetative and Global groups. Using the above validated reference genes, M. oryzae MGG_Crh2 expression was found to be significantly (p<0.05) elevated three-fold during vegetative growth as compared with dormant spores and two fold higher under cell wall stress (Congo Red) compared to growth under optimal conditions. We recommend the combinatorial use of two reference genes, belonging to the cytoskeleton and ribosomal synthesis functional groups, MGG_Actin, MGG_40s, MGG_S8 (Ribosomal subunit 40S S8) or MGG

  13. Methionine Biosynthesis is Essential for Infection in the Rice Blast Fungus Magnaporthe oryzae

    PubMed Central

    Gagey, Marie Josèphe; Frelin, Océane; Beffa, Roland; Lebrun, Marc Henri; Droux, Michel

    2015-01-01

    Methionine is a sulfur amino acid standing at the crossroads of several biosynthetic pathways. In fungi, the last step of methionine biosynthesis is catalyzed by a cobalamine-independent methionine synthase (Met6, EC 2.1.1.14). In the present work, we studied the role of Met6 in the infection process of the rice blast fungus, Magnaporthe oryzae. To this end MET6 null mutants were obtained by targeted gene replacement. On minimum medium, MET6 null mutants were auxotrophic for methionine. Even when grown in presence of excess methionine, these mutants displayed developmental defects, such as reduced mycelium pigmentation, aerial hypha formation and sporulation. They also displayed characteristic metabolic signatures such as increased levels of cysteine, cystathionine, homocysteine, S-adenosylmethionine, S-adenosylhomocysteine while methionine and glutathione levels remained unchanged. These metabolic perturbations were associated with the over-expression of MgCBS1 involved in the reversed transsulfuration pathway that metabolizes homocysteine into cysteine and MgSAM1 and MgSAHH1 involved in the methyl cycle. This suggests a physiological adaptation of M. oryzae to metabolic defects induced by the loss of Met6, in particular an increase in homocysteine levels. Pathogenicity assays showed that MET6 null mutants were non-pathogenic on both barley and rice leaves. These mutants were defective in appressorium-mediated penetration and invasive infectious growth. These pathogenicity defects were rescued by addition of exogenous methionine and S-methylmethionine. These results show that M. oryzae cannot assimilate sufficient methionine from plant tissues and must synthesize this amino acid de novo to fulfill its sulfur amino acid requirement during infection. PMID:25856162

  14. Phylogenomic analysis uncovers the evolutionary history of nutrition and infection mode in rice blast fungus and other Magnaporthales.

    PubMed

    Luo, Jing; Qiu, Huan; Cai, Guohong; Wagner, Nicole E; Bhattacharya, Debashish; Zhang, Ning

    2015-03-30

    The order Magnaporthales (Ascomycota, Fungi) includes devastating pathogens of cereals, such as the rice blast fungus Pyricularia (Magnaporthe) oryzae, which is a model in host-pathogen interaction studies. Magnaporthales also includes saprotrophic species associated with grass roots and submerged wood. Despite its scientific and economic importance, the phylogenetic position of Magnaporthales within Sordariomycetes and the interrelationships of its constituent taxa, remain controversial. In this study, we generated novel transcriptome data from 21 taxa that represent key Magnaporthales lineages of different infection and nutrition modes and phenotypes. Phylogenomic analysis of >200 conserved genes allowed the reconstruction of a robust Sordariomycetes tree of life that placed the monophyletic group of Magnaporthales sister to Ophiostomatales. Among Magnaporthales, three major clades were recognized: 1) an early diverging clade A comprised of saprotrophs associated with submerged woods; 2) clade B that includes the rice blast fungus and other pathogens that cause blast diseases of monocot plants. These species infect the above-ground tissues of host plants using the penetration structure, appressorium; and 3) clade C comprised primarily of root-associated species that penetrate the root tissue with hyphopodia. The well-supported phylogenies provide a robust framework for elucidating evolution of pathogenesis, nutrition modes, and phenotypic characters in Magnaporthales.

  15. Phylogenomic analysis uncovers the evolutionary history of nutrition and infection mode in rice blast fungus and other Magnaporthales

    PubMed Central

    Luo, Jing; Qiu, Huan; Cai, Guohong; Wagner, Nicole E.; Bhattacharya, Debashish; Zhang, Ning

    2015-01-01

    The order Magnaporthales (Ascomycota, Fungi) includes devastating pathogens of cereals, such as the rice blast fungus Pyricularia (Magnaporthe) oryzae, which is a model in host-pathogen interaction studies. Magnaporthales also includes saprotrophic species associated with grass roots and submerged wood. Despite its scientific and economic importance, the phylogenetic position of Magnaporthales within Sordariomycetes and the interrelationships of its constituent taxa, remain controversial. In this study, we generated novel transcriptome data from 21 taxa that represent key Magnaporthales lineages of different infection and nutrition modes and phenotypes. Phylogenomic analysis of >200 conserved genes allowed the reconstruction of a robust Sordariomycetes tree of life that placed the monophyletic group of Magnaporthales sister to Ophiostomatales. Among Magnaporthales, three major clades were recognized: 1) an early diverging clade A comprised of saprotrophs associated with submerged woods; 2) clade B that includes the rice blast fungus and other pathogens that cause blast diseases of monocot plants. These species infect the above-ground tissues of host plants using the penetration structure, appressorium; and 3) clade C comprised primarily of root-associated species that penetrate the root tissue with hyphopodia. The well-supported phylogenies provide a robust framework for elucidating evolution of pathogenesis, nutrition modes, and phenotypic characters in Magnaporthales. PMID:25819715

  16. Production of Beauveria bassiana Fungal Spores on Rice to Control the Coffee Berry Borer, Hypothenemus hampei, in Colombia

    PubMed Central

    Posada-Flórez, Francisco J

    2008-01-01

    Two isolates of fungal entomopathogen Beauveria bassiana (Balsamo) Vuillemin (Hypocreales: Clavicipitaceae) were grown on cooked rice using diphasic liquid-solid fermentation in plastic bags to produce and harvest spore powder. The cultures were dried and significant differences were found for isolates and time of harvest. The spores were harvested manually and mechanically and after the cultures were dried for nine days, when moisture content was near 10%. After harvesting, spores were submitted to quality control to assess concentration, germination, purity, moisture content, particle size and pathogenicity to the coffee berry borer, Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae). Spore productivity on cooked rice was less than 1×1010 spores/g using both manually and mechanically harvesting methodologies. Germination at 24 hours was over 75% and pathogenicity against H. hampei was over 92.5%. This methodology is suitable for laboratory and field studies, but not for industrial production when a high concentration of spores are required for formulation and field applications.

  17. One of two major paralogs of AVR-Pita1 is functional in Japanese rice blast isolates.

    PubMed

    Takahashi, Mami; Ashizawa, Taketo; Hirayae, Kazuyuki; Moriwaki, Jouji; Sone, Teruo; Sonoda, Ryoichi; Noguchi, Masako Tsujimoto; Nagashima, Susumu; Ishikawa, Kouji; Arai, Michiyoshi

    2010-06-01

    We analyzed the avirulence gene AVR-Pita1 in Japanese rice blast isolates to determine how they gain virulence toward rice cultivars containing the Pita resistance gene. An avirulent isolate, OS99-G-7a (G7a), from a Japanese commercial field contained two paralogs of AVR-Pita1, designated as AVR-Pita1(JA) and AVR-Pita1(JB). Analysis of virulent, independent mutants derived from G7a, a single avirulent progenitor strain, indicated that AVR-Pita1(JA) was functional but AVR-Pita1(JB) was nonfunctional. The most frequent mutation was loss of AVR-Pita1(JA). Analyses of field isolates collected from diverse areas in Japan revealed that most of the AVR-Pita1 genes carried by Japanese isolates were identical to AVR-Pita1(JA) or AVR-Pita1(JB). The relationship between these major paralogs in Japanese isolates and the virulence of the strains carrying them indicate that AVR-Pita1(JA) is functional but AVR-Pita1(JB) is not, as is the case in G7a. Isolates that show virulence toward rice cultivars containing the Pita gene are presumed to have evolved virulence from avirulent origins via loss of AVR-Pita1(JA), except for one case in which virulence resulted from a base substitution. In this study, we discuss the properties and specificities of Japanese rice blasts that relate to virulence against Pita-containing rice. Furthermore, we present a method to amplify AVR-Pita1(JA) and AVR-Pita1(JB) separately and, specifically, to monitor functional AVR-Pita1 in Japan.

  18. Tripartite chimeric pseudogene from the genome of rice blast fungus Magnaporthe grisea suggests double template jumps during long interspersed nuclear element (LINE) reverse transcription

    PubMed Central

    Gogvadze, Elena; Barbisan, Crystel; Lebrun, Marc-Henri; Buzdin, Anton

    2007-01-01

    Background A systematic survey of loci carrying retrotransposons in the genome of the rice blast fungus Magnaporthe grisea allowed the identification of novel non-canonical retropseudogenes. These elements are chimeric retrogenes composed of DNA copies from different cellular transcripts directly fused to each other. Their components are copies of a non protein-coding highly expressed RNA of unknown function termed WEIRD and of two fungal retrotransposons: MGL and Mg-SINE. Many of these chimeras are transcribed in various M. grisea tissues and during plant infection. Chimeric retroelements with a similar structure were recently found in three mammalian genomes. All these chimeras are likely formed by RNA template switches during the reverse transcription of diverse LINE elements. Results We have shown that in M. grisea template switching occurs at specific sites within the initial template RNA which contains a characteristic consensus sequence. We also provide evidence that both single and double template switches may occur during LINE retrotransposition, resulting in the fusion of three different transcript copies. In addition to the 33 bipartite elements, one tripartite chimera corresponding to the fusion of three retrotranscripts (WEIRD, Mg-SINE, MGL-LINE) was identified in the M. grisea genome. Unlike the previously reported two human tripartite elements, this fungal retroelement is flanked by identical 14 bp-long direct repeats. The presence of these short terminal direct repeats demonstrates that the LINE enzymatic machinery was involved in the formation of this chimera and its integration in the M. grisea genome. Conclusion A survey of mammalian genomic databases also revealed two novel tripartite chimeric retroelements, suggesting that double template switches occur during reverse transcription of LINE retrotransposons in different eukaryotic organisms. PMID:17922896

  19. Wheat Blast: A New Fungal Inhabitant to Bangladesh Threatening World Wheat Production.

    PubMed

    Sadat, Md Abu; Choi, Jaehyuk

    2017-04-01

    World wheat production is now under threat due to the wheat blast outbreak in Bangladesh in early March 2016. This is a new disease in this area, indicating the higher possibility of this pathogen spreading throughout the Asia, the world's largest wheat producing area. Occurrence of this disease caused ~3.5% reduction of the total wheat fields in Bangladesh. Its economic effect on the Bangladesh wheat market was little because wheat contributes to 3% of total cereal consumption, among which ~70% have been imported from other countries. However, as a long-term perspective, much greater losses will occur once this disease spreads to other major wheat producing areas of Bangladesh, India, and Pakistan due to the existing favorable condition for the blast pathogen. The wheat blast pathogen belongs to the Magnaporthe oryzae species complex causing blast disease on multiple hosts in the Poaceae family. Phylogenetic analysis revealed that the Bangladesh outbreak strains and the Brazil outbreak strains were the same phylogenetic lineage, suggesting that they might be migrated from Brazil to Bangladesh during the seed import. To protect wheat production of Bangladesh and its neighbors, several measures including rigorous testing of seed health, use of chemicals, crop rotation, reinforcement of quarantine procedures, and increased field monitoring should be implemented. Development of blast resistant wheat varieties should be a long-term solution and combination of different methods with partial resistant lines may suppress this disease for some time.

  20. Wheat Blast: A New Fungal Inhabitant to Bangladesh Threatening World Wheat Production

    PubMed Central

    Sadat, Md. Abu; Choi, Jaehyuk

    2017-01-01

    World wheat production is now under threat due to the wheat blast outbreak in Bangladesh in early March 2016. This is a new disease in this area, indicating the higher possibility of this pathogen spreading throughout the Asia, the world’s largest wheat producing area. Occurrence of this disease caused ~3.5% reduction of the total wheat fields in Bangladesh. Its economic effect on the Bangladesh wheat market was little because wheat contributes to 3% of total cereal consumption, among which ~70% have been imported from other countries. However, as a long-term perspective, much greater losses will occur once this disease spreads to other major wheat producing areas of Bangladesh, India, and Pakistan due to the existing favorable condition for the blast pathogen. The wheat blast pathogen belongs to the Magnaporthe oryzae species complex causing blast disease on multiple hosts in the Poaceae family. Phylogenetic analysis revealed that the Bangladesh outbreak strains and the Brazil outbreak strains were the same phylogenetic lineage, suggesting that they might be migrated from Brazil to Bangladesh during the seed import. To protect wheat production of Bangladesh and its neighbors, several measures including rigorous testing of seed health, use of chemicals, crop rotation, reinforcement of quarantine procedures, and increased field monitoring should be implemented. Development of blast resistant wheat varieties should be a long-term solution and combination of different methods with partial resistant lines may suppress this disease for some time. PMID:28381956

  1. Effect of rice cultivation systems on indigenous arbuscular mycorrhizal fungal community structure.

    PubMed

    Watanarojanaporn, Nantida; Boonkerd, Nantakorn; Tittabutr, Panlada; Longtonglang, Aphakorn; Young, J Peter W; Teaumroong, Neung

    2013-01-01

    Arbuscular mycorrhizal fungi (AMF) in an agricultural ecosystem are necessary for proper management of beneficial symbiosis. Here we explored how the patterns of the AMF community in rice roots were affected by rice cultivation systems (the system of rice intensification [SRI] and the conventional rice cultivation system [CS]), and by compost application during growth stages. Rice plants harvested from SRI-managed plots exhibited considerably higher total biomass, root dry weight, and seed fill than those obtained from conventionally managed plots. Our findings revealed that all AMF sequences observed from CS plots belonged (only) to the genus Glomus, colonizing in rice roots grown under this type of cultivation, while rice roots sown in SRI showed sequences belonging to both Glomus and Acaulospora. The AMF community was compared between the different cultivation types (CS and SRI) and compost applications by principle component analysis. In all rice growth stages, AMF assemblages of CS management were not separated from those of SRI management. The distribution of AMF community composition based on T-RFLP data showed that the AMF community structure was different among four cultivation systems, and there was a gradual increase of Shannon-Weaver indices of diversity (H') of the AMF community under SRI during growth stages. The results of this research indicated that rice grown in SRI-managed plots had more diverse AMF communities than those grown in CS plots.

  2. Effect of Rice Cultivation Systems on Indigenous Arbuscular Mycorrhizal Fungal Community Structure

    PubMed Central

    Watanarojanaporn, Nantida; Boonkerd, Nantakorn; Tittabutr, Panlada; Longtonglang, Aphakorn; Young, J. Peter W.; Teaumroong, Neung

    2013-01-01

    Arbuscular mycorrhizal fungi (AMF) in an agricultural ecosystem are necessary for proper management of beneficial symbiosis. Here we explored how the patterns of the AMF community in rice roots were affected by rice cultivation systems (the system of rice intensification [SRI] and the conventional rice cultivation system [CS]), and by compost application during growth stages. Rice plants harvested from SRI-managed plots exhibited considerably higher total biomass, root dry weight, and seed fill than those obtained from conventionally managed plots. Our findings revealed that all AMF sequences observed from CS plots belonged (only) to the genus Glomus, colonizing in rice roots grown under this type of cultivation, while rice roots sown in SRI showed sequences belonging to both Glomus and Acaulospora. The AMF community was compared between the different cultivation types (CS and SRI) and compost applications by principle component analysis. In all rice growth stages, AMF assemblages of CS management were not separated from those of SRI management. The distribution of AMF community composition based on T-RFLP data showed that the AMF community structure was different among four cultivation systems, and there was a gradual increase of Shannon-Weaver indices of diversity (H′) of the AMF community under SRI during growth stages. The results of this research indicated that rice grown in SRI-managed plots had more diverse AMF communities than those grown in CS plots. PMID:23719585

  3. A novel gene, Pi40(t), linked to the DNA markers derived from NBS-LRR motifs confers broad spectrum of blast resistance in rice.

    PubMed

    Jeung, J U; Kim, B R; Cho, Y C; Han, S S; Moon, H P; Lee, Y T; Jena, K K

    2007-11-01

    Rice blast disease caused by Magnaporthe grisea is a continuous threat to stable rice production worldwide. In a modernized agricultural system, the development of varieties with broad-spectrum and durable resistance to blast disease is essential for increased rice production and sustainability. In this study, a new gene is identified in the introgression line IR65482-4-136-2-2 that has inherited the resistance gene from an EE genome wild Oryza species, O. australiensis (Acc. 100882). Genetic and molecular analysis localized a major resistance gene, Pi40(t), on the short arm of chromosome 6, where four blast resistance genes (Piz, Piz-5, Piz-t, and Pi9) were also identified, flanked by the markers S2539 and RM3330. Through e-Landing, 14 BAC/PAC clones within the 1.81-Mb equivalent virtual contig were identified on Rice Pseudomolecule3. Highly stringent primer sets designed for 6 NBS-LRR motifs located within PAC clone P0649C11 facilitated high-resolution mapping of the new resistance gene, Pi40(t). Following association analysis and detailed haplotyping approaches, a DNA marker, 9871.T7E2b, was identified to be linked to the Pi40(t) gene at the 70 Kb chromosomal region, and differentiated the Pi40(t) gene from the LTH monogenic differential lines possessing genes Piz, Piz-5, Piz-t, and Pi-9. Pi40(t) was validated using the most virulent isolates of Korea as well as the Philippines, suggesting a broad spectrum for the resistance gene. Marker-assisted selection (MAS) and pathotyping of BC progenies having two japonica cultivar genetic backgrounds further supported the potential of the resistance gene in rice breeding. Our study based on new gene identification strategies provides insight into novel genetic resources for blast resistance as well as future studies on cloning and functional analysis of a blast resistance gene useful for rice improvement.

  4. Transcriptional Basis of Drought-Induced Susceptibility to the Rice Blast Fungus Magnaporthe oryzae

    PubMed Central

    Bidzinski, Przemyslaw; Ballini, Elsa; Ducasse, Aurélie; Michel, Corinne; Zuluaga, Paola; Genga, Annamaria; Chiozzotto, Remo; Morel, Jean-Benoit

    2016-01-01

    Plants are often facing several stresses simultaneously. Understanding how they react and the way pathogens adapt to such combinational stresses is poorly documented. Here, we developed an experimental system mimicking field intermittent drought on rice followed by inoculation by the pathogenic fungus Magnaporthe oryzae. This experimental system triggers an enhancement of susceptibility that could be correlated with the dampening of several aspects of plant immunity, namely the oxidative burst and the transcription of several pathogenesis-related genes. Quite strikingly, the analysis of fungal transcription by RNASeq analysis under drought reveals that the fungus is greatly modifying its virulence program: genes coding for small secreted proteins were massively repressed in droughted plants compared to unstressed ones whereas genes coding for enzymes involved in degradation of cell-wall were induced. We also show that drought can lead to the partial breakdown of several major resistance genes by affecting R plant gene and/or pathogen effector expression. We propose a model where a yet unknown plant signal can trigger a change in the virulence program of the pathogen to adapt to a plant host that was affected by drought prior to infection. PMID:27833621

  5. Transcriptional Basis of Drought-Induced Susceptibility to the Rice Blast Fungus Magnaporthe oryzae.

    PubMed

    Bidzinski, Przemyslaw; Ballini, Elsa; Ducasse, Aurélie; Michel, Corinne; Zuluaga, Paola; Genga, Annamaria; Chiozzotto, Remo; Morel, Jean-Benoit

    2016-01-01

    Plants are often facing several stresses simultaneously. Understanding how they react and the way pathogens adapt to such combinational stresses is poorly documented. Here, we developed an experimental system mimicking field intermittent drought on rice followed by inoculation by the pathogenic fungus Magnaporthe oryzae. This experimental system triggers an enhancement of susceptibility that could be correlated with the dampening of several aspects of plant immunity, namely the oxidative burst and the transcription of several pathogenesis-related genes. Quite strikingly, the analysis of fungal transcription by RNASeq analysis under drought reveals that the fungus is greatly modifying its virulence program: genes coding for small secreted proteins were massively repressed in droughted plants compared to unstressed ones whereas genes coding for enzymes involved in degradation of cell-wall were induced. We also show that drought can lead to the partial breakdown of several major resistance genes by affecting R plant gene and/or pathogen effector expression. We propose a model where a yet unknown plant signal can trigger a change in the virulence program of the pathogen to adapt to a plant host that was affected by drought prior to infection.

  6. Gene Deletion of 7,8-Linoleate Diol Synthase of the Rice Blast Fungus

    PubMed Central

    Jernerén, Fredrik; Sesma, Ane; Francheschetti, Marina; Hamberg, Mats; Oliw, Ernst H.

    2010-01-01

    Linoleate diol synthases (LDS) are heme enzymes, which oxygenate 18:2n-6 sequentially to (8R)-hydroperoxylinoleic acid ((8R)-HPODE) and to (5S,8R)-dihydroxy-, (7S,8S)-dihydroxy-, or (8R,11S)-dihydroxylinoleic acids (DiHODE). The genome of the rice blast fungus, Magnaporthe oryzae, contains two genes with homology to LDS. M. oryzae oxidized 18:2n-6 to (8R)-HPODE and to (7S,8S)-DiHODE, (6S,8R)-DiHODE, and (8R,11S)-HODE. Small amounts of 10-hydroxy-(8E,12Z)-octadecadienoic acid and traces of 5,8-DiHODE were also detected by liquid chromatography-mass spectrometry. The contribution of the 7,8-LDS gene to M. oryzae pathogenicity was evaluated by replacement of the catalytic domain with hygromycin and green fluorescent protein variant (SGFP) cassettes. This genetically modified strain Δ7,8-LDS infected rice leaves and roots and formed appressoria and conidia as the native fungus. The Δ7,8-LDS mutant had lost the capacity to biosynthesize all the metabolites except small amounts of 8-hydroxylinoleic acid. Studies with stereospecifically deuterated linoleic acids showed that (8R)-HPODE was formed by abstraction of the pro-S hydrogen at C-8 and antarafacial oxygenation, whereas (7S,8S)-DiHODE and (8R,11S)-DiHODE were formed from (8R)-HPODE by suprafacial hydrogen abstraction and oxygenation at C-7 and C-11, respectively. A mac1 suppressor mutant (Δmac1 sum1–99) of M. oryzae, which shows cAMP-independent protein kinase A activity, oxygenated 18:2n-6 to increased amounts of (10R)-HPODE and (5S,8R)-DiHODE. Expression of the 7,8-LDS gene but not of the second homologue was detected in the suppressor mutant. This suggests that PKA-mediated signaling pathway regulates the dioxygenase and hydroperoxide isomerase activities of M. oryzae. PMID:20023302

  7. Morphological and molecular characterization of Magnaporthe oryzae (fungus) from infected rice leaf samples

    NASA Astrophysics Data System (ADS)

    Muni, Nurulhidayah Mat; Nadarajah, Kalaivani

    2014-09-01

    Magnaporthe oryzae is a plant-pathogenic fungus that causes a serious disease affecting rice called rice blast. Outbreaks of rice blast have been a threat to the global production of rice. This fungal disease is estimated to cause production losses of US55 million each year in South and Southeast Asia. It has been used as a primary model for elucidating various aspects of the host-pathogen interaction with its host. We have isolated five isolates of Magnaporthe oryzae from diseased leaf samples obtained from the field at Kompleks Latihan MADA, Kedah, Malaysia. We have identified the isolates using morphological and microscopic studies on the fungal spores and the lesions on the diseased leaves. Amplification of the internal transcribed spacer (ITS) was carried out with universal primers ITS1 and ITS4. The sequence of each isolates showed at least 99% nucleotide identity with the corresponding sequence in GenBank for Magnaporthe oryzae.

  8. Crystal Structure of Manganese Lipoxygenase of the Rice Blast Fungus Magnaporthe oryzae*

    PubMed Central

    Wennman, Anneli; Oliw, Ernst H.; Karkehabadi, Saeid; Chen, Yang

    2016-01-01

    Lipoxygenases (LOX) are non-heme metal enzymes, which oxidize polyunsaturated fatty acids to hydroperoxides. All LOX belong to the same gene family, and they are widely distributed. LOX of animals, plants, and prokaryotes contain iron as the catalytic metal, whereas fungi express LOX with iron or with manganese. Little is known about metal selection by LOX and the adjustment of the redox potentials of their protein-bound catalytic metals. Thirteen three-dimensional structures of animal, plant, and prokaryotic FeLOX are available, but none of MnLOX. The MnLOX of the most important plant pathogen, the rice blast fungus Magnaporthe oryzae (Mo), was expressed in Pichia pastoris. Mo-MnLOX was deglycosylated, purified to homogeneity, and subjected to crystal screening and x-ray diffraction. The structure was solved by sulfur and manganese single wavelength anomalous dispersion to a resolution of 2.0 Å. The manganese coordinating sphere is similar to iron ligands of coral 8R-LOX and soybean LOX-1 but is not overlapping. The Asn-473 is positioned on a short loop (Asn-Gln-Gly-Glu-Pro) instead of an α-helix and forms hydrogen bonds with Gln-281. Comparison with FeLOX suggests that Phe-332 and Phe-525 might contribute to the unique suprafacial hydrogen abstraction and oxygenation mechanism of Mo-MnLOX by controlling oxygen access to the pentadiene radical. Modeling suggests that Arg-525 is positioned close to Arg-182 of 8R-LOX, and both residues likely tether the carboxylate group of the substrate. An oxygen channel could not be identified. We conclude that Mo-MnLOX illustrates a partly unique variation of the structural theme of FeLOX. PMID:26783260

  9. Characterization and fine mapping of the rice blast resistance gene Pia.

    PubMed

    Zeng, Xiaoshan; Yang, Xianfeng; Zhao, Zhenghong; Lin, Fei; Wang, Ling; Pan, Qinghua

    2011-04-01

    Blast, caused by Magnaporthe oryzae, is one of the most widespread and destructive diseases of rice. Breeding durable resistant cultivars (cvs) can be achieved by pyramiding of various resistance (R) genes. Pia, carried by cv. Aichi Asahi, was evaluated against 612 isolates of M. oryzae collected from 10 Chinese provinces. The Pia gene expresses weak resistance in all the provinces except for Jiangsu. Genomic position-ready marker-based linkage analysis was carried out in a mapping population consisting of 800 F(2) plants derived from a cross of Aichi Asahi×Kasalath. The locus was defined in an interval of approximately 90 kb, flanked by markers A16 and A21. Four candidate genes (Pia-1, Pia-2, Pia-3, and Pia-4), all having the R gene conserved structure, were predicted in the interval using the cv. Nipponbare genomic sequence. Four candidate resistance gene (CRG) markers (A17, A25, A26, and A27), derived from the four candidates, were subjected to genotyping with the recombinants detected at the flanking markers. The first three markers completely co-segregated with the Pia locus, and the fourth was absent in the Aichi Asahi genome and disordered with the Pia locus and its flanking markers, indicating that the fourth candidate gene, Pia-4, could be excluded. Co-segregation marker-based genotyping of the three sets of differentials with known R gene genotypes revealed that the genotype of A26 (Pia-3) perfectly matched the R gene genotype of Pia, indicating that Pia-3 is the strongest candidate gene for Pia.

  10. Crystal Structure of Manganese Lipoxygenase of the Rice Blast Fungus Magnaporthe oryzae.

    PubMed

    Wennman, Anneli; Oliw, Ernst H; Karkehabadi, Saeid; Chen, Yang

    2016-04-08

    Lipoxygenases (LOX) are non-heme metal enzymes, which oxidize polyunsaturated fatty acids to hydroperoxides. All LOX belong to the same gene family, and they are widely distributed. LOX of animals, plants, and prokaryotes contain iron as the catalytic metal, whereas fungi express LOX with iron or with manganese. Little is known about metal selection by LOX and the adjustment of the redox potentials of their protein-bound catalytic metals. Thirteen three-dimensional structures of animal, plant, and prokaryotic FeLOX are available, but none of MnLOX. The MnLOX of the most important plant pathogen, the rice blast fungusMagnaporthe oryzae(Mo), was expressed inPichia pastoris.Mo-MnLOX was deglycosylated, purified to homogeneity, and subjected to crystal screening and x-ray diffraction. The structure was solved by sulfur and manganese single wavelength anomalous dispersion to a resolution of 2.0 Å. The manganese coordinating sphere is similar to iron ligands of coral 8R-LOX and soybean LOX-1 but is not overlapping. The Asn-473 is positioned on a short loop (Asn-Gln-Gly-Glu-Pro) instead of an α-helix and forms hydrogen bonds with Gln-281. Comparison with FeLOX suggests that Phe-332 and Phe-525 might contribute to the unique suprafacial hydrogen abstraction and oxygenation mechanism of Mo-MnLOX by controlling oxygen access to the pentadiene radical. Modeling suggests that Arg-525 is positioned close to Arg-182 of 8R-LOX, and both residues likely tether the carboxylate group of the substrate. An oxygen channel could not be identified. We conclude that Mo-MnLOX illustrates a partly unique variation of the structural theme of FeLOX.

  11. Rice C2-domain proteins are induced and translocated to the plasma membrane in response to a fungal elicitor.

    PubMed

    Kim, Cha Young; Koo, Yoon Duck; Jin, Jing Bo; Moon, Byeong Cheol; Kang, Chang Ho; Kim, Sun Tae; Park, Byung Ouk; Lee, So Young; Kim, Man Lyang; Hwang, Inhwan; Kang, Kyu Young; Bahk, Jeong Dong; Lee, Sang Yeol; Cho, Moo Je

    2003-10-14

    Hundreds of proteins involved in signaling pathways contain a Ca(2+)-dependent membrane-binding motif called the C2-domain. However, no small C2-domain proteins consisting of a single C2-domain have been reported in animal cells. We have isolated two cDNA clones, OsERG1a and OsERG1b, that encode two small C2-domain proteins of 156 and 159 amino acids, respectively, from a fungal elicitor-treated rice cDNA library. The clones are believed to have originated from a single gene by alternative splicing. Transcript levels of the OsERG1 gene are dramatically elevated by a fungal elicitor prepared from Magnaporthe grisea or by Ca(2+) ions. The OsERG1 protein produced in Escherichia coli binds to phospholipid vesicles in a Ca(2+)-dependent manner and is translocated to the plasma membrane of plant cells by treatment with either a fungal elicitor or a Ca(2+) ionophore. These results suggest that OsERG1 proteins containing a single C2-domain are involved in plant defense signaling systems.

  12. Plant defence suppression is mediated by a fungal sirtuin during rice infection by Magnaporthe oryzae.

    PubMed

    Fernandez, Jessie; Marroquin-Guzman, Margarita; Nandakumar, Renu; Shijo, Sara; Cornwell, Kathryn M; Li, Gang; Wilson, Richard A

    2014-10-01

    Crop destruction by the hemibiotrophic rice pathogen Magnaporthe oryzae requires plant defence suppression to facilitate extensive biotrophic growth in host cells before the onset of necrosis. How this is achieved at the genetic level is not well understood. Here, we report that a M. oryzae sirtuin, MoSir2, plays an essential role in rice defence suppression and colonization by controlling superoxide dismutase (SOD) gene expression. Loss of MoSir2 function in Δsir2 strains did not affect appressorial function, but biotrophic growth in rice cells was attenuated. Compared to wild type, Δsir2 strains failed to neutralize plant-derived reactive oxygen species (ROS) and elicited robust defence responses in rice epidermal cells that included elevated pathogenesis-related gene expression and granular depositions. Deletion of a SOD-encoding gene under MoSir2 control generated Δsod1 deletion strains that mimicked Δsir2 for impaired rice defence suppression, confirming SOD activity as a downstream output of MoSir2. In addition, comparative protein acetylation studies and forward genetic analyses identified a JmjC domain-containing protein as a likely target of MoSir2, and a Δsir2 Δjmjc double mutant was restored for MoSOD1 expression and defence suppression in rice epidermal cells. Together, this work reveals MoSir2 and MoJmjC as novel regulators of early rice cell infection.

  13. The MET13 methylenetetrahydrofolate reductase gene is essential for infection-related morphogenesis in the rice blast fungus Magnaporthe oryzae.

    PubMed

    Yan, Xia; Que, Yawei; Wang, Hong; Wang, Congcong; Li, Ya; Yue, Xiaofeng; Ma, Zhonghua; Talbot, Nicholas J; Wang, Zhengyi

    2013-01-01

    Methylenetetrahydrofolate reductases (MTHFRs) play a key role in the biosynthesis of methionine in both prokaryotic and eukaryotic organisms. In this study, we report the identification of a novel T-DNA-tagged mutant WH672 in the rice blast fungus Magnaporthe oryzae, which was defective in vegetative growth, conidiation and pathogenicity. Analysis of the mutation confirmed a single T-DNA insertion upstream of MET13, which encodes a 626-amino-acid protein encoding a MTHFR. Targeted gene deletion of MET13 resulted in mutants that were non-pathogenic and significantly impaired in aerial growth and melanin pigmentation. All phenotypes associated with Δmet13 mutants could be overcome by addition of exogenous methionine. The M. oryzae genome contains a second predicted MTHFR-encoding gene, MET12. The deduced amino acid sequences of Met13 and Met12 share 32% identity. Interestingly, Δmet12 mutants produced significantly less conidia compared with the isogenic wild-type strain and grew very poorly in the absence of methionine, but were fully pathogenic. Deletion of both genes resulted in Δmet13Δmet12 mutants that showed similar phenotypes to single Δmet13 mutants. Taken together, we conclude that the MTHFR gene, MET13, is essential for infection-related morphogenesis by the rice blast fungus M. oryzae.

  14. The MET13 Methylenetetrahydrofolate Reductase Gene Is Essential for Infection-Related Morphogenesis in the Rice Blast Fungus Magnaporthe oryzae

    PubMed Central

    Wang, Hong; Wang, Congcong; Li, Ya; Yue, Xiaofeng; Ma, Zhonghua; Talbot, Nicholas J.; Wang, Zhengyi

    2013-01-01

    Methylenetetrahydrofolate reductases (MTHFRs) play a key role in the biosynthesis of methionine in both prokaryotic and eukaryotic organisms. In this study, we report the identification of a novel T-DNA-tagged mutant WH672 in the rice blast fungus Magnaporthe oryzae, which was defective in vegetative growth, conidiation and pathogenicity. Analysis of the mutation confirmed a single T-DNA insertion upstream of MET13, which encodes a 626-amino-acid protein encoding a MTHFR. Targeted gene deletion of MET13 resulted in mutants that were non-pathogenic and significantly impaired in aerial growth and melanin pigmentation. All phenotypes associated with Δmet13 mutants could be overcome by addition of exogenous methionine. The M. oryzae genome contains a second predicted MTHFR-encoding gene, MET12. The deduced amino acid sequences of Met13 and Met12 share 32% identity. Interestingly, Δmet12 mutants produced significantly less conidia compared with the isogenic wild-type strain and grew very poorly in the absence of methionine, but were fully pathogenic. Deletion of both genes resulted in Δmet13Δmet12 mutants that showed similar phenotypes to single Δmet13 mutants. Taken together, we conclude that the MTHFR gene, MET13, is essential for infection-related morphogenesis by the rice blast fungus M. oryzae. PMID:24116181

  15. Close linkage of a blast resistance gene, Pias(t), with a bacterial leaf blight resistance gene, Xa1-as(t), in a rice cultivar 'Asominori'.

    PubMed

    Endo, Takashi; Yamaguchi, Masayuki; Kaji, Ryota; Nakagomi, Koji; Kataoka, Tomomori; Yokogami, Narifumi; Nakamura, Toshiki; Ishikawa, Goro; Yonemaru, Jun-Ichi; Nishio, Takeshi

    2012-12-01

    It has long been known that a bacterial leaf blight-resistant line in rice obtained from a crossing using 'Asominori' as a resistant parent also has resistance to blast, but a blast resistance gene in 'Asominori' has not been investigated in detail. In the present study, a blast resistance gene in 'Asominori', tentatively named Pias(t), was revealed to be located within 162-kb region between DNA markers YX4-3 and NX4-1 on chromosome 4 and to be linked with an 'Asominori' allele of the bacterial leaf blight resistance gene Xa1, tentatively named Xa1-as(t). An 'Asominori' allele of Pias(t) was found to be dominant and difference of disease severity between lines having the 'Asominori' allele of Pias(t) and those without it was 1.2 in disease index from 0 to 10. Pias(t) was also closely linked with the Ph gene controlling phenol reaction, suggesting the possibility of successful selection of blast resistance using the phenol reaction. Since blast-resistant commercial cultivars have been developed using 'Asominori' as a parent, Pias(t) is considered to be a useful gene in rice breeding for blast resistance.

  16. Multiplex SSR-PCR approaches for semi-automated genotyping and characterization of loci linked to blast disease resistance genes in rice.

    PubMed

    Ashkani, Sadegh; Rafii, Mohd Yusop; Shabanimofrad, Mahmoodreza; Foroughi, Majid; Azizia, Parisa; Akhtar, Mohd Sayeed; Sahebi, Mahbod; Harun, Abd Rahim; Nasehi, Abbas

    2015-11-01

    In the present study, 63 polymorphic microsatellite markers related to rice blast resistance genes were fluorescently labelled at the 5'-end with either 6-FAM or HEX using the G5 dye set and incorporated into a multiplex SSR-PCR for the detection of fragments using an automated system. For rice F3 families obtained from crosses between Pongsu Seribu 2 (Malaysian blast resistant cultivar) and Mahsuri (a susceptible rice cultivar), the genotypes for 13 designated multiplex SSR panels were determined. The genotyping assays were performed using a capillary-based ABIPRISM 3100 genetic analyser. The sizes of the SSRs alleles observed in the range from 79 to 324 bp. The observed marker segregation data were analysed using the Chi(2) test. A genetic linkage map covering ten chromosomes and comprising 63 polymorphic SSR markers was constructed, and the distorted loci were localised to linkage groups. The results indicated that distorted loci are presented on eight chromosomes.

  17. Coevolutionary Dynamics of Rice Blast Resistance Gene Pi-ta and Magnaporthe oryzae Avirulence Gene AVR-Pita 1.

    PubMed

    Jia, Yulin; Zhou, Erxun; Lee, Seonghee; Bianco, Tracy

    2016-07-01

    The Pi-ta gene in rice is effective in preventing infections by Magnaporthe oryzae strains that contain the corresponding avirulence gene, AVR-Pita1. Diverse haplotypes of AVR-Pita1 have been identified from isolates of M. oryzae from rice production areas in the United States and worldwide. DNA sequencing and mapping studies have revealed that AVR-Pita1 is highly unstable, while expression analysis and quantitative resistance loci mapping of the Pi-ta locus revealed complex evolutionary mechanisms of Pi-ta-mediated resistance. Among these studies, several Pi-ta transcripts were identified, most of which are probably derived from alternative splicing and exon skipping, which could produce functional resistance proteins that support a new concept of coevolution of Pi-ta and AVR-Pita1. User-friendly DNA markers for Pi-ta have been developed to support marker-assisted selection, and development of new rice varieties with the Pi-ta markers. Genome-wide association studies revealed a link between Pi-ta-mediated resistance and yield components suggesting that rice has evolved a complicated defense mechanism against the blast fungus. In this review, we detail the current understanding of Pi-ta allelic variation, its linkage with rice productivity, AVR-Pita allelic variation, and the coevolution of Pi-ta and AVR-Pita in Oryza species and M. oryzae populations, respectively. We also review the genetic and molecular basis of Pi-ta and AVR-Pita interaction, and its value in marker-assisted selection and engineering resistance.

  18. Effect of flour-blasting of brown rice on reduction of cooking time and resulting texture

    USDA-ARS?s Scientific Manuscript database

    Long grain non-parboiled, long grain parboiled, and American basmati-type brown rice were bombarded with parboiled rice flour sufficient to create microperforations in the water-resistant outer coat of the seed. These microperforations in the treated rice significantly increased the rate of hydratio...

  19. The Arabidopsis AtNPR1 inversely modulates defense responses against fungal, bacterial, or viral pathogens while conferring hypersensitivity to abiotic stresses in transgenic rice.

    PubMed

    Quilis, Jordi; Peñas, Gisela; Messeguer, Joaquima; Brugidou, Christophe; San Segundo, Blanca

    2008-09-01

    The nonexpressor of pathogenesis-related (PR) genes (NPR1) protein plays an important role in mediating defense responses activated by pathogens in Arabidopsis. In rice, a disease-resistance pathway similar to the Arabidopsis NPR1-mediated signaling pathway one has been described. Here, we show that constitutive expression of the Arabidopsis NPR1 (AtNPR1) gene in rice confers resistance against fungal and bacterial pathogens. AtNPR1 exerts its protective effects against fungal pathogens by priming the expression of salicylic acid (SA)-responsive endogenous genes, such as the PR1b, TLP (PR5), PR10, and PBZ1. However, expression of AtNPR1 in rice has negative effects on viral infections. The AtNPR1-expressing rice plants showed a higher susceptibility to infection by the Rice yellow mottle virus (RYMV) which correlated well with a misregulation of RYMV-responsive genes, including expression of the SA-regulated RNA-dependent RNA polymerase 1 gene (OsRDR1). Moreover, AtNPR1 negatively regulates the expression of genes playing a role in the plant response to salt and drought stress (rab21, salT, and dip1), which results in a higher sensitivity of AtNPR1 rice to the two types of abiotic stress. These observations suggest that AtNPR1 has both positive and negative regulatory roles in mediating defense responses against biotic and abiotic stresses.

  20. Common Genetic Pathways Regulate Organ-Specific Infection-Related Development in the Rice Blast Fungus[W

    PubMed Central

    Tucker, Sara L.; Besi, Maria I.; Galhano, Rita; Franceschetti, Marina; Goetz, Stephan; Lenhert, Steven; Osbourn, Anne; Sesma, Ane

    2010-01-01

    Magnaporthe oryzae is the most important fungal pathogen of rice (Oryza sativa). Under laboratory conditions, it is able to colonize both aerial and underground plant organs using different mechanisms. Here, we characterize an infection-related development in M. oryzae produced on hydrophilic polystyrene (PHIL-PS) and on roots. We show that fungal spores develop preinvasive hyphae (pre-IH) from hyphopodia (root penetration structures) or germ tubes and that pre-IH also enter root cells. Changes in fungal cell wall structure accompanying pre-IH are seen on both artificial and root surfaces. Using characterized mutants, we show that the PMK1 (for pathogenicity mitogen-activated protein kinase 1) pathway is required for pre-IH development. Twenty mutants with altered pre-IH differentiation on PHIL-PS identified from an insertional library of 2885 M. oryzae T-DNA transformants were found to be defective in pathogenicity. The phenotypic analysis of these mutants revealed that appressorium, hyphopodium, and pre-IH formation are genetically linked fungal developmental processes. We further characterized one of these mutants, M1373, which lacked the M. oryzae ortholog of exportin-5/Msn5p (EXP5). Mutants lacking EXP5 were much less virulent on roots, suggesting an important involvement of proteins and/or RNAs transported by EXP5 during M. oryzae root infection. PMID:20348434

  1. Different farming and water regimes in Italian rice fields affect arbuscular mycorrhizal fungal soil communities.

    PubMed

    Lumini, Erica; Vallino, Marta; Alguacil, Maria M; Romani, Marco; Bianciotto, Valeria

    2011-07-01

    Arbuscular mycorrhizal fungi (AMF) comprise one of the main components of soil microbiota in most agroecosystems. These obligate mutualistic symbionts colonize the roots of most plants, including crop plants. Many papers have indicated that different crop management practices could affect AMF communities and their root colonization. However, there is little knowledge available on the influence of conventional and low-input agriculture on root colonization and AMF molecular diversity in rice fields. Two different agroecosystems (continuous conventional high-input rice monocropping and organic farming with a five-year crop rotation) and two different water management regimes have been considered in this study. Both morphological and molecular analyses were performed. The soil mycorrhizal potential, estimated using clover trap cultures, was high and similar in the two agroecosystems. The diversity of the AMF community in the soil, calculated by means of PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism) and 18S rDNA sequencing on clover trap cultures roots, was higher for the organic cultivation. The rice roots cultivated in the conventional agrosystem or under permanent flooding showed no AMF colonization, while the rice plants grown under the organic agriculture system showed typical mycorrhization patterns. Considered together, our data suggest that a high-input cropping system and conventional flooding depress AMF colonization in rice roots and that organic managements could help maintain a higher diversity of AMF communities in soil.

  2. Expression of a plant defensin in rice confers resistance to fungal phytopathogens.

    PubMed

    Jha, Sanjay; Chattoo, Bharat B

    2010-06-01

    Transgenic rice (Oryza sativa L. cv. Pusa basmati 1), overexpressing the Rs-AFP2 defensin gene from the Raphanus sativus was generated by Agrobacterium tumefaciens-mediated transformation. Expression levels of Rs-AFP2 ranged from 0.45 to 0.53% of total soluble protein in transgenic plants. It was observed that constitutive expression of Rs-AFP2 suppresses the growth of Magnaporthe oryzae and Rhizoctonia solani by 77 and 45%, respectively. No effect on plant morphology was observed in the Rs-AFP2 expressing rice lines. The inhibitory activity of protein extracts prepared from leaves of Rs-AFP2 plants on the in vitro growth of M. oryzae indicated that the Rs-AFP2 protein produced by transgenic rice plants was biologically active. Transgene expression of Rs-AFP2 was not accompanied by an induction of pathogenesis-related (PR) gene expression, suggesting that the expression of Rs-AFP2 directly inhibits the pathogens. Here, we demonstrate that transgenic rice plants expressing the Rs-AFP2 gene show enhanced resistance to M. oryzae and R. solani, two of the most important pathogens of rice.

  3. Machine learning techniques in disease forecasting: a case study on rice blast prediction

    PubMed Central

    Kaundal, Rakesh; Kapoor, Amar S; Raghava, Gajendra PS

    2006-01-01

    -based web server for rice blast prediction, a first of its kind worldwide, which can help the plant science community and farmers in their decision making process. The server is freely available at . PMID:17083731

  4. Structure of a rice beta-glucanase gene regulated by ethylene, cytokinin, wounding, salicylic acid and fungal elicitors.

    PubMed

    Simmons, C R; Litts, J C; Huang, N; Rodriguez, R L

    1992-01-01

    A rice beta-glucanase gene was sequenced and its expression analyzed at the level of mRNA accumulation. This gene (Gns1) is expressed at relatively low levels in germinating seeds, shoots, leaves, panicles and callus, but it is expressed at higher levels in roots. Expression in the roots appears to be constitutive. Shoots express Gns1 at much higher levels when treated with ethylene, cytokinin, salicylic acid, and fungal elicitors derived from the pathogen Sclerotium oryzae or from the non-pathogen Saccharomyces cereviseae. Shoots also express Gns1 at higher levels in response to wounding. Expression in the shoots is not significantly affected by auxin, gibberellic acid or abscisic acid. The beta-glucanase shows 82% amino acid similarity to the barley 1,3;1,4-beta-D-glucanases, and from hybridization studies it is the beta-glucanase gene in the rice genome closest to the barley 1,3;1,4-beta-glucanase EI gene. The mature peptide has a calculated molecular mass of 32 kDa. The gene has a large 3145 bp intron in the codon for the 25th amino acid of the signal peptide. The gene exhibits a very strong codon bias of 99% G + C in the third position of the codon in the mature peptide coding region, but only 61% G + C in the signal peptide region.

  5. A novel blast resistance gene, Pi54rh cloned from wild species of rice, Oryza rhizomatis confers broad spectrum resistance to Magnaporthe oryzae.

    PubMed

    Das, Alok; Soubam, D; Singh, P K; Thakur, S; Singh, N K; Sharma, T R

    2012-06-01

    The dominant rice blast resistance gene, Pi54 confers resistance to Magnaporthe oryzae in different parts of India. In our effort to identify more effective forms of this gene, we isolated an orthologue of Pi54 named as Pi54rh from the blast-resistant wild species of rice, Oryza rhizomatis, using allele mining approach and validated by complementation. The Pi54rh belongs to CC-NBS-LRR family of disease resistance genes with a unique Zinc finger (C(3)H type) domain. The 1,447 bp Pi54rh transcript comprises of 101 bp 5'-UTR, 1,083 bp coding region and 263 bp 3'-UTR, driven by pathogen inducible promoter. We showed the extracellular localization of Pi54rh protein and the presence of glycosylation, myristoylation and phosphorylation sites which implicates its role in signal transduction process. This is in contrast to other blast resistance genes that are predicted to be intracellular NBS-LRR-type resistance proteins. The Pi54rh was found to express constitutively at basal level in the leaves, but upregulates 3.8-fold at 96 h post-inoculation with the pathogen. Functional validation of cloned Pi54rh gene using complementation test showed high degree of resistance to seven isolates of M. oryzae collected from different geographical locations of India. In this study, for the first time, we demonstrated that a rice blast resistance gene Pi54rh cloned from wild species of rice provides broad spectrum resistance to M. oryzae hence can be used in rice improvement breeding programme.

  6. Fungal endophyte Phomopsis liquidambari affects nitrogen transformation processes and related microorganisms in the rice rhizosphere

    PubMed Central

    Yang, Bo; Wang, Xiao-Mi; Ma, Hai-Yan; Yang, Teng; Jia, Yong; Zhou, Jun; Dai, Chuan-Chao

    2015-01-01

    The endophytic fungus Phomopsis liquidambari performs an important ecosystem service by assisting its host with acquiring soil nitrogen (N), but little is known regarding how this fungus influences soil N nutrient properties and microbial communities. In this study, we investigated the impact of P. liquidambari on N dynamics, the abundance and composition of N cycling genes in rhizosphere soil treated with three levels of N (urea). Ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB) and diazotrophs were assayed using quantitative real-time polymerase chain reaction and denaturing gradient gel electrophoresis at four rice growing stages (S0: before planting, S1: tillering stage, S2: grain filling stage, and S3: ripening stage). A significant increase in the available nitrate and ammonium contents was found in the rhizosphere soil of endophyte-infected rice under low N conditions. Moreover, P. liquidambari significantly increased the potential nitrification rates, affected the abundance and community structure of AOA, AOB, and diazotrophs under low N conditions in the S1 and S2 stages. The root exudates were determined due to their important role in rhizosphere interactions. P. liquidambari colonization altered the exudation of organic compounds by rice roots and P. liquidambari increased the concentration of soluble saccharides, total free amino acids and organic acids in root exudates. Plant-soil feedback mechanisms may be mediated by the rice-endophyte interaction, especially in nutrient-limited soil. PMID:26441912

  7. The DnaJ protein OsDjA6 negatively regulates rice innate immunity to the blast fungus Magnaporthe oryzae.

    PubMed

    Zhong, Xionghui; Yang, Jiuxia; Shi, Yanlong; Wang, Xuli; Wang, Guo-Liang

    2017-02-21

    Rice blast, caused by Magnaporthe oryzae (synonym: Pyricularia oryzae), severely reduces rice production and grain quality. The molecular mechanism of rice resistance to M. oryzae is not fully understood. In the present study, we identified a chaperone DnaJ protein, OsDjA6, that is involved in basal resistance to M. oryzae in rice. The OsDjA6 protein is distributed in the entire rice cell. The expression of OsDjA6 is significantly induced in rice after infection with a compatible isolate. Silencing of OsDjA6 in transgenic rice enhances resistance to M. oryzae and also results in an increased burst of reactive oxygen species after flg22 and chitin treatments. In addition, the expression levels of WRKY45, NPR1, and PR5 are increased in the OsDjA6 RNAi plants, indicating that OsDjA6 may mediate resistance by affecting the salicylic acid pathway. Finally, we found that OsDjA6 directly interacts with the E3 ligase OsZFP1 in vitro and in vivo. These results suggest that the DnaJ protein OsDjA6 negatively regulates rice innate immunity, probably via the ubiquitination proteasome degradation pathway. This article is protected by copyright. All rights reserved.

  8. Enhanced Rice Blast Resistance by CRISPR/Cas9-Targeted Mutagenesis of the ERF Transcription Factor Gene OsERF922

    PubMed Central

    Wang, Chunlian; Liu, Piqing; Lei, Cailin; Hao, Wei; Gao, Ying; Liu, Yao-Guang; Zhao, Kaijun

    2016-01-01

    Rice blast is one of the most destructive diseases affecting rice worldwide. The adoption of host resistance has proven to be the most economical and effective approach to control rice blast. In recent years, sequence-specific nucleases (SSNs) have been demonstrated to be powerful tools for the improvement of crops via gene-specific genome editing, and CRISPR/Cas9 is thought to be the most effective SSN. Here, we report the improvement of rice blast resistance by engineering a CRISPR/Cas9 SSN (C-ERF922) targeting the OsERF922 gene in rice. Twenty-one C-ERF922-induced mutant plants (42.0%) were identified from 50 T0 transgenic plants. Sanger sequencing revealed that these plants harbored various insertion or deletion (InDel) mutations at the target site. We showed that all of the C-ERF922-induced allele mutations were transmitted to subsequent generations. Mutant plants harboring the desired gene modification but not containing the transferred DNA were obtained by segregation in the T1 and T2 generations. Six T2 homozygous mutant lines were further examined for a blast resistance phenotype and agronomic traits, such as plant height, flag leaf length and width, number of productive panicles, panicle length, number of grains per panicle, seed setting percentage and thousand seed weight. The results revealed that the number of blast lesions formed following pathogen infection was significantly decreased in all 6 mutant lines compared with wild-type plants at both the seedling and tillering stages. Furthermore, there were no significant differences between any of the 6 T2 mutant lines and the wild-type plants with regard to the agronomic traits tested. We also simultaneously targeted multiple sites within OsERF922 by using Cas9/Multi-target-sgRNAs (C-ERF922S1S2 and C-ERF922S1S2S3) to obtain plants harboring mutations at two or three sites. Our results indicate that gene modification via CRISPR/Cas9 is a useful approach for enhancing blast resistance in rice. PMID

  9. Enhanced Rice Blast Resistance by CRISPR/Cas9-Targeted Mutagenesis of the ERF Transcription Factor Gene OsERF922.

    PubMed

    Wang, Fujun; Wang, Chunlian; Liu, Piqing; Lei, Cailin; Hao, Wei; Gao, Ying; Liu, Yao-Guang; Zhao, Kaijun

    2016-01-01

    Rice blast is one of the most destructive diseases affecting rice worldwide. The adoption of host resistance has proven to be the most economical and effective approach to control rice blast. In recent years, sequence-specific nucleases (SSNs) have been demonstrated to be powerful tools for the improvement of crops via gene-specific genome editing, and CRISPR/Cas9 is thought to be the most effective SSN. Here, we report the improvement of rice blast resistance by engineering a CRISPR/Cas9 SSN (C-ERF922) targeting the OsERF922 gene in rice. Twenty-one C-ERF922-induced mutant plants (42.0%) were identified from 50 T0 transgenic plants. Sanger sequencing revealed that these plants harbored various insertion or deletion (InDel) mutations at the target site. We showed that all of the C-ERF922-induced allele mutations were transmitted to subsequent generations. Mutant plants harboring the desired gene modification but not containing the transferred DNA were obtained by segregation in the T1 and T2 generations. Six T2 homozygous mutant lines were further examined for a blast resistance phenotype and agronomic traits, such as plant height, flag leaf length and width, number of productive panicles, panicle length, number of grains per panicle, seed setting percentage and thousand seed weight. The results revealed that the number of blast lesions formed following pathogen infection was significantly decreased in all 6 mutant lines compared with wild-type plants at both the seedling and tillering stages. Furthermore, there were no significant differences between any of the 6 T2 mutant lines and the wild-type plants with regard to the agronomic traits tested. We also simultaneously targeted multiple sites within OsERF922 by using Cas9/Multi-target-sgRNAs (C-ERF922S1S2 and C-ERF922S1S2S3) to obtain plants harboring mutations at two or three sites. Our results indicate that gene modification via CRISPR/Cas9 is a useful approach for enhancing blast resistance in rice.

  10. Calpains are involved in asexual and sexual development, cell wall integrity and pathogenicity of the rice blast fungus

    PubMed Central

    Liu, Xiao-Hong; Ning, Guo-Ao; Huang, Lu-Yao; Zhao, Ya-Hui; Dong, Bo; Lu, Jian-Ping; Lin, Fu-Cheng

    2016-01-01

    Calpains are ubiquitous and well-conserved proteins that belong to the calcium-dependent, non-lysosomal cysteine protease family. In this study, 8 putative calpains were identified using Pfam domain analysis and BlastP searches in M. oryzae. Three single gene deletion mutants (ΔMocapn7, ΔMocapn9 and ΔMocapn14) and two double gene deletion mutants (ΔMocapn4ΔMocapn7 and ΔMocapn9ΔMocapn7) were obtained using the high-throughput gene knockout system. The calpain disruption mutants showed defects in colony characteristics, conidiation, sexual reproduction and cell wall integrity. The mycelia of the ΔMocapn7, ΔMocapn4ΔMocapn7 and ΔMocapn9ΔMocapn7 mutants showed reduced pathogenicity on rice and barley. PMID:27502542

  11. Identification, cloning, and characterization of PWL2, a gene for host species specificity in the rice blast fungus.

    PubMed Central

    Sweigard, J A; Carroll, A M; Kang, S; Farrall, L; Chumley, F G; Valent, B

    1995-01-01

    Genetic analysis of host specificity in the rice blast fungus (Magnaporthe grisea) identified a single gene, PWL2 (for Pathogenicity toward Weeping Lovegrass), that exerts a major effect on the ability of this fungus to infect weeping lovegrass (Eragrostis curvula). The allele of the PWL2 gene conferring nonpathogenicity was genetically unstable, with the frequent appearance of spontaneous pathogenic mutants. PWL2 was cloned based on its map position. Large deletions detected in pathogenic mutants guided the gene cloning efforts. Transformants harboring the cloned PWL2 gene lost pathogenicity toward weeping lovegrass but remained fully pathogenic toward other host plants. Thus, the PWL2 host species specificity gene has properties analogous to classical avirulence genes, which function to prevent infection of certain cultivars of a particular host species. The PWL2 gene encodes a glycine-rich, hydrophilic protein (16 kD) with a putative secretion signal sequence. The pathogenic allele segregating in the mapping population, pwl2-2, differed from PWL2 by a single base pair substitution that resulted in a loss of function. The PWL2 locus is highly polymorphic among rice pathogens from diverse geographic locations. PMID:7549480

  12. Effect of Early Screening for Invasive Fungal Infections in U.S. Service Members with Explosive Blast Injuries

    PubMed Central

    Weintrob, Amy C.; Rodriguez, Carlos; Dunne, James R.; Weisbrod, Allison B.; Hinkle, Mary; Warkentien, Tyler; Murray, Clinton K.; Oh, John; Millar, Eugene V.; Shah, Jinesh; Shaikh, Faraz; Gregg, Stacie; Lloyd, Gina; Stevens, Julie; Carson, M. Leigh; Aggarwal, Deepak; Tribble, David R.

    2014-01-01

    Abstract Background: An outbreak of invasive fungal infections (IFI) began in 2009 among United States servicemen who sustained blast injuries in Afghanistan. In response, the military trauma community sought a uniform approach to early diagnosis and treatment. Toward this goal, a local clinical practice guideline (CPG) was implemented at Landstuhl Regional Medical Center (LRMC) in early 2011 to screen for IFI in high-risk patients using tissue histopathology and fungal cultures. Methods: We compared IFI cases identified after initiation of the CPG (February through August 2011) to cases from a pre-CPG period (June 2009 through January 2011). Results: Sixty-one patients were screened in the CPG period, among whom 30 IFI cases were identified and compared with 44 pre-CPG IFI cases. Demographics between the two study periods were similar, although significantly higher transfusion requirements (p<0.05) and non-significant trends in injury severity scores and early lower extremity amputation rates suggested more severe injuries in CPG-period cases. Pre-CPG IFI cases were more likely to be associated with angioinvasion on histopathology than CPG IFI cases (48% versus 17%; p<0.001). Time to IFI diagnosis (three versus nine days) and to initiation of antifungal therapy (seven versus 14 days) were significantly decreased in the CPG period (p<0.001). Additionally, more IFI patients received antifungal agent at LRMC during the CPG period (30%) versus pre-CPG period (5%; p=0.005). The CPG IFI cases were also prescribed more commonly dual antifungal therapy (73% versus 36%; p=0.002). There was no statistical difference in length of stay or mortality between pre-CPG and CPG IFI cases; although a non-significant reduction in crude mortality from 11.4% to 6.7% was observed. Conclusions: Angioinvasive IFI as a percentage of total IFI cases decreased during the CPG period. Earlier diagnosis and commencement of more timely treatment was achieved. Despite these improvements, no

  13. Molecular mapping of the new blast resistance genes Pi47 and Pi48 in the durably resistant local rice cultivar Xiangzi 3150.

    PubMed

    Huang, Hongmei; Huang, Ling; Feng, Guangping; Wang, Suhua; Wang, Yue; Liu, Jinling; Jiang, Nan; Yan, Weiting; Xu, Lingchao; Sun, Pingyong; Li, Zhiqiang; Pan, Sujun; Liu, Xionglun; Xiao, Yinghui; Liu, Erming; Dai, Liangying; Wang, Guo-Liang

    2011-05-01

    The indica rice cultivar Xiangzi 3150 (XZ3150) confers a high level of resistance to 95% of the isolates of Magnaporthe oryzae (the agent of rice blast disease) collected in Hunan Province, China. To identify the resistance (R) gene(s) controlling the high level of resistance in this cultivar, we developed 286 F(9) recombinant inbred lines (RILs) from a cross between XZ3150 and the highly susceptible cultivar CO39. Inoculation of the RILs and an F(2) population from a cross between the two cultivars with the avirulent isolate 193-1-1 in the growth chamber indicated the presence of two dominant R genes in XZ3150. A linkage map with 134 polymorphic simple sequence repeat and single feature polymorphism markers was constructed with the genotype data of the 286 RILs. Composite interval mapping (CIM) using the results of 193-1-1 inoculation showed that two major R genes, designated Pi47 and Pi48, were located between RM206 and RM224 on chromosome 11, and between RM5364 and RM7102 on chromosome 12, respectively. Interestingly, the CIM analysis of the four resistant components of the RILs to the field blast population revealed that Pi47 and Pi48 were also the major genetic factors responsible for the field resistance in XZ3150. The DNA markers linked to the new R genes identified in this study should be useful for further fine mapping, gene cloning, and marker-aided breeding of blast-resistant rice cultivars.

  14. Antimicrobial activity of UV-induced phenylamides from rice leaves.

    PubMed

    Park, Hye Lin; Yoo, Youngchul; Hahn, Tae-Ryong; Bhoo, Seong Hee; Lee, Sang-Won; Cho, Man-Ho

    2014-11-06

    Rice produces a wide array of phytoalexins in response to pathogen attacks and UV-irradiation. Except for the flavonoid sakuranetin, most phytoalexins identified in rice are diterpenoid compounds. Analysis of phenolic-enriched fractions from UV-treated rice leaves showed that several phenolic compounds in addition to sakuranetin accumulated remarkably in rice leaves. We isolated two compounds from UV-treated rice leaves using silica gel column chromatography and preparative HPLC. The isolated phenolic compounds were identified as phenylamide compounds: N-trans-cinnamoyltryptamine and N-p-coumaroylserotonin. Expression analysis of biosynthetic genes demonstrated that genes for arylamine biosynthesis were upregulated by UV irradiation. This result suggested that phenylamide biosynthetic pathways are activated in rice leaves by UV treatment. To unravel the role of UV-induced phenylamides as phytoalexins, we examined their antimicrobial activity against rice fungal and bacterial pathogens. N-trans-Cinnamoyltryptamine inhibited the growth of rice brown spot fungus (Bipolaris oryzae). In addition to the known antifungal activity to the blast fungus, sakuranetin had antimicrobial activity toward B. oryzae and Rhizoctonia solani (rice sheath blight fungus). UV-induced phenylamides and sakuranetin also had antimicrobial activity against rice bacterial pathogens for grain rot (Burkholderia glumae), blight (Xanthomonas oryzae pv. oryzae) and leaf streak (X. oryzae pv. oryzicola) diseases. These findings suggested that the UV-induced phenylamides in rice are phytoalexins against a diverse array of pathogens.

  15. Fine mapping and identification of blast resistance gene Pi-hk1 in a broad-spectrum resistant japonica rice landrace.

    PubMed

    Wu, Yunyu; Bao, Yongmei; Xie, Liujie; Su, Yunyun; Chu, Ruizhen; He, Wanwan; Huang, Ji; Wang, Jianfei; Zhang, Hongsheng

    2013-11-01

    One Japonica rice landrace, Heikezijing, from the Taihu Lake region of China, exhibits broad-spectrum resistance to rice blast. As characterized in our previous research, a main-effect resistance (R) gene, Pi-hk1, in Heikezijing against five isolates (GD10-279a, JS2004-141-1, JS2004-185, JS90-78, and Hoku1) was roughly mapped on the long arm of chromosome 11. To fine map Pi-hk1, one recombinant inbred line (RIL), RIL72 (F2:8), from the cross between Heikezijing and blast-susceptible variety Suyunuo, was further crossed and backcrossed with Suyunuo to produce a BC1F2 population of 477 individuals. Inoculation experiments with the representative isolate Hoku 1 indicated that RIL72 carries a single dominant R gene for blast resistance. With the help of advanced BC1F3 (915 plants), BC1F4 (4,459 plants), and BC1F5 (2,000 plants) mapping populations, Pi-hk1 was finally mapped to a 107-kb region between molecular markers P3586 and ILP3, and co-segregated with the markers P4098, RM7654, and P4099. By sequence analysis of Heikezijing bacterial artificial chromosome clones covering Pi-hk1 region, 16 predicted genes were identified within this region, including three nucleotide-binding site leucine-rich repeat candidate genes. These results provide essential information for cloning of Pi-hk1 and its application in rice breeding for broad-spectrum blast resistance by marker-assisted selection.

  16. MoEnd3 regulates appressorium formation and virulence through mediating endocytosis in rice blast fungus Magnaporthe oryzae

    PubMed Central

    Li, Xiao; Gao, Chuyun; Li, Lianwei; Liu, Muxing; Yin, Ziyi; Zhang, Haifeng; Zheng, Xiaobo; Wang, Ping

    2017-01-01

    Eukaryotic cells respond to environmental stimuli when cell surface receptors are bound by environmental ligands. The binding initiates a signal transduction cascade that results in the appropriate intracellular responses. Studies have shown that endocytosis is critical for receptor internalization and signaling activation. In the rice blast fungus Magnaporthe oryzae, a non-canonical G-protein coupled receptor, Pth11, and membrane sensors MoMsb2 and MoSho1 are thought to function upstream of G-protein/cAMP signaling and the Pmk1 MAPK pathway to regulate appressorium formation and pathogenesis. However, little is known about how these receptors or sensors are internalized and transported into intracellular compartments. We found that the MoEnd3 protein is important for endocytic transport and that the ΔMoend3 mutant exhibited defects in efficient internalization of Pth11 and MoSho1. The ΔMoend3 mutant was also defective in Pmk1 phosphorylation, autophagy, appressorium formation and function. Intriguingly, restoring Pmk1 phosphorylation levels in ΔMoend3 suppressed most of these defects. Moreover, we demonstrated that MoEnd3 is subject to regulation by MoArk1 through protein phosphorylation. We also found that MoEnd3 has additional functions in facilitating the secretion of effectors, including Avr-Pia and AvrPiz-t that suppress rice immunity. Taken together, our findings suggest that MoEnd3 plays a critical role in mediating receptor endocytosis that is critical for the signal transduction-regulated development and virulence of M. oryzae. PMID:28628655

  17. Natural variation of rice blast resistant gene Pi-ta in Oryza species

    USDA-ARS?s Scientific Manuscript database

    The Pi-ta gene in rice is a putative NBS type cytoplasmic receptor conferring resistance to races of Magnaporthe oryzae in a gene-for-gene manner. A Functional Nucleotide Polymorphism (FNP) change resulting in an amino acid substitution of Alanine to Serine at position 918 (nucleotide G to T at posi...

  18. Genetic variation and evolution of the Pit blast resistance locus in rice

    USDA-ARS?s Scientific Manuscript database

    Resistance (R) gene Pit in rice, encodes a protein with nucleotide binding sites-leucine rich repeat domain (NBS-LRR), prevents infections by strains of M. oryzae in a gene for gene manner. Here, we analyzed the open reading frame (ORF) of Pit in 26 varieties including Aus (AUS), indica (IND), tempe...

  19. Decline in topsoil microbial quotient, fungal abundance and C utilization efficiency of rice paddies under heavy metal pollution across South China.

    PubMed

    Liu, Yongzhuo; Zhou, Tong; Crowley, David; Li, Lianqing; Liu, Dawen; Zheng, Jinwei; Yu, Xinyan; Pan, Genxing; Hussain, Qaiser; Zhang, Xuhui; Zheng, Jufeng

    2012-01-01

    Agricultural soils have been increasingly subject to heavy metal pollution worldwide. However, the impacts on soil microbial community structure and activity of field soils have been not yet well characterized. Topsoil samples were collected from heavy metal polluted (PS) and their background (BGS) fields of rice paddies in four sites across South China in 2009. Changes with metal pollution relative to the BGS in the size and community structure of soil microorganisms were examined with multiple microbiological assays of biomass carbon (MBC) and nitrogen (MBN) measurement, plate counting of culturable colonies and phospholipids fatty acids (PLFAs) analysis along with denaturing gradient gel electrophoresis (DGGE) profile of 16S rRNA and 18S rRNA gene and real-time PCR assay. In addition, a 7-day lab incubation under constantly 25°C was conducted to further track the changes in metabolic activity. While the decrease under metal pollution in MBC and MBN, as well as in culturable population size, total PLFA contents and DGGE band numbers of bacteria were not significantly and consistently seen, a significant reduction was indeed observed under metal pollution in microbial quotient, in culturable fungal population size and in ratio of fungal to bacterial PLFAs consistently across the sites by an extent ranging from 6% to 74%. Moreover, a consistently significant increase in metabolic quotient was observed by up to 68% under pollution across the sites. These observations supported a shift of microbial community with decline in its abundance, decrease in fungal proportion and thus in C utilization efficiency under pollution in the soils. In addition, ratios of microbial quotient, of fungal to bacterial and qCO(2) are proved better indicative of heavy metal impacts on microbial community structure and activity. The potential effects of these changes on C cycling and CO(2) production in the polluted rice paddies deserve further field studies.

  20. Decline in Topsoil Microbial Quotient, Fungal Abundance and C Utilization Efficiency of Rice Paddies under Heavy Metal Pollution across South China

    PubMed Central

    Liu, Yongzhuo; Zhou, Tong; Crowley, David; Li, Lianqing; Liu, Dawen; Zheng, Jinwei; Yu, Xinyan; Pan, Genxing; Hussain, Qaiser; Zhang, Xuhui; Zheng, Jufeng

    2012-01-01

    Agricultural soils have been increasingly subject to heavy metal pollution worldwide. However, the impacts on soil microbial community structure and activity of field soils have been not yet well characterized. Topsoil samples were collected from heavy metal polluted (PS) and their background (BGS) fields of rice paddies in four sites across South China in 2009. Changes with metal pollution relative to the BGS in the size and community structure of soil microorganisms were examined with multiple microbiological assays of biomass carbon (MBC) and nitrogen (MBN) measurement, plate counting of culturable colonies and phospholipids fatty acids (PLFAs) analysis along with denaturing gradient gel electrophoresis (DGGE) profile of 16S rRNA and 18S rRNA gene and real-time PCR assay. In addition, a 7-day lab incubation under constantly 25°C was conducted to further track the changes in metabolic activity. While the decrease under metal pollution in MBC and MBN, as well as in culturable population size, total PLFA contents and DGGE band numbers of bacteria were not significantly and consistently seen, a significant reduction was indeed observed under metal pollution in microbial quotient, in culturable fungal population size and in ratio of fungal to bacterial PLFAs consistently across the sites by an extent ranging from 6% to 74%. Moreover, a consistently significant increase in metabolic quotient was observed by up to 68% under pollution across the sites. These observations supported a shift of microbial community with decline in its abundance, decrease in fungal proportion and thus in C utilization efficiency under pollution in the soils. In addition, ratios of microbial quotient, of fungal to bacterial and qCO2 are proved better indicative of heavy metal impacts on microbial community structure and activity. The potential effects of these changes on C cycling and CO2 production in the polluted rice paddies deserve further field studies. PMID:22701725

  1. Overexpression of MoSM1, encoding for an immunity-inducing protein from Magnaporthe oryzae, in rice confers broad-spectrum resistance against fungal and bacterial diseases

    PubMed Central

    Hong, Yongbo; Yang, Yayun; Zhang, Huijuan; Huang, Lei; Li, Dayong; Song, Fengming

    2017-01-01

    Potential of MoSM1, encoding for a cerato-platanin protein from Magnaporthe oryzae, in improvement of rice disease resistance was examined. Transient expression of MoSM1 in rice leaves initiated hypersensitive response and upregulated expression of defense genes. When transiently expressed in tobacco leaves, MoSM1 targeted to plasma membrane. The MoSM1-overexpressing (MoSM1-OE) transgenic rice lines showed an improved resistance, as revealed by the reduced disease severity and decreased in planta pathogen growth, against 2 strains belonging to two different races of M. oryzae, causing blast disease, and against 2 strains of Xanthomonas oryzae pv. oryzae, causing bacterial leaf blight disease. However, no alteration in resistance to sheath blight disease was observed in MoSM1-OE lines. The MoSM1-OE plants contained elevated levels of salicylic acid (SA) and jasmonic acid (JA) and constitutively activated the expression of SA and JA signaling-related regulatory and defense genes. Furthermore, the MoSM1-OE plants had no effect on drought and salt stress tolerance and on grain yield. We conclude that MoSM1 confers a broad-spectrum resistance against different pathogens through modulating SA- and JA-mediated signaling pathways without any penalty on abiotic stress tolerance and grain yield, providing a promising potential for application of MoSM1 in improvement of disease resistance in crops. PMID:28106116

  2. Overexpression of MoSM1, encoding for an immunity-inducing protein from Magnaporthe oryzae, in rice confers broad-spectrum resistance against fungal and bacterial diseases.

    PubMed

    Hong, Yongbo; Yang, Yayun; Zhang, Huijuan; Huang, Lei; Li, Dayong; Song, Fengming

    2017-01-20

    Potential of MoSM1, encoding for a cerato-platanin protein from Magnaporthe oryzae, in improvement of rice disease resistance was examined. Transient expression of MoSM1 in rice leaves initiated hypersensitive response and upregulated expression of defense genes. When transiently expressed in tobacco leaves, MoSM1 targeted to plasma membrane. The MoSM1-overexpressing (MoSM1-OE) transgenic rice lines showed an improved resistance, as revealed by the reduced disease severity and decreased in planta pathogen growth, against 2 strains belonging to two different races of M. oryzae, causing blast disease, and against 2 strains of Xanthomonas oryzae pv. oryzae, causing bacterial leaf blight disease. However, no alteration in resistance to sheath blight disease was observed in MoSM1-OE lines. The MoSM1-OE plants contained elevated levels of salicylic acid (SA) and jasmonic acid (JA) and constitutively activated the expression of SA and JA signaling-related regulatory and defense genes. Furthermore, the MoSM1-OE plants had no effect on drought and salt stress tolerance and on grain yield. We conclude that MoSM1 confers a broad-spectrum resistance against different pathogens through modulating SA- and JA-mediated signaling pathways without any penalty on abiotic stress tolerance and grain yield, providing a promising potential for application of MoSM1 in improvement of disease resistance in crops.

  3. ON RELATION OF SOIL MOISTURE TO DEVELOPMENT OF RICE BLAST DISEASE WITH SPECIAL REFERENCE TO INOCULATION EXPERIMENTS ON PLANTS GROWN IN SOILS DIFFERING IN MOISTURE AND AMOUNTS OF NITROGENOUS MANURE. PART A-1

    DTIC Science & Technology

    humidity and amount of nitrogenous fertilizer . The results of investigation of the natural infection of the adult leaf are also discussed. Using the ash...figure technique, anatomical differences in the adult leaf were studied. Irrespective of the amount of nitrogenous fertilizer applied, rice plants...on dry soil. Plants grown on soil with double the amount of nitrogenous fertilizer but well irrigated were found to be more resistant to rice blast

  4. ON RELATION OF SOIL MOISTURE TO DEVELOPMENT OF RICE BLAST DISEASE WITH SPECIAL REFERENCE TO RESULTS OF INOCULATION EXPERIMENTS ON LEAVES AND SPIKE PEDICELS OF PLANTS GROWN IN SOILS DIFFERING IN MOISTURE AND IN AMOUNTS OF SILICA AND FERTILIZER,

    DTIC Science & Technology

    moisture content, and fertilizer and silica application. The susceptibility of the rice plant to rice blast disease varied inversely with the moisture...content of the soil irrespective of the amount of fertilizer or silica applied or of the stage of growth of the plant. Dryness of the soil tended to...fertilization were more easily infected than plants grown on irrigated soil with double the amount of fertilizer . This proves that even with double the

  5. Over-Expression of the Pikh Gene with a CaMV 35S Promoter Leads to Improved Blast Disease (Magnaporthe oryzae) Tolerance in Rice.

    PubMed

    Azizi, Parisa; Rafii, Mohd Y; Abdullah, Siti N A; Hanafi, Mohamed M; Maziah, M; Sahebi, Mahbod; Ashkani, Sadegh; Taheri, Sima; Jahromi, Mohammad F

    2016-01-01

    Magnaporthe oryzae is a rice blast fungus and plant pathogen that causes a serious rice disease and, therefore, poses a threat to the world's second most important food security crop. Plant transformation technology has become an adaptable system for cultivar improvement and to functionally analyze genes in plants. The objective of this study was to determine the effects (through over-expressing and using the CaMV 35S promoter) of Pikh on MR219 resistance because it is a rice variety that is susceptible to the blast fungus pathotype P7.2. Thus, a full DNA and coding DNA sequence (CDS) of the Pikh gene, 3172 bp, and 1206 bp in length, were obtained through amplifying the gDNA and cDNA template from a PH9-resistant rice variety using a specific primer. Agrobacterium-mediated transformation technology was also used to introduce the Pikh gene into the MR219 callus. Subsequently, transgenic plants were evaluated from the DNA to protein stages using polymerase chain reaction (PCR), semi-quantitative RT-PCR, real-time quantitative PCR and high performance liquid chromatography (HPLC). Transgenic plants were also compared with a control using a real-time quantification technique (to quantify the pathogen population), and transgenic and control plants were challenged with the local most virulent M. oryzae pathotype, P7.2. Based on the results, the Pikh gene encodes a hydrophilic protein with 18 sheets, 4 helixes, and 21 coils. This protein contains 401 amino acids, among which the amino acid sequence from 1 to 376 is a non-cytoplasmic region, that from 377 to 397 is a transmembrane region, and that from 398 to 401 is a cytoplasmic region with no identified disordered regions. The Pikh gene was up-regulated in the transgenic plants compared with the control plants. The quantity of the amino acid leucine in the transgenic rice plants increased significantly from 17.131 in the wild-type to 47.865 mg g(-1) in transgenic plants. The M. oryzae population was constant at 31, 48

  6. Over-Expression of the Pikh Gene with a CaMV 35S Promoter Leads to Improved Blast Disease (Magnaporthe oryzae) Tolerance in Rice

    PubMed Central

    Azizi, Parisa; Rafii, Mohd Y.; Abdullah, Siti N. A.; Hanafi, Mohamed M.; Maziah, M.; Sahebi, Mahbod; Ashkani, Sadegh; Taheri, Sima; Jahromi, Mohammad F.

    2016-01-01

    Magnaporthe oryzae is a rice blast fungus and plant pathogen that causes a serious rice disease and, therefore, poses a threat to the world's second most important food security crop. Plant transformation technology has become an adaptable system for cultivar improvement and to functionally analyze genes in plants. The objective of this study was to determine the effects (through over-expressing and using the CaMV 35S promoter) of Pikh on MR219 resistance because it is a rice variety that is susceptible to the blast fungus pathotype P7.2. Thus, a full DNA and coding DNA sequence (CDS) of the Pikh gene, 3172 bp, and 1206 bp in length, were obtained through amplifying the gDNA and cDNA template from a PH9-resistant rice variety using a specific primer. Agrobacterium-mediated transformation technology was also used to introduce the Pikh gene into the MR219 callus. Subsequently, transgenic plants were evaluated from the DNA to protein stages using polymerase chain reaction (PCR), semi-quantitative RT-PCR, real-time quantitative PCR and high performance liquid chromatography (HPLC). Transgenic plants were also compared with a control using a real-time quantification technique (to quantify the pathogen population), and transgenic and control plants were challenged with the local most virulent M. oryzae pathotype, P7.2. Based on the results, the Pikh gene encodes a hydrophilic protein with 18 sheets, 4 helixes, and 21 coils. This protein contains 401 amino acids, among which the amino acid sequence from 1 to 376 is a non-cytoplasmic region, that from 377 to 397 is a transmembrane region, and that from 398 to 401 is a cytoplasmic region with no identified disordered regions. The Pikh gene was up-regulated in the transgenic plants compared with the control plants. The quantity of the amino acid leucine in the transgenic rice plants increased significantly from 17.131 in the wild-type to 47.865 mg g−1 in transgenic plants. The M. oryzae population was constant at 31, 48

  7. Epigenetic regulation of antagonistic receptors confers rice blast resistance with yield balance.

    PubMed

    Deng, Yiwen; Zhai, Keran; Xie, Zhen; Yang, Dongyong; Zhu, Xudong; Liu, Junzhong; Wang, Xin; Qin, Peng; Yang, Yuanzhu; Zhang, Guomin; Li, Qun; Zhang, Jianfu; Wu, Shuangqing; Milazzo, Joëlle; Mao, Bizeng; Wang, Ertao; Xie, Huaan; Tharreau, Didier; He, Zuhua

    2017-03-03

    Crop breeding aims to balance disease resistance with yield; however, single resistance (R) genes can lead to resistance breakdown, and R gene pyramiding may affect growth fitness. Here we report that the rice Pigm locus contains a cluster of genes encoding nucleotide-binding leucine-rich repeat (NLR) receptors that confer durable resistance to the fungus Magnaporthe oryzae without yield penalty. Among these NLR receptors, PigmR confers broad-spectrum resistance, whereas PigmS competitively attenuates PigmR homodimerization to suppress resistance. PigmS expression, and thus PigmR-mediated resistance, are subjected to tight epigenetic regulation. PigmS increases seed production to counteract the yield cost induced by PigmR Therefore, our study reveals a mechanism balancing high disease resistance and yield through epigenetic regulation of paired antagonistic NLR receptors, providing a tool to develop elite crop varieties.

  8. Characterisation of Four LIM Protein-Encoding Genes Involved in Infection-Related Development and Pathogenicity by the Rice Blast Fungus Magnaporthe oryzae

    PubMed Central

    Li, Ya; Yue, Xiaofeng; Que, Yawei; Yan, Xia; Ma, Zhonghua; Talbot, Nicholas J.; Wang, Zhengyi

    2014-01-01

    LIM domain proteins contain contiguous double-zinc finger domains and play important roles in cytoskeletal re-organisation and organ development in multi-cellular eukaryotes. Here, we report the characterization of four genes encoding LIM proteins in the rice blast fungus Magnaporthe oryzae. Targeted gene replacement of either the paxillin-encoding gene, PAX1, or LRG1 resulted in a significant reduction in hyphal growth and loss of pathogenicity, while deletion of RGA1 caused defects in conidiogenesis and appressorium development. A fourth LIM domain gene, LDP1, was not required for infection-associated development by M. oryzae. Live cell imaging revealed that Lrg1-GFP and Rga1-GFP both localize to septal pores, while Pax1-GFP is present in the cytoplasm. To explore the function of individual LIM domains, we carried out systematic deletion of each LIM domain, which revealed the importance of the Lrg1-LIM2 and Lrg1-RhoGAP domains for Lrg1 function and overlapping functions of the three LIM domains of Pax1. Interestingly, deletion of either PAX1 or LRG1 led to decreased sensitivity to cell wall-perturbing agents, such as Congo Red and SDS (sodium dodecyl sulfate). qRT-PCR analysis demonstrated the importance of both Lrg1 and Pax1 to regulation of genes associated with cell wall biogenesis. When considered together, our results indicate that LIM domain proteins are key regulators of infection-associated morphogenesis by the rice blast fungus. PMID:24505448

  9. Production of β-xylosidase from Trichoderma asperellum KIF125 and its application in efficient hydrolysis of pretreated rice straw with fungal cellulase.

    PubMed

    Inoue, Hiroyuki; Kitao, Chiaki; Yano, Shinichi; Sawayama, Shigeki

    2016-11-01

    On-site cellulase and hemicellulase production is a promising way to reduce enzyme cost in the commercialization of the lignocellulose-to-ethanol process. A hemicellulase-producing fungal strain suitable for on-site enzyme production was selected from cultures prepared using wet disc-milling rice straw (WDM-RS) and identified as Trichoderma asperellum KIF125. KIF125 hemicellulase showed uniquely high abundance of β-xylosidase in the xylanolytic enzyme system compared to other fungal hemicellulase preparations. Supplementation of Talaromyces cellulolyticus cellulase with KIF125 hemicellulase was more effective than that with the hemicellulases from other fungal sources in reducing the total enzyme loading for the improvement of xylose yield in the hydrolysis of ball-milling RS, due to its high β-xylosidase dominance. β-Xylosidase in KIF125 hemicellulase was purified and classified as a glycosyl hydrolase family 3 enzyme with relatively high specificity for xylobiose. The production of KIF125 β-xylosidase in the fermentor was estimated as 118 U/g-WDM-RS (2350 U/L culture) at 48 h. These results demonstrate that KIF125 is promising as a practical hemicellulase source to combine with on-site cellulase production using T. cellulolyticus.

  10. Morphological and molecular characterization of fungal pathogen, Magnaphorthe oryzae

    SciTech Connect

    Hasan, Nor’Aishah; Rafii, Mohd Y.; Rahim, Harun A.; Ali, Nusaibah Syd; Mazlan, Norida; Abdullah, Shamsiah

    2016-02-01

    Rice is arguably the most crucial food crops supplying quarter of calories intake. Fungal pathogen, Magnaphorthe oryzae promotes blast disease unconditionally to gramineous host including rice species. This disease spurred an outbreaks and constant threat to cereal production. Global rice yield declining almost 10-30% including Malaysia. As Magnaphorthe oryzae and its host is model in disease plant study, the rice blast pathosystem has been the subject of intense interest to overcome the importance of the disease to world agriculture. Therefore, in this study, our prime objective was to isolate samples of Magnaphorthe oryzae from diseased leaf obtained from MARDI Seberang Perai, Penang, Malaysia. Molecular identification was performed by sequences analysis from internal transcribed spacer (ITS) region of nuclear ribosomal RNA genes. Phylogenetic affiliation of the isolated samples were analyzed by comparing the ITS sequences with those deposited in the GenBank database. The sequence of the isolate demonstrated at least 99% nucleotide identity with the corresponding sequence in GenBank for Magnaphorthe oryzae. Morphological observed under microscope demonstrated that the structure of conidia followed similar characteristic as M. oryzae. Finding in this study provide useful information for breeding programs, epidemiology studies and improved disease management.

  11. 4-Coumarate-CoA Ligase-Like Gene OsAAE3 Negatively Mediates the Rice Blast Resistance, Floret Development and Lignin Biosynthesis

    PubMed Central

    Liu, Hao; Guo, Zhenhua; Gu, Fengwei; Ke, Shanwen; Sun, Dayuan; Dong, Shuangyu; Liu, Wei; Huang, Ming; Xiao, Wuming; Yang, Guili; Liu, Yongzhu; Guo, Tao; Wang, Hui; Wang, Jiafeng; Chen, Zhiqiang

    2017-01-01

    Although adenosine monophosphate (AMP) binding domain is widely distributed in multiple plant species, detailed molecular functions of AMP binding proteins (AMPBPs) in plant development and plant-pathogen interaction remain unclear. In the present study, we identified an AMPBP OsAAE3 from a previous analysis of early responsive genes in rice during Magnaporthe oryzae infection. OsAAE3 is a homolog of Arabidopsis AAE3 in rice, which encodes a 4-coumarate-Co-A ligase (4CL) like protein. A phylogenetic analysis showed that OsAAE3 was most likely 4CL-like 10 in an independent group. OsAAE3 was localized to cytoplasm, and it could be expressed in various tissues. Histochemical staining of transgenic plants carrying OsAAE3 promoter-driven GUS (β-glucuronidase) reporter gene suggested that OsAAE3 was expressed in all tissues of rice. Furthermore, OsAAE3-OX plants showed increased susceptibility to M. Oryzae, and this finding was attributable to decreased expression of pathogen-related 1a (PR1) and low level of peroxidase (POD) activity. Moreover, OsAAE3 over-expression resulted in increased content of H2O2, leading to programmed cell-death induced by reactive oxygen species (ROS). In addition, OsAAE3 over-expression repressed the floret development, exhibiting dramatically twisted glume and decreased fertility rate of anther. Meanwhile, the expressions of lignin biosynthesis genes were significantly decreased in OsAAE3-OX plants, thereby leading to reduced lignin content. Taken together, OsAAE3 functioned as a negative regulator in rice blast resistance, floret development, and lignin biosynthesis. Our findings further expanded the knowledge in functions of AMBPs in plant floret development and the regulation of rice-fungus interaction. PMID:28119718

  12. FAR1 and FAR2 regulate the expression of genes associated with lipid metabolism in the rice blast fungus Magnaporthe oryzae.

    PubMed

    bin Yusof, Mohammad Termizi; Kershaw, Michael J; Soanes, Darren M; Talbot, Nicholas J

    2014-01-01

    The rice blast fungus Magnaporthe oryzae causes plant disease via specialised infection structures called appressoria. These dome-shaped cells are able to generate enormous internal pressure, which enables penetration of rice tissue by invasive hyphae. Previous studies have shown that mobilisation of lipid bodies and subsequent lipid metabolism are essential pre-requisites for successful appressorium-mediated plant infection, which requires autophagic recycling of the contents of germinated spores and germ tubes to the developing appressorium. Here, we set out to identify putative regulators of lipid metabolism in the rice blast fungus. We report the identification of FAR1 and FAR2, which encode highly conserved members of the Zn2-Cys6 family of transcriptional regulators. We generated Δfar1, Δfar2 and Δfar1Δfar2 double mutants in M. oryzae and show that these deletion mutants are deficient in growth on long chain fatty acids. In addition, Δfar2 mutants are also unable to grow on acetate and short chain fatty acids. FAR1 and FAR2 are necessary for differential expression of genes involved in fatty acid β-oxidation, acetyl-CoA translocation, peroxisomal biogenesis, and the glyoxylate cycle in response to the presence of lipids. Furthermore, FAR2 is necessary for expression of genes associated with acetyl-CoA synthesis. Interestingly, Δfar1, Δfar2 and Δfar1Δfar2 mutants show no observable delay or reduction in lipid body mobilisation during plant infection, suggesting that these transcriptional regulators control lipid substrate utilization by the fungus but not the mobilisation of intracellular lipid reserves during infection-related morphogenesis.

  13. FAR1 and FAR2 Regulate the Expression of Genes Associated with Lipid Metabolism in the Rice Blast Fungus Magnaporthe oryzae

    PubMed Central

    bin Yusof, Mohammad Termizi; Kershaw, Michael J.; Soanes, Darren M.; Talbot, Nicholas J.

    2014-01-01

    The rice blast fungus Magnaporthe oryzae causes plant disease via specialised infection structures called appressoria. These dome-shaped cells are able to generate enormous internal pressure, which enables penetration of rice tissue by invasive hyphae. Previous studies have shown that mobilisation of lipid bodies and subsequent lipid metabolism are essential pre-requisites for successful appressorium-mediated plant infection, which requires autophagic recycling of the contents of germinated spores and germ tubes to the developing appressorium. Here, we set out to identify putative regulators of lipid metabolism in the rice blast fungus. We report the identification of FAR1 and FAR2, which encode highly conserved members of the Zn2-Cys6 family of transcriptional regulators. We generated Δfar1, Δfar2 and Δfar1Δfar2 double mutants in M. oryzae and show that these deletion mutants are deficient in growth on long chain fatty acids. In addition, Δfar2 mutants are also unable to grow on acetate and short chain fatty acids. FAR1 and FAR2 are necessary for differential expression of genes involved in fatty acid β-oxidation, acetyl-CoA translocation, peroxisomal biogenesis, and the glyoxylate cycle in response to the presence of lipids. Furthermore, FAR2 is necessary for expression of genes associated with acetyl-CoA synthesis. Interestingly, Δfar1, Δfar2 and Δfar1Δfar2 mutants show no observable delay or reduction in lipid body mobilisation during plant infection, suggesting that these transcriptional regulators control lipid substrate utilization by the fungus but not the mobilisation of intracellular lipid reserves during infection-related morphogenesis. PMID:24949933

  14. A large-insert (130 kbp) bacterial artificial chromosome library of the rice blast fungus Magnaporthe grisea: genome analysis, contig assembly, and gene cloning.

    PubMed

    Zhu, H; Choi, S; Johnston, A K; Wing, R A; Dean, R A

    1997-06-01

    Magnaporthe grisea (Hebert) Barr causes rice blast, one of the most devastating diseases of rice (Oryza sativa) worldwide. This fungus is an ideal organism for studying a number of aspects of plant-pathogen interactions, including infection-related morphogenesis, avirulence, and pathogen evolution. To facilitate M. grisea genome analysis, physical mapping, and positional cloning, we have constructed a bacterial artificial chromosome (BAC) library from the rice infecting strain 70-15. A new method was developed for separation of partially digested large-molecular-weight DNA fragments that facilitated library construction with large inserts. The library contains 9216 clones, with an average insert size of 130 kbp (> 25 genome equivalents) stored in 384-well microtiter plates that can be double spotted robotically on to a single nylon membrane. Several unlinked single-copy DNA probes were used to screen 4608 clones in the library and an average of 13 (minimum of 6) overlapping BAC clones was found in each case. Hybridization of total genomic DNA to the library and analysis of individual clones indicated that approximately 26% of the clones contain single-copy DNA. Approximately 35% of BAC clones contained the retrotransposon MAGGY. The library was used to identify BAC clones containing a adenylate cyclase gene (mac1). In addition, a 550-kbp contig composed of 6 BAC clones was constructed that encompassed two adjacent RFLP markers on chromosome 2. These data show that the BAC library is suitable for genome analysis of M. grisea. Copies of colony hybridization membranes are available upon request.

  15. A multifaceted genomics approach allows the isolation of the rice Pia-blast resistance gene consisting of two adjacent NBS-LRR protein genes.

    PubMed

    Okuyama, Yudai; Kanzaki, Hiroyuki; Abe, Akira; Yoshida, Kentaro; Tamiru, Muluneh; Saitoh, Hiromasa; Fujibe, Takahiro; Matsumura, Hideo; Shenton, Matt; Galam, Dominique Clark; Undan, Jerwin; Ito, Akiko; Sone, Teruo; Terauchi, Ryohei

    2011-05-01

    The Oryza sativa (rice) resistance gene Pia confers resistance to the blast fungus Magnaporthe oryzae carrying the AVR-Pia avirulence gene. To clone Pia, we employed a multifaceted genomics approach. First, we selected 12 R-gene analog (RGA) genes encoding nucleotide binding site-leucine rich repeats (NBS-LRRs) proteins from a region on chromosome 11 that shows linkage to Pia. By using seven rice accessions, we examined the association between Pia phenotypes and DNA polymorphisms in the 10 genes, which revealed three genes (Os11gRGA3-Os11gRGA5) exhibiting a perfect association with the Pia phenotypes. We also screened ethyl methane sulfonate (EMS)-treated mutant lines of the rice cultivar 'Sasanishiki' harboring Pia, and isolated two mutants that lost the Pia phenotype. DNA sequencing of Os11gRGA3-Os11gRGA5 from the two mutant lines identified independent mutations of major effects in Os11gRGA4. The wild-type 'Sasanishiki' allele of Os11gRGA4 (SasRGA4) complemented Pia function in both mutants, suggesting that SasRGA4 is necessary for Pia function. However, when the rice cultivar 'Himenomochi' lacking Pia was transfected with SasRGA4, the Pia phenotype was not recovered. An additional complementation study revealed that the two NBS-LRR-type R genes, SasRGA4 and SasRGA5, that are located next to each other and oriented in the opposite direction are necessary for Pia function. A population genetics analysis of SasRGA4 and SasRGA5 suggests that the two genes are under long-term balancing selection. © 2011 The Authors. The Plant Journal © 2011 Blackwell Publishing Ltd.

  16. Expression profiling of common and specific defense responses of rice to Magnaporthe oryzae infection using deep sequencing technologies

    USDA-ARS?s Scientific Manuscript database

    Rice blast caused by Magnaporthe oryzae is a serious disease in rice production. Wild type Nipponbare and transgenic rice plants (carrying the Pi9 blast resistance gene) were challenged with the rice blast strain KJ201 to identify the early, mid and late host responses to M. oryzae infection at the ...

  17. Agrobacterium tumefaciens-mediated transformation of taro (Colocasia esculenta (L.) Schott) with a rice chitinase gene for improved tolerance to a fungal pathogen Sclerotium rolfsii.

    PubMed

    He, Xiaoling; Miyasaka, Susan C; Fitch, Maureen M M; Moore, Paul H; Zhu, Yun J

    2008-05-01

    Taro (Colocasia esculenta) is one of the most important crops in the Pacific Islands, however, taro yields have been declining in Hawaii over the past 30 years partly due to diseases caused by oomycete and fungal pathogens. In this study, an efficient Agrobacterium tumefaciens-mediated transformation method for taro is first reported. In total, approximately 200 pieces (8 g) of embryogenic calluses were infected with the super-virulent A. tumefaciens strain EHA105 harboring the plant transformation plasmid pBI121/ricchi11 that contains the rice chitinase gene ricchi11. The presence and expression of the transgene ricchi11 in six independent transgenic lines was confirmed using polymerase chain reaction (PCR) and reverse transcription-PCR (RT-PCR). Southern blot analysis of the six independent lines indicated that three out of six (50%) had integrated a single copy of the transgene, and the other three lines had two or three copies of the transgene. Compared to the particle bombardment transformation of taro method, which was used in the previous studies, the Agrobacterium-mediated transformation method obtained 43-fold higher transformation efficiency. In addition, these six transgenic lines via Agrobacterium may be more effective for transgene expression as a result of single-copy or low-copy insertion of the transgene than the single line with multiple copies of the transgene via particle bombardment. In a laboratory bioassay, all six transgenic lines exhibited increased tolerance to the fungal pathogen Sclerotium rolfsii, ranging from 42 to 63% reduction in lesion expansion.

  18. Optimization of a protein extraction technique for fungal proteomics.

    PubMed

    Bhadauria, Vijai; Peng, You-Liang

    2010-10-01

    Protein extraction is a critical step in any proteomics study. Since most fungi possess a robust cell wall, efficient isolation of total proteins has become challenge to fungal proteomics. To circumvent this bottleneck of fungal proteomics, we standardized a protocol named as Mg/CHAPS extraction by comparing with an established method of protein extraction (Tris/EDTA extraction), using 2-DE and MALDI-TOF MS. Total mycelial proteins were isolated using both protocols from Magnaporthe grisea (causal agent of rice blast disease). Six hundred forty two proteins were resolved on two 2-DE gels corresponding to mycelial proteomes isolated by Mg/CHAPS and Tris/EDTA. Mycelial proteome extracted by Mg/CHAPS showed higher number protein spots than to Tris/EDTA. Quantitative analysis of mycelial proteome, histogram and MS analyses of a protein spot suggested that Mg/CHAPS extraction is more effective than the widely used protocol i.e. Tris/EDTA.

  19. Proteomic and genetic approaches to identifying defence-related proteins in rice challenged with the fungal pathogen Rhizoctonia solani.

    PubMed

    Lee, Joohyun; Bricker, Terry M; Lefevre, Michael; Pinson, Shannon R M; Oard, James H

    2006-09-01

    SUMMARY Sheath blight, caused by the fungus Rhizoctonia solani, is a major disease of rice world-wide, but little is known about the host response to infection. The objective of this study was to identify proteins and DNA markers in resistant and susceptible rice associated with response to infection by R. solani. Replicated two-dimensional polyacrylamide gel electrophoresis experiments were conducted to detect proteins differentially expressed under inoculated and non-inoculated conditions. Tandem mass spectra analysis using electrospray ionization quadrupole-time of flight mass spectrometry (ESI Q-TOF MS) was carried out for protein identification with the NCBI non-redundant protein database. Seven proteins were increased after inoculation in both susceptible and resistant plants. Six of the seven proteins were identified with presumed antifungal, photosynthetic and proteolytic activities. An additional 14 proteins were detected in the response of the resistant line. Eleven of the 14 proteins were identified with presumed functions relating to antifungal activity, signal transduction, energy metabolism, photosynthesis, molecular chaperone, proteolysis and antioxidation. The induction of 3-beta-hydroxysteroid dehydrogenase/isomerase was detected for the first time in resistant rice plants after pathogen challenge, suggesting a defensive role of this enzyme in rice against attack by R. solani. The chromosomal locations of four induced proteins were found to be in close physical proximity to genetic markers for sheath blight resistance in two genetic mapping populations. The proteomic and genetic results from this study indicate a complex response of rice to challenge by R. solani that involves simultaneous induction of proteins from multiple defence pathways.

  20. Genetic variation in resistance to blast disease (Pyricularia oryzae Cavara) in Japanese rice (Oryza sativa L.), as determined using a differential system.

    PubMed

    Kawasaki-Tanaka, Akiko; Fukuta, Yoshimichi

    2014-06-01

    A total of 324 Japanese rice accessions, including landrace, improved, and weedy types were used to 1) investigate genetic variations in blast resistance to standard differential isolates, and 2) across the genome using polymorphism data on 64 SSR markers. From the polymorphism data, the accessions were classified into two clusters,. Accessions from irrigated lowland areas were included mainly in cluster I, and upland and Indica types were mainly in cluster II. The accessions were classified into three resistance subgroups, A2, B1 and B2, based on the reaction patterns to blast isolates. The accessions in A2 were postulated to have at least two resistance genes Pish and Pik-s, whereas those in B1 had various combinations of the resistance genes Pish, Pia, Pii, Pi3, Pi5(t), and Pik alleles. The B2 accessions were resistant to almost all isolates, and many accessions of cluster II were included, and had Pish, Pia, Pii, Pi3, Pi5(t), certain Pik, Piz and Pita alleles, and unknown genes. The frequencies of accessions of B1 originating in Hokkaido, and those of B2 originating in the Kanto and Tohoku regions were remarkably higher than in the other regions.

  1. Marker-assisted improvement of the elite restorer line of rice, RPHR-1005 for resistance against bacterial blight and blast diseases.

    PubMed

    Kumar, V Abhilash; Balachiranjeevi, C H; Naik, S Bhaskar; Rambabu, R; Rekha, G; Harika, G; Hajira, S K; Pranathi, K; Vijay, S; Anila, M; Mahadevaswamy, H K; Kousik, M; Yugander, A; Aruna, J; Hari Prasad, A S; Madhav, M S; Laha, G S; Balachandran, S M; Prasad, M S; Babu, V Ravindra; Sundaram, R M

    2016-12-01

    This study was carried out to improve the RPHR-1005, a stable restorer line of the popular medium slender grain type rice hybrid, DRRH-3 for bacterial blight (BB) and blast resistance through marker-assisted backcross breeding (MABB). Two major BB resistance genes, Xa21 and Xa33 and a major blast resistance gene, Pi2 were transferred to RPHR-1005 as two individual crosses. Foreground selection for Xa21, Xa33, Pi2, Rf3 and Rf4 was done by using gene-specific functional markers, while 59 simple sequence repeat (SSR) markers polymorphic between the donors and recipient parents were used to select the best plant possessing target resistance genes at each backcross generation. Backcrossing was continued till BC2F2 and a promising homozygous backcross derived line possessing Xa21+ Pi2 and another possessing Xa33 were intercrossed to stack the target resistance genes into the genetic background of RPHR-1005. At ICF4, 10 promising lines possessing three resistance genes in homozygous condition along with fine-grain type, complete fertility restoration, better panicle exertion and taller plant type (compared to RPHR-1005) were identified.

  2. Identification of major blast resistance genes in the southern US

    USDA-ARS?s Scientific Manuscript database

    Resistance (R) genes in rice play important roles in preventing infections of rice blast fungus, Magnaporthe oryzae. In order to identify more R genes for different rice growing areas in the Southern US, an extensive field survey of the blast fungus was performed from 2012 to 2013. A total of 500 is...

  3. Asexual reproduction induces a rapid and permanent loss of sexual reproduction capacity in the rice fungal pathogen Magnaporthe oryzae: results of in vitro experimental evolution assays.

    PubMed

    Saleh, Dounia; Milazzo, Joëlle; Adreit, Henri; Tharreau, Didier; Fournier, Elisabeth

    2012-03-29

    Sexual reproduction is common in eukaryotic microorganisms, with few species reproducing exclusively asexually. However, in some organisms, such as fungi, asexual reproduction alternates with episodic sexual reproduction events. Fungi are thus appropriate organisms for studies of the reasons for the selection of sexuality or clonality and of the mechanisms underlying this selection. Magnaporthe oryzae, an Ascomycete causing blast disease on rice, reproduces mostly asexually in natura. Sexual reproduction is possible in vitro and requires (i) two strains of opposite mating types including (ii) at least one female-fertile strain (i.e. a strain able to produce perithecia, the female organs in which meiosis occurs). Female-fertile strains are found only in limited areas of Asia, in which evidence for contemporary recombination has recently been obtained. We induced the forced evolution of four Chinese female-fertile strains in vitro by the weekly transfer of asexual spores (conidia) between Petri dishes. We aimed to determine whether female fertility was rapidly lost in the absence of sexual reproduction and whether this loss was controlled genetically or epigenetically. All the strains became female-sterile after 10 to 19 rounds of selection under asexual conditions. As no single-spore isolation was carried out, the observed decrease in the production of perithecia reflected the emergence and the invasion of female-sterile mutants. The female-sterile phenotype segregated in the offspring of crosses between female-sterile evolved strains and female-fertile wild-type strains. This segregation was maintained in the second generation in backcrosses. Female-sterile evolved strains were subjected to several stresses, but none induced the restoration of female fertility. This loss of fertility was therefore probably due to genetic rather than epigenetic mechanisms. In competition experiments, female-sterile mutants produced similar numbers of viable conidia to wild

  4. Asexual reproduction induces a rapid and permanent loss of sexual reproduction capacity in the rice fungal pathogen Magnaporthe oryzae: results of in vitro experimental evolution assays

    PubMed Central

    2012-01-01

    Background Sexual reproduction is common in eukaryotic microorganisms, with few species reproducing exclusively asexually. However, in some organisms, such as fungi, asexual reproduction alternates with episodic sexual reproduction events. Fungi are thus appropriate organisms for studies of the reasons for the selection of sexuality or clonality and of the mechanisms underlying this selection. Magnaporthe oryzae, an Ascomycete causing blast disease on rice, reproduces mostly asexually in natura. Sexual reproduction is possible in vitro and requires (i) two strains of opposite mating types including (ii) at least one female-fertile strain (i.e. a strain able to produce perithecia, the female organs in which meiosis occurs). Female-fertile strains are found only in limited areas of Asia, in which evidence for contemporary recombination has recently been obtained. We induced the forced evolution of four Chinese female-fertile strains in vitro by the weekly transfer of asexual spores (conidia) between Petri dishes. We aimed to determine whether female fertility was rapidly lost in the absence of sexual reproduction and whether this loss was controlled genetically or epigenetically. Results All the strains became female-sterile after 10 to 19 rounds of selection under asexual conditions. As no single-spore isolation was carried out, the observed decrease in the production of perithecia reflected the emergence and the invasion of female-sterile mutants. The female-sterile phenotype segregated in the offspring of crosses between female-sterile evolved strains and female-fertile wild-type strains. This segregation was maintained in the second generation in backcrosses. Female-sterile evolved strains were subjected to several stresses, but none induced the restoration of female fertility. This loss of fertility was therefore probably due to genetic rather than epigenetic mechanisms. In competition experiments, female-sterile mutants produced similar numbers of viable

  5. A rice calcium-dependent protein kinase OsCPK12 oppositely modulates salt-stress tolerance and blast disease resistance.

    PubMed

    Asano, Takayuki; Hayashi, Nagao; Kobayashi, Michie; Aoki, Naohiro; Miyao, Akio; Mitsuhara, Ichiro; Ichikawa, Hiroaki; Komatsu, Setsuko; Hirochika, Hirohiko; Kikuchi, Shoshi; Ohsugi, Ryu

    2012-01-01

    Calcium-dependent protein kinases (CDPKs) regulate the downstream components in calcium signaling pathways. We investigated the effects of overexpression and disruption of an Oryza sativa (rice) CDPK (OsCPK12) on the plant's response to abiotic and biotic stresses. OsCPK12-overexpressing (OsCPK12-OX) plants exhibited increased tolerance to salt stress. The accumulation of hydrogen peroxide (H(2) O(2) ) in the leaves was less in OsCPK12-OX plants than in wild-type (WT) plants. Genes encoding reactive oxygen species (ROS) scavenging enzymes (OsAPx2 and OsAPx8) were more highly expressed in OsCPK12-OX plants than in WT plants, whereas the expression of the NADPH oxidase gene, OsrbohI, was decreased in OsCPK12-OX plants compared with WT plants. Conversely, a retrotransposon (Tos17) insertion mutant, oscpk12, and plants transformed with an OsCPK12 RNA interference (RNAi) construct were more sensitive to high salinity than were WT plants. The level of H(2) O(2) accumulation was greater in oscpk12 and OsCPK12 RNAi plants than in the WT. These results suggest that OsCPK12 promotes tolerance to salt stress by reducing the accumulation of ROS. We also observed that OsCPK12-OX seedlings had increased sensitivity to abscisic acid (ABA) and increased susceptibility to blast fungus, probably resulting from the repression of ROS production and/or the involvement of OsCPK12 in the ABA signaling pathway. Collectively, our results suggest that OsCPK12 functions in multiple signaling pathways, positively regulating salt tolerance and negatively modulating blast resistance.

  6. Rice Exo70 interacts with a fungal effector, AVR-Pii, and is required for AVR-Pii-triggered immunity.

    PubMed

    Fujisaki, Koki; Abe, Yoshiko; Ito, Akiko; Saitoh, Hiromasa; Yoshida, Kentaro; Kanzaki, Hiroyuki; Kanzaki, Eiko; Utsushi, Hiroe; Yamashita, Tetsuro; Kamoun, Sophien; Terauchi, Ryohei

    2015-09-01

    Vesicle trafficking including the exocytosis pathway is intimately associated with host immunity against pathogens. However, we still have insufficient knowledge about how it contributes to immunity, and how pathogen factors affect it. In this study, we explore host factors that interact with the Magnaporthe oryzae effector AVR-Pii. Gel filtration chromatography and co-immunoprecipitation assays identified a 150 kDa complex of proteins in the soluble fraction comprising AVR-Pii and OsExo70-F2 and OsExo70-F3, two rice Exo70 proteins presumably involved in exocytosis. Simultaneous knockdown of OsExo70-F2 and F3 totally abrogated Pii immune receptor-dependent resistance, but had no effect on Pia- and Pik-dependent resistance. Knockdown levels of OsExo70-F3 but not OsExo70-F2 correlated with reduction of Pii function, suggesting that OsExo70-F3 is specifically involved in Pii-dependent resistance. Under our current experimental conditions, over-expression of AVR-Pii or knockdown of OsExo70-F2 and -F3 genes in rice did not affect the virulence of compatible isolates of M. oryzae. AVR-Pii interaction with OsExo70-F3 appears to play a crucial role in immunity triggered by Pii, suggesting a role for OsExo70 as a decoy or helper in Pii/AVR-Pii interactions. © 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.

  7. Coevolutionary dynamics of rice blast resistance gene Pi-ta and Magnaporthe oryzae avirulence gene AVR-Pita 1

    USDA-ARS?s Scientific Manuscript database

    The Pi-ta gene in rice is effective in preventing infections by Magnaporthe oryzae strains that contain the corresponding avirulence gene, AVR-Pita1. Genome sequencing and mapping studies demonstrated that AVR-Pita1 is highly unstable, and diverse haplotypes of AVR-Pita1 have been identified from is...

  8. Germin-like protein 2 gene promoter from rice is responsive to fungal pathogens in transgenic potato plants.

    PubMed

    Munir, Faiza; Hayashi, Satomi; Batley, Jacqueline; Naqvi, Syed Muhammad Saqlan; Mahmood, Tariq

    2016-01-01

    Controlled transgene expression via a promoter is particularly triggered in response to pathogen infiltration. This is significant for eliciting disease-resistant features in crops through genetic engineering. The germins and germin-like proteins (GLPs) are known to be associated with plant and developmental stages. The 1107-bp Oryza sativa root GLP2 (OsRGLP2) gene promoter fused to a β-glucuronidase (GUS) reporter gene was transformed into potato plants through an Agrobacterium-mediated transformation. The OsRGLP2 promoter was activated in response to Fusarium solani (Mart.) Sacc. and Alternaria solani Sorauer. Quantitative real-time PCR results revealed 4-5-fold increase in promoter activity every 24 h following infection. There was a 15-fold increase in OsRGLP2 promoter activity after 72 h of F. solani (Mart.) Sacc. treatment and a 12-fold increase observed with A. solani Sorauer. Our results confirmed that the OsRGLP2 promoter activity was enhanced under fungal stress. Furthermore, a hyperaccumulation of H2O2 in transgenic plants is a clear signal for the involvement of OsRGLP2 promoter region in the activation of specific genes in the potato genome involved in H2O2-mediated defense response. The OsRGLP2 promoter evidently harbors copies of GT-I and Dof transcription factors (AAAG) that act in response to elicitors generated in the wake of pathogen infection.

  9. The durably resistant rice cultivar Digu activates defence gene expression before the full maturation of Magnaporthe oryzae appressorium.

    PubMed

    Li, Weitao; Liu, Ya; Wang, Jing; He, Min; Zhou, Xiaogang; Yang, Chao; Yuan, Can; Wang, Jichun; Chern, Mawsheng; Yin, Junjie; Chen, Weilan; Ma, Bingtian; Wang, Yuping; Qin, Peng; Li, Shigui; Ronald, Pamela; Chen, Xuewei

    2016-04-01

    Rice blast caused by the fungal pathogen Magnaporthe oryzae is one of the most destructive diseases worldwide. Although the rice-M. oryzae interaction has been studied extensively, the early molecular events that occur in rice before full maturation of the appressorium during M. oryzae invasion are unknown. Here, we report a comparative transcriptomics analysis of the durably resistant rice variety Digu and the susceptible rice variety Lijiangxintuanheigu (LTH) in response to infection by M. oryzae (5, 10 and 20 h post-inoculation, prior to full development of the appressorium). We found that the transcriptional responses differed significantly between these two rice varieties. Gene ontology and pathway analyses revealed that many biological processes, including extracellular recognition and biosynthesis of antioxidants, terpenes and hormones, were specifically activated in Digu shortly after infection. Forty-eight genes encoding receptor kinases (RKs) were significantly differentially regulated by M. oryzae infection in Digu. One of these genes, LOC_Os08g10300, encoding a leucine-rich repeat RK from the LRR VIII-2 subfamily, conferred enhanced resistance to M. oryzae when overexpressed in rice. Our study reveals that a multitude of molecular events occur in the durably resistant rice Digu before the full maturation of the appressorium after M. oryzae infection and that membrane-associated RKs play important roles in the early response.

  10. Fungal histidine phosphotransferase plays a crucial role in photomorphogenesis and pathogenesis in Magnaporthe oryzae

    NASA Astrophysics Data System (ADS)

    Mohanan, Varsha C.; Chandarana, Pinal M.; Chattoo, Bharat. B.; Patkar, Rajesh N.; Manjrekar, Johannes

    2017-05-01

    Two-component signal transduction (TCST) pathways play crucial roles in many cellular functions such as stress responses, biofilm formation and sporulation. The histidine phosphotransferase (HPt), which is an intermediate phosphotransfer protein in a two-component system, transfers a phosphate group to a phosphorylatable aspartate residue in the target protein(s), and up-regulates stress-activated MAP kinase cascades. Most fungal genomes carry a single copy of the gene coding for HPt, which are potential antifungal targets. However, unlike the histidine kinases (HK) or the downstream response regulators (RR) in two-component system, the HPts have not been well studied in phytopathogenic fungi. In this study, we investigated the role of HPt in the model rice-blast fungal pathogen Magnaporthe oryzae. We found that in M. oryzae an additional isoform of the HPT gene YPD1 was expressed specifically in response to light. Further, the expression of light-regulated genes such as those encoding envoy and blue-light-harvesting protein, and PAS domain containing HKs was significantly reduced upon down-regulation of YPD1 in M. oryzae. Importantly, down-regulation of YPD1 led to a significant decrease in the ability to penetrate the host cuticle and in light-dependent conidiation in M. oryzae. Thus, our results indicate that Ypd1 plays an important role in asexual development and host invasion, and suggest that YPD1 isoforms likely have distinct roles to play in the rice-blast pathogen M. oryzae.

  11. Effects of catalase on the accumulation of H(2)O(2) in rice cells inoculated with rice blast fungus, Magnaporthe oryzae.

    PubMed

    Tanabe, Shigeru; Nishizawa, Yoko; Minami, Eiichi

    2009-10-01

    Roles of H(2)O(2) in the infection process of Magnaporthe oryzae on rice were investigated. In a leaf sheath assay for up to 48 h post-inoculation, the absence or presence of catalase in the conidia suspension was correlated with the level of accumulated H(2)O(2) in infected leaf cells, as observed by staining with 3',3-diaminobenzidine tetrahydrochloride. In the incompatible interaction, the appearance of autofluorescence or frequency of cell death characterized by granulation (symptoms characteristic of hypersensitive responses) was not significantly affected by the presence of catalase in the conidia suspension. In the leaf blade assay, inoculation of compatible conidia in the presence of catalase produced more severe symptoms than that of conidia in the absence of catalase at 6 days post-inoculation. These results suggest that, in this host-parasite interaction, the primary role of host-produced H(2)O(2) is in limiting hyphal growth after penetration through toxic action. Furthermore, in incompatible interactions, H(2)O(2) is implied not to be a major mediator of hypersensitive cell death.

  12. A Rice Gene Homologous to Arabidopsis AGD2-LIKE DEFENSE1 Participates in Disease Resistance Response against Infection with Magnaporthe oryzae.

    PubMed

    Jung, Ga Young; Park, Ju Yeon; Choi, Hyo Ju; Yoo, Sung-Je; Park, Jung-Kwon; Jung, Ho Won

    2016-08-01

    ALD1 (ABERRANT GROWTH AND DEATH2 [AGD2]-LIKE DEFENSE1) is one of the key defense regulators in Arabidopsis thaliana and Nicotiana benthamiana. In these model plants, ALD1 is responsible for triggering basal defense response and systemic resistance against bacterial infection. As well ALD1 is involved in the production of pipecolic acid and an unidentified compound(s) for systemic resistance and priming syndrome, respectively. These previous studies proposed that ALD1 is a potential candidate for developing genetically modified (GM) plants that may be resistant to pathogen infection. Here we introduce a role of ALD1-LIKE gene of Oryza sativa, named as OsALD1, during plant immunity. OsALD1 mRNA was strongly transcribed in the infected leaves of rice plants by Magnaporthe oryzae, the rice blast fungus. OsALD1 proteins predominantly localized at the chloroplast in the plant cells. GM rice plants over-expressing OsALD1 were resistant to the fungal infection. The stable expression of OsALD1 also triggered strong mRNA expression of PATHOGENESIS-RELATED PROTEIN1 genes in the leaves of rice plants during infection. Taken together, we conclude that OsALD1 plays a role in disease resistance response of rice against the infection with rice blast fungus.

  13. Identity, Diversity, and Molecular Phylogeny of the Endophytic Mycobiota in the Roots of Rare Wild Rice (Oryza granulate) from a Nature Reserve in Yunnan, China▿ †

    PubMed Central

    Yuan, Zhi-lin; Zhang, Chu-long; Lin, Fu-cheng; Kubicek, Christian P.

    2010-01-01

    Rice (Oryza sativa L.) is, on a global scale, one of the most important food crops. Although endophytic fungi and bacteria associated with rice have been investigated, little is known about the endophytic fungi of wild rice (Oryza granulate) in China. Here we studied the root endophytic mycobiota residing in roots of O. granulate by the use of an integrated approach consisting of microscopy, cultivation, ecological indices, and direct PCR. Microscopy confirmed the ubiquitousness of dark septate endophytes (DSEs) and sclerotium-like structures in root tissues. Isolations from 204 root segments from 15 wild rice plants yielded 58 isolates, for which 31 internal transcribed spacer (ITS)-based genotypes were recorded. The best BLAST match indicated that 34.5% of all taxa encountered may represent hitherto undescribed species. Most of the fungi were isolated with a very low frequency. Calculation of ecological indices and estimation of taxon accumulation curves indicated a high diversity of fungal species. A culture-independent approach was also performed to analyze the endophytic fungal community. Three individual clone libraries were constructed. Using a threshold of 90% similarity, 35 potentially different sequences (phylotypes) were found among 186 positive clones. Phylogenetic analysis showed that frequently detected clones were classified as Basidiomycota, and 60.2% of total analyzed clones were affiliated with unknown taxa. Exophiala, Cladophialophora, Harpophora, Periconia macrospinosa, and the Ceratobasidium/Rhizoctonia complex may act as potential DSE groups. A comparison of the fungal communities characterized by the two approaches demonstrated distinctive fungal groups, and only a few taxa overlapped. Our findings indicate a complex and rich endophytic fungal consortium in wild rice roots, thus offering a potential bioresource for establishing a novel model of plant-fungal mutualistic interactions. PMID:20038691

  14. Regulation of Cellular Diacylglycerol through Lipid Phosphate Phosphatases Is Required for Pathogenesis of the Rice Blast Fungus, Magnaporthe oryzae

    PubMed Central

    Mir, Albely Afifa; Choi, Jaeyoung; Choi, Jaehyuk; Lee, Yong-Hwan

    2014-01-01

    Considering implication of diacylglycerol in both metabolism and signaling pathways, maintaining proper levels of diacylglycerol (DAG) is critical to cellular homeostasis and development. Except the PIP2-PLC mediated pathway, metabolic pathways leading to generation of DAG converge on dephosphorylation of phosphatidic acid catalyzed by lipid phosphate phosphatases. Here we report the role of such enzymes in a model plant pathogenic fungus, Magnaporthe oryzae. We identified five genes encoding putative lipid phosphate phosphatases (MoLPP1 to MoLPP5). Targeted disruption of four genes (except MoLPP4) showed that MoLPP3 and MoLPP5 are required for normal progression of infection-specific development and proliferation within host plants, whereas MoLPP1 and MoLPP2 are indispensable for fungal pathogenicity. Reintroduction of MoLPP3 and MoLPP5 into individual deletion mutants restored all the defects. Furthermore, exogenous addition of saturated DAG not only restored defect in appressorium formation but also complemented reduced virulence in both mutants. Taken together, our data indicate differential roles of lipid phosphate phosphatase genes and requirement of proper regulation of cellular DAGs for fungal development and pathogenesis. PMID:24959955

  15. Principles of Carbon Catabolite Repression in the Rice Blast Fungus: Tps1, Nmr1-3, and a MATE–Family Pump Regulate Glucose Metabolism during Infection

    PubMed Central

    Hartline, David; Quispe, Cristian F.; Madayiputhiya, Nandakumar; Wilson, Richard A.

    2012-01-01

    Understanding the genetic pathways that regulate how pathogenic fungi respond to their environment is paramount to developing effective mitigation strategies against disease. Carbon catabolite repression (CCR) is a global regulatory mechanism found in a wide range of microbial organisms that ensures the preferential utilization of glucose over less favourable carbon sources, but little is known about the components of CCR in filamentous fungi. Here we report three new mediators of CCR in the devastating rice blast fungus Magnaporthe oryzae: the sugar sensor Tps1, the Nmr1-3 inhibitor proteins, and the multidrug and toxin extrusion (MATE)–family pump, Mdt1. Using simple plate tests coupled with transcriptional analysis, we show that Tps1, in response to glucose-6-phosphate sensing, triggers CCR via the inactivation of Nmr1-3. In addition, by dissecting the CCR pathway using Agrobacterium tumefaciens-mediated mutagenesis, we also show that Mdt1 is an additional and previously unknown regulator of glucose metabolism. Mdt1 regulates glucose assimilation downstream of Tps1 and is necessary for nutrient utilization, sporulation, and pathogenicity. This is the first functional characterization of a MATE–family protein in filamentous fungi and the first description of a MATE protein in genetic regulation or plant pathogenicity. Perturbing CCR in Δtps1 and MDT1 disruption strains thus results in physiological defects that impact pathogenesis, possibly through the early expression of cell wall–degrading enzymes. Taken together, the importance of discovering three new regulators of carbon metabolism lies in understanding how M. oryzae and other pathogenic fungi respond to nutrient availability and control development during infection. PMID:22570632

  16. The bZIP Transcription Factor MoAP1 Mediates the Oxidative Stress Response and Is Critical for Pathogenicity of the Rice Blast Fungus Magnaporthe oryzae

    PubMed Central

    Guo, Min; Chen, Yue; Du, Yan; Dong, Yanhan; Guo, Wang; Zhai, Su; Zhang, Haifeng; Dong, Suomeng; Zhang, Zhengguang; Wang, Yuanchao; Wang, Ping; Zheng, Xiaobo

    2011-01-01

    Saccharomyces cerevisiae Yap1 protein is an AP1-like transcription factor involved in the regulation of the oxidative stress response. An ortholog of Yap1, MoAP1, was recently identified from the rice blast fungus Magnaporthe oryzae genome. We found that MoAP1 is highly expressed in conidia and during invasive hyphal growth. The Moap1 mutant was sensitive to H2O2, similar to S. cerevisiae yap1 mutants, and MoAP1 complemented Yap1 function in resistance to H2O2, albeit partially. The Moap1 mutant also exhibited various defects in aerial hyphal growth, mycelial branching, conidia formation, the production of extracellular peroxidases and laccases, and melanin pigmentation. Consequently, the Moap1 mutant was unable to infect the host plant. The MoAP1-eGFP fusion protein is localized inside the nucleus upon exposure to H2O2, suggesting that MoAP1 also functions as a redox sensor. Moreover, through RNA sequence analysis, many MoAP1-regulated genes were identified, including several novel ones that were also involved in pathogenicity. Disruption of respective MGG_01662 (MoAAT) and MGG_02531 (encoding hypothetical protein) genes did not result in any detectable changes in conidial germination and appressorium formation but reduced pathogenicity, whereas the mutant strains of MGG_01230 (MoSSADH) and MGG_15157 (MoACT) showed marketed reductions in aerial hyphal growth, mycelial branching, and loss of conidiation as well as pathogenicity, similar to the Moap1 mutant. Taken together, our studies identify MoAP1 as a positive transcription factor that regulates transcriptions of MGG_01662, MGG_02531, MGG_01230, and MGG_15157 that are important in the growth, development, and pathogenicity of M. oryzae. PMID:21383978

  17. Isolation, fine mapping and expression profiling of a lesion mimic genotype, spl(NF4050-8) that confers blast resistance in rice.

    PubMed

    Babu, Raman; Jiang, Chang-Jie; Xu, Xin; Kottapalli, Kameswara Rao; Takatsuji, Hiroshi; Miyao, Akio; Hirochika, Hirohiko; Kawasaki, Shinji

    2011-03-01

    We evaluated a large collection of Tos17 mutant panel lines for their reaction to three different races of Magnaporthe oryzae and identified a lesion mimic mutant, NF4050-8, that showed lesions similar to naturally occurring spl5 mutant and enhanced resistance to all the three blast races tested. Nested modified-AFLP using Tos17-specific primers and southern hybridization experiments of segregating individuals indicated that the lesion mimic phenotype in NF4050-8 is most likely due to a nucleotide change acquired during the culturing process and not due to Tos17 insertion per se. Inheritance and genetic analyses in two japonica × indica populations identified an overlapping genomic region of 13 cM on short arm of chromosome 7 that was linked with the lesion mimic phenotype. High-resolution genetic mapping using 950 F(3) and 3,821 F(4) plants of NF4050-8 × CO39 delimited a 35 kb region flanked by NBARC1 (5.262 Mb) and RM8262 (5.297 Mb), which contained 6 ORFs; 3 of them were 'resistance gene related' with typical NBS-LRR signatures. One of them harbored a NB-ARC domain, which had been previously demonstrated to be associated with cell death in animals. Microarray analysis of NF4050-8 revealed significant up-regulation of numerous defense/pathogenesis-related genes and down-regulation of heme peroxidase genes. Real-time PCR analysis of WRKY45 and PR1b genes suggested possible constitutive activation of a defense signaling pathway downstream of salicylic acid but independent of NH1 in these mutant lines of rice.

  18. Systematic characterization of the peroxidase gene family provides new insights into fungal pathogenicity in Magnaporthe oryzae

    PubMed Central

    Mir, Albely Afifa; Park, Sook-Young; Sadat, Md. Abu; Kim, Seongbeom; Choi, Jaeyoung; Jeon, Junhyun; Lee, Yong-Hwan

    2015-01-01

    Fungal pathogens have evolved antioxidant defense against reactive oxygen species produced as a part of host innate immunity. Recent studies proposed peroxidases as components of antioxidant defense system. However, the role of fungal peroxidases during interaction with host plants has not been explored at the genomic level. Here, we systematically identified peroxidase genes and analyzed their impact on fungal pathogenesis in a model plant pathogenic fungus, Magnaporthe oryzae. Phylogeny reconstruction placed 27 putative peroxidase genes into 15 clades. Expression profiles showed that majority of them are responsive to in planta condition and in vitro H2O2. Our analysis of individual deletion mutants for seven selected genes including MoPRX1 revealed that these genes contribute to fungal development and/or pathogenesis. We identified significant and positive correlations among sensitivity to H2O2, peroxidase activity and fungal pathogenicity. In-depth analysis of MoPRX1 demonstrated that it is a functional ortholog of thioredoxin peroxidase in Saccharomyces cerevisiae and is required for detoxification of the oxidative burst within host cells. Transcriptional profiling of other peroxidases in ΔMoprx1 suggested interwoven nature of the peroxidase-mediated antioxidant defense system. The results from this study provide insight into the infection strategy built on evolutionarily conserved peroxidases in the rice blast fungus. PMID:26134974

  19. Systematic characterization of the peroxidase gene family provides new insights into fungal pathogenicity in Magnaporthe oryzae.

    PubMed

    Mir, Albely Afifa; Park, Sook-Young; Abu Sadat, Md; Kim, Seongbeom; Choi, Jaeyoung; Jeon, Junhyun; Lee, Yong-Hwan

    2015-07-02

    Fungal pathogens have evolved antioxidant defense against reactive oxygen species produced as a part of host innate immunity. Recent studies proposed peroxidases as components of antioxidant defense system. However, the role of fungal peroxidases during interaction with host plants has not been explored at the genomic level. Here, we systematically identified peroxidase genes and analyzed their impact on fungal pathogenesis in a model plant pathogenic fungus, Magnaporthe oryzae. Phylogeny reconstruction placed 27 putative peroxidase genes into 15 clades. Expression profiles showed that majority of them are responsive to in planta condition and in vitro H2O2. Our analysis of individual deletion mutants for seven selected genes including MoPRX1 revealed that these genes contribute to fungal development and/or pathogenesis. We identified significant and positive correlations among sensitivity to H2O2, peroxidase activity and fungal pathogenicity. In-depth analysis of MoPRX1 demonstrated that it is a functional ortholog of thioredoxin peroxidase in Saccharomyces cerevisiae and is required for detoxification of the oxidative burst within host cells. Transcriptional profiling of other peroxidases in ΔMoprx1 suggested interwoven nature of the peroxidase-mediated antioxidant defense system. The results from this study provide insight into the infection strategy built on evolutionarily conserved peroxidases in the rice blast fungus.

  20. Identification of a New Locus, Ptr(t), Required for Rice Blast Resistance Gene Pi-ta-Mediated Resistance

    SciTech Connect

    Jia, Yulin; Martin, Rodger Carl

    2008-01-01

    Resistance to the blast pathogen Magnaporthe oryzae is proposed to be initiated by physical binding of a putative cytoplasmic receptor encoded by a NBS type resistance gene Pi-ta to the processed elicitor encoded by the corresponding avirulence gene AVR-Pita. Here we report the identification of a new locus Ptr(t) that is required for Pi-ta-mediated signal recognition. A Pi-ta expressing susceptible mutant was identified using a genetic screen. Putative mutations at Ptr(t) does not alter recognition specificity to another resistance gene Pi-ks in the Pi-ta homozygote indicate that Ptr(t) is more likely specific to Pi-ta-mediated signal recognition. Genetic crosses of Pi-ta Ptr(t) and Pi-ta ptr(t) homozygotes suggest that Ptr(t) segregate at single dominant nuclear gene. A ratio of 1 resistant: 1 susceptible of a BC1 using Pi-ta Ptr(t) with pi-ta ptr(t) homozygotes indicates that Pi-ta and Ptr(t) are linked and co-segregated. Genotyping of mutants of pi-ta ptr(t) and Pi-ta Ptr(t) homozygotes using ten simple sequence repeat markers spanning 9 megabase of Pi-ta determines that Pi-ta and Ptr(t) are of indica origin. Identification of Ptr(t) is a significant advancement in studying Pi-ta-mediated signal recognition and transduction.

  1. Induced Pib Expression and Resistance to Magnaporthe grisea are Compromised by Cytosine Demethylation at Critical Promoter Regions in Rice.

    PubMed

    Li, Yuan; Xia, Qiong; Kou, Hongping; Wang, Dan; Lin, Xiuyun; Wu, Ying; Xu, Chunming; Xing, Shaochen; Liu, Bao

    2011-10-01

    Pib is a well-characterized rice blast-resistance gene belonging to the nucleotide binding site (NBS) and leucine-rich repeat (LRR) superfamily. Expression of Pib was low under non-challenged conditions, but strongly induced by the blast-causing fungal pathogen Magnaporthe grisea, thereby conferring resistance to the pathogen. It is generally established that cytosine methylation of the promoter-region often plays a repressive role in modulating expression of the gene in question. We report here that two critical regions of the Pib promoter were heavily CG cytosine-methylated in both cultivars studied. Surprisingly, induced expression of Pib by M. grisea infection did not entail its promoter demethylation, and partial demethylation by 5-azacytidine-treatment actually reduced Pib expression relative to wild-type plants. Accordingly, the blast disease-resistance was compromised in the 5'-azaC-treated plants relative to wild-type. In contrast, the disease susceptibility was not affected by the 5'-azaC treatment in another two rice cultivars that did not contain the Pib gene, ruling out effects of other R genes and non-specific genotoxic effects by the drug-treatment as a cause for the compromised Pib-conditioned blast-resistance. Taken together, our results suggest that promoter DNA methylation plays a novel enhancing role in conditioning high-level of induced expression of the Pib gene in times of M. grisea infection, and its conferred resistance to the pathogen.

  2. Multiple plant surface signals are sensed by different mechanisms in the rice blast fungus for appressorium formation.

    PubMed

    Liu, Wende; Zhou, Xiaoying; Li, Guotian; Li, Lei; Kong, Lingan; Wang, Chenfang; Zhang, Haifeng; Xu, Jin-Rong

    2011-01-20

    Surface recognition and penetration are among the most critical plant infection processes in foliar pathogens. In Magnaporthe oryzae, the Pmk1 MAP kinase regulates appressorium formation and penetration. Its orthologs also are known to be required for various plant infection processes in other phytopathogenic fungi. Although a number of upstream components of this important pathway have been characterized, the upstream sensors for surface signals have not been well characterized. Pmk1 is orthologous to Kss1 in yeast that functions downstream from Msb2 and Sho1 for filamentous growth. Because of the conserved nature of the Pmk1 and Kss1 pathways and reduced expression of MoMSB2 in the pmk1 mutant, in this study we functionally characterized the MoMSB2 and MoSHO1 genes. Whereas the Momsb2 mutant was significantly reduced in appressorium formation and virulence, the Mosho1 mutant was only slightly reduced. The Mosho1 Momsb2 double mutant rarely formed appressoria on artificial hydrophobic surfaces, had a reduced Pmk1 phosphorylation level, and was nonresponsive to cutin monomers. However, it still formed appressoria and caused rare, restricted lesions on rice leaves. On artificial hydrophilic surfaces, leaf surface waxes and primary alcohols-but not paraffin waxes and alkanes- stimulated appressorium formation in the Mosho1 Momsb2 mutant, but more efficiently in the Momsb2 mutant. Furthermore, expression of a dominant active MST7 allele partially suppressed the defects of the Momsb2 mutant. These results indicate that, besides surface hydrophobicity and cutin monomers, primary alcohols, a major component of epicuticular leaf waxes in grasses, are recognized by M. oryzae as signals for appressorium formation. Our data also suggest that MoMsb2 and MoSho1 may have overlapping functions in recognizing various surface signals for Pmk1 activation and appressorium formation. While MoMsb2 is critical for sensing surface hydrophobicity and cutin monomers, MoSho1 may play a

  3. Improvement of Basmati rice varieties for resistance to blast and bacterial blight diseases using marker assisted backcross breeding.

    PubMed

    Ellur, Ranjith K; Khanna, Apurva; Yadav, Ashutosh; Pathania, Sandeep; Rajashekara, H; Singh, Vikas K; Gopala Krishnan, S; Bhowmick, Prolay K; Nagarajan, M; Vinod, K K; Prakash, G; Mondal, Kalyan K; Singh, Nagendra K; Vinod Prabhu, K; Singh, Ashok K

    2016-01-01

    Marker assisted backcross breeding was employed to incorporate the blast resistance genes, Pi2 and Pi54 and bacterial blight (BB) resistance genes xa13 and Xa21 into the genetic background of Pusa Basmati 1121 (PB1121) and Pusa Basmati 6. Foreground selection for target gene(s) was followed by arduous phenotypic and background selection which fast-tracked the recovery of recurrent parent genome (RPG) to an extent of 95.8% in one of the near-isogenic lines (NILs) namely, Pusa 1728-23-33-31-56, which also showed high degree of resemblance to recurrent parent, PB6 in phenotype. The phenotypic selection prior to background selection provided an additional opportunity for identifying the novel recombinants viz., Pusa 1884-9-12-14 and Pusa 1884-3-9-175, superior to parental lines in terms of early maturity, higher yield and improved quality parameters. There was no significant difference between the RPG recovery estimated based on SSR or SNP markers, however, the panel of SNPs markers was considered as the better choice for background selection as it provided better genome coverage and included SNPs in the genic regions. Multi-location evaluation of NILs depicted their stable and high mean performance in comparison to the respective recurrent parents. The Pi2+Pi54 carrying NILs were effective in combating a pan-India panel of Magnaporthe oryzae isolates with high level of field resistance in northern, eastern and southern parts of India. Alongside, the PB1121-NILs and PB6-NILs carrying BB resistance genes xa13+Xa21 were resistant against Xanthomonas oryzae pv. oryzae races of north-western, southern and eastern parts of the country. Three of NILs developed in this study, have been promoted to final stage of testing during the ​Kharif 2015 in the Indian National Basmati Trial. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  4. Molecular characterization of a novel ssRNA ourmia-like virus from the rice blast fungus Magnaporthe oryzae.

    PubMed

    Illana, Adriana; Marconi, Marco; Rodríguez-Romero, Julio; Xu, Ping; Dalmay, Tamas; Wilkinson, Mark D; Ayllón, Maria Ángeles; Sesma, Ane

    2017-03-01

    In this study we characterize a novel positive and single stranded RNA (ssRNA) mycovirus isolated from the rice field isolate of Magnaporthe oryzae Guy11. The ssRNA contains a single open reading frame (ORF) of 2,373 nucleotides in length and encodes an RNA-dependent RNA polymerase (RdRp) closely related to ourmiaviruses (plant viruses) and ourmia-like mycoviruses. Accordingly, we name this virus Magnaporthe oryzae ourmia-like virus 1 (MOLV1). Although phylogenetic analysis suggests that MOLV1 is closely related to ourmia and ourmia-like viruses, it has some features never reported before within the Ourmiavirus genus. 3' RLM-RACE (RNA ligase-mediated rapid amplification of cDNA ends) and extension poly(A) tests (ePAT) suggest that the MOLV1 genome contains a poly(A) tail whereas the three cytosine and the three guanine residues present in 5' and 3' untranslated regions (UTRs) of ourmia viruses are not observed in the MOLV1 sequence. The discovery of this novel viral genome supports the hypothesis that plant pathogenic fungi may have acquired this type of viruses from their host plants.

  5. Fungal Diseases

    MedlinePlus

    ... after a disaster . Global emergence of multidrug-resistant Candida auris Fungal Outbreaks Fungal Diseases Types of Fungal ... Treatment & Outcomes Health Professionals Statistics More Resources Candidiasis Candida infections of the mouth, throat, and esophagus Vaginal ...

  6. Intracellular catalase/peroxidase from the phytopathogenic rice blast fungus Magnaporthe grisea: expression analysis and biochemical characterization of the recombinant protein.

    PubMed

    Zamocky, Marcel; Furtmüller, Paul G; Bellei, Marzia; Battistuzzi, Gianantonio; Stadlmann, Johannes; Vlasits, Jutta; Obinger, Christian

    2009-03-01

    Phytopathogenic fungi such as the rice blast fungus Magnaporthe grisea are unique in having two catalase/peroxidase (KatG) paralogues located either intracellularly (KatG1) or extracellularly (KatG2). The coding genes have recently been shown to derive from a lateral gene transfer from a (proteo)bacterial genome followed by gene duplication and diversification. Here we demonstrate that KatG1 is expressed constitutively in M. grisea. It is the first eukaryotic catalase/peroxidase to be expressed heterologously in Escherichia coli in high amounts, with high purity and with almost 100% haem occupancy. Recombinant MagKatG1 is an acidic, mainly homodimeric, oxidoreductase with a predominant five-co-ordinated high-spin haem b. At 25 degrees C and pH 7.0, the E(0)' (standard reduction potential) of the Fe(III)/Fe(II) couple was found to be -186+/-10 mV. It bound cyanide monophasically with an apparent bimolecular rate constant of (9.0+/-0.4)x10(5) M(-1).s(-1) at pH 7.0 and at 25 degrees C and with a K(d) value of 1.5 muM. Its predominantly catalase activity was characterized by a pH optimum at 6.0 and k(cat) and K(m) values of 7010 s(-1) and 4.8 mM respectively. In addition, it acts as a versatile peroxidase with a pH optimum in the range 5.0-5.5 using both one-electron [2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) o-dianisidine, pyrogallol or guaiacol] and two-electron (Br(-), I(-) or ethanol) donors. Structure-function relationships are discussed with respect to data reported for prokaryotic KatGs, as is the physiological role of MagKatG1. Phylogenetic analysis suggests that (intracellular) MagKatG1 can be regarded as a typical representative for catalase/peroxidase of both phytopathogenic and saprotrophic fungi.

  7. Magnesium Uptake by CorA Transporters Is Essential for Growth, Development and Infection in the Rice Blast Fungus Magnaporthe oryzae

    PubMed Central

    Reza, Md. Hashim; Shah, Hiral; Manjrekar, Johannes; Chattoo, Bharat B.

    2016-01-01

    Magnaporthe oryzae, the causative organism of rice blast, infects cereal crops and grasses at various stages of plant development. A comprehensive understanding of its metabolism and the implications on pathogenesis is necessary for countering this devastating crop disease. We present the role of the CorA magnesium transporters, MoAlr2 and MoMnr2, in development and pathogenicity of M. oryzae. The MoALR2 and MoMNR2 genes individually complement the Mg2+ uptake defects of a S. cerevisiae CorA transporter double mutant. MoALR2 and MoMNR2 respond to extracellular Mg2+ and Ca2+ levels and their expression is elevated under Mg2+ scarce conditions. RNA silencing mediated knockdown of MoALR2 (WT+siALR2, Δmnr2+siALR2 and ALR2+MNR2 simultaneous silencing) drastically alters intracellular cation concentrations and sensitivity to metal ions. MoALR2 silencing is detrimental to vegetative growth and surface hydrophobicity of mycelia, and the transformants display loss of cell wall integrity. MoALR2 is required for conidiogenesis and appressorium development, and is essential for infection. Investigation of knockdown transformants reveal low cAMP levels and altered expression of genes encoding proteins involved in MoMps1 cell wall integrity and cAMP MoPmk1 driven MAP Kinase signaling pathways. In contrast to MoALR2 knockdowns, the MoMNR2 deletion (Δmnr2) shows increased sensitivity to CorA inhibitors as well as altered cation sensitivity, but has limited effect on surface hydrophobicity and severity of plant infection. Interestingly, MoALR2 expression is elevated in Δmnr2. Impairment of development and infectivity of knockdown transformants and altered intracellular cation composition suggest that CorA transporters are essential for Mg2+ homeostasis within the cell, and are crucial to maintaining normal gene expression associated with cell structure, signal transduction and surface hydrophobicity in M. oryzae. We suggest that CorA transporters, and especially MoALR2

  8. Regulation of expression of rice thaumatin-like protein: inducibility by elicitor requires promoter W-box elements.

    PubMed

    Hiroyuki, Kanzaki; Terauchi, Ryohei

    2008-09-01

    Rice thaumatin-like protein (Rtlp1) is a high-molecular-weight antimicrobial pathogenesis-related protein that plays a role in plant stress response. This study examines transcriptional regulation of Rtlp1 using wild type and transgenic rice plants carrying a beta-glucuronidase (GUS) reporter gene driven by the Rtlp1 promoter (pRtlp1GUS). The Rtlp1 promoter is induced within 6 h after infection with rice blast fungus (Magnaporthe grisea). The Rtlp1 promoter is also induced by salicylic acid (SA), methyl jasmonate (MeJA), wounding or an elicitor from rice blast fungus. The function of the pRtlp1GUS reporter gene was analyzed by deletion mapping and transient expression assays in cell culture. A 120 bp truncated fusion construct with six W-boxes (5'-TGAC-3') demonstrated a strong dose-dependent elicitor-response. These results suggest that W-box elements are required for the response of the Rtlp1 promoter to fungal elicitors.

  9. Comparative study of genes expressed from rice fungus-resistant and susceptible lines during interactions with Magnaporthe oryzae.

    PubMed

    Shi, Bu-Jun; Wang, Guo-Liang

    2008-12-31

    Rice blast disease caused by Magnaporthe oryzae is the most important fungal disease of rice. To understand the molecular basis of interaction between the fungus and rice, we constructed a cDNA library from a rice-resistant line inoculated with M. oryzae. One hundred and fifty-three cDNA clones were sequence analyzed, of which 129 exhibited significant nucleotide sequence homology to known genes, 21 were homologous to unknown genes, while three clones did not match to any database. However, these three unmatched clones showed sequence homology at protein level in the protein databases and one of them encoded a disease resistance-related protein kinase and was abundant in the EST collection. Northern analysis showed that this disease resistance-related protein kinase gene was induced by inoculation and only expressed in the rice-resistant, but not susceptible, lines. Southern analysis showed that this gene was present in a single copy in the rice genome and co-segregated with the M. oryzae resistance in the cross of the resistant and susceptible lines. This study illustrates that sequencing of ESTs from inoculated resistant plants can reveal genes responsive to pathogen infection, which could help understand plant defense mechanisms.

  10. Enhancement of innate immune system in monocot rice by transferring the dicotyledonous elongation factor Tu receptor EFR.

    PubMed

    Lu, Fen; Wang, Huiqin; Wang, Shanzhi; Jiang, Wendi; Shan, Changlin; Li, Bin; Yang, Jun; Zhang, Shiyong; Sun, Wenxian

    2015-07-01

    The elongation factor Tu (EF-Tu) receptor (EFR) in cruciferous plants specifically recognizes the N-terminal acetylated elf18 region of bacterial EF-Tu and thereby activates plant immunity. It has been demonstrated that Arabidopsis EFR confers broad-spectrum bacterial resistance in the EFR transgenic solanaceous plants. Here, the transgenic rice plants (Oryza sativa L. ssp. japonica cv. Zhonghua 17) and cell cultures with constitutive expression of AtEFR were developed to investigate whether AtEFR senses EF-Tu and thus enhances bacterial resistance in the monocot plants. We demonstrated that the Xanthomonas oryzae-derived elf18 peptide induced oxidative burst and mitogen-activated protein kinase activation in the AtEFR transgenic rice cells and plants, respectively. Pathogenesis-related genes, such as OsPBZ1, were upregulated dramatically in transgenic rice plant and cell lines in response to elf18 stimulation. Importantly, pretreatment with elf18 triggered strong resistance to X. oryzae pv. oryzae in the transgenic plants, which was largely dependent on the AtEFR expression level. These plants also exhibited enhanced resistance to rice bacterial brown stripe, but not to rice fungal blast. Collectively, the results indicate that the rice plants with heterologous expression of AtEFR recognize bacterial EF-Tu and exhibit enhanced broad-spectrum bacterial disease resistance and that pattern recognition receptor-mediated immunity may be manipulated across the two plant classes, dicots and monocots.

  11. Analysis of genetic and molecular identity among field isolates of the rice blast fungus with an international differential system, rep-PCR and DNA sequencing

    USDA-ARS?s Scientific Manuscript database

    The Pi-ta gene deployed in the Southern US rice germplasm is effective in preventing the infection by strains of Magnaporthe oryzae isolates that carry the avirulence gene AVR-Pita1. In the present study, a total of 169 isolates from rice (Oryza sativa) cultivars, with and without Pi-ta, were analyz...

  12. Toward understanding of rice innate immunity against Magnaporthe oryzae.

    PubMed

    Azizi, P; Rafii, M Y; Abdullah, S N A; Nejat, N; Maziah, M; Hanafi, M M; Latif, M A; Sahebi, M

    2016-01-01

    The blast fungus, Magnaporthe oryzae, causes serious disease on a wide variety of grasses including rice, wheat and barley. The recognition of pathogens is an amazing ability of plants including strategies for displacing virulence effectors through the adaption of both conserved and variable pathogen elicitors. The pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) and effector-triggered immunity (ETI) were reported as two main innate immune responses in plants, where PTI gives basal resistance and ETI confers durable resistance. The PTI consists of extracellular surface receptors that are able to recognize PAMPs. PAMPs detect microbial features such as fungal chitin that complete a vital function during the organism's life. In contrast, ETI is mediated by intracellular receptor molecules containing nucleotide-binding (NB) and leucine rich repeat (LRR) domains that specifically recognize effector proteins produced by the pathogen. To enhance crop resistance, understanding the host resistance mechanisms against pathogen infection strategies and having a deeper knowledge of innate immunity system are essential. This review summarizes the recent advances on the molecular mechanism of innate immunity systems of rice against M. oryzae. The discussion will be centered on the latest success reported in plant-pathogen interactions and integrated defense responses in rice.

  13. A secreted fungal effector of Glomus intraradices promotes symbiotic biotrophy.

    PubMed

    Kloppholz, Silke; Kuhn, Hannah; Requena, Natalia

    2011-07-26

    Biotrophic fungi interacting with plants establish long-term relationships with their hosts to fulfill their life cycles. In contrast to necrotrophs, they need to contend with the defense mechanisms of the plant to develop within the host and feed on living cells. It is generally accepted that microbial pathogens produce and deliver a myriad of effector proteins to hijack the cellular program of their hosts. Arbuscular mycorrhizal (AM) fungi are the most widespread biotrophs of plant roots. We investigated whether AM fungi use effector proteins to short-circuit the plant defense program. Here we show that Glomus intraradices secretes a protein, SP7, that interacts with the pathogenesis-related transcription factor ERF19 in the plant nucleus. ERF19 is highly induced in roots by the fungal pathogen Colletotrichum trifolii as well as by several fungal extracts, but only transiently during mycorrhiza colonization. When constitutively expressed in roots, SP7 leads to higher mycorrhization while reducing the levels of C. trifolii-mediated defense responses. Furthermore, expression of SP7 in the rice blast fungus Magnaporthe oryzae attenuates root decay symptoms. Taken together, these results suggest that SP7 is an effector that contributes to develop the biotrophic status of AM fungi in roots by counteracting the plant immune program.

  14. Oscillating Transcriptome during Rice-Magnaporthe Interaction.

    PubMed

    Sharma, T R; Das, Alok; Thakur, Shallu; Devanna, B N; Singh, Pankaj Kumar; Jain, Priyanka; Vijayan, Joshitha; Kumar, Shrawan

    2016-01-01

    Rice blast disease caused by the fungus, Magnaporthe oryzae, is one of the most devastating diseases of rice. Deciphering molecular mechanism of host-pathogen interactions is of great importance in devising disease management strategies. Transcription being the first step for gene regulation in eukaryotes, basic understanding of the transcriptome is sine qua non for devising effective management strategy. The availability of genome sequences of rice and M. oryzae has facilitated the process to a large extent. The current review summarizes recent understanding of rice-blast pathosystem, application of transcriptomics approaches to understand the interactions employing different platforms, major determinants in the interaction and possibility of using certain candidate for conditioning enhanced disease resistance (Effector Triggered Immunity and PAMP Triggered Immunity) and downstream signalling in rice. A better understanding of the interaction elements and effective strategies hold potential to reduce yield losses in rice caused by M. oryzae.

  15. Optimizing tillage schedule for maintaining activity of the arbuscular mycorrhizal fungal population in a rainfed upland rice (Oryza sativa L.) agro-ecosystem.

    PubMed

    Maiti, D; Variar, M; Singh, R K

    2011-04-01

    Rainfed uplands in India are predominantly mono-cropped with rice (Oryza sativa L.) in the wet season (June/July to September/October) and grown under aerobic soil conditions. The remaining fallow period (winter followed by summer) of about 8-9 months leads to natural crash in the population of native arbuscular mycorrhizal fungi (AMF) in the soil. Attempts have been made to minimize this population crash by reducing soil disturbance-induced deleterious effects on native AMF activity of improperly scheduled off-season tillage, an agronomic recommendation for weed and disease (soil-borne) management, practiced by the upland farmers. On-farm (farmers' field) evaluation of effects of all suitable off-season tillage schedule combinations on rice during wet seasons of 2004, 2005, and 2006 revealed that a maximum of two off-season tillage schedules with a minimum gap of 13 weeks between them minimized the population crash of native AMF with a concomitant increase in phosphorus (P) uptake and grain yield of upland rice (variety "Vandana").

  16. The Magnaporthe oryzae Effector AvrPiz-t Targets the RING E3 Ubiquitin Ligase APIP6 to Suppress Pathogen-Associated Molecular Pattern–Triggered Immunity in Rice[W][OA

    PubMed Central

    Park, Chan-Ho; Chen, Songbiao; Shirsekar, Gautam; Zhou, Bo; Khang, Chang Hyun; Songkumarn, Pattavipha; Afzal, Ahmed J.; Ning, Yuese; Wang, Ruyi; Bellizzi, Maria; Valent, Barbara; Wang, Guo-Liang

    2012-01-01

    Although the functions of a few effector proteins produced by bacterial and oomycete plant pathogens have been elucidated in recent years, information for the vast majority of pathogen effectors is still lacking, particularly for those of plant-pathogenic fungi. Here, we show that the avirulence effector AvrPiz-t from the rice blast fungus Magnaporthe oryzae preferentially accumulates in the specialized structure called the biotrophic interfacial complex and is then translocated into rice (Oryza sativa) cells. Ectopic expression of AvrPiz-t in transgenic rice suppresses the flg22- and chitin-induced generation of reactive oxygen species (ROS) and enhances susceptibility to M. oryzae, indicating that AvrPiz-t functions to suppress pathogen-associated molecular pattern (PAMP)-triggered immunity in rice. Interaction assays show that AvrPiz-t suppresses the ubiquitin ligase activity of the rice RING E3 ubiquitin ligase APIP6 and that, in return, APIP6 ubiquitinates AvrPiz-t in vitro. Interestingly, agroinfection assays reveal that AvrPiz-t and AvrPiz-t Interacting Protein 6 (APIP6) are both degraded when coexpressed in Nicotiana benthamiana. Silencing of APIP6 in transgenic rice leads to a significant reduction of flg22-induced ROS generation, suppression of defense-related gene expression, and enhanced susceptibility of rice plants to M. oryzae. Taken together, our results reveal a mechanism in which a fungal effector targets the host ubiquitin proteasome system for the suppression of PAMP-triggered immunity in plants. PMID:23204406

  17. Pigeonpea Hybrid-Proline-Rich Protein (CcHyPRP) Confers Biotic and Abiotic Stress Tolerance in Transgenic Rice.

    PubMed

    Mellacheruvu, Sunitha; Tamirisa, Srinath; Vudem, Dashavantha Reddy; Khareedu, Venkateswara Rao

    2015-01-01

    In this study, we report the overexpression of Cajanus cajan hybrid-proline-rich protein encoding gene (CcHyPRP) in rice which resulted in increased tolerance to both abiotic and biotic stresses. Compared to the control plants, the transgenic rice lines, expressing CcHyPRP, exhibited high-level tolerance against major abiotic stresses, viz., drought, salinity, and heat, as evidenced by increased biomass, chlorophyll content, survival rate, root, and shoot growth. Further, transgenic rice lines showed increased panicle size and grain number compared to the control plants under different stress conditions. The CcHyPRP transgenics, as compared to the control, revealed enhanced activities of catalase and superoxide dismutase (SOD) enzymes and reduced malondialdehyde (MDA) levels. Expression pattern of CcHyPRP::GFP fusion-protein confirmed its predominant localization in cell walls. Moreover, the CcHyPRP transgenics, as compared to the control, exhibited increased resistance to the fungal pathogen Magnaporthe grisea which causes blast disease in rice. Higher levels of bZIP and endochitinase transcripts as well as endochitinase activity were observed in transgenic rice compared to the control plants. The overall results demonstrate the intrinsic role of CcHyPRP in conferring multiple stress tolerance at the whole-plant level. The multipotent CcHyPRP seems promising as a prime candidate gene to fortify crop plants for enhanced tolerance/resistance to different stress factors.

  18. Pigeonpea Hybrid-Proline-Rich Protein (CcHyPRP) Confers Biotic and Abiotic Stress Tolerance in Transgenic Rice

    PubMed Central

    Mellacheruvu, Sunitha; Tamirisa, Srinath; Vudem, Dashavantha Reddy; Khareedu, Venkateswara Rao

    2016-01-01

    In this study, we report the overexpression of Cajanus cajan hybrid-proline-rich protein encoding gene (CcHyPRP) in rice which resulted in increased tolerance to both abiotic and biotic stresses. Compared to the control plants, the transgenic rice lines, expressing CcHyPRP, exhibited high-level tolerance against major abiotic stresses, viz., drought, salinity, and heat, as evidenced by increased biomass, chlorophyll content, survival rate, root, and shoot growth. Further, transgenic rice lines showed increased panicle size and grain number compared to the control plants under different stress conditions. The CcHyPRP transgenics, as compared to the control, revealed enhanced activities of catalase and superoxide dismutase (SOD) enzymes and reduced malondialdehyde (MDA) levels. Expression pattern of CcHyPRP::GFP fusion-protein confirmed its predominant localization in cell walls. Moreover, the CcHyPRP transgenics, as compared to the control, exhibited increased resistance to the fungal pathogen Magnaporthe grisea which causes blast disease in rice. Higher levels of bZIP and endochitinase transcripts as well as endochitinase activity were observed in transgenic rice compared to the control plants. The overall results demonstrate the intrinsic role of CcHyPRP in conferring multiple stress tolerance at the whole-plant level. The multipotent CcHyPRP seems promising as a prime candidate gene to fortify crop plants for enhanced tolerance/resistance to different stress factors. PMID:26834756

  19. Friend or foe: differential responses of rice to invasion by mutualistic or pathogenic fungi revealed by RNAseq and metabolite profiling

    PubMed Central

    Xu, Xi-Hui; Wang, Chen; Li, Shu-Xian; Su, Zhen-Zhu; Zhou, Hui-Na; Mao, Li-Juan; Feng, Xiao-Xiao; Liu, Ping-Ping; Chen, Xia; Hugh Snyder, John; Kubicek, Christian P.; Zhang, Chu-Long; Lin, Fu-Cheng

    2015-01-01

    The rice endophyte Harpophora oryzae shares a common pathogenic ancestor with the rice blast fungus Magnaporthe oryzae. Direct comparison of the interactions between a single plant species and two closely-related (1) pathogenic and (2) mutualistic fungi species can improve our understanding of the evolution of the interactions between plants and fungi that lead to either mutualistic or pathogenic interactions. Differences in the metabolome and transcriptome of rice in response to challenge by H. or M. oryzae were investigated with GC-MS, RNA-seq, and qRT-PCR. Levels of metabolites of the shikimate and lignin biosynthesis pathways increased continuously in the M. oryzae-challenged rice roots (Mo-roots); these pathways were initially induced, but then suppressed, in the H. oryzae-challenged rice roots (Ho-roots). Compared to control samples, concentrations of sucrose and maltose were reduced in the Ho-roots and Mo-roots. The expression of most genes encoding enzymes involved in glycolysis and the TCA cycle were suppressed in the Ho-roots, but enhanced in the Mo-roots. The suppressed glycolysis in Ho-roots would result in the accumulation of glucose and fructose which was not detected in the Mo-roots. A novel co-evolution pattern of fungi-host interaction is proposed which highlights the importance of plant host in the evolution of fungal symbioses. PMID:26346313

  20. Friend or foe: differential responses of rice to invasion by mutualistic or pathogenic fungi revealed by RNAseq and metabolite profiling.

    PubMed

    Xu, Xi-Hui; Wang, Chen; Li, Shu-Xian; Su, Zhen-Zhu; Zhou, Hui-Na; Mao, Li-Juan; Feng, Xiao-Xiao; Liu, Ping-Ping; Chen, Xia; Hugh Snyder, John; Kubicek, Christian P; Zhang, Chu-Long; Lin, Fu-Cheng

    2015-09-08

    The rice endophyte Harpophora oryzae shares a common pathogenic ancestor with the rice blast fungus Magnaporthe oryzae. Direct comparison of the interactions between a single plant species and two closely-related (1) pathogenic and (2) mutualistic fungi species can improve our understanding of the evolution of the interactions between plants and fungi that lead to either mutualistic or pathogenic interactions. Differences in the metabolome and transcriptome of rice in response to challenge by H. or M. oryzae were investigated with GC-MS, RNA-seq, and qRT-PCR. Levels of metabolites of the shikimate and lignin biosynthesis pathways increased continuously in the M. oryzae-challenged rice roots (Mo-roots); these pathways were initially induced, but then suppressed, in the H. oryzae-challenged rice roots (Ho-roots). Compared to control samples, concentrations of sucrose and maltose were reduced in the Ho-roots and Mo-roots. The expression of most genes encoding enzymes involved in glycolysis and the TCA cycle were suppressed in the Ho-roots, but enhanced in the Mo-roots. The suppressed glycolysis in Ho-roots would result in the accumulation of glucose and fructose which was not detected in the Mo-roots. A novel co-evolution pattern of fungi-host interaction is proposed which highlights the importance of plant host in the evolution of fungal symbioses.

  1. Serotonin attenuates biotic stress and leads to lesion browning caused by a hypersensitive response to Magnaporthe oryzae penetration in rice.

    PubMed

    Hayashi, Keiko; Fujita, Yoshikatsu; Ashizawa, Taketo; Suzuki, Fumihiko; Nagamura, Yoshiaki; Hayano-Saito, Yuriko

    2016-01-01

    The hypersensitive response (HR) of plants is one of the earliest responses to prevent pathogen invasion. A brown dot lesion on a leaf is visual evidence of the HR against the blast fungus Magnaporthe oryzae in rice, but tracking the browning process has been difficult. In this study, we induced the HR in rice cultivars harboring the blast resistance gene Pit by inoculation of an incompatible M. oryzae strain, which generated a unique resistance lesion with a brown ring (halo) around the brown fungal penetration site. Inoculation analysis using a plant harboring Pit but lacking an enzyme that catalyzes tryptamine to serotonin showed that high accumulation of the oxidized form of serotonin was the cause of the browning at the halo and penetration site. Our analysis of the halo browning process in the rice leaf revealed that abscisic acid enhanced biosynthesis of serotonin under light conditions, and serotonin changed to the oxidized form via hydrogen peroxide produced by light. The dramatic increase in serotonin, which has a high antioxidant activity, suppressed leaf damage outside the halo, blocked expansion of the browning area and attenuated inhibition of plant growth. These results suggest that serotonin helps to reduce biotic stress in the plant by acting as a scavenger of oxygen radicals to protect uninfected tissues from oxidative damage caused by the HR. The deposition of its oxide at the HR lesion is observed as lesion browning. © 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.

  2. Comparing systemic defence-related gene expression changes upon migratory and sedentary nematode attack in rice.

    PubMed

    Kyndt, T; Nahar, K; Haegeman, A; De Vleesschauwer, D; Höfte, M; Gheysen, G

    2012-03-01

    Complex defence signalling pathways, controlled by different hormones, are known to be involved in the reaction of plants to a wide range of biotic and abiotic stress factors. Here, we studied the differential expression of genes involved in stress and defence responses in systemic tissue of rice infected with the root knot nematode (RKN) Meloidogyne graminicola and the migratory root rot nematode Hirschmanniella oryzae, two agronomically important rice pathogens with very different lifestyles. qRT-PCR revealed that all investigated systemic tissues had significantly lower expression of isochorismate synthase, a key enzyme for salicylic acid production involved in basal defence and systemic acquired resistance. The systemic defence response upon migratory nematode infection was remarkably similar to fungal rice blast infection. Almost all investigated defence-related genes were up-regulated in rice shoots 3 days after root rot nematode attack, including the phenylpropanoid pathway, ethylene pathway and PR genes, but many of which were suppressed at 7 dpi. Systemic shoot tissue of RKN-infected plants showed similar attenuation of expression of almost all studied genes already at 3 dpi, with clear attenuation of the ethylene pathway and methyl jasmonate biosynthesis. These results provide an interesting starting point for further studies to elucidate how nematodes are able to suppress systemic plant defence mechanisms and the effect in multitrophic interactions.

  3. Innate immunity in rice

    PubMed Central

    Chen, Xuewei; Ronald, Pamela C.

    2011-01-01

    Advances in studies of rice innate immunity have led to the identification and characterization of host sensors encoding receptor kinases that perceive conserved microbial signatures. The non-RD domain, a newly recognized hallmark of these receptor kinases is highly expanded in rice (Oryza sativa) compared with Arabidopsis (Arabidopsis thaliana). Researchers have also identified a diverse array of microbial effectors from bacterial and fungal pathogens that triggers immune responses upon perception. These include both, effectors that indirectly target host Nucleotide binding site/Leucine rice repeat (NBS-LRR) proteins and transcription activator-like (TAL) effectors that directly bind promoters of host genes. Here we review the recognition and signaling events that govern rice innate immunity. PMID:21602092

  4. Twilight, a Novel Circadian-Regulated Gene, Integrates Phototropism with Nutrient and Redox Homeostasis during Fungal Development.

    PubMed

    Deng, Yi Zhen; Qu, Ziwei; Naqvi, Naweed I

    2015-06-01

    Phototropic regulation of circadian clock is important for environmental adaptation, organismal growth and differentiation. Light plays a critical role in fungal development and virulence. However, it is unclear what governs the intracellular metabolic response to such dark-light rhythms in fungi. Here, we describe a novel circadian-regulated Twilight (TWL) function essential for phototropic induction of asexual development and pathogenesis in the rice-blast fungus Magnaporthe oryzae. The TWL transcript oscillates during circadian cycles and peaks at subjective twilight. GFP-Twl remains acetylated and cytosolic in the dark, whereas light-induced phosphorylation (by the carbon sensor Snf1 kinase) drives it into the nucleus. The mRNA level of the transcription/repair factor TFB5, was significantly down regulated in the twl∆ mutant. Overexpression of TFB5 significantly suppressed the conidiation defects in the twl∆ mutant. Furthermore, Tfb5-GFP translocates to the nucleus during the phototropic response and under redox stress, while it failed to do so in the twl∆ mutant. Thus, we provide mechanistic insight into Twl-based regulation of nutrient and redox homeostasis in response to light during pathogen adaptation to the host milieu in the rice blast pathosystem.

  5. Twilight, a Novel Circadian-Regulated Gene, Integrates Phototropism with Nutrient and Redox Homeostasis during Fungal Development

    PubMed Central

    Naqvi, Naweed I.

    2015-01-01

    Phototropic regulation of circadian clock is important for environmental adaptation, organismal growth and differentiation. Light plays a critical role in fungal development and virulence. However, it is unclear what governs the intracellular metabolic response to such dark-light rhythms in fungi. Here, we describe a novel circadian-regulated Twilight (TWL) function essential for phototropic induction of asexual development and pathogenesis in the rice-blast fungus Magnaporthe oryzae. The TWL transcript oscillates during circadian cycles and peaks at subjective twilight. GFP-Twl remains acetylated and cytosolic in the dark, whereas light-induced phosphorylation (by the carbon sensor Snf1 kinase) drives it into the nucleus. The mRNA level of the transcription/repair factor TFB5, was significantly down regulated in the twl∆ mutant. Overexpression of TFB5 significantly suppressed the conidiation defects in the twl∆ mutant. Furthermore, Tfb5-GFP translocates to the nucleus during the phototropic response and under redox stress, while it failed to do so in the twl∆ mutant. Thus, we provide mechanistic insight into Twl-based regulation of nutrient and redox homeostasis in response to light during pathogen adaptation to the host milieu in the rice blast pathosystem. PMID:26102503

  6. Preparation of Chitosan nanoparticles and its effect on detached rice leaves infected with Pyricularia grisea.

    PubMed

    Manikandan, Appu; Sathiyabama, Muthukrishnan

    2016-03-01

    The aim of the present study was to prepare chitosan nanoparticles to evaluate their effect on protection of rice plants from blast fungus. Nanoparticles were prepared using the ionic gelation method by the interaction of Chitosan and sodium tripolyphosphate. The particle size, polydispersity index, zetapotential and structure was confirmed by DLS, FTIR, TEM and XRD. The Chitosan nanoparticle was evaluated for suppression of rice blast fungus (Pyricularia grisea) under the detached leaf condition. It is evident from our results that chitosan nanoparticle have potential in suppressing blast disease of rice which can be used further under field condition to protect rice plants from the devastating fungus.

  7. Fungal Sinusitis.

    PubMed

    Raz, Eytan; Win, William; Hagiwara, Mari; Lui, Yvonne W; Cohen, Benjamin; Fatterpekar, Girish M

    2015-11-01

    Fungal sinusitis is characterized into invasive and noninvasive forms. The invasive variety is further classified into acute, chronic and granulomatous forms; and the noninvasive variety into fungus ball and allergic fungal sinusitis. Each of these different forms has a unique radiologic appearance. The clinicopathologic and corresponding radiologic spectrum and differences in treatment strategies of fungal sinusitis make it an important diagnosis for clinicians and radiologists to always consider. This is particularly true of invasive fungal sinusitis, which typically affects immuno compromised patients and is associated with significant morbidity and mortality. Early diagnosis allows initiation of appropriate treatment strategies resulting in favorable outcome. Published by Elsevier Inc.

  8. Fungal melanonychia.

    PubMed

    Finch, Justin; Arenas, Roberto; Baran, Robert

    2012-05-01

    Fungal melanonychia is a relatively rare nail disorder caused by nail infection that produces brown-to-black pigmentation of the nail unit. The number of organisms implicated as etiologic agents of fungal melanonychia is increasing, and the list currently tops 21 species of dematiaceous fungi and at least 8 species of nondematiaceous fungi. These superficial infections may clinically mimic subungual melanoma and are often not responsive to traditional antifungal therapy. This article reviews the literature on fungal melanonychia and the role of fungal melanin in infection.

  9. Blast Technologies

    DTIC Science & Technology

    2011-06-27

    Team Leader Risa Scherer Blast Mitigation Interior and Laboratory Team Leader Blast Technologies POC’s Government Point Of Contacts (POCs): To...to yield injury assessments at higher fidelities and with higher confidence UNCLASSIFIED UNCLASSIFIED Risa Scherer Blast Mitigation Interior and

  10. Evolutionary dynamics of the genomic region around the blast resistance gene Pi-ta in AA genome Oryza species

    USDA-ARS?s Scientific Manuscript database

    The Pi-ta gene in rice has been predicted to directly detect the pathogen signaling molecule in preventing blast disease. The resistance Pi-ta allale (alanine at 918) has been introgressed between cultivated rice to confer blast resistance. To understand the evolutionary dynamics present of Pi-ta, w...

  11. Comparative transcriptome profiling of the early response to Magnaporthe oryzae in durable resistant vs susceptible rice (Oryza sativa L.) genotypes.

    PubMed

    Bagnaresi, Paolo; Biselli, Chiara; Orrù, Luigi; Urso, Simona; Crispino, Laura; Abbruscato, Pamela; Piffanelli, Pietro; Lupotto, Elisabetta; Cattivelli, Luigi; Valè, Giampiero

    2012-01-01

    Durable resistance to blast, the most significant fungal disease of rice, represents an agronomically relevant character. Gigante Vercelli (GV) and Vialone Nano (VN) are two old temperate japonica Italian rice cultivars with contrasting response to blast infection: GV displays durable and broad resistance while VN is highly susceptible. RNA-seq was used to dissect the early molecular processes deployed during the resistance response of GV at 24 h after blast inoculation. Differential gene expression analysis identified 1,070 and 1,484 modulated genes, of which 726 and 699 were up regulated in response to infection in GV and VN, respectively. Gene ontology (GO) enrichment analyses revealed a set of GO terms enriched in both varieties but, despite this commonality, the gene sets contributing to common GO enriched terms were dissimilar. The expression patterns of genes grouped in GV-specific enriched GO terms were examined in detail including at the transcript isoform level. GV exhibited a dramatic up-regulation of genes encoding diterpene phytoalexin biosynthetic enzymes, flavin-containing monooxygenase, class I chitinase and glycosyl hydrolase 17. The sensitivity and high dynamic range of RNA-seq allowed the identification of genes critically involved in conferring GV resistance during the early steps of defence perception-signalling. These included chitin oligosaccharides sensing factors, wall associated kinases, MAPK cascades and WRKY transcription factors. Candidate genes with expression patterns consistent with a potential role as GV-specific functional resistance (R) gene(s) were also identified. This first application of RNA-seq to dissect durable blast resistance supports a crucial role of the prompt induction of a battery of responses including defence-related genes as well as members of gene families involved in signalling and pathogen-related gene expression regulation.

  12. Fungal rhinosinusitis.

    PubMed

    Netkovski, J; Shirgoska, B

    2012-01-01

    Fungi are a major part of the ecosystem. In fact, over 250 fungal species have been reported to produce human infections. More than ever, fungal diseases have emerged as major challenges for physicians and clinical microbiologists. The aim of this study was to summarize the diagnostic procedures and endoscopic surgical treatment of patients with fungal rhinosinusitis. Eleven patients, i.e. 10% of all cases with chronic inflammation of paranasal sinuses, were diagnosed with fungal rhinosinusitis. Ten of them were patients with a noninvasive form, fungus ball, while only one patient was classified in the group of chronic invasive fungal rhinosinusitis which was accompanied with diabetes mellitus. All patients underwent nasal endoscopic examination, skin allergy test and had preoperative computed tomography (CT) scans of the sinuses in axial and coronal plane. Functional endoscopic sinus surgery was performed in 10 patients with fungus ball, while a combined approach, endoscopic and external, was done in the immunocompromised patient with the chronic invasive form of fungal rhinosinusitis. Most cases (9/11) had unilateral infection. In 9 cases infection was restricted to a single sinus, and here the maxillary sinus was most commonly affected (8/9) with infections in other patients being restricted to the sphenoid sinus (1/9). Two patients had infections affecting two or more sinuses. In patients with an invasive form of the fungal disease there was involvement of the periorbital and orbital tissues. In patients with fungus ball the mycelia masses were completely removed from the sinus cavities. Long-term outcome was positive in all the operated patients and no recurrence was detected. The most frequent fungal agent that caused rhinosinusitis was Aspergillus. Mucor was identified in the patient with the invasive form. Endoscopic examination of the nasal cavity and CT scanning of paranasal sinuses followed by endoscopic sinus surgery were represented as valuable

  13. Fungal hemolysins

    PubMed Central

    Nayak, Ajay P.; Green, Brett J.; Beezhold, Donald H.

    2015-01-01

    Hemolysins are a class of proteins defined by their ability to lyse red cells but have been described to exhibit pleiotropic functions. These proteins have been extensively studied in bacteria and more recently in fungi. Within the last decade, a number of studies have characterized fungal hemolysins and revealed a fascinating yet diverse group of proteins. The purpose of this review is to provide a synopsis of the known fungal hemolysins with an emphasis on those belonging to the aegerolysin protein family. New insight and perspective into fungal hemolysins in biotechnology and health are additionally presented. PMID:22769586

  14. Tracing QTLs for Leaf Blast Resistance and Agronomic Performance of Finger Millet (Eleusine coracana (L.) Gaertn.) Genotypes through Association Mapping and in silico Comparative Genomics Analyses

    PubMed Central

    Ramakrishnan, M.; Antony Ceasar, S.; Duraipandiyan, V.; Vinod, K. K.; Kalpana, Krishnan; Al-Dhabi, N. A.; Ignacimuthu, S.

    2016-01-01

    Finger millet is one of the small millets with high nutritive value. This crop is vulnerable to blast disease caused by Pyricularia grisea, which occurs annually during rainy and winter seasons. Leaf blast occurs at early crop stage and is highly damaging. Mapping of resistance genes and other quantitative trait loci (QTLs) for agronomic performance can be of great use for improving finger millet genotypes. Evaluation of one hundred and twenty-eight finger millet genotypes in natural field conditions revealed that leaf blast caused severe setback on agronomic performance for susceptible genotypes, most significant traits being plant height and root length. Plant height was reduced under disease severity while root length was increased. Among the genotypes, IE4795 showed superior response in terms of both disease resistance and better agronomic performance. A total of seven unambiguous QTLs were found to be associated with various agronomic traits including leaf blast resistance by association mapping analysis. The markers, UGEP101 and UGEP95, were strongly associated with blast resistance. UGEP98 was associated with tiller number and UGEP9 was associated with root length and seed yield. Cross species validation of markers revealed that 12 candidate genes were associated with 8 QTLs in the genomes of grass species such as rice, foxtail millet, maize, Brachypodium stacei, B. distachyon, Panicum hallii and switchgrass. Several candidate genes were found proximal to orthologous sequences of the identified QTLs such as 1,4-β-glucanase for leaf blast resistance, cytokinin dehydrogenase (CKX) for tiller production, calmodulin (CaM) binding protein for seed yield and pectin methylesterase inhibitor (PMEI) for root growth and development. Most of these QTLs and their putatively associated candidate genes are reported for first time in finger millet. On validation, these novel QTLs may be utilized in future for marker assisted breeding for the development of fungal

  15. Relationship between disease resistance and rice oxalate oxidases in transgenic rice.

    PubMed

    Zhang, Xian Yong; Nie, Zhuan Hua; Wang, Wen Juan; Leung, David W M; Xu, Da Gao; Chen, Bai Ling; Chen, Zhe; Zeng, Lie Xian; Liu, E E

    2013-01-01

    Differential expression of rice oxalate oxidase genes (OsOxO1-4) in rice leaves (Oryza sativa L.) in response to biotic stress was assayed using RT-PCR. OsOxO4 was induced transiently at 12 h in plants inoculated with the pathogens of bacterial blight and that of the wounding control. Inoculation with the rice blast pathogen induced OsOxO2 expression compared to the mock spray control. Overexpressing OsOxO1 or OsOxO4 in rice resulted in elevated transcript levels of the respective transgene as well as OsOxO3 in leaves compared to that in untransformed wild type (WT). In a line of RNA-i transgenic rice plants (i-12), expression of all four OsOxO genes except that of OsOxO2 was severely inhibited. Oxalate oxidase (OxO, EC 1.2.3.4) activity in plants overexpressing OsOxO1 or OsOxO4 was substantially higher than that in WT and the RNA-i lines. It was found that transgenic rice plants with substantially higher OxO activity were not more resistant to rice blast and bacterial blight than WT. In contrast, some RNA-i lines with less OxO activity seemed to be more resistant to rice blast while some overexpressing lines were more susceptible to rice blast than WT. Therefore, OxO might not be a disease resistance factor in rice.

  16. Fungal Tests

    MedlinePlus

    ... diagnosis is needed, as in cases of persistent, deep, or systemic infections, more extensive testing may be ... mouth (thrush) Vaginal itching and discharge (yeast infection) Deep and systemic fungal infections may cause a variety ...

  17. Fungal allergens.

    PubMed Central

    Horner, W E; Helbling, A; Salvaggio, J E; Lehrer, S B

    1995-01-01

    Airborne fungal spores occur widely and often in far greater concentrations than pollen grains. Immunoglobulin E-specific antigens (allergens) on airborne fungal spores induce type I hypersensitivity (allergic) respiratory reactions in sensitized atopic subjects, causing rhinitis and/or asthma. The prevalence of respiratory allergy to fungi is imprecisely known but is estimated at 20 to 30% of atopic (allergy-predisposed) individuals or up to 6% of the general population. Diagnosis and immunotherapy of allergy to fungi require well-characterized or standardized extracts that contain the relevant allergen(s) of the appropriate fungus. Production of standardized extracts is difficult since fungal extracts are complex mixtures and a variety of fungi are allergenic. Thus, the currently available extracts are largely nonstandardized, even uncharacterized, crude extracts. Recent significant progress in isolating and characterizing relevant fungal allergens is summarized in the present review. Particularly, some allergens from the genera Alternaria, Aspergillus, and Cladosporium are now thoroughly characterized, and allergens from several other genera, including some basidiomycetes, have also been purified. The availability of these extracts will facilitate definitive studies of fungal allergy prevalence and immunotherapy efficacy as well as enhance both the diagnosis and therapy of fungal allergy. PMID:7621398

  18. Purification and Characterization of a Novel Hypersensitive Response-Inducing Elicitor from Magnaporthe oryzae that Triggers Defense Response in Rice

    PubMed Central

    Chen, Mingjia; Zeng, Hongmei; Qiu, Dewen; Guo, Lihua; Yang, Xiufen; Shi, Huaixing; Zhou, Tingting; Zhao, Jing

    2012-01-01

    Background Magnaporthe oryzae, the rice blast fungus, might secrete certain proteins related to plant-fungal pathogen interactions. Methodology/Principal Findings In this study, we report the purification, characterization, and gene cloning of a novel hypersensitive response-inducing protein elicitor (MoHrip1) secreted by M. oryzae. The protein fraction was purified and identified by de novo sequencing, and the sequence matched the genomic sequence of a putative protein from M. oryzae strain 70-15 (GenBank accession No. XP_366602.1). The elicitor-encoding gene mohrip1 was isolated; it consisted of a 429 bp cDNA, which encodes a polypeptide of 142 amino acids with a molecular weight of 14.322 kDa and a pI of 4.53. The deduced protein, MoHrip1, was expressed in E. coli. And the expression protein collected from bacterium also forms necrotic lesions in tobacco. MoHrip1 could induce the early events of the defense response, including hydrogen peroxide production, callose deposition, and alkalization of the extracellular medium, in tobacco. Moreover, MoHrip1-treated rice seedlings possessed significantly enhanced systemic resistance to M. oryzae compared to the control seedlings. The real-time PCR results indicated that the expression of some pathogenesis-related genes and genes involved in signal transduction could also be induced by MoHrip1. Conclusion/Significance The results demonstrate that MoHrip1 triggers defense responses in rice and could be used for controlling rice blast disease. PMID:22624059

  19. Mycotoxin Contamination of Rice in China.

    PubMed

    Sun, Xiang Dong; Su, Ping; Shan, Hong

    2017-03-01

    Mycotoxin contamination in rice is generally lower than in other cereals such as corn or wheat. However, over 65% of the population in China consumes rice as a staple food. Due to the diversity of the climate across China, the southern region is characterized by high temperatures and humidities, especially in rainy season. Such conditions are optimal for the growth of fungi. The accumulative and transferrable characteristics of fungi mycotoxins pose a great potential threat as confirmed by high incidences of liver cancer in the Yangtze delta region. Major mycotoxins identified in China are aflatoxins and ochratoxin A, as well as fumonisins. The contents of aflatoxin B1 (AFB1 ) in rice are varied among different provinces and regions and generally less than 5 μg/kg. Although high incidences of positive aflatoxins samples have widely been detected, few samples were detected as exceeding the national's maximum residue limit (10 μg/kg). Limited information is available on risk assessment of human health hazards of mycotoxins in rice, children should be paid more attention to due to their having the highest mycotoxins exposure level, although the risks are generally at low levels from rice. Mycotoxins are mainly distributed in the outer layer of the paddy rice (also called rough rice, referring to whole rice grain with the hulls), and the AFB1 content in bran is 8.4 times greater than that in brown rice (hulled rice). Further investigation should focus on isolation and identification of mycotoxins-producing fungal strains, especially unknown mycotoxigenic fungal strains determination. Infection resistant rice breeding of mycotoxigenic fungal species may be a fundamental approach to guaranteeing rice safety in China. © 2017 Institute of Food Technologists®.

  20. MoVrp1, a putative verprolin protein, is required for asexual development and infection in the rice blast fungus Magnaporthe oryzae

    PubMed Central

    Huang, Lin; Zhang, Shengpei; Yin, Ziyi; Liu, Muxing; Li, Bing; Zhang, Haifeng; Zheng, Xiaobo; Wang, Ping; Zhang, Zhengguang

    2017-01-01

    Endocytosis is a crucial cellular process in eukaryotic cells which involves clathrin and/or adaptor proteins, lipid kinases, phosphatases and the actin cytoskeleton. Verprolin proteins, such as Vrp1 in Saccharomyces cerevisiae, are conserved family proteins that regulate actin binding and endocytosis. Here, we identified and characterized MoVrp1 as the yeast Vrp1 homolog in Magnaporthe oryzae. Deletion of the MoVRP1 gene resulted in defects in vegetative growth, asexual development, and infection of the host plant. The ∆Movrp1 mutants also exhibited decreased extracellular peroxidase and laccase activities and showed defects in colony pigmentation, hyphal surface hydrophobicity, cell wall integrity, autophagy, endocytosis, and secretion of avirulent effector. Our studies provided new evidences that MoVrp1 involved in actin cytoskeleton is important for growth, morphogenesis, cellular trafficking, and fungal pathogenesis. PMID:28117435

  1. Identification of UV-Induced Diterpenes Including a New Diterpene Phytoalexin, Phytocassane F, from Rice Leaves by Complementary GC/MS and LC/MS Approaches.

    PubMed

    Horie, Kiyotaka; Inoue, Yasuno; Sakai, Miki; Yao, Qun; Tanimoto, Yosuke; Koga, Jinichiro; Toshima, Hiroaki; Hasegawa, Morifumi

    2015-04-29

    Rice phytoalexins are regarded as one of the most important weapons against pathogenic microorganisms. We attempted to identify novel phytoalexins and their derivatives using GC/MS and LC/MS analyses. Diterpene derivatives, 9β-pimara-7,15-diene-3β,6β,19-triol, 1, stemar-13-en-2α-ol, 2, and 1α,2α-dihydroxy-ent-12,15-cassadiene-3,11-dione, 3, were isolated from UV-irradiated rice leaves by chromatographic methods. These structures were confirmed by 1D- and 2D-NMR and MS analyses. Interestingly, all three compounds were accumulated following an infection by the rice blast pathogen Magnaporthe oryzae. Compounds 1 and 2 exhibited weak antifungal activity and may be the biosynthetic intermediates of rice phytoalexins momilactones and oryzalexin S, respectively. Compound 3 exhibited relatively high inhibitory activity against the fungal mycelial growth of M. oryzae to the same extent as the known phytoalexin phytocassane A. We conclude that 3 is a member of the cassane-type phytoalexin family and propose the name phytocassane F.

  2. Fungal Entomopathogens

    USDA-ARS?s Scientific Manuscript database

    Fungal entomopathogens are important biological control agents worldwide and have been the subject of intense research for more than100 years. They exhibit both sexual and asexual reproduction and produce different types of infective propagules. Their mode of action against insects involves attachme...

  3. Fungal arthritis

    MedlinePlus

    ... A.D.A.M. Editorial team. Related MedlinePlus Health Topics Fungal Infections Infectious Arthritis Browse the Encyclopedia A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare ... for online health information and services. Learn more about A.D. ...

  4. Fungal Infections

    MedlinePlus

    ... it, you'll be saying bye-bye to fungi (say: FUN-guy). What Is a Fungal Infection? Fungi , the word for more than one fungus, can ... but of course, they're not!). Because the fungi that cause tinea (ringworm) live on different parts ...

  5. Fungal polysaccharides.

    PubMed

    San-Blas, G; Suzuki, S; Hearn, V; Pinel, C; Kobayashi, H; Mendez, C; Niño, G; Nishikawa, A; San-Blas, F; Shibata, N

    1994-01-01

    Fungal polysaccharides are cell wall components which may act as antigens or as structural substrates. As antigens, the role of mannans in Saccharomyces cerevisiae and Candida albicans, and of glycoproteins in Aspergillus fumigatus are discussed. Analyses on beta-glucan synthetase in Paracoccidioides brasiliensis and the inhibitory effect of Hansenula mrakii killer toxin on beta-glucan biosynthesis are also considered.

  6. Fungal Infections

    MedlinePlus

    ... it, you'll be saying bye-bye to fungi (say: FUN-guy). What Is a Fungal Infection? Fungi , the word for more than one fungus, can ... but of course, they're not!). Because the fungi that cause tinea (ringworm) live on different parts ...

  7. Fungal Infections

    MedlinePlus

    ... of all types of fungi are harmful. Some fungi reproduce through tiny spores in the air. You can inhale the spores or they can land on you. As a result, fungal infections often start in the lungs ... or take antibiotics. Fungi can be difficult to kill. For skin and ...

  8. Enhanced disease resistance and drought tolerance in transgenic rice plants overexpressing protein elicitors from Magnaporthe oryzae.

    PubMed

    Wang, Zhenzhen; Han, Qiang; Zi, Qian; Lv, Shun; Qiu, Dewen; Zeng, Hongmei

    2017-01-01

    Exogenous application of the protein elicitors MoHrip1 and MoHrip2, which were isolated from the pathogenic fungus Magnaporthe oryzae (M. oryzae), was previously shown to induce a hypersensitive response in tobacco and to enhance resistance to rice blast. In this work, we successfully transformed rice with the mohrip1 and mohrip2 genes separately. The MoHrip1 and MoHrip2 transgenic rice plants displayed higher resistance to rice blast and stronger tolerance to drought stress than wild-type (WT) rice and the vector-control pCXUN rice. The expression of salicylic acid (SA)- and abscisic acid (ABA)-related genes was also increased, suggesting that these two elicitors may trigger SA signaling to protect the rice from damage during pathogen infection and regulate the ABA content to increase drought tolerance in transgenic rice. Trypan blue staining indicated that expressing MoHrip1 and MoHrip2 in rice plants inhibited hyphal growth of the rice blast fungus. Relative water content (RWC), water usage efficiency (WUE) and water loss rate (WLR) were measured to confirm the high capacity for water retention in transgenic rice. The MoHrip1 and MoHrip2 transgenic rice also exhibited enhanced agronomic traits such as increased plant height and tiller number.

  9. Combining ChIP-chip and Expression Profiling to Model the MoCRZ1 Mediated Circuit for Ca2+/Calcineurin Signaling in the Rice Blast Fungus

    PubMed Central

    Kim, Soonok; Hu, Jinnan; Oh, Yeonyee; Park, Jongsun; Choi, Jinhee; Lee, Yong-Hwan; Dean, Ralph A.; Mitchell, Thomas K.

    2010-01-01

    Significant progress has been made in defining the central signaling networks in many organisms, but collectively we know little about the downstream targets of these networks and the genes they regulate. To reconstruct the regulatory circuit of calcineurin signal transduction via MoCRZ1, a Magnaporthe oryzae C2H2 transcription factor activated by calcineurin dephosphorylation, we used a combined approach of chromatin immunoprecipitation - chip (ChIP-chip), coupled with microarray expression studies. One hundred forty genes were identified as being both a direct target of MoCRZ1 and having expression concurrently differentially regulated in a calcium/calcineurin/MoCRZ1 dependent manner. Highly represented were genes involved in calcium signaling, small molecule transport, ion homeostasis, cell wall synthesis/maintenance, and fungal virulence. Of particular note, genes involved in vesicle mediated secretion necessary for establishing host associations, were also found. MoCRZ1 itself was a target, suggesting a previously unreported autoregulation control point. The data also implicated a previously unreported feedback regulation mechanism of calcineurin activity. We propose that calcium/calcineurin regulated signal transduction circuits controlling development and pathogenicity manifest through multiple layers of regulation. We present results from the ChIP-chip and expression analysis along with a refined model of calcium/calcineurin signaling in this important plant pathogen. PMID:20502632

  10. MoJMJ1, Encoding a Histone Demethylase Containing JmjC Domain, Is Required for Pathogenic Development of the Rice Blast Fungus, Magnaporthe oryzae.

    PubMed

    Huh, Aram; Dubey, Akanksha; Kim, Seongbeom; Jeon, Junhyun; Lee, Yong-Hwan

    2017-04-01

    Histone methylation plays important roles in regulating chromatin dynamics and transcription in eukaryotes. Implication of histone modifications in fungal pathogenesis is, however, beginning to emerge. Here, we report identification and functional analysis of a putative JmjC-domain-containing histone demethylase in Magnaporthe oryzae. Through bioinformatics analysis, we identified seven genes, which encode putative histone demethylases containing JmjC domain. Deletion of one gene, MoJMJ1, belonging to JARID group, resulted in defects in vegetative growth, asexual reproduction, appressorium formation as well as invasive growth in the fungus. Western blot analysis showed that global H3K4me3 level increased in the deletion mutant, compared to wild-type strain, indicating histone demethylase activity of MoJMJ1. Introduction of MoJMJ1 gene into ΔMojmj1 restored defects in pre-penetration developments including appressorium formation, indicating the importance of histone demethylation through MoJMJ1 during infection-specific morphogenesis. However, defects in penetration and invasive growth were not complemented. We discuss such incomplete complementation in detail here. Our work on MoJMJ1 provides insights into H3K4me3-mediated regulation of infection-specific development in the plant pathogenic fungus.

  11. MoJMJ1, Encoding a Histone Demethylase Containing JmjC Domain, Is Required for Pathogenic Development of the Rice Blast Fungus, Magnaporthe oryzae

    PubMed Central

    Huh, Aram; Dubey, Akanksha; Kim, Seongbeom; Jeon, Junhyun; Lee, Yong-Hwan

    2017-01-01

    Histone methylation plays important roles in regulating chromatin dynamics and transcription in eukaryotes. Implication of histone modifications in fungal pathogenesis is, however, beginning to emerge. Here, we report identification and functional analysis of a putative JmjC-domain-containing histone demethylase in Magnaporthe oryzae. Through bioinformatics analysis, we identified seven genes, which encode putative histone demethylases containing JmjC domain. Deletion of one gene, MoJMJ1, belonging to JARID group, resulted in defects in vegetative growth, asexual reproduction, appressorium formation as well as invasive growth in the fungus. Western blot analysis showed that global H3K4me3 level increased in the deletion mutant, compared to wild-type strain, indicating histone demethylase activity of MoJMJ1. Introduction of MoJMJ1 gene into ΔMojmj1 restored defects in pre-penetration developments including appressorium formation, indicating the importance of histone demethylation through MoJMJ1 during infection-specific morphogenesis. However, defects in penetration and invasive growth were not complemented. We discuss such incomplete complementation in detail here. Our work on MoJMJ1 provides insights into H3K4me3-mediated regulation of infection-specific development in the plant pathogenic fungus. PMID:28381966

  12. The regulatory factor X protein MoRfx1 is required for development and pathogenicity in the rice blast fungus Magnaporthe oryzae.

    PubMed

    Sun, Dandan; Cao, Huijuan; Shi, Yongkai; Huang, Pengyun; Dong, Bo; Liu, Xiaohong; Lin, Fucheng; Lu, Jianping

    2017-10-01

    Magnaporthe oryzae is a cereal pathogen causing 20%-30% rice yield losses. Regulatory factor X transcription factors are highly conserved proteins with diverse functions among organisms. Here, we show that MoRfx1 is required for cell division, development and pathogenicity in M. oryzae. Deletion of MoRFX1 resulted in reduced growth and conidiation, decreased appressorium turgor and impaired virulence. ΔMorfx1 displayed increased sensitivity to UV light, four DNA-damaging agents and three cell wall-perturbing compounds. However, ΔMorfx1 showed decreased sensitivity to bleomycin, a DNA/cell wall-damaging agent, and increased chitin content of the cell wall in vegetative mycelium. In addition, cell division speed was reduced in ΔMorfx1, and ΔMorfx1 did not produce three-celled conidia. RNA-sequencing and quantitative polymerase chain reaction analyses suggested that MoRfx1 has bipartite functions in the control of the expression of genes required for cell division and chitin metabolism, not only as a transcriptional repressor, but also as a transcriptional activator. In particular, the expression of chitin deacetylase genes MoCDA2 and MoCDA1 was greatly down-regulated in ΔMorfx1, and deletion of MoCDA2 and MoCDA1, similar to ΔMorfx1, increased resistance to bleomycin. Taken together, our results indicate that MoRFX1 regulates development and pathogenicity by modulating the expression of genes involved in cell division and cell wall integrity. © 2016 BSPP AND JOHN WILEY & SONS LTD.

  13. Detection of fungal pathogens by a new broad range real-time PCR assay targeting the fungal ITS2 region.

    PubMed

    Zeller, Iris; Schabereiter-Gurtner, Claudia; Mihalits, Verena; Selitsch, Brigitte; Barousch, Wolfgang; Hirschl, Alexander M; Makristathis, Athanasios; Willinger, Birgit

    2017-09-08

    The rise in the incidence of fungal infections and the expanding spectrum of fungal pathogens make early and broad detection of fungal pathogens essential. In the present study, a panfungal real-time PCR assay for the broad-range detection of fungal DNA (Fungi assay) in a wide variety of clinical specimens was developed. Our in-house, HybProbe real-time PCR assay targets the ITS2 region of fungal DNA. The applicability was evaluated by testing 105 clinical samples from 98 patients with suspected fungal infection. Samples included tissue biopsies, paraffin embedded tissues, aspirates, EDTA-anticoagulated blood, cerebrospinal fluids and bronchoalveolar lavages. Fungal pathogens were identified by the Fungi assay in 47 samples. In all of these cases, conventional methods and clinical data were also indicative for a fungal infection. Five samples were interpreted false negative. blast analyses of the amplicons derived from 11 samples revealed the presence of environmental fungal species while other tests and clinical data did not suggest a fungal infection. This fact might indicate contaminated samples. The remaining 42 samples were negative by the Fungi assay as well as the conventional methods and were therefore regarded as true negatives. Thus, sensitivity was 90.4 % and specificity 79.2 %. The Fungi assay improved the targeted diagnosis of fungal infections allowing pathogen identification in samples that were histologically positive but culture negative. For reliable diagnosis, results have to be interpreted in context with conventional methods and clinical data.

  14. Inoculation and scoring methods for rice sheath blight disease.

    PubMed

    Jia, Yulin; Liu, Guangjie; Park, Dong-Soo; Yang, Yinong

    2013-01-01

    Sheath blight disease of rice caused by the soilborne fungal pathogen Rhizoctonia solani has been a major disease of rice with a serious threat to stable rice production worldwide. Although various cultural practices have been used to manage the disease, it is advantageous and important to screen rice germplasm and identify resistant rice cultivars for more effective disease control. Recent advances in methods for the fungal inoculation and disease evaluation have enabled a better measurement of host resistance by minimizing confounding factors from plant architectures and environmental conditions. This chapter introduces five such methods: (1) detached leaf method; (2) micro-chamber method; (3) mist-chamber method; (4) parafilm sachet method; and (5) aluminum foil method. These methods are useful for screening and evaluating disease reactions of rice germplasm and facilitating the genetic mapping of disease resistance genes.

  15. Brassica cover cropping for management of sheath blight of rice

    USDA-ARS?s Scientific Manuscript database

    Sheath blight, caused by Rhizoctonia solani, is the most important disease limiting rice production in Texas and other rice-producing states. The fungal pathogen survives between crops as soilborne sclerotia and mycelium in infected plant debris. These sclerotia and colonized plant debris float on t...

  16. Fungal genome resources at NCBI

    PubMed Central

    Robbertse, B.; Tatusova, T.

    2011-01-01

    The National Center for Biotechnology Information (NCBI) is well known for the nucleotide sequence archive, GenBank and sequence analysis tool BLAST. However, NCBI integrates many types of biomolecular data from variety of sources and makes it available to the scientific community as interactive web resources as well as organized releases of bulk data. These tools are available to explore and compare fungal genomes. Searching all databases with Fungi [organism] at http://www.ncbi.nlm.nih.gov/ is the quickest way to find resources of interest with fungal entries. Some tools though are resources specific and can be indirectly accessed from a particular database in the Entrez system. These include graphical viewers and comparative analysis tools such as TaxPlot, TaxMap and UniGene DDD (found via UniGene Homepage). Gene and BioProject pages also serve as portals to external data such as community annotation websites, BioGrid and UniProt. There are many different ways of accessing genomic data at NCBI. Depending on the focus and goal of research projects or the level of interest, a user would select a particular route for accessing genomic databases and resources. This review article describes methods of accessing fungal genome data and provides examples that illustrate the use of analysis tools. PMID:22737589

  17. Fungal genome resources at NCBI.

    PubMed

    Robbertse, B; Tatusova, T

    2011-09-01

    The National Center for Biotechnology Information (NCBI) is well known for the nucleotide sequence archive, GenBank and sequence analysis tool BLAST. However, NCBI integrates many types of biomolecular data from variety of sources and makes it available to the scientific community as interactive web resources as well as organized releases of bulk data. These tools are available to explore and compare fungal genomes. Searching all databases with Fungi [organism] at http://www.ncbi.nlm.nih.gov/ is the quickest way to find resources of interest with fungal entries. Some tools though are resources specific and can be indirectly accessed from a particular database in the Entrez system. These include graphical viewers and comparative analysis tools such as TaxPlot, TaxMap and UniGene DDD (found via UniGene Homepage). Gene and BioProject pages also serve as portals to external data such as community annotation websites, BioGrid and UniProt. There are many different ways of accessing genomic data at NCBI. Depending on the focus and goal of research projects or the level of interest, a user would select a particular route for accessing genomic databases and resources. This review article describes methods of accessing fungal genome data and provides examples that illustrate the use of analysis tools.

  18. Abscisic acid interacts antagonistically with salicylic acid signaling pathway in rice-Magnaporthe grisea interaction.

    PubMed

    Jiang, Chang-Jie; Shimono, Masaki; Sugano, Shoji; Kojima, Mikiko; Yazawa, Katsumi; Yoshida, Riichiro; Inoue, Haruhiko; Hayashi, Nagao; Sakakibara, Hitoshi; Takatsuji, Hiroshi

    2010-06-01

    Plant hormones play pivotal signaling roles in plant-pathogen interactions. Here, we report characterization of an antagonistic interaction of abscisic acid (ABA) with salicylic acid (SA) signaling pathways in the rice-Magnaporthe grisea interaction. Exogenous application of ABA drastically compromised the rice resistance to both compatible and incompatible M. grisea strains, indicating that ABA negatively regulates both basal and resistance gene-mediated blast resistance. ABA markedly suppressed the transcriptional upregulation of WRKY45 and OsNPR1, the two key components of the SA signaling pathway in rice, induced by SA or benzothiadiazole or by blast infection. Overexpression of OsNPR1 or WRKY45 largely negated the enhancement of blast susceptibility by ABA, suggesting that ABA acts upstream of WRKY45 and OsNPR1 in the rice SA pathway. ABA-responsive genes were induced during blast infection in a pattern reciprocal to those of WRKY45 and OsPR1b in the compatible rice-blast interaction but only marginally in the incompatible one. These results suggest that the balance of SA and ABA signaling is an important determinant for the outcome of the rice-M. grisea interaction. ABA was detected in hyphae and conidia of M. grisea as well as in culture media, implying that blast-fungus-derived ABA could play a role in triggering ABA signaling at host infection sites.

  19. Blast resistance of CC-NB-LRR protein Pb1 is mediated by WRKY45 through protein-protein interaction.

    PubMed

    Inoue, Haruhiko; Hayashi, Nagao; Matsushita, Akane; Xinqiong, Liu; Nakayama, Akira; Sugano, Shoji; Jiang, Chang-Jie; Takatsuji, Hiroshi

    2013-06-04

    Panicle blast 1 (Pb1) is a panicle blast resistance gene derived from the indica rice cultivar "Modan." Pb1 encodes a coiled-coil-nucleotide-binding site-leucine-rich repeat (CC-NB-LRR) protein and confers durable, broad-spectrum resistance to Magnaporthe oryzae races. Here, we investigated the molecular mechanisms underlying Pb1-mediated blast resistance. The Pb1 protein interacted with WRKY45, a transcription factor involved in induced resistance via the salicylic acid signaling pathway that is regulated by the ubiquitin proteasome system. Pb1-mediated panicle blast resistance was largely compromised when WRKY45 was knocked down in a Pb1-containing rice cultivar. Leaf-blast resistance by Pb1 overexpression (Pb1-ox) was also compromised in WRKY45 knockdown/Pb1-ox rice. Blast infection induced higher accumulation of WRKY45 in Pb1-ox than in control Nipponbare rice. Overexpression of Pb1-Quad, a coiled-coil domain mutant that had weak interaction with WRKY45, resulted in significantly weaker blast resistance than that of wild-type Pb1. Overexpression of Pb1 with a nuclear export sequence failed to confer blast resistance to rice. These results suggest that the blast resistance of Pb1 depends on its interaction with WRKY45 in the nucleus. In a transient system using rice protoplasts, coexpression of Pb1 enhanced WRKY45 accumulation and increased WRKY45-dependent transactivation activity, suggesting that protection of WRKY45 from ubiquitin proteasome system degradation is possibly involved in Pb1-dependent blast resistance.

  20. Inducibility by pathogen attack and developmental regulation of the rice Ltp1 gene.

    PubMed

    Guiderdoni, Emmanuel; Cordero, Maria José; Vignols, Florence; Garcia-Garrido, José Manuel; Lescot, Magali; Tharreau, Didier; Meynard, Donaldo; Ferrière, Nicole; Notteghem, Jean-Loup; Delseny, Michel

    2002-08-01

    Using a genomic clone encoding a rice lipid transfer protein, LTP1, we analysed the activity of the 5' region of the Ltp1 gene in transgenic rice (Oryza sativa L.) during plant development and under pathogen attack. The -1176/+13, -556/+13 and -284/+13 regions of the promoter were fused upstream from the uidA reporter gene and nos 3' polyadenylation signal, resulting in the pdelta1176Gus, pdelta556Gus and pdelta284Gus constructs which were transferred to rice by microprojectile bombardment. Histochemical and fluorometric GUS assays and in situ detection of uidA transcripts in transgenic homozygous lines harbouring the pdelta1176Gus construct demonstrated that the Ltp1 promoter is preferentially active in aerial vegetative and reproductive organs and that both specificity and level of expression are regulated during organ development. In leaf sheath, GUS activity which is initially strictly localized in the epidermis of growing tissue, becomes restricted to the vascular system in mature tissues. In expanded leaf blade, expression of the uidA gene was restricted to the cutting level suggesting inducibility by wounding. Strong activity was detected in lemma and palea, sterile glumes, and immature anther walls and microspores but not in female reproductive organs. No GUS activity was detected during seed embryo maturation whereas the uidA gene was strongly expressed at early stages of somatic embryogenesis in scutellum tissue. The Ltp1 transcripts were found to strongly accumulate in response to inoculation with the fungal agent of the blast disease, Magnaporthe grisea, in two rice cultivars exhibiting compatible or incompatible host-pathogen interactions. Analysis of pdelta1176Gus leaf samples inoculated with the blast fungus demonstrated that the Ltp1 promoter is induced in all cell types of tissues surrounding the lesion and notably in stomata guard cells. In plants harbouring the Ltp1 promoter deletion construct pdelta556Gus, activity was solely detected in the

  1. Cloning and characterization of two rice long-chain base kinase genes and their function in disease resistance and cell death.

    PubMed

    Zhang, Huijuan; Li, Li; Yu, Yongmei; Mo, Jibo; Sun, Lijun; Liu, Bo; Li, Dayong; Song, Fengming

    2013-01-01

    Sphingolipid metabolites such as long-chain base 1-phosphates (LCBPs) have been shown to play an important role in plants; however, little is known about their function in plant disease resistance and programmed cell death (PCD). In the present study, we cloned and identified two rice long-chain base kinase (LCBK) genes (OsLCBK1 and OsLCBK2), which are involved in biosynthesis of LCBPs, and performed functional analysis in transgenic tobacco. Expression of OsLCBK1 and OsLCBK2 was induced in rice seedlings after treatments with defense signaling molecules and after infection by Magnaporthe grisea, the causal agent of blast disease. Transgenic tobacco plants overexpressing OsLCBK1 were generated and disease resistance assays indicate that the OsLCBK1-overexpressing plants showed enhanced disease resistance against Pseudmonas syringae pv. tabacci, the causal agent of wildfire disease, and tobacco mosaic virus. Expression levels of some defense-related genes were constitutively up-regulated and further induced after pathogen infection in the OsLCBK1-overexpressing plants. Treatment with fungal toxin fumonisin B1, an effective inducer of PCD in plants, resulted in reduced level of cell death in the OsLCBK1-overexpressing plants, as indicated by cell death staining, leakage of electrolyte and expression of hypersensitive response indicator genes. These data suggest that rice LCBKs, probably through regulation of endogenous LCBP level, play important roles in disease resistance response and PCD in plants.

  2. Brain injuries from blast.

    PubMed

    Bass, Cameron R; Panzer, Matthew B; Rafaels, Karen A; Wood, Garrett; Shridharani, Jay; Capehart, Bruce

    2012-01-01

    Traumatic brain injury (TBI) from blast produces a number of conundrums. This review focuses on five fundamental questions including: (1) What are the physical correlates for blast TBI in humans? (2) Why is there limited evidence of traditional pulmonary injury from blast in current military field epidemiology? (3) What are the primary blast brain injury mechanisms in humans? (4) If TBI can present with clinical symptoms similar to those of Post-Traumatic Stress Disorder (PTSD), how do we clinically differentiate blast TBI from PTSD and other psychiatric conditions? (5) How do we scale experimental animal models to human response? The preponderance of the evidence from a combination of clinical practice and experimental models suggests that blast TBI from direct blast exposure occurs on the modern battlefield. Progress has been made in establishing injury risk functions in terms of blast overpressure time histories, and there is strong experimental evidence in animal models that mild brain injuries occur at blast intensities that are similar to the pulmonary injury threshold. Enhanced thoracic protection from ballistic protective body armor likely plays a role in the occurrence of blast TBI by preventing lung injuries at blast intensities that could cause TBI. Principal areas of uncertainty include the need for a more comprehensive injury assessment for mild blast injuries in humans, an improved understanding of blast TBI pathophysiology of blast TBI in animal models and humans, the relationship between clinical manifestations of PTSD and mild TBI from blunt or blast trauma including possible synergistic effects, and scaling between animals models and human exposure to blasts in wartime and terrorist attacks. Experimental methodologies, including location of the animal model relative to the shock or blast source, should be carefully designed to provide a realistic blast experiment with conditions comparable to blasts on humans. If traditional blast scaling is

  3. Establishment and application of an efficient, economic, and rapid rice DNA extraction method

    USDA-ARS?s Scientific Manuscript database

    A rapid, economic, and efficient method for DNA extraction from rice leaf, root and seed was developed, and the extracted DNA was used as a template to successfully amplify the rice blast resistance gene Pi-ta. Profiles of Pi-ta in 165 breeding lines detected by DNA markers were verified using diff...

  4. Effectiveness and durability of the rice Pi-ta gene in Yunnan province of China

    USDA-ARS?s Scientific Manuscript database

    Rice blast is one of the most damaging diseases of rice worldwide. In the present study, we analyzed DNA sequence variation of avirulence genes of AVR-Pita1 in field isolates of M. oryzae in order to understand the effectiveness of the resistance gene Pi-ta in China. Genomic DNA of 366 isolates of M...

  5. Changes in rice allelopathy and rhizosphere microflora by inhibiting rice phenylalanine ammonia-lyase gene expression.

    PubMed

    Fang, Changxun; Zhuang, Yuee; Xu, Tiecheng; Li, Yingzhe; Li, Yue; Lin, Wenxiong

    2013-02-01

    Gene expression of phenylalanine ammonia-lyase (PAL) in allelopathic rice PI312777 was inhibited by RNA interference (RNAi). Transgenic rice showed lower levels of PAL gene expression and PAL activity than wild type rice (WT). The concentrations of phenolic compounds were lower in the root tissues and root exudates of transgenic rice than in those of wild type plants. When barndyardgrass (BYG) was used as the receiver plant, the allelopathic potential of transgenic rice was reduced. The sizes of the bacterial and fungal populations in rice rhizospheric soil at the 3-, 5-, and 7-leaf stages were estimated by using quantitative PCR (qPCR), which showed a decrease in both populations at all stages of leaf development analyzed. However, PI312777 had a larger microbial population than transgenic rice. In addition, in T-RFLP studies, 14 different groups of bacteria were detected in WT and only 6 were detected in transgenic rice. This indicates that there was less rhizospheric bacterial diversity associated with transgenic rice than with WT. These findings collectively suggest that PAL functions as a positive regulator of rice allelopathic potential.

  6. Blast Injury

    PubMed Central

    de Candole, C. A.

    1967-01-01

    The shock wave generated by an explosion (“blast wave”) may cause injury in any or all of the following: (1) direct impact on the tissues of variations in environmental pressure; (2) flying glass and other debris set in motion by it; (3) propulsion of the body. Injuries in the first category affect gas-containing organs (ears, lungs and intestines), and acute death is attributed to air forced into the coronary vessels via damaged pulmonary alveoli. It is estimated that overpressure sufficient to cause lung injury may occur up to five miles from a 20-megaton nuclear explosion. The greatest single hazard from blast is, however, flying glass, and serious wounding from this cause is possible up to 12 miles from an explosion of this magnitude. PMID:6015742

  7. Automated Blast Cleaner

    NASA Technical Reports Server (NTRS)

    Pickett, Isaiah R.; Yulfo, Alyce R.

    1992-01-01

    Automatic grit-blasting machine removes melted-layer residue from electrical-discharge-machined surfaces of turbine blades. Automatic control system of machine provides steady flow of grit and maintains blast nozzles at proper distance and in correct orientation perpendicular to surface being blasted, regardless of contour. Eliminates localized excessive blasting and consequent excessive removal of underlying material, blasting of adjacent surfaces, and missed areas.

  8. A systems-wide comparison of red rice (Oryza longistaminata) tissues identifies rhizome specific genes and proteins that are targets for cultivated rice improvement

    PubMed Central

    2014-01-01

    Background The rhizome, the original stem of land plants, enables species to invade new territory and is a critical component of perenniality, especially in grasses. Red rice (Oryza longistaminata) is a perennial wild rice species with many valuable traits that could be used to improve cultivated rice cultivars, including rhizomatousness, disease resistance and drought tolerance. Despite these features, little is known about the molecular mechanisms that contribute to rhizome growth, development and function in this plant. Results We used an integrated approach to compare the transcriptome, proteome and metabolome of the rhizome to other tissues of red rice. 116 Gb of transcriptome sequence was obtained from various tissues and used to identify rhizome-specific and preferentially expressed genes, including transcription factors and hormone metabolism and stress response-related genes. Proteomics and metabolomics approaches identified 41 proteins and more than 100 primary metabolites and plant hormones with rhizome preferential accumulation. Of particular interest was the identification of a large number of gene transcripts from Magnaportha oryzae, the fungus that causes rice blast disease in cultivated rice, even though the red rice plants showed no sign of disease. Conclusions A significant set of genes, proteins and metabolites appear to be specifically or preferentially expressed in the rhizome of O. longistaminata. The presence of M. oryzae gene transcripts at a high level in apparently healthy plants suggests that red rice is resistant to this pathogen, and may be able to provide genes to cultivated rice that will enable resistance to rice blast disease. PMID:24521476

  9. Exploring African Rice Genetic Diversity for Genetic Stock Development

    USDA-ARS?s Scientific Manuscript database

    West African cultivated rice (Oryza glaberrima) and its progenitor species, O. barthii, are a source of genes for crop improvement especially pest resistance (blast, sheath blight, brown spot, bacterial blight, bacterial leaf streak, green leafhopper) and tolerance to abiotic stress (drought, acid s...

  10. Fungal endophytes for sustainable crop production.

    PubMed

    Lugtenberg, Ben J J; Caradus, John R; Johnson, Linda J

    2016-12-01

    This minireview highlights the importance of endophytic fungi for sustainable agriculture and horticulture production. Fungal endophytes play a key role in habitat adaptation of plants resulting in improved plant performance and plant protection against biotic and abiotic stresses. They encode a vast variety of novel secondary metabolites including volatile organic compounds. In addition to protecting plants against pathogens and pests, selected fungal endophytes have been used to remove animal toxicities associated with fungal endophytes in temperate grasses, to create corn and rice plants that are tolerant to a range of biotic and abiotic stresses, and for improved management of post-harvest control. We argue that practices used in plant breeding, seed treatments and agriculture, often caused by poor knowledge of the importance of fungal endophytes, are among the reasons for the loss of fungal endophyte diversity in domesticated plants and also accounts for the reduced effectiveness of some endophyte strains to confer plant benefits. We provide recommendations on how to mitigate against these negative impacts in modern agriculture. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  11. Disease reactions of IRRI near-isogenic rice lines to U.S. isolates of Magnaporthe oryzae

    USDA-ARS?s Scientific Manuscript database

    Rice blast, caused by Magnaporthe oryzae, is a destructive disease of rice. The use of resistant cultivars is the most effective way to manage this disease. However, to be effective, it is necessary to know how the isolates of the pathogen within a population respond to specific resistance genes. Tw...

  12. The heterotrimeric G protein α subunit acts upstream of the small GTPase Rac in disease resistance of rice

    PubMed Central

    Suharsono, Utut; Fujisawa, Yukiko; Kawasaki, Tsutomu; Iwasaki, Yukimoto; Satoh, Hikaru; Shimamoto, Ko

    2002-01-01

    We used rice dwarf1 (d1) mutants lacking a single-copy Gα gene and addressed Gα's role in disease resistance. d1 mutants exhibited a highly reduced hypersensitive response to infection by an avirulent race of rice blast. Activation of PR gene expression in the leaves of the mutants infected with rice blast was delayed for 24 h relative to the wild type. H2O2 production and PR gene expression induced by sphingolipid elicitors (SE) were strongly suppressed in d1 cell cultures. Expression of the constitutively active OsRac1, a small GTPase Rac of rice, in d1 mutants restored SE-dependent defense signaling and resistance to rice blast. Gα mRNA was induced by an avirulent race of rice blast and SE application on the leaf. These results indicated the role of Gα in R gene-mediated disease resistance of rice. We have proposed a model for the defense signaling of rice in which the heterotrimeric G protein functions upstream of the small GTPase OsRac1 in the early steps of signaling. PMID:12237405

  13. Production of rice straw hydrolysis enzymes by the fungi Trichoderma reesei and Humicola insolens using rice straw as a carbon source.

    PubMed

    Kogo, Takashi; Yoshida, Yuki; Koganei, Keisuke; Matsumoto, Hitoshi; Watanabe, Taisuke; Ogihara, Jun; Kasumi, Takafumi

    2017-02-11

    Rice straw was evaluated as a carbon source for the fungi, Trichoderma reesei and Humicola insolens, to produce enzymes for rice straw hydrolysis. The enzyme activity of T. reesei and H. insolens cultivated in medium containing non-treated rice straw were almost equivalent to the enzyme of T. reesei cultivated in Avicel medium, a form of refined cellulose. The enzyme activity of T. reesei cultivated in medium containing NH4OH-treated rice straw was 4-fold higher than enzyme from cultures grown in Avicel medium. In contrast, H. insolens enzyme from cultures grown in NH4OH-treated rice straw had significantly lower activity compared with non-treated rice straw or Avicel. The combined use of T. reesei and H. insolens enzymes resulted in a significant synergistic enhancement in enzymatic activity. Our data suggest that rice straw is a promising low-cost carbon source for fungal enzyme production for rice straw hydrolysis.

  14. secureBLAST.

    PubMed

    Wiezer, Arnim; Merkl, Rainer

    2003-01-01

    secureBLAST supplements NCBI wwwblast with features necessary to control in an easy manageable way usage of BLAST data sets and their update. The concept we implemented allows to offer on a single BLAST server several data sets with individually configurable access rights. Security is provided by user authentication and encryption of the http traffic via SSL. By using secureBLAST, the administration of users and databases can be done via a web interface. Therefore, secureBLAST is valuable for institutions that have to restrict access to their datasets or just want to administer BLAST servers via a web interface.

  15. Deep blast

    NASA Astrophysics Data System (ADS)

    From southern New Mexico to the Great Slave Lake of Canada, scientists from the United States and Canada recently detonated 10 underground chemical explosions to generate a clearer picture of the Earth's crust and upper mantle. Called Project Deep Probe, the experiment is designed to see through the crust and into the upper mantle to a depth of 300 miles.In the United States, Earth scientists from Rice University, Purdue University, and the University of Oregon are participating in the project. “Researchers hope to get a picture of the upper mantle beneath the Rocky Mountains and the Colorado Plateau, to understand the role the mantle played in formation and uplift,” says Alan Levander of Rice. To enhance that “picture,” 750 portable seismographs were placed along a roughly north-south line extending from Crownpoint, New Mexico to Edmonton, Alberta. The seismic recordings will be used to enhance weak seismic waves that penetrated the upper mantle.

  16. Combat-Related Invasive Fungal Wound Infections

    PubMed Central

    Rodriguez, Carlos J.

    2014-01-01

    Combat-related invasive fungal (mold) wound infections (IFIs) have emerged as an important and morbid complication following explosive blast injuries among military personnel. Similar to trauma-associated IFI cases among civilian populations, as in agricultural accidents and natural disasters, these infections occur in the setting of penetrating wounds contaminated by environmental debris. Specific risk factors for combat-related IFI include dismounted (patrolling on foot) blast injuries occurring mostly in southern Afghanistan, resulting in above knee amputations requiring resuscitation with large-volume blood transfusions. Diagnosis of IFI is based upon early identification of a recurrently necrotic wound following serial debridement and tissue-based histopathology examination with special stains to detect invasive disease. Fungal culture of affected tissue also provides supportive information. Aggressive surgical debridement of affected tissue is the primary therapy. Empiric antifungal therapy should be considered when there is a strong suspicion for IFI. Both liposomal amphotericin B and voriconazole should be considered initially for treatment since many of the cases involve not only Mucorales species but also Aspergillus or Fusarium spp., with narrowing of regimen based upon clinical mycology findings. PMID:25530825

  17. Combat-Related Invasive Fungal Wound Infections.

    PubMed

    Tribble, David R; Rodriguez, Carlos J

    2014-12-01

    Combat-related invasive fungal (mold) wound infections (IFIs) have emerged as an important and morbid complication following explosive blast injuries among military personnel. Similar to trauma-associated IFI cases among civilian populations, as in agricultural accidents and natural disasters, these infections occur in the setting of penetrating wounds contaminated by environmental debris. Specific risk factors for combat-related IFI include dismounted (patrolling on foot) blast injuries occurring mostly in southern Afghanistan, resulting in above knee amputations requiring resuscitation with large-volume blood transfusions. Diagnosis of IFI is based upon early identification of a recurrently necrotic wound following serial debridement and tissue-based histopathology examination with special stains to detect invasive disease. Fungal culture of affected tissue also provides supportive information. Aggressive surgical debridement of affected tissue is the primary therapy. Empiric antifungal therapy should be considered when there is a strong suspicion for IFI. Both liposomal amphotericin B and voriconazole should be considered initially for treatment since many of the cases involve not only Mucorales species but also Aspergillus or Fusarium spp., with narrowing of regimen based upon clinical mycology findings.

  18. [Safety of rice grains and mycotoxins - a historical review of yellow rice mycotoxicoses].

    PubMed

    Udagawa, Shun-ichi; Tatsuno, Takashi

    2004-01-01

    Aflatoxins, the most powerful mycotoxins, were brought to the attention fo the people in the early 1960s with the outbreak of the turkey "X" disease in England. However, the history of mycotoxin research in Japan began 100 years ago. In 1891, Sakaki demonstrated that moldy, unpolished rice was fatal to experimental animals, with symptoms indicating paralysis of the central nervous system (Shoshin-kakke). In 1920, Prof. I. Miyake and Dr. Takada first reported that Penicillium commune, which was known as a causal agent of "Mossy diseased rice" was found to be toxic to experimental animals by feeding the moldy rice to rabbits and rats.With such a historical background, taking the idea of "rice, fungus and toxin" as a working hypothesis, Miyake and his co-workers discovered the first sample of yellow rice grains from Taiwanese and domestic rice, from which was isolated a species of Penicillium and later identified it with P. citreonigrum (=P. toxicarium). The fungus produced a highly toxic metabolite, citreoviridin. Unfortunately because this study was published during wartime, it failed to alert the world to the potential or actual dangers of the toxicity of common molds. After World War II, Japanese people suffered for some years from a shortage in domestic rice production and depended on foreign countries to supply rice, which led to the toxicological screening on fungal isolates from polluted rice grains by Dr. Tsunoda and his co-workers. AMong the isolates from imported rice, there were two species of Penicillium which were particularly associated with high toxicity; P. islandicum responsible for brownish discolored rice, and P. citrinum responsible for yellowish rice. P. islandicum produces two hepatotoxic metabolites: luteoskyrin and cyclochlorotine, while a nephrotoxic of P. citrinum is citrinin. These toxicological characters, including the induction of cancer and chemical structures, were studied by Profs. uraguchi, Saito, Shibata, Tatsuno and their co

  19. Genetic and genomic dissection of resistance genes to the rice sheath blight pathogen

    USDA-ARS?s Scientific Manuscript database

    Rice sheath blight disease caused by the anastomosis group AG1-IA of the fungal pathogen Rhizoctonia solani is one of the most serious rice diseases in the southern US and the world. The use of fungicides is a popular but costly method to control this disease worldwide. Genetic analysis of host re...

  20. RL-SAGE and microarray analysis of the rice defense transcriptome after Rhizoctonia solani infection

    USDA-ARS?s Scientific Manuscript database

    Sheath blight caused by the fungal pathogen Rhizoctonia solani is an emerging problem in rice production worldwide. To elucidate the molecular basis of rice defense to the pathogen, RNA isolated from R. solani-infected leaves of Jasmine 85 was used for both RL-SAGE library construction and microarra...

  1. Survey of fungal counts and natural occurrence of aflatoxins in Malaysian starch-based foods.

    PubMed

    Abdullah, N; Nawawi, A; Othman, I

    1998-01-01

    In a survey of starch-based foods sampled from retail outlets in Malaysia, fungal colonies were mostly detected in wheat flour (100%), followed by rice flour (74%), glutinous rice grains (72%), ordinary rice grains (60%), glutinous rice flour (48%) and corn flour (26%). All positive samples of ordinary rice and glutinous rice grains had total fungal counts below 10(3) cfu/g sample, while among the positive rice flour, glutinous rice flour and corn flour samples, the highest total fungal count was more than 10(3) but less than 10(4) cfu/g sample respectively. However, in wheat flour samples total fungal count ranged from 10(2) cfu/g sample to slightly more than 10(4) cfu/g sample. Aflatoxigenic colonies were mostly detected in wheat flour (20%), followed by ordinary rice grains (4%), glutinous rice grains (4%) and glutinous rice flour (2%). No aflatoxigenic colonies were isolated from rice flour and corn flour samples. Screening of aflatoxin B1, aflatoxin B2, aflatoxin G1 and aflatoxin G2 using reversed-phase HPLC were carried out on 84 samples of ordinary rice grains and 83 samples of wheat flour. Two point four percent (2.4%) of ordinary rice grains were positive for aflatoxin G1 and 3.6% were positive for aflatoxin G2. All the positive samples were collected from private homes at concentrations ranging from 3.69-77.50 micrograms/kg. One point two percent (1.2%) of wheat flour samples were positive for aflatoxin B1 at a concentration of 25.62 micrograms/kg, 4.8% were positive for aflatoxin B2 at concentrations ranging from 11.25-252.50 micrograms/kg, 3.6% were positive for aflatoxin G1 at concentrations ranging from 25.00-289.38 micrograms/kg and 13.25% were positive for aflatoxin G2 at concentrations ranging from 16.25-436.25 micrograms/kg. Similarly, positive wheat flour samples were mostly collected from private homes.

  2. FunSecKB: the Fungal Secretome KnowledgeBase

    PubMed Central

    Lum, Gengkon; Min, Xiang Jia

    2011-01-01

    The Fungal Secretome KnowledgeBase (FunSecKB) provides a resource of secreted fungal proteins, i.e. secretomes, identified from all available fungal protein data in the NCBI RefSeq database. The secreted proteins were identified using a well evaluated computational protocol which includes SignalP, WolfPsort and Phobius for signal peptide or subcellular location prediction, TMHMM for identifying membrane proteins, and PS-Scan for identifying endoplasmic reticulum (ER) target proteins. The entries were mapped to the UniProt database and any annotations of subcellular locations that were either manually curated or computationally predicted were included in FunSecKB. Using a web-based user interface, the database is searchable, browsable and downloadable by using NCBI’s RefSeq accession or gi number, UniProt accession number, keyword or by species. A BLAST utility was integrated to allow users to query the database by sequence similarity. A user submission tool was implemented to support community annotation of subcellular locations of fungal proteins. With the complete fungal data from RefSeq and associated web-based tools, FunSecKB will be a valuable resource for exploring the potential applications of fungal secreted proteins. Database URL: http://proteomics.ysu.edu/secretomes/fungi.php PMID:21300622

  3. Promising cellulolytic fungi isolates for rice straw degradation.

    PubMed

    Pedraza-Zapata, Diana Catalina; Sánchez-Garibello, Andrea Melissa; Quevedo-Hidalgo, Balkys; Moreno-Sarmiento, Nubia; Gutiérrez-Rojas, Ivonne

    2017-09-01

    The objective of this study was to evaluate the potential of eight fungal isolates obtained from soils in rice crops for straw degradation in situ. From the initial eight isolates, Pleurotus ostreatus T1.1 and Penicillium sp. HC1 were selected for further characterization based on qualitative cellulolytic enzyme production and capacity to use rice straw as a sole carbon source. Subsequently, cellulolytic, xylanolytic, and lignolytic (Pleurotus ostreatus) activity on carboxymethyl cellulose, oat xylan, and rice straw with different nitrogen sources was evaluated. From the results obtained it was concluded both isolates are capable to produce enzymes necessary for rice straw degradation. However, their production is dependent upon carbon and nitrogen source. Last, it was established that Pleurotus ostreatus T1.1 and Penicillium sp. HC1 capability to colonize and mineralize rice straw, in mono-and co-culture, without affecting nitrogen soil content.

  4. Identification of a novel casbane-type diterpene phytoalexin, ent-10-oxodepressin, from rice leaves.

    PubMed

    Inoue, Yasuno; Sakai, Miki; Yao, Qun; Tanimoto, Yosuke; Toshima, Hiroaki; Hasegawa, Morifumi

    2013-01-01

    A 70% methanol extract of UV-irradiated rice leaves (400 g) was separated by chromatographic methods to give UV-induced compound 1 (2.1 mg) which showed a possible molecular ion at m/z 300 in the GC/MS analysis. Its structure was determined by NMR and MS methods. The 1H- and 13C-NMR spectra of 1 were identical to those of 10-oxodepressin (2), a casbane-type diterpene derived from the soft coral, Sinularia depressa. The specific rotation of 1 was positive, whereas that of 2 was negative. We therefore established 1 as ent-10-oxodepressin. The accumulation of 1 was also induced by an inoculation of the rice blast fungus. Compound 1 inhibited spore germination (IC50 30 ppm) and germ tube growth (IC50 10 ppm) of the rice blast fungus. We thus concluded that 1 was a novel rice phytoalexin.

  5. Blast assessment and optimization for high quarry face-blasting

    SciTech Connect

    Sames, F.; O`Meara, R.

    1996-12-01

    Where applicable, high production benches can improve efficiency in quarrying. Quality control, geological, cost or other considerations might result in the development of quarry benches higher than 30 m and sometimes up to 60 m. Production blasts on high quarry faces require a confident blast design with respect to safety, cost efficiency and minimized environmental effects. Careful pre-blast assessment of the design parameters, blast monitoring of the product performance and the environmental effects and post-blast assessment of the overall blast performance are essential for the successful implementation of the blast design. The blast geometry for high quarry faces and a blast design that often includes multiple explosive charges in a blasthole, make a reliable assessment of the blast parameters difficult. Assessment techniques, their applications and limitations are described and discussed. This will include such methods as blast surveying using laser profiling and borehole deviation measurements, blast monitoring using continuous velocity of detonation measurement systems, high speed photography and seismographs for blast performance and environmental effects. Observations of low frequency airblast and high standard deviations in ground vibration measurements are described and discussed against a background of timing assessment and frequency spectra analysis. Approaches where an optimized design was implemented based on the blast parameter assessment and modeling are presented. An improvement in blast efficiency lies in the combination of blast assessment and blast modeling, whilst adequate documentation supports the process of designing and implementing successful blasts.

  6. Phenolic Phytoalexins in Rice: Biological Functions and Biosynthesis

    PubMed Central

    Cho, Man-Ho; Lee, Sang-Won

    2015-01-01

    Phytoalexins are inducible secondary metabolites possessing antimicrobial activity against phytopathogens. Rice produces a wide array of phytoalexins in response to pathogen attacks and environmental stresses. With few exceptions, most phytoalexins identified in rice are diterpenoid compounds. Until very recently, flavonoid sakuranetin was the only known phenolic phytoalexin in rice. However, recent studies have shown that phenylamides are involved in defense against pathogen attacks in rice. Phenylamides are amine-conjugated phenolic acids that are induced by pathogen infections and abiotic stresses including ultra violet (UV) radiation in rice. Stress-induced phenylamides, such as N-trans-cinnamoyltryptamine, N-p-coumaroylserotonin and N-cinnamoyltyramine, have been reported to possess antimicrobial activities against rice bacterial and fungal pathogens, an indication of their direct inhibitory roles against invading pathogens. This finding suggests that phenylamides act as phytoalexins in rice and belong to phenolic phytoalexins along with sakuranetin. Phenylamides also have been implicated in cell wall reinforcement for disease resistance and allelopathy of rice. Synthesis of phenolic phytoalexins is stimulated by phytopathogen attacks and abiotic challenges including UV radiation. Accumulating evidence has demonstrated that biosynthetic pathways including the shikimate, phenylpropanoid and arylmonoamine pathways are coordinately activated for phenolic phytoalexin synthesis, and related genes are induced by biotic and abiotic stresses in rice. PMID:26690131

  7. Fungal diagnostics in pneumonia.

    PubMed

    Lease, Erika D; Alexander, Barbara D

    2011-12-01

    Fungal pneumonia is increasingly common, particularly in highly immunosuppressed patients, such as solid organ or hematopoietic stem cell transplant recipients, and the diagnosis is evolving. Although standard techniques such as microscopy and culture remain the mainstays of diagnosis, relatively recent advances in serological and molecular testing are important additions to the field. This article reviews the laboratory tools used to diagnose fungal respiratory disease.

  8. Universal fungal vaccines

    PubMed Central

    Hamad, Mawieh

    2012-01-01

    The complex nature of fungal pathogens, the intricate host-pathogen relationship and the health status of subjects in need of antifungal vaccination continue to hamper efforts to develop fungal vaccines for clinical use. That said, the rise of the universal vaccine concept is hoped to revive fungal vaccine research by expanding the pool of vaccine candidates worthy of clinical evaluation. It can do so through antigenic commonality-based screening for vaccine candidates from a wide range of pathogens and by reassessing the sizable collection of already available experimental and approved vaccines. Development of experimental vaccines protective against multiple fungal pathogens is evidence of the utility of this concept in fungal vaccine research. However, universal fungal vaccines are not without difficulties; for instance, development of vaccines with differential effectiveness is an issue that should be addressed. Additionally, rationalizing the development of universal fungal vaccines on health or economic basis could be contentious. Herein, universal fungal vaccines are discussed in terms of their potential usefulness and possible drawbacks. PMID:22922769

  9. Simultaneous pretreatment and sacchariffication of rice husk by Phanerochete chrysosporium for improved production of reducing sugars.

    PubMed

    Potumarthi, Ravichandra; Baadhe, Rama Raju; Nayak, Priyanka; Jetty, Annapurna

    2013-01-01

    Phanerochete chrysosporium, the white-rot fungus, (a best source for lignolytic enzymes system) was used in the biological pretreatment of rice husk for reducing sugars production. Usually reducing sugar production through biochemical process involves two steps: solid state fermentation (SSF) of fungal pretreatment for delignification, subsequently pretreated biomass subjected to enzymatic hydrolysis. During the fungal pretreatment of rice husk for reducing sugar production along with cellulase and xylanse, the activities of lignin degradation-related enzymes such as lignin peroxidases (LiP), GLOX (glyoxidase), and aryl alcohol oxidases (AAO), were observed. The fungal pretreated rice husk produced highest (895.9 mg/ml/2g of rise husk) reducing sugars on 18th day of fungal treatment. This method may be good alternative to avoid operational costs associated with washing and the removal of inhibitors during the conventional pretreatment methods.

  10. Fungicide sensitivity in the wild rice pathogen Bipolaris oryzae

    USDA-ARS?s Scientific Manuscript database

    In recent years the occurrence of fungal brown spot, caused by Bipolaris oryzae has increased in cultivated wild rice (Zizania palustris) paddies in spite of the use of fungicides. To implement an efficient integrated disease management system, we are exploring whether field isolates have developed ...

  11. Signaling in the Rhizoctonia solani-rice pathosystem

    USDA-ARS?s Scientific Manuscript database

    Rhizoctonia solani is a necrotrophic soil borne fungal pathogen known to be a serious crop killer worldwide. A better understanding of the molecular signaling will benefit the development of effective methods to control the pathogen. To dissect molecular signaling between rice and R. solani a combin...

  12. Dry ice blasting

    NASA Astrophysics Data System (ADS)

    Lonergan, Jeffrey M.

    1992-04-01

    As legal and societal pressures against the use of hazardous waste generating materials has increased, so has the motivation to find safe, effective, and permanent replacements. Dry ice blasting is a technology which uses CO2 pellets as a blasting medium. The use of CO2 for cleaning and stripping operations offers potential for significant environmental, safety, and productivity improvements over grit blasting, plastic media blasting, and chemical solvent cleaning. Because CO2 pellets break up and sublime upon impact, there is no expended media to dispose of. Unlike grit or plastic media blasting which produce large quantities of expended media, the only waste produced by CO2 blasting is the material removed. The quantity of hazardous waste produced, and thus the cost of hazardous waste disposal is significantly reduced.

  13. Fungal Genomics Program

    SciTech Connect

    Grigoriev, Igor

    2012-03-12

    The JGI Fungal Genomics Program aims to scale up sequencing and analysis of fungal genomes to explore the diversity of fungi important for energy and the environment, and to promote functional studies on a system level. Combining new sequencing technologies and comparative genomics tools, JGI is now leading the world in fungal genome sequencing and analysis. Over 120 sequenced fungal genomes with analytical tools are available via MycoCosm (www.jgi.doe.gov/fungi), a web-portal for fungal biologists. Our model of interacting with user communities, unique among other sequencing centers, helps organize these communities, improves genome annotation and analysis work, and facilitates new larger-scale genomic projects. This resulted in 20 high-profile papers published in 2011 alone and contributing to the Genomics Encyclopedia of Fungi, which targets fungi related to plant health (symbionts, pathogens, and biocontrol agents) and biorefinery processes (cellulose degradation, sugar fermentation, industrial hosts). Our next grand challenges include larger scale exploration of fungal diversity (1000 fungal genomes), developing molecular tools for DOE-relevant model organisms, and analysis of complex systems and metagenomes.

  14. Fungal DNA barcoding.

    PubMed

    Xu, Jianping

    2016-11-01

    Fungi are ubiquitous in both natural and human-made environments. They play important roles in the health of plants, animals, and humans, and in broad ecosystem functions. Thus, having an efficient species-level identification system could significantly enhance our ability to treat fungal diseases and to monitor the spatial and temporal patterns of fungal distributions and migrations. DNA barcoding is a potent approach for rapid identification of fungal specimens, generating novel species hypothesis, and guiding biodiversity and ecological studies. In this mini-review, I briefly summarize (i) the history of DNA sequence-based fungal identification; (ii) the emergence of the ITS region as the consensus primary fungal barcode; (iii) the use of the ITS barcodes to address a variety of issues on fungal diversity from local to global scales, including generating a large number of species hypothesis; and (iv) the problems with the ITS barcode region and the approaches to overcome these problems. Similar to DNA barcoding research on plants and animals, significant progress has been achieved over the last few years in terms of both the questions being addressed and the foundations being laid for future research endeavors. However, significant challenges remain. I suggest three broad areas of research to enhance the usefulness of fungal DNA barcoding to meet the current and future challenges: (i) develop a common set of primers and technologies that allow the amplification and sequencing of all fungi at both the primary and secondary barcode loci; (ii) compile a centralized reference database that includes all recognized fungal species as well as species hypothesis, and allows regular updates from the research community; and (iii) establish a consensus set of new species recognition criteria based on barcode DNA sequences that can be applied across the fungal kingdom.

  15. Blast furnace stove control

    SciTech Connect

    Muske, K.R.; Hansen, G.A.; Howse, J.W.; Cagliostro, D.J.; Chaubal, P.C.

    1998-12-31

    This paper outlines the process model and model-based control techniques implemented on the hot blast stoves for the No. 7 Blast Furnace at the Inland Steel facility in East Chicago, Indiana. A detailed heat transfer model of the stoves is developed. It is then used as part of a predictive control scheme to determine the minimum amount of fuel necessary to achieve the blast air requirements. The controller also considers maximum and minimum temperature constraints within the stove.

  16. Fungal arthritis and osteomyelitis.

    PubMed

    Kohli, Rakhi; Hadley, Susan

    2005-12-01

    Fungal arthritis and osteomyelitis are uncommon diseases and generally present in an indolent fashion. The incidence of fungal bone and joint dis-ease is increasing with an increase in the prevalence of factors predisposing to invasive fungal disease, such as the use of central venous catheters, broad spectrum antibiotics, immunosuppression, and abdominal surgery. Definitive diagnosis relies on bone or synovial culture or biopsy. Successful management has traditionally consisted of amphotericin B in combination with surgical debridement. Given the rarity of this disease, treatment is not well defined, but reports of success with the use of azole antifungal agents, including itraconazole, fluconazole, voriconazole, and posaconazole, are promising.

  17. Fungal Vaccines and Immunotherapeutics

    PubMed Central

    Santos, Evelyn; Levitz, Stuart M.

    2014-01-01

    Concomitant with the increased prevalence of immunocompromised persons, invasive fungal infections have become considerably more frequent in the last 50 years. High mortality rates caused by invasive mycoses and high morbidity because of intractable mucosal infections have created an unmet need for innovative prophylactic and therapeutic strategies against fungal pathogens. Several immunotherapeutics and vaccines are in development to address this need, although one has yet to reach the clinic. This review focuses on past and current immunotherapeutic and vaccine strategies being tested to either prevent or treat fungal infections, as well as the challenges associated with their development. PMID:25368016

  18. Blast injury research models

    PubMed Central

    Kirkman, E.; Watts, S.; Cooper, G.

    2011-01-01

    Blast injuries are an increasing problem in both military and civilian practice. Primary blast injury to the lungs (blast lung) is found in a clinically significant proportion of casualties from explosions even in an open environment, and in a high proportion of severely injured casualties following explosions in confined spaces. Blast casualties also commonly suffer secondary and tertiary blast injuries resulting in significant blood loss. The presence of hypoxaemia owing to blast lung complicates the process of fluid resuscitation. Consequently, prolonged hypotensive resuscitation was found to be incompatible with survival after combined blast lung and haemorrhage. This article describes studies addressing new forward resuscitation strategies involving a hybrid blood pressure profile (initially hypotensive followed later by normotensive resuscitation) and the use of supplemental oxygen to increase survival and reduce physiological deterioration during prolonged resuscitation. Surprisingly, hypertonic saline dextran was found to be inferior to normal saline after combined blast injury and haemorrhage. New strategies have therefore been developed to address the needs of blast-injured casualties and are likely to be particularly useful under circumstances of enforced delayed evacuation to surgical care. PMID:21149352

  19. General view of blast furnace plant, with blast furnace "A" ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    General view of blast furnace plant, with blast furnace "A" (built in 1907) to the left; in the foreground is the turbo-blower and blast furnace gas-powered electric generating station (built in 1919), looking northwest - Bethlehem Steel Corporation, South Bethlehem Works, Blast Furnace "A", Along Lehigh River, North of Fourth Street, West of Minsi Trail Bridge, Bethlehem, Northampton County, PA

  20. Fungal symbiosis unearthed

    Treesearch

    Daniel Cullen

    2008-01-01

    Associations between plant roots and fungi are a feature of many terrestrial ecosystems. The genome sequence of a prominent fungal partner opens new avenues for studying such mycorrhizal interactions....

  1. Fungal diseases of reptiles.

    PubMed

    Schumacher, Juergen

    2003-05-01

    Fungal infections affecting the integumentary system, the upper and lower respiratory system and the gastro-intestinal tract have been reported in many species of captive reptiles. Systemic mycoses are diagnosed rarely in reptiles, and in most cases, they are a postmortem finding. Commonly, immunocompromised reptiles, kept in suboptimal environmental conditions are affected. In many cases, mixed bacterial and fungal infections of opportunistic organisms may be present. A diagnosis of a primary fungal infection is based on proper selection and collection of diagnostic specimens such as biopsies of infected tissues. Treatment of fungal infections in reptiles includes administration of effective antifungal agents and correction of inappropriate environmental conditions such as poor hygiene, too high or too low temperature and humidity, inadequate diet, and stress from overcrowding. Few studies have investigated effective dosages and dosage intervals of antifungal agents in reptiles.

  2. Granuloma, fungal (Majocchi's) (image)

    MedlinePlus

    This is a picture of a fungal granuloma, a large, red (erythematous) patch (plaque) with a prominent border. Within the borders of the lesion are scattered blisters (pustules) that indicate deeper ...

  3. JGI Fungal Genomics Program

    SciTech Connect

    Grigoriev, Igor V.

    2011-03-14

    Genomes of energy and environment fungi are in focus of the Fungal Genomic Program at the US Department of Energy Joint Genome Institute (JGI). Its key project, the Genomics Encyclopedia of Fungi, targets fungi related to plant health (symbionts, pathogens, and biocontrol agents) and biorefinery processes (cellulose degradation, sugar fermentation, industrial hosts), and explores fungal diversity by means of genome sequencing and analysis. Over 50 fungal genomes have been sequenced by JGI to date and released through MycoCosm (www.jgi.doe.gov/fungi), a fungal web-portal, which integrates sequence and functional data with genome analysis tools for user community. Sequence analysis supported by functional genomics leads to developing parts list for complex systems ranging from ecosystems of biofuel crops to biorefineries. Recent examples of such 'parts' suggested by comparative genomics and functional analysis in these areas are presented here

  4. Overexpression of a Novel Biotrophy-Specific Colletotrichum truncatum Effector, CtNUDIX, in Hemibiotrophic Fungal Phytopathogens Causes Incompatibility with Their Host Plants

    PubMed Central

    Bhadauria, Vijai; Vandenberg, Albert; Selvaraj, Gopalan

    2013-01-01

    The hemibiotrophic fungus Colletotrichum truncatum causes anthracnose disease on lentils and a few other grain legumes. It shows initial symptomless intracellular growth, where colonized host cells remain viable (biotrophy), and then switches to necrotrophic growth, killing the colonized host plant tissues. Here, we report a novel effector gene, CtNUDIX, from C. truncatum that is exclusively expressed during the late biotrophic phase (before the switch to necrotrophy) and elicits a hypersensitive response (HR)-like cell death in tobacco leaves transiently expressing the effector. CtNUDIX homologs, which contain a signal peptide and a Nudix hydrolase domain, may be unique to hemibiotrophic fungal and fungus-like plant pathogens. CtNUDIX lacking a signal peptide or a Nudix motif failed to induce cell death in tobacco. Expression of CtNUDIX:eGFP in tobacco suggested that the fusion protein might act on the host cell plasma membrane. Overexpression of CtNUDIX in C. truncatum and the rice blast pathogen, Magnaporthe oryzae, resulted in incompatibility with the hosts lentil and barley, respectively, by causing an HR-like response in infected host cells associated with the biotrophic invasive hyphae. These results suggest that C. truncatum and possibly M. oryzae elicit cell death to signal the transition from biotrophy to necrotrophy. PMID:22962277

  5. Roles of plant hormones and their interplay in rice immunity.

    PubMed

    Yang, Dong-Lei; Yang, Yinong; He, Zuhua

    2013-05-01

    Plant hormones have been extensively studied for their importance in innate immunity particularly in the dicotyledonous model plant Arabidopsis thaliana. However, only in the last decade, plant hormones were demonstrated to play conserved and divergent roles in fine-tuning immune in rice (Oryza sativa L.), a monocotyledonous model crop plant. Emerging evidence showed that salicylic acid (SA) plays a role in rice basal defense but is differentially required by rice pattern recognition receptor (PRR) and resistance (R) protein-mediated immunity, and its function is likely dependent on the signaling pathway rather than the change of endogenous levels. Jasmonate (JA) plays an important role in rice basal defense against bacterial and fungal infection and may be involved in the SA-mediated resistance. Ethylene (ET) can act as a positive or negative modulator of disease resistance, depending on the pathogen type and environmental conditions. Brassinosteroid (BR) signaling and abscisic acid (ABA) either promote or defend against infection of pathogens with distinct infection/colonization strategies. Auxin and gibberellin (GA) are generally thought of as negative regulators of innate immunity in rice. Moreover, GA interacts antagonistically with JA signaling in rice development and immunity through the DELLA protein as a master regulator of the two hormone pathways. In this review, we summarize the roles of plant hormones in rice immunity and discuss their interplay/crosstalk mechanisms and the complex regulatory network of plant hormone pathways in fine-tuning rice immunity and growth.

  6. [Techniques of diseases, insect pests and weeds control and their efficacy in bio-rational rice production].

    PubMed

    Li, Baotong; Shi, Qinghua; Fang, Jiahai; Pan, Xiaohua

    2004-01-01

    Studies on the efficacy of bio-rational pesticides and agricultural methods against the chief diseases, insect pests and weeds of rice showed that the efficacy of the mixtures of jingangmycin and bacillus-cereus, and jingangmycin and polyoxin against rice sheath blight were 75.16%-94.27% after sprayed once at the tiller and boot end stages of rice, respectively, and better than that of chemical fungicide triadimefon. The efficacy of kasugamycin and blasticidin was 50.54%-72.67% on rice leaf blast and 76.66%-87.42% on rice head blast, and equal to the chemical fungicide tricyclazole after sprayed once at the initial stage of rice leaf blast occurrence and the initial and end stages of earing, respectively. The efficacy of bacillus thuringiensis on Chilo suppressalis and Cnaphalocrocis medinalis was better than that of chemical insecticide bisultap, and the efficacy of saponin-nicotine and matrine was equal to that of chemical insecticide bisultap when the three biorational insecticides were sprayed at 1-2 instar larvae of pests. The efficacy of saponin-nicotine and matrine was above 70%, and lower than that of chemical insecticide imidacloprid 3-30 d after sprayed at 1-2 instar larvae of Nilaparvata lugens. The occurrence of weeds could be controlled, and the rice yield could be raised when the suitable non-thorough decomposed organism was applied or weeding was carried after the field had been ploughed twice before rice transplant. The rice yield could be raised by using biorational pesticides and agricultural methods against the chief diseases, insect pests and weeds of rice. The residue of pesticides in rice was lower in the bio-control area than in the chemical control area, according with the demands of health target of green food.

  7. Diverse Rice Landraces of North-East India Enables the Identification of Novel Genetic Resources for Magnaporthe Resistance.

    PubMed

    Umakanth, Bangale; Vishalakshi, Balija; Sathish Kumar, P; Rama Devi, S J S; Bhadana, Vijay Pal; Senguttuvel, P; Kumar, Sudhir; Sharma, Susheel Kumar; Sharma, Pawan Kumar; Prasad, M S; Madhav, Maganti S

    2017-01-01

    North-East (NE) India, the probable origin of rice has diverse genetic resources. Many rice landraces of NE India were not yet characterized for blast resistance. A set of 232 landraces of NE India, were screened for field resistance at two different hotspots of rice blast, viz., IIRR-UBN, Hyderabad and ICAR-NEH, Manipur in two consecutive seasons. The phenotypic evaluation as well as gene profiling for 12 major blast resistance genes (Pitp, Pi33, Pi54, Pib, Pi20, Pi38, Pita2, Pi1, Piz, Pi9, Pizt, and Pi40) with linked as well as gene-specific markers, identified 84 resistant landraces possessing different gene(s) either in singly or in combinations and also identified seven resistant landraces which do not have the tested genes, indicating the valuable genetic resources for blast resistance. To understand the molecular diversity existing in the population, distance and model based analysis were performed using 120 SSR markers. Results of both analyses are highly correlated by forming two distinct subgroups and the existence of high diversity (24.9% among the subgroups; 75.1% among individuals of each subgroup) was observed. To practically utilize the diversity in the breeding program, a robust core set having an efficiency index of 0.82 which consists of 33 landraces were identified through data of molecular, blast phenotyping, and important agro-morphological traits. The association of eight novel SSR markers for important agronomic traits which includes leaf and neck blast resistance was determined using genome-wide association analysis. The current study focuses on identifying novel resources having field resistance to blast as well as markers which can be explored in rice improvement programs. It also entails the development of a core set which can aid in representing the entire diversity for efficiently harnessing its properties to broaden the gene pool of rice.

  8. Immunotherapy of Fungal Infections.

    PubMed

    Datta, Kausik; Hamad, Mawieh

    2015-01-01

    Fungal organisms are ubiquitous in the environment. Pathogenic fungi, although relatively few in the whole gamut of microbial pathogens, are able to cause disease with varying degrees of severity in individuals with normal or impaired immunity. The disease state is an outcome of the fungal pathogen's interactions with the host immunity, and therefore, it stands to reason that deep/invasive fungal diseases be amenable to immunotherapy. Therefore, antifungal immunotherapy continues to be attractive as an adjunct to the currently available antifungal chemotherapy options for a number of reasons, including the fact that existing antifungal drugs, albeit largely effective, are not without limitations, and that morbidity and mortality associated with invasive mycoses are still unacceptably high. For several decades, intense basic research efforts have been directed at development of fungal immunotherapies. Nevertheless, this approach suffers from a severe bench-bedside disconnect owing to several reasons: the chemical and biological peculiarities of the fungal antigens, the complexities of host-pathogen interactions, an under-appreciation of the fungal disease landscape, the requirement of considerable financial investment to bring these therapies to clinical use, as well as practical problems associated with immunizations. In this general, non-exhaustive review, we summarize the features of ongoing research efforts directed towards devising safe and effective immunotherapeutic options for mycotic diseases, encompassing work on antifungal vaccines, adoptive cell transfers, cytokines, antimicrobial peptides (AMPs), monoclonal antibodies (mAbs), and other agents.

  9. Metabolism in Fungal Pathogenesis

    PubMed Central

    Ene, Iuliana V.; Brunke, Sascha; Brown, Alistair J.P.; Hube, Bernhard

    2014-01-01

    Fungal pathogens must assimilate local nutrients to establish an infection in their mammalian host. We focus on carbon, nitrogen, and micronutrient assimilation mechanisms, discussing how these influence host–fungus interactions during infection. We highlight several emerging trends based on the available data. First, the perturbation of carbon, nitrogen, or micronutrient assimilation attenuates fungal pathogenicity. Second, the contrasting evolutionary pressures exerted on facultative versus obligatory pathogens have led to contemporary pathogenic fungal species that display differing degrees of metabolic flexibility. The evolutionarily ancient metabolic pathways are conserved in most fungal pathogen, but interesting gaps exist in some species (e.g., Candida glabrata). Third, metabolic flexibility is generally essential for fungal pathogenicity, and in particular, for the adaptation to contrasting host microenvironments such as the gastrointestinal tract, mucosal surfaces, bloodstream, and internal organs. Fourth, this metabolic flexibility relies on complex regulatory networks, some of which are conserved across lineages, whereas others have undergone significant evolutionary rewiring. Fifth, metabolic adaptation affects fungal susceptibility to antifungal drugs and also presents exciting opportunities for the development of novel therapies. PMID:25190251

  10. Rice ( Oryza) hemoglobins

    PubMed Central

    Arredondo-Peter, Raúl; Moran, Jose F.; Sarath, Gautam

    2014-01-01

    Hemoglobins (Hbs) corresponding to non-symbiotic (nsHb) and truncated (tHb) Hbs have been identified in rice ( Oryza). This review discusses the major findings from the current studies on rice Hbs. At the molecular level, a family of the nshb genes, consisting of hb1, hb2, hb3, hb4 and hb5, and a single copy of the thb gene exist in Oryza sativa var. indica and O. sativa var. japonica, Hb transcripts coexist in rice organs and Hb polypeptides exist in rice embryonic and vegetative organs and in the cytoplasm of differentiating cells. At the structural level, the crystal structure of rice Hb1 has been elucidated, and the structures of the other rice Hbs have been modeled. Kinetic analysis indicated that rice Hb1 and 2, and possibly rice Hb3 and 4, exhibit a very high affinity for O 2, whereas rice Hb5 and tHb possibly exhibit a low to moderate affinity for O 2. Based on the accumulated information on the properties of rice Hbs and data from the analysis of other plant and non-plant Hbs, it is likely that Hbs play a variety of roles in rice organs, including O 2-transport, O 2-sensing, NO-scavenging and redox-signaling. From an evolutionary perspective, an outline for the evolution of rice Hbs is available. Rice nshb and thb genes vertically evolved through different lineages, rice nsHbs evolved into clade I and clade II lineages and rice nshbs and thbs evolved under the effect of neutral selection. This review also reveals lacunae in our ability to completely understand rice Hbs. Primary lacunae are the absence of experimental information about the precise functions of rice Hbs, the properties of modeled rice Hbs and the cis-elements and trans-acting factors that regulate the expression of rice hb genes, and the partial understanding of the evolution of rice Hbs. PMID:25653837

  11. Rice ( Oryza) hemoglobins.

    PubMed

    Arredondo-Peter, Raúl; Moran, Jose F; Sarath, Gautam

    2014-01-01

    Hemoglobins (Hbs) corresponding to non-symbiotic (nsHb) and truncated (tHb) Hbs have been identified in rice ( Oryza). This review discusses the major findings from the current studies on rice Hbs. At the molecular level, a family of the nshb genes, consisting of hb1, hb2, hb3, hb4 and hb5, and a single copy of the thb gene exist in Oryza sativa var. indica and O. sativa var. japonica, Hb transcripts coexist in rice organs and Hb polypeptides exist in rice embryonic and vegetative organs and in the cytoplasm of differentiating cells. At the structural level, the crystal structure of rice Hb1 has been elucidated, and the structures of the other rice Hbs have been modeled. Kinetic analysis indicated that rice Hb1 and 2, and possibly rice Hb3 and 4, exhibit a very high affinity for O 2, whereas rice Hb5 and tHb possibly exhibit a low to moderate affinity for O 2. Based on the accumulated information on the properties of rice Hbs and data from the analysis of other plant and non-plant Hbs, it is likely that Hbs play a variety of roles in rice organs, including O 2-transport, O 2-sensing, NO-scavenging and redox-signaling. From an evolutionary perspective, an outline for the evolution of rice Hbs is available. Rice nshb and thb genes vertically evolved through different lineages, rice nsHbs evolved into clade I and clade II lineages and rice nshbs and thbs evolved under the effect of neutral selection. This review also reveals lacunae in our ability to completely understand rice Hbs. Primary lacunae are the absence of experimental information about the precise functions of rice Hbs, the properties of modeled rice Hbs and the cis-elements and trans-acting factors that regulate the expression of rice hb genes, and the partial understanding of the evolution of rice Hbs.

  12. Exogenous superoxide dismutase may lose its antidotal ability on rice leaves

    USDA-ARS?s Scientific Manuscript database

    Leaf diffusates of the resistant rice cultivars suppressed spore germination of blast fungus (Magnaporthe grisea). Bovine Cu-Zn superoxide dismutase (SOD) added to the diffusate abolished its toxicity. However, the enzyme added to the inoculum did not affect the toxicity of the diffusate. Even the s...

  13. Identification of a Pi9 containing rice germplasm with a newly developed robust marker

    USDA-ARS?s Scientific Manuscript database

    The Pi9 gene, originating from Oryza minuta, is an effective resistance gene for controlling rice blast disease (Magnaporthe oryzae). However, currently available linked DNA markers do not accurately identify the function of Pi9, thus hindering its efficient incorporation into new cultivars through...

  14. Internal transcribed spacer (ITS) sequencing reveals considerable fungal diversity in dairy products.

    PubMed

    Buehler, A J; Evanowski, R L; Martin, N H; Boor, K J; Wiedmann, M

    2017-09-13

    Fungi are important spoilage organisms in dairy products. However, little is known about the diversity of naturally occurring spoilage fungi in raw milk and processed dairy products, due at least in part to the fact that classical fungal identification methods require considerable expertise. To gain further insight into the fungal diversity in the dairy system, we isolated fungi from raw milk, raw and pasteurized milk cheese, and yogurt using the selective dichloran rose bengal chloramphenicol agar. In total, 361 fungal isolates were obtained and further characterized by DNA sequencing of the internal transcribed spacer (ITS) region and the nuclear ribosomal large subunit (LSU) rRNA gene if needed. We conducted BLAST (https://blast.ncbi.nlm.nih.gov/Blast.cgi) searches of the ITS region sequences against the UNITE Database (https://unite.ut.ee/analysis.php), and selected other databases if needed, which allowed identification to the species level of 183 isolates and to the genus level of 107 of the 346 isolates that were successfully ITS sequenced. The isolates characterized represented 3 phyla and 19 genera; the most common genera isolated were Penicillium (25% of isolates), Debaryomyces (18%), and Candida (9%). This study not only provides, by using modern molecular tools, a baseline understanding of the types of fungi in dairy products, but also confirms that ITS sequencing is a useful approach for identification of fungal organisms found in the dairy food chain. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  15. Robotic Water Blast Cleaner

    NASA Technical Reports Server (NTRS)

    Sharpe, M. H.; Roberts, M. L.; Hill, W. E.; Jackson, C. H.

    1983-01-01

    Water blasting system under development removes hard, dense, extraneous material from surfaces. High pressure pump forces water at supersonic speed through nozzle manipulated by robot. Impact of water blasts away unwanted material from workpiece rotated on air bearing turntable. Designed for removing thermal-protection material, system is adaptable to such industrial processes as cleaning iron or steel castings.

  16. Lightweight blast shield

    DOEpatents

    Mixon, Larry C.; Snyder, George W.; Hill, Scott D.; Johnson, Gregory L.; Wlodarski, J. Frank; von Spakovsky, Alexis P.; Emerson, John D.; Cole, James M.; Tipton, John P.

    1991-01-01

    A tandem warhead missile arrangement that has a composite material housing structure with a first warhead mounted at one end and a second warhead mounted near another end of the composite structure with a dome shaped composite material blast shield mounted between the warheads to protect the second warhead from the blast of the first warhead.

  17. Robotic Water Blast Cleaner

    NASA Technical Reports Server (NTRS)

    Sharpe, M. H.; Roberts, M. L.; Hill, W. E.; Jackson, C. H.

    1983-01-01

    Water blasting system under development removes hard, dense, extraneous material from surfaces. High pressure pump forces water at supersonic speed through nozzle manipulated by robot. Impact of water blasts away unwanted material from workpiece rotated on air bearing turntable. Designed for removing thermal-protection material, system is adaptable to such industrial processes as cleaning iron or steel castings.

  18. Fungal endocarditis: current challenges.

    PubMed

    Tattevin, Pierre; Revest, Matthieu; Lefort, Agnès; Michelet, Christian; Lortholary, Olivier

    2014-10-01

    Whilst it used to affect mostly intravenous drug users and patients who underwent valvular surgery with suboptimal infection control procedures, fungal endocarditis is now mostly observed in patients with severe immunodeficiency (onco-haematology), in association with chronic central venous access and broad-spectrum antibiotic use. The incidence of fungal endocarditis has probably decreased in most developed countries with access to harm-reduction policies (i.e. needle exchange programmes) and with improved infection control procedures during cardiac surgery. Use of specific blood culture bottles for diagnosis of fungal endocarditis has decreased due to optimisation of media and automated culture systems. Meanwhile, the advent of rapid techniques, including fungal antigen detection (galactomannan, mannan/anti-mannan antibodies and β-1,3-d-glucans) and PCR (e.g. universal fungal PCR targeting 18S rRNA genes), shall improve sensitivity and reduce diagnostics delays, although limited data are available on their use for the diagnosis of fungal endocarditis. New antifungal agents available since the early 2000s may represent dramatic improvement for fungal endocarditis: (i) a new class, the echinocandins, has the potential to improve the management of Candida endocarditis owing to its fungicidal effect on yeasts as well as tolerability of increased dosages; and (ii) improved survival in patients with invasive aspergillosis with voriconazole compared with amphotericin B, and this may apply to Aspergillus sp. endocarditis as well, although its prognosis remains dismal. These achievements may allow selected patients to be cured with prolonged medical treatment alone when surgery is considered too risky. Copyright © 2014 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

  19. Integrated metabolomics and phytochemical genomics approaches for studies on rice.

    PubMed

    Okazaki, Yozo; Saito, Kazuki

    2016-01-01

    Metabolomics is widely employed to monitor the cellular metabolic state and assess the quality of plant-derived foodstuffs because it can be used to manage datasets that include a wide range of metabolites in their analytical samples. In this review, we discuss metabolomics research on rice in order to elucidate the overall regulation of the metabolism as it is related to the growth and mechanisms of adaptation to genetic modifications and environmental stresses such as fungal infections, submergence, and oxidative stress. We also focus on phytochemical genomics studies based on a combination of metabolomics and quantitative trait locus (QTL) mapping techniques. In addition to starch, rice produces many metabolites that also serve as nutrients for human consumers. The outcomes of recent phytochemical genomics studies of diverse natural rice resources suggest there is potential for using further effective breeding strategies to improve the quality of ingredients in rice grains.

  20. Diversity of Gram negative bacteria antagonistic against major pathogens of rice from rice seed in the tropic environment.

    PubMed

    Xie, Guan-Lin; Soad, Algam; Swings, J; Mew, T W

    2003-01-01

    With the use of a seed washing technique, more than 4000 Gram negative bacteria were isolated by two improved isolation methods from 446 batches of 1 kg rice seed samples obtained from 22 provinces in the Philippines. They were initially characterized on the basis of colony morphology and results of biochemical and pathogenicity tests. Six hundred and fifty-two strains were further identified by Biolog, from which 133 were selected for fatty acid methylester (FAME) analysis together with 80 standard reference strains. Sixteen species or types of Pseudomonas and 17 genera of non-pseudomonads were identified, more than one third of which have not been recorded in rice. The most predominant species observed were P.putida and P. fulva. About 17% of the strains of Pseudomonas and 2% of the non pseudomonads were antagonistic to one or more fungal or bacterial pathogens of rice. Rice seed is an important source of biological control agents.

  1. Effect of industrial by-products containing electron acceptors on mitigating methane emission during rice cultivation.

    PubMed

    Ali, Muhammad Aslam; Lee, Chang Hoon; Kim, Sang Yoon; Kim, Pil Joo

    2009-10-01

    Three industrial by-products (fly ash, phosphogypsum and blast furnace slag), were evaluated for their potential re-use as soil amendments to reduce methane (CH(4)) emission resulting from rice cultivation. In laboratory incubations, CH(4) production rates from anoxic soil slurries were significantly reduced at amendment levels of 0.5%, 1%, 2% and 5% (wt wt(-1)), while observed CO(2) production rates were enhanced. The level of suppression in methane production was the highest for phosphogypsum, followed by blast slag and then fly ash. In the greenhouse experiment, CH(4) emission rates from the rice planted potted soils significantly decreased with the increasing levels (2-20 Mg ha(-1)) of the selected amendments applied, while rice yield simultaneously increased compared to the control treatment. At 10 Mg ha(-1) application level of the amendments, total seasonal CH(4) emissions were reduced by 20%, 27% and 25%, while rice grain yields were increased by 17%, 15% and 23% over the control with fly ash, phosphogypsum, and blast slag amendments, respectively. The suppression of CH(4) production rates as well as total seasonal CH(4) flux could be due to the increased concentrations of active iron, free iron, manganese oxides, and sulfate in the amended soil, which acted as electron acceptors and controlled methanogens' activity by limiting substrates availability. Among the amendments, blast furnace slag and fly ash contributed mainly to improve the soil nutrients balance and increased the soil pH level towards neutral point, but soil acidity was developed with phosphogypsum application. Conclusively, blast slag among the selected amendments would be a suitable soil amendment for reducing CH(4) emissions as well as sustaining rice productivity.

  2. Effect of industrial by-products containing electron acceptors on mitigating methane emission during rice cultivation

    SciTech Connect

    Ali, Muhammad Aslam; Lee, Chang Hoon; Kim, Sang Yoon; Kim, Pil Joo

    2009-10-15

    Three industrial by-products (fly ash, phosphogypsum and blast furnace slag), were evaluated for their potential re-use as soil amendments to reduce methane (CH{sub 4}) emission resulting from rice cultivation. In laboratory incubations, CH{sub 4} production rates from anoxic soil slurries were significantly reduced at amendment levels of 0.5%, 1%, 2% and 5% (wt wt{sup -1}), while observed CO{sub 2} production rates were enhanced. The level of suppression in methane production was the highest for phosphogypsum, followed by blast slag and then fly ash. In the greenhouse experiment, CH{sub 4} emission rates from the rice planted potted soils significantly decreased with the increasing levels (2-20 Mg ha{sup -1}) of the selected amendments applied, while rice yield simultaneously increased compared to the control treatment. At 10 Mg ha{sup -1} application level of the amendments, total seasonal CH{sub 4} emissions were reduced by 20%, 27% and 25%, while rice grain yields were increased by 17%, 15% and 23% over the control with fly ash, phosphogypsum, and blast slag amendments, respectively. The suppression of CH{sub 4} production rates as well as total seasonal CH{sub 4} flux could be due to the increased concentrations of active iron, free iron, manganese oxides, and sulfate in the amended soil, which acted as electron acceptors and controlled methanogens' activity by limiting substrates availability. Among the amendments, blast furnace slag and fly ash contributed mainly to improve the soil nutrients balance and increased the soil pH level towards neutral point, but soil acidity was developed with phosphogypsum application. Conclusively, blast slag among the selected amendments would be a suitable soil amendment for reducing CH{sub 4} emissions as well as sustaining rice productivity.

  3. Microbe-Mediated Control of Mycotoxigenic Grain Fungi in Stored Rice with Focus on Aflatoxin Biodegradation and Biosynthesis Inhibition

    PubMed Central

    Mannaa, Mohamed

    2016-01-01

    Rice contaminated with fungal species during storage is not only of poor quality and low economic value, but may also have harmful effects on human and animal health. The predominant fungal species isolated from rice grains during storage belong to the genera Aspergillus and Penicillium. Some of these fungal species produce mycotoxins; they are responsible for adverse health effects in humans and animals, particularly Aspergillus flavus, which produces the extremely carcinogenic aflatoxins. Not surprisingly, there have been numerous attempts to devise safety procedure for the control of such harmful fungi and production of mycotoxins, including aflatoxins. This review provides information about fungal and mycotoxin contamination of stored rice grains, and microbe-based (biological) strategies to control grain fungi and mycotoxins. The latter will include information regarding attempts undertaken for mycotoxin (especially aflatoxin) bio-detoxification and microbial interference with the aflatoxin-biosynthetic pathway in the toxin-producing fungi. PMID:27433116

  4. Passive blast pressure sensor

    DOEpatents

    King, Michael J.; Sanchez, Roberto J.; Moss, William C.

    2013-03-19

    A passive blast pressure sensor for detecting blast overpressures of at least a predetermined minimum threshold pressure. The blast pressure sensor includes a piston-cylinder arrangement with one end of the piston having a detection surface exposed to a blast event monitored medium through one end of the cylinder and the other end of the piston having a striker surface positioned to impact a contact stress sensitive film that is positioned against a strike surface of a rigid body, such as a backing plate. The contact stress sensitive film is of a type which changes color in response to at least a predetermined minimum contact stress which is defined as a product of the predetermined minimum threshold pressure and an amplification factor of the piston. In this manner, a color change in the film arising from impact of the piston accelerated by a blast event provides visual indication that a blast overpressure encountered from the blast event was not less than the predetermined minimum threshold pressure.

  5. Allergic fungal rhinosinusitis.

    PubMed

    Ryan, Matthew W

    2011-06-01

    Allergic fungal rhinosinusitis is a phenotype of chronic rhinosinusitis with nasal polyposis, characterized by type 1 hypersensitivity to fungi, eosinophilic mucin with fungal hyphae in sinus secretions, and propensity for mucocele formation and bone erosion. Although its differentiation from other forms of chronic polypoid rhinosinusitis with eosinophilic mucin is sometimes problematic, type 1 hypersensitivity is a component of the disease process. Medical and surgical management can be augmented by immunotherapy directed toward the patient's specific allergen sensitivities. The primary rationale for immunotherapy is to control the allergic diathesis that may be contributing to the patient's chronic sinus inflammation. Copyright © 2011 Elsevier Inc. All rights reserved.

  6. Nucleotide variation and identification of novel blast resistance alleles of Pib by allele mining strategy.

    PubMed

    Ramkumar, G; Madhav, M S; Devi, S J S Rama; Prasad, M S; Babu, V Ravindra

    2015-04-01

    Pib is one of significant rice blast resistant genes, which provides resistance to wide range of isolates of rice blast pathogen, Magnaporthe oryzae. Identification and isolation of novel and beneficial alleles help in crop enhancement. Allele mining is one of the best strategies for dissecting the allelic variations at candidate gene and identification of novel alleles. Hence, in the present study, Pib was analyzed by allele mining strategy, and coding and non-coding (upstream and intron) regions were examined to identify novel Pib alleles. Allelic sequences comparison revealed that nucleotide polymorphisms at coding regions affected the amino acid sequences, while the polymorphism at upstream (non-coding) region affected the motifs arrangements. Pib alleles from resistant landraces, Sercher and Krengosa showed better resistance than Pib donor variety, might be due to acquired mutations, especially at LRR region. The evolutionary distance, Ka/Ks and phylogenetic analyzes also supported these results. Transcription factor binding motif analysis revealed that Pib (Sr) had a unique motif (DPBFCOREDCDC3), while five different motifs differentiated the resistance and susceptible Pib alleles. As the Pib is an inducible gene, the identified differential motifs helps to understand the Pib expression mechanism. The identified novel Pib resistant alleles, which showed high resistance to the rice blast, can be used directly in blast resistance breeding program as alternative Pib resistant sources.

  7. Characterization of Microbial Communities in Chinese Rice Wine Collected at Yichang City and Suzhou City in China.

    PubMed

    Lü, Yucai; Gong, Yanli; Li, Yajie; Pan, Zejiang; Yao, Yi; Li, Ning; Guo, Jinling; Gong, Dachun; Tian, Yihong; Peng, Caiyun

    2017-08-28

    Two typical microbial communities from Chinese rice wine fermentation collected in Yichang city and Suzhou city in China were investigated. Both communities could ferment glutinous rice to rice wine in 2 days. The sugar and ethanol contents were 198.67 and 14.47 mg/g, respectively, for rice wine from Yichang city, and 292.50 and 12.31 mg/g, respectively, for rice wine from Suzhou city. Acetic acid and lactic acid were the most abundant organic acids. Abundant fungi and bacteria were detected in both communities by high-throughput sequencing. Saccharomycopsis fibuligera and Rhizopus oryzae were the dominant fungi in rice wine from Suzhou city, compared with R. oryzae, Wickerhamomyces anomalus, Saccharomyces cerevisiae, Mucor indicus, and Rhizopus microsporus in rice wine from Yichang city. Bacterial diversity was greater than fungal diversity in both communities. Citrobacter was the most abundant genus. Furthermore, Exiguobacterium, Aeromonas, Acinetobacter, Pseudomonas, Enterobacter, Bacillus, and Lactococcus were highly abundant in both communities.

  8. Simple and rapid detection of Tilletia horrida causing rice kernel smut in rice seeds

    PubMed Central

    Chen, Yu; Yang, Xue; Yao, Jian; Kyaw, Ei Phyu; Zhang, Ai-Fang; Li, Yun-Fei; Gu, Chun-Yan; Zang, Hao-Yu; Gao, Tong-Chun

    2016-01-01

    A simple and rapid method for the detection of Tilletia horrida, the causal agent of rice kernel smut, in rice seeds is developed based on specific polymerase chain reaction (PCR). To design the specific primers for the detection of T. horrida, partial sequences of internal transcribed spacer (ITS) DNA region of T. horrida, T. controversa, T. walkeri, T. ehrhartae, T. indica and T. caries were analyzed and compared. A 503-bp fragment was amplified with the designed primers from the T. horrida genomic DNA. However, no PCR product was obtained from the DNA of other five Tilletia species and 22 fungal plant pathogens tested in the present work indicating the specificity of the primers for the detection of T. horrida. The PCR was performed by directly using the spores, isolated from the 21 different rice seed samples, as template DNA. The T. horrida was detected in 6 of the samples, indicating that 28.6% of the rice samples were contaminated with the kernel smut pathogen. This simple PCR based diagnostic assay can be applied for the direct and rapid detection and identification of T. horrida to screen large numbers of rice seed samples. PMID:27624858

  9. Simple and rapid detection of Tilletia horrida causing rice kernel smut in rice seeds.

    PubMed

    Chen, Yu; Yang, Xue; Yao, Jian; Kyaw, Ei Phyu; Zhang, Ai-Fang; Li, Yun-Fei; Gu, Chun-Yan; Zang, Hao-Yu; Gao, Tong-Chun

    2016-09-14

    A simple and rapid method for the detection of Tilletia horrida, the causal agent of rice kernel smut, in rice seeds is developed based on specific polymerase chain reaction (PCR). To design the specific primers for the detection of T. horrida, partial sequences of internal transcribed spacer (ITS) DNA region of T. horrida, T. controversa, T. walkeri, T. ehrhartae, T. indica and T. caries were analyzed and compared. A 503-bp fragment was amplified with the designed primers from the T. horrida genomic DNA. However, no PCR product was obtained from the DNA of other five Tilletia species and 22 fungal plant pathogens tested in the present work indicating the specificity of the primers for the detection of T. horrida. The PCR was performed by directly using the spores, isolated from the 21 different rice seed samples, as template DNA. The T. horrida was detected in 6 of the samples, indicating that 28.6% of the rice samples were contaminated with the kernel smut pathogen. This simple PCR based diagnostic assay can be applied for the direct and rapid detection and identification of T. horrida to screen large numbers of rice seed samples.

  10. CFGP: a web-based, comparative fungal genomics platform.

    PubMed

    Park, Jongsun; Park, Bongsoo; Jung, Kyongyong; Jang, Suwang; Yu, Kwangyul; Choi, Jaeyoung; Kong, Sunghyung; Park, Jaejin; Kim, Seryun; Kim, Hyojeong; Kim, Soonok; Kim, Jihyun F; Blair, Jaime E; Lee, Kwangwon; Kang, Seogchan; Lee, Yong-Hwan

    2008-01-01

    Since the completion of the Saccharomyces cerevisiae genome sequencing project in 1996, the genomes of over 80 fungal species have been sequenced or are currently being sequenced. Resulting data provide opportunities for studying and comparing fungal biology and evolution at the genome level. To support such studies, the Comparative Fungal Genomics Platform (CFGP; http://cfgp.snu.ac.kr), a web-based multifunctional informatics workbench, was developed. The CFGP comprises three layers, including the basal layer, middleware and the user interface. The data warehouse in the basal layer contains standardized genome sequences of 65 fungal species. The middleware processes queries via six analysis tools, including BLAST, ClustalW, InterProScan, SignalP 3.0, PSORT II and a newly developed tool named BLASTMatrix. The BLASTMatrix permits the identification and visualization of genes homologous to a query across multiple species. The Data-driven User Interface (DUI) of the CFGP was built on a new concept of pre-collecting data and post-executing analysis instead of the 'fill-in-the-form-and-press-SUBMIT' user interfaces utilized by most bioinformatics sites. A tool termed Favorite, which supports the management of encapsulated sequence data and provides a personalized data repository to users, is another novel feature in the DUI.

  11. The receptor-like cytoplasmic kinase BSR1 mediates chitin-induced defense signaling in rice cells.

    PubMed

    Kanda, Yasukazu; Yokotani, Naoki; Maeda, Satoru; Nishizawa, Yoko; Kamakura, Takashi; Mori, Masaki

    2017-08-01

    Broad-Spectrum Resistance 1 (BSR1) encodes a rice receptor-like cytoplasmic kinase, and enhances disease resistance when overexpressed. Rice plants overexpressing BSR1 are highly resistant to diverse pathogens, including rice blast fungus. However, the mechanism responsible for this resistance has not been fully characterized. To analyze the BSR1 function, BSR1-knockout (BSR1-KO) plants were generated using a clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 9 (Cas9) system. Experiments using suspension-cultured cells revealed that defense responses including H2O2 production (i.e. oxidative burst) and expression of defense-related genes induced by autoclaved conidia of the rice blast fungus significantly decreased in BSR1-KO cells. Furthermore, a treatment with chitin oligomers which function as microbe-associated molecular patterns (MAMPs) of the rice blast fungus resulted in considerably suppressed defense responses in BSR1-KO cells. These results suggest that BSR1 is important for the rice innate immunity triggered by the perception of chitin.

  12. A preliminary survey on the occurrence of mycotoxigenic fungi and mycotoxins contaminating red rice at consumer level in Selangor, Malaysia.

    PubMed

    Samsudin, Nik Iskandar Putra; Abdullah, Noorlidah

    2013-05-01

    Red rice is a fermented product of Monascus spp. It is widely consumed by Malaysian Chinese who believe in its pharmacological properties. The traditional method of red rice preparation disregards safety regulation and renders red rice susceptible to fungal infestation and mycotoxin contamination. A preliminary study was undertaken aiming to determine the occurrence of mycotoxigenic fungi and mycotoxins contamination on red rice at consumer level in Selangor, Malaysia. Fifty red rice samples were obtained and subjected to fungal isolation, enumeration, and identification. Citrinin, aflatoxin, and ochratoxin-A were quantitated by ELISA based on the presence of predominant causal fungi. Fungal loads of 1.4 × 10(4) to 2.1 × 10(6) CFU/g exceeded Malaysian limits. Monascus spp. as starter fungi were present in 50 samples (100%), followed by Penicillium chrysogenum (62%), Aspergillus niger (54%), and Aspergillus flavus (44%). Citrinin was present in 100% samples (0.23-20.65 mg/kg), aflatoxin in 92% samples (0.61-77.33 μg/kg) and Ochratoxin-A in 100% samples (0.23-2.48 μg/kg); 100% citrinin and 76.09% aflatoxin exceeded Malaysian limits. The presence of mycotoxigenic fungi served as an indicator of mycotoxins contamination and might imply improper production, handling, transportation, and storage of red rice. Further confirmatory analysis (e.g., HPLC) is required to verify the mycotoxins level in red rice samples and to validate the safety status of red rice.

  13. Molecular mapping of four blast resistance genes using recombinant inbred lines of 93-11 and nipponbare

    USDA-ARS?s Scientific Manuscript database

    Molecular mapping of new blast resistance genes is important for developing resistant rice cultivars using marker-assisted selection. In this study, 259 recombinant inbred lines (RILs) were developed from a cross between Nipponbare and 93-11, and were used to construct a 1165.8-cM linkage map with 1...

  14. Immunoregulation in Fungal Diseases

    PubMed Central

    Roussey, Jonathan A.; Olszewski, Michal A.; Osterholzer, John J.

    2016-01-01

    This review addresses specific regulatory mechanisms involved in the host immune response to fungal organisms. We focus on key cells and regulatory pathways involved in these responses, including a brief overview of their broader function preceding a discussion of their specific relevance to fungal disease. Important cell types discussed include dendritic cells and regulatory T cells, with a focus on specific studies relating to their effects on immune responses to fungi. We highlight the interleukin-10, programmed cell death 1, and cytotoxic T lymphocyte-associated protein 4 signaling pathways and emphasize interrelationships between these pathways and the regulatory functions of dendritic cells and regulatory T cells. Throughout our discussion, we identify selected studies best illustrating the role of these cells and pathways in response to specific fungal pathogens to provide a contextual understanding of the tightly-controlled network of regulatory mechanisms critical to determining the outcome of exposure to fungal pathogens. Lastly, we discuss two unique phenomena relating to immunoregulation, protective tolerance and immune reactivation inflammatory syndrome. These two clinically-relevant conditions provide perspective as to the range of immunoregulatory mechanisms active in response to fungi. PMID:27973396

  15. Fungal Burn Wound Infection

    DTIC Science & Technology

    1991-01-01

    severely limits the may prove to be useful in burn patients. Clotrimazole , applied clinical utility of such a culture. Biopsy and frozen-section and as...useful in wound and permit prompt institution of appropriate the treatment of systemic fungal infections. Clotrimazole is treatment. poorly absorbed

  16. Fungal biodegradation of lignocelluloses

    Treesearch

    Annele Hatakka; Kenneth E. Hammel

    2010-01-01

    Uncertainties in the basic structures of especially lignin but also other components in lignocellulose make fungal biodegradation studies a challenging task. The following properties are important in terms of microbial or enzymatic attack: (1) lignin polymers have compact structures that are insoluble in water and difficult to penetrate by microbes or enzymes, (2) the...

  17. Fungal rhinitis in dogs.

    PubMed

    Ostrzeszewicz, M; Sapierzyński, R

    2015-01-01

    Fungal rhinitis and sinusitis in dogs are quite common reasons of chronic nasal discharge and rhinoscopy in such cases is commonly suggested. Forty three dogs were examined using rhinoscopy because of the presence of chronic airway symptoms. Clinical examination, routine hematology and serum biochemistry profiles, nasal and frontal sinus radiographs were made in all animals. Additionally, computed tomography in one dog was performed. Samples for histopathology were taken from 9 patients during rhinoscopy, additionally, from 8 of these patients samples for cytopathology were collected by blind nasal swab technique. In 9 of 43 dogs (20,5%), all males aged 1 to 13 years, examinations led to a diagnosis of fungal rhinitis. In 2 cases a diagnosis of fungal rhinitis was obtained based solely on cytopathology, while in 7 cases - mycosis of nasal mucosa was confirmed by histopathology. The present study revealed that cytopathological examination of nasal swabs has a low diagnostic value in the case of nasal infections in dogs. Although, in some dogs cytopathology, together with other widely available diagnostic techniques was sufficient to reliably diagnose fungal rhinitis, histopathology of samples collected during rhinoscopy is still the gold standard in such cases.

  18. Mycotoxins: A fungal genomics perspective

    USDA-ARS?s Scientific Manuscript database

    The chemical and enzymatic diversity in the fungal kingdom is staggering. Large-scale fungal genome sequencing projects are generating a massive catalog of secondary metabolite biosynthetic genes and pathways. Fungal natural products are a boon and bane to man as valuable pharmaceuticals and harmful...

  19. Rice Production and Marketing.

    ERIC Educational Resources Information Center

    Briers, Gary; Lee, Jasper S.

    This guide contains lesson plans for use in secondary programs of agricultural education in geographical areas in which rice is produced. Six units and 13 problem areas are organized into teaching plans that cover the broad nature of rice production. The six units are: (1) determining the importance and history of rice production; (2) determining…

  20. [Emerging invasive fungal infections].

    PubMed

    Alvez, F; Figueras, C; Roselló, E

    2010-07-01

    The frequency and diversity of invasive fungal infections has changed over the last 25 years. The emergence of less common, but medically important fungi has increased, and the children at risk has expanded, with the inclusion of medical conditions such as cancer, mainly haematological malignancy or stem cell transplant, immunosuppressive therapy, prolonged neutropenia, and T-cell immunodeficiency. Among mould infections, fusariosis and phaeohyphomycosis (Dematiaceous fungi) have been increasingly reported in this group of patients. To successfully manage these challenging infections, it is imperative that paediatricians and sub-specialists remain aware of the optimal and timely diagnosis and therapeutic options. Unlike other common mycoses that cause human disease, there no simple antigen or serological tests available to detect these pathogens in tissue or blood. The outcome for these disseminate, and often refractory fungal infections in neutropenic patients and transplant recipients remains extremely poor, requiring early and aggressive therapy. Unfortunately there are no guidelines outlining the choices for optimal therapy in the treatment of paediatric invasive fungal infections do not exist, and on the other hand are limited paediatric data available comparing antifungal agents in children with proven, probable or suspected invasive fungal infection. The options for treatment rest mainly on some adult guidelines that comment on the treatment of these emerging and uncommon important fungi in children. Despite the sparse clinical trials available on treatment and its poor outcome, options for treatment of invasive fungal infections have increased with the advance of new antifungal agents, with improved tolerability and increased range of activity. The epidemiology, clinical manifestations, diagnosis and treatment of fusariosis and phaeohyphomycosis are discussed in this article.

  1. Overview of fungal rhinosinusitis.

    PubMed

    Chakrabarti, Arunaloke; Das, Ashim; Panda, Naresh K

    2004-10-01

    The incidence of fungal rhinosinusitis has increased to such extent in recent years that fungal infection should be considered in all patients with chronic rhino sinusitis. In India though the disease was reported earlier only from northern regions of this country, nowadays the disease is increasingly diagnosed from other parts as well. The disease has been categorized with possible five types: acute necrothing (fulminant), chronic invasive, chronic granulomatous invasive, fungal hall (sinus mycetoma), allergic. The first three types are tissue-invasive and the last two are non-invasive fungal rhinosinusitis. However, the categorization is still controversial and open to discussion. Chronic fungal rhinosinusitis can occur in otherwise healthy host and Aspergillus flavus is the common etiological agent in Indian scenario. The pathophys iologic mechanism of the disease remains unclear. It may represent an allergic IgE response, a cell-mediated reaction, or a combination of two. Early diagnosis may prevent multiple surgical procedures and lead to effective treatment. Histopathology and radio-imaging techniques help to distinguish different types and delineate extension of disease process. Culture helps to identify the responsible etiological agent. The presence or absence oj precipitating antibody correlates well with disease progression or recovery. The most immediate need regarding management is to establish the respective roles of surgery and antifungal therapy. Non-invasive disease requires surgical debridement and sinus ventilation only, though, additional oral or local corticosterold therapy may be beneficial in allergie type. For invasive disease, the adjuvant medical therapy is recommended to prevent recurrence and further extension. Itraconazole has been found as an effective drug in such situation. Patients with acute neerotizing type require radical surgery and amphotericin B therapy.

  2. High-resolution mapping of Rsn1, a locus controlling sensitivity of rice to a necrosis-inducing phytotoxin from Rhizoctonia solani AG1-IA

    USDA-ARS?s Scientific Manuscript database

    Rhizoctonia solani is a necrotrophic fungal pathogen that causes disease on all major crop-plant species. Anastomosis group 1-IA is the causal agent of sheath blight of rice (Oryza sativa), one of the most important rice diseases worldwide. R. solani AG-IA produces a necrosis-inducing phytotoxin a...

  3. Computer cast blast modelling

    SciTech Connect

    Chung, S.; McGill, M.; Preece, D.S.

    1994-07-01

    Cast blasting can be designed to utilize explosive energy effectively and economically for coal mining operations to remove overburden material. The more overburden removed by explosives, the less blasted material there is left to be transported with mechanical equipment, such as draglines and trucks. In order to optimize the percentage of rock that is cast, a higher powder factor than normal is required plus an initiation technique designed to produce a much greater degree of horizontal muck movement. This paper compares two blast models known as DMC (Distinct Motion Code) and SABREX (Scientific Approach to Breaking Rock with Explosives). DMC, applies discrete spherical elements interacted with the flow of explosive gases and the explicit time integration to track particle motion resulting from a blast. The input to this model includes multi-layer rock properties, and both loading geometry and explosives equation-of-state parameters. It enables the user to have a wide range of control over drill pattern and explosive loading design parameters. SABREX assumes that heave process is controlled by the explosive gases which determines the velocity and time of initial movement of blocks within the burden, and then tracks the motion of the blocks until they come to a rest. In order to reduce computing time, the in-flight collisions of blocks are not considered and the motion of the first row is made to limit the motion of subsequent rows. Although modelling a blast is a complex task, the DMC can perform a blast simulation in 0.5 hours on the SUN SPARCstation 10--41 while the new SABREX 3.5 produces results of a cast blast in ten seconds on a 486-PC computer. Predicted percentage of cast and face velocities from both computer codes compare well with the measured results from a full scale cast blast.

  4. Cytokinins act synergistically with salicylic acid to activate defense gene expression in rice.

    PubMed

    Jiang, Chang-Jie; Shimono, Masaki; Sugano, Shoji; Kojima, Mikiko; Liu, Xinqiong; Inoue, Haruhiko; Sakakibara, Hitoshi; Takatsuji, Hiroshi

    2013-03-01

    Hormone crosstalk is pivotal in plant-pathogen interactions. Here, we report on the accumulation of cytokinins (CK) in rice seedlings after infection of blast fungus Magnaporthe oryzae and its potential significance in rice-M. oryzae interaction. Blast infection to rice seedlings increased levels of N(6)-(Δ(2)-isopentenyl) adenine (iP), iP riboside (iPR), and iPR 5'-phosphates (iPRP) in leaf blades. Consistent with this, CK signaling was activated around the infection sites, as shown by histochemical staining for β-glucuronidase activity driven by a CK-responsive OsRR6 promoter. Diverse CK species were also detected in the hyphae (mycelium), conidia, and culture filtrates of blast fungus, indicating that M. oryzae is capable of production as well as hyphal secretion of CK. Co-treatment of leaf blades with CK and salicylic acid (SA), but not with either one alone, markedly induced pathogenesis-related genes OsPR1b and probenazole-induced protein 1 (PBZ1). These effects were diminished by RNAi-knockdown of OsNPR1 or WRKY45, the key regulators of the SA signaling pathway in rice, indicating that the effects of CK depend on these two regulators. Taken together, our data imply a coevolutionary rice-M. oryzae interaction, wherein M. oryzae probably elevates rice CK levels for its own benefits such as nutrient translocation. Rice plants, on the other hand, sense it as an infection signal and activate defense reactions through the synergistic action with SA.

  5. Improvement of nitrogen accumulation and metabolism in rice (Oryza sativa L.) by the endophyte Phomopsis liquidambari.

    PubMed

    Yang, Bo; Ma, Hai-Yan; Wang, Xiao-Mi; Jia, Yong; Hu, Jing; Li, Xia; Dai, Chuan-Chao

    2014-09-01

    The fungal endophyte Phomopsis liquidambari can enhance nitrogen (N) uptake and metabolism of rice plants under hydroponic conditions. To investigate the effects of P. liquidambari on N accumulation and metabolism in rice (Oryza sativa L.) under field conditions during the entire growing season (S1, the seedling stage; S2, the tillering stage; S3, the heading stage; S4, the ripening stage), we utilized pot experiments to examine metabolic and physiological levels in both shoot and root tissues of rice, with endophyte (E+) and without endophyte (E-), in response to three different N levels. We found that under low-N treatment, P. liquidambari symbiosis increased the rice yield and N use efficiency by 12% and by 11.59%, respectively; that the total N contents in E+ rice plants at the four growth stages were separately increased by 29.05%, 14.65%, 21.06% and 18.38%, respectively; and that the activities of nitrate reductase and glutamine synthetase in E+ rice roots and shoots were significantly increased by fungal infection during the S1 to S3 stages. Moreover, P. liquidambari significantly increased the free NH4(+), NO3(-), amino acid and soluble protein contents in infected rice tissues under low-N treatment during the S1 to S3 stages. The obtained results offer novel data concerning the systemic changes induced by P. liquidambari in rice during the entire growth period and confirm the hypothesis that the rice-P. liquidambari interaction improved the N accumulation and metabolism of rice plants, consequently increasing rice N utilization in nutrient-limited soil. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  6. Functional analysis of rice NPR1-like genes reveals that OsNPR1/NH1 is the rice orthologue conferring disease resistance with enhanced herbivore susceptibility.

    PubMed

    Yuan, Yuexing; Zhong, Sihui; Li, Qun; Zhu, Zengrong; Lou, Yonggen; Wang, Linyou; Wang, Jianjun; Wang, Muyang; Li, Qiaoli; Yang, Donglei; He, Zuhua

    2007-03-01

    The key regulator of salicylic acid (SA)-mediated resistance, NPR1, is functionally conserved in diverse plant species, including rice (Oryza sativa L.). Investigation in depth is needed to provide an understanding of NPR1-mediated resistance and a practical strategy for the improvement of disease resistance in the model crop rice. The rice genome contains five NPR1-like genes. In our study, three rice homologous genes, OsNPR1/NH1, OsNPR2/NH2 and OsNPR3, were found to be induced by rice bacterial blight Xanthomonas oryzae pv. oryzae and rice blast Magnaporthe grisea, and the defence molecules benzothiadiazole, methyl jasmonate and ethylene. We confirmed that OsNPR1 is the rice orthologue by complementing the Arabidopsis npr1 mutant. Over-expression of OsNPR1 conferred disease resistance to bacterial blight, but also enhanced herbivore susceptibility in transgenic plants. The OsNPR1-green fluorescent protein (GFP) fusion protein was localized in the cytoplasm and moved into the nucleus after redox change. Mutations in its conserved cysteine residues led to the constitutive localization of OsNPR1(2CA)-GFP in the nucleus and also abolished herbivore hypersensitivity in transgenic rice. Different subcellular localizations of OsNPR1 antagonistically regulated SA- and jasmonic acid (JA)-responsive genes, but not SA and JA levels, indicating that OsNPR1 might mediate antagonistic cross-talk between the SA- and JA-dependent pathways in rice. This study demonstrates that rice has evolved an SA-mediated systemic acquired resistance similar to that in Arabidopsis, and also provides a practical approach for the improvement of disease resistance without the penalty of decreased herbivore resistance in rice.

  7. Cerebrovascular Injury in Blast Loading

    DTIC Science & Technology

    2010-01-01

    TITLE: Cerebrovascular injury in blast loading PRINCIPAL INVESTIGATOR: Kenneth L. Monson, PhD...SUBTITLE Cerebrovascular injury in blast loading 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH-08-1-0295 5c. PROGRAM ELEMENT NUMBER 6...and pH control. 15. SUBJECT TERMS Blast brain injury; cerebrovascular injury and dysfunction; shock tube 16. SECURITY CLASSIFICATION OF: 17

  8. Research in rice fields

    USGS Publications Warehouse

    ,

    2000-01-01

    Between 1987 and 1999, 2.4-3 million acres of rice were planted annually nationwide. Rice fields are a major component of the contemporary landscapes in the Gulf Coastal Plain, the Mississippi Alluvial Valley, and Central Valley of California. In 1998, approximately 600,000 acres of rice were planted in Louisiana. In the Louisiana plant commodities report for 1998, total value for rice was over $350 million; sugarcane was the only plant commodity that exceeded this value. Louisiana has over 2,000 rice farmers supporting over 12,000 jobs in the state. Rice fields in the United States receive high use by wildlife, especially shorebirds, wading birds, and waterfowl. Waterbirds use rice fields for food, shelter, and breeding habitat.

  9. Unusual fungal niches.

    PubMed

    Cantrell, S A; Dianese, J C; Fell, J; Gunde-Cimerman, N; Zalar, P

    2011-01-01

    Fungi are found in all aerobic ecosystems, colonizing a diversity of substrates and performing a wide diversity of functions, some of which are not well understood. Many spices of fungi are cosmopolitan and generalists or habitats. Unus