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1

Dominant gene for common bean resistance to common bacterial blight caused by Xanthomonas axonopodis pv. phaseoli  

Microsoft Academic Search

The common bacterial blight pathogen [Xanthomonas axonopodis pv. phaseoli (Xap)] is a limiting factor for common bean (Phaseolus vulgaris L.) production worldwide and resistance to the pathogen in most commercial cultivars is inadequate. Variability in virulence\\u000a of the bacterial pathogen has been observed in strains isolated from Puerto Rico and Central America. A few common bean lines\\u000a show a differential

Mildred Zapata; James S. Beaver; Timothy G. Porch

2011-01-01

2

The genome sequence of Xanthomonas oryzae pathovar oryzae KACC10331, the bacterial blight pathogen of rice  

Microsoft Academic Search

The nucleotide sequence was determined for the genome of Xanthomonas oryzae pathovar oryzae (Xoo) KACC10331, a bacterium that causes bacterial blight in rice (Oryza sativa L.). The genome is com- prised of a single, 4 941 439 bp, circular chromosome that is G 1 C rich (63.7%). The genome includes 4637 open reading frames (ORFs) of which 3340 (72.0%) could

Byoung-Moo Lee; Young-Jin Park; Dong-Suk Park; Hee-Wan Kang; Jeong-Gu Kim; Eun-Sung Song; In-Cheol Park; Ung-Han Yoon; Jang-Ho Hahn; Bon-Sung Koo; Gil-Bok Lee; Hyungtae Kim; Hyun-Seok Park; Kyong-Oh Yoon; Jeong-Hyun Kim; Chol-hee Jung; Nae-Hyung Koh; Jeong-Sun Seo; Seung-Joo Go

2005-01-01

3

Involvement of catalase in bacterial Blight disease development of rice caused by Xanthomonas oryzae pv. oryzae  

Microsoft Academic Search

We investigated the role of catalase in determining the virulence of Xanthomonas oryzae pv. oryzae isolates and the reaction of different rice cultivars to virulent isolates. Catalase, being an antioxidant enzyme, plays a major role in combating the toxic effect of reactive oxygen species (ROS) in plant cells. Among the 11 isolates studied, a variable level of catalase activity and

M. S. Choodamani; P. Hariprasad; M. K. Sateesh; S. Umesha

2009-01-01

4

Single Cell Culture of Xanthomonas Oryzae (Uyeda et Ishiyama) Dowson, The Casual Organism of Bacterial Leaf Blight of Rice Plant.  

National Technical Information Service (NTIS)

Various culture media were investigated for the purpose of single cell isolation of Xanthomonas oryzae. Colony formation from single cells in the case of a potato ring-rot medium supplemented with a hot water extract of the bacterial cells, rice seedling ...

T. Suwa

1969-01-01

5

Testing the model for a dominant resistance gene expresed on leaves of Phaseolus vulgaris F2 (0313-58 X Rosada Nativa) to the common bacterial blight pathogen, Xanthomonas axonopodis pv. Phaseoli  

Technology Transfer Automated Retrieval System (TEKTRAN)

The common bean bacterial blight pathogen, Xanthomonas axonopodis pv. phaseoli, is a limiting factor for bean, Phaseolus vulgaris, production worldwide and resistance to the pathogen in commercial varieties is inadequate. To test the hypothesis of the presence of strain specific genes for resistance...

6

Evaluating the effects of cold water diffusates against Xanthomonas oryzae Pv. Oryzae causing bacterial leaf blight (BLB) in rice  

Microsoft Academic Search

The crude extracts of 63 plants were used for testing antibacterial activity against Xanthmonas oryazae Pv. oryzae that causes bacterial leaf blight (BLB) in rice plants. Only ten aqueous extracts of botanicals (Thuja orientalis, Prunus domestica, Citrus limon, Allium sativum, Vitis vinefera, Mangifera indica, Phyllanthus emblica, and Terminalia chebula) showed maximum activity against Xanthmonas oryazae in a plate agar diffusion

Rukhsana Jabeen; Muhammad Ashraf; Iftikhar Ahmad

2009-01-01

7

MARKER AIDED BREEDING FOR RESISTANCE TO COMMON BACTERIAL BLIGHT IN COMMON BEAN  

Technology Transfer Automated Retrieval System (TEKTRAN)

Common bacterial blight caused by Xanthomonas axonopodis pv. phaseoli is a serious seedborne disease limiting common bean production worldwide. Genetic resistance is the most important component of integrated strategies including planting pathogen-free seed, crop rotation, and chemical applications,...

8

Registration of Common Bacterial Blight Resistant White Kidney Bean Germplasm Line USWK-CBB-17  

Technology Transfer Automated Retrieval System (TEKTRAN)

White kidney bean germplasm line USWK-CBB-17 was developed by USDA-ARS in cooperation with the Idaho Agricultural Experiment Station and released in 2006. This line was bred with a high level of resistance to common bacterial blight caused by Xanthomonas axonopodis pv. phaseoli (Xap). Common bacteri...

9

Sensitive detection of Xanthomonas axonopodis pv. dieffenbachiae on Anthurium andreanum by immunocapture-PCR (IC-PCR) using primers designed from sequence characterized amplified regions (SCAR) of the blight pathogen  

Microsoft Academic Search

One of the most devastating Xanthomonas diseases affecting the Anthurium cut flower industry worldwide is the bacterial blight caused by Xanthomonas axonopodis pv. dieffenbachiae (Xad). The disease can be spread through latently infected tissue-cultured plants that are used for the propagation of Anthurium worldwide. Current disease diagnostic techniques involve the use of semi-selective media and serological tests. This study describes

M. H. R. Khoodoo; F. Sahin; Y. Jaufeerally-Fakim

2005-01-01

10

Microarray analysis of the semi-compatible pathogenic response and recovery of leafy spurge inoculated with the Cassava bacterial blight pathogen Xanthomonas axonopodis pv. manihotis  

Technology Transfer Automated Retrieval System (TEKTRAN)

Infection by Xanthomonas axonopodis pv. manihotis (Xam)of the model perennial range land weed leafy spurge was tested to see if Xam might serve a potential biological control agent for this invasive weed. Although leafy spurge was susceptible to Xam infection, it recovered with 21 days after inocula...

11

Gamete Selection for Resistance to Common and Halo Bacterial Blights in Dry Bean Intergene Pool Populations  

Microsoft Academic Search

The common (caused by Xanthomonas campestris pv. phaseoli (Smith) Dye (Xcp) and X. campestris pv. phaseoli var. fuscans (Xcpf)) and halo bacterial blights (caused by Pseudomonas syringae pv. phase- olicola (Burkh.) Young et al. (Psp)) are seed-borne diseases that cause severe yield losses in dry and snap bean (Phaseolus vulgaris L.) worldwide. Use of cultivars resistant to these diseases is

M. Carmen Asensio-S.-Manzanera; Carmen Asensio; Shree P. Singh

2006-01-01

12

RELEASE OF COMMON BACTERIAL BLIGHT RESISTANT DARK RED KIDNEY BEAN GERMPLASM LINE USDK-CBB-15  

Technology Transfer Automated Retrieval System (TEKTRAN)

The Agricultural Research Service, U.S. Department of Agriculture, and the Idaho Agricultural Experiment Station announce the release of USDK-CBB-15 dark red kidney (Phaseolus vulgaris L.) germplasm line with a high level of resistance to common bacterial blight caused by Xanthomonas axonopodis pv. ...

13

EFFECT OF NITROGEN FERTILIZATION AND SEED CONTAMINATION ON EPIPHYTIC POPULATIONS OF XANTHOMONAS AXONOPODIS PV. ALLII AND DEVELOPMENT OF XANTHOMONAS LEAF BLIGHT OF ONION  

Technology Transfer Automated Retrieval System (TEKTRAN)

Xanthomonas leaf blight of onion, caused by Xanthomonas axonopodis pv. allii, is a yield-limiting disease in Colorado, for which few effective management strategies are available. The effects of rates of nitrogen fertilization and levels of seed contamination by X. axonopodis pv. allii on epiphytic...

14

Controlling rice bacterial blight in Africa: needs and prospects.  

PubMed

Rice cultivation has drastically increased in Africa over the last decade. During this time, the region has also seen a rise in the incidence of rice bacterial blight caused by the pathogen Xanthomonas oryzae pv. oryzae. The disease is expanding to new rice production areas and threatens food security in the region. Yield losses caused by X. oryzae pv. oryzae range from 20 to 30% and can be as high as 50% in some areas. Employing resistant cultivars is the most economical and effective way to control this disease. To facilitate development and strategic deployment of rice cultivars with resistance to bacterial blight, biotechnology tools and approaches, including marker-assisted breeding, gene combinations for disease control, and multiplex-PCR for pathogen diagnosis, have been developed. Although these technologies are routinely used elsewhere, their application in Africa remains limited, usually due to high cost and advanced technical skills required. To combat this problem, developers of the technologies at research institutions need to work with farmers from an early stage to create and promote the integration of successful, low cost applications of research biotech products. Here, we review the current knowledge and biotechnologies available to improve bacterial blight control. We will also discuss how to facilitate their application in Africa and delivery to the field. PMID:21963588

Verdier, Valérie; Vera Cruz, Casiana; Leach, Jan E

2011-09-22

15

Identification of a 47-kb DNA fragment containing Xa4 , a locus for bacterial blight resistance in rice  

Microsoft Academic Search

Bacterial blight caused by Xanthomonas oryzae pv oryzae is a devastating disease in rice worldwide. The resistance gene Xa4 has been widely used in breeding programs and played an important role in protecting rice from this disease. Using 642 highly susceptible individuals and a random sample of 255 individuals from an F2 population developed from a cross between IRBB4 and

X. Sun; Z. Yang; S. Wang; Q. Zhang

2003-01-01

16

Suppression of Bacterial Blight by a Bacterial Community Isolated from the Guttation Fluids of Anthuriums†  

PubMed Central

Growth and survival of Xanthomonas campestris pv. dieffenbachiae in guttation fluids (xylem sap exuded from leaf margins) of anthuriums were suppressed by several bacterial strains indigenous to leaves of various anthurium cultivars. Inhibition of growth was not observed in filter-sterilized guttation fluids and was restored to original levels only by reintroducing specific mixtures of bacteria into filter-sterilized guttation fluids. The inhibitory effect was related to the species in the bacterial community rather than to the total numbers of bacteria in the guttation fluids. One very effective bacterial community consisted of five species isolated from inhibitory guttation fluids of two susceptible anthurium cultivars. The individual strains in this community had no effect on the pathogen, but the mixture was inhibitory to X. campestris pv. dieffenbachiae in guttation fluids. The populations of the individual strains remained near the initial inoculum levels for at least 14 days. The effect of the five inhibitory strains on reducing disease in susceptible anthurium plants was tested by using a bioluminescent strain of X. campestris pv. dieffenbachiae to monitor the progression of disease in leaves nondestructively. Invasion of the pathogen through hydathodes at leaf margins was reduced by applying the strain mixture to the leaves. When the strain mixture was applied directly to wounds created on the leaf margins, the pathogen failed to invade through the wounds. This bacterial community has potential for biological control of anthurium blight.

Fukui, R.; Fukui, H.; Alvarez, A. M.

1999-01-01

17

Contamination of bean seeds by Xanthomonas axonopodis pv. phaseoli associated with low bacterial densities in the phyllosphere under field and greenhouse conditions  

Microsoft Academic Search

Xanthomonas axonopodis pv. phaseoli and its variant fuscans are the causal agents of common bacterial blight of bean. Production of seeds is recommended in arid climates with the use\\u000a of pathogen-free seeds. However, contamination of seeds still occurs in these seed production areas. To verify if low contamination\\u000a levels of sown seeds could explain these field contaminations, we used seeds

Armelle Darrasse; Christine Bureau; Régine Samson; Cindy E. Morris; Marie-Agnès Jacques

2007-01-01

18

Expression of Xa1, a bacterial blight-resistance gene in rice, is induced by bacterial inoculation  

PubMed Central

The Xa1 gene in rice confers resistance to Japanese race 1 of Xanthomonas oryzae pv. oryzae, the causal pathogen of bacterial blight (BB). We isolated the Xa1 gene by a map-based cloning strategy. The deduced amino acid sequence of the Xa1 gene product contains nucleotide binding sites (NBS) and a new type of leucine-rich repeats (LRR); thus, Xa1 is a member of the NBS-LRR class of plant disease-resistance genes, but quite different from Xa21, another BB-resistance gene isolated from rice. Interestingly, Xa1 gene expression was induced on inoculation with a bacterial pathogen and wound, unlike other isolated resistance genes in plants, which show constitutive expression. The induced expression may be involved in enhancement of resistance against the pathogen.

Yoshimura, Satomi; Yamanouchi, Utako; Katayose, Yuichi; Toki, Seiichi; Wang, Zi-Xuan; Kono, Izumi; Kurata, Nori; Yano, Masahiro; Iwata, Nobuo; Sasaki, Takuji

1998-01-01

19

A benefit of high temperature: increased effectiveness of a rice bacterial blight disease resistance gene.  

PubMed

*Continuous planting of crops containing single disease resistance (R) genes imposes a strong selection for virulence in pathogen populations, often rendering the R gene ineffective. Increasing environmental temperatures may complicate R-gene-mediated disease control because high temperatures often promote disease development and reduce R gene effectiveness. Here, performance of one rice bacterial blight disease R gene was assessed in field and growth chamber studies to determine the influence of temperature on R gene effectiveness and durability. *Disease severity and virulence of Xanthomonas oryzae pv. oryzae (Xoo) populations were monitored in field plots planted to rice with and without the bacterial blight R gene Xa7 over 11 yr. The performance of Xa7 was determined in high- and low-temperature regimes in growth chambers. *Rice with Xa7 exhibited less disease than lines without Xa7 over 11 yr, even though virulence of Xoo field populations increased. Xa7 restricted disease more effectively at high than at low temperatures. Other R genes were less effective at high temperatures. *We propose that Xa7 restricts disease and Xoo population size more efficiently in high temperature cropping seasons compared with cool seasons creating fluctuating selection, thereby positively impacting durability of Xa7. PMID:19878463

Webb, K M; Oña, I; Bai, J; Garrett, K A; Mew, T; Vera Cruz, C M; Leach, J E

2009-10-29

20

The Bacterial Pathogen Xanthomonas oryzae Overcomes Rice Defenses by Regulating Host Copper Redistribution[W][OA  

PubMed Central

Pathogen effectors are virulence factors causing plant diseases. How the host targets of these effectors facilitate pathogen infection is largely unknown. An effector of Xanthomonas oryzae pv oryzae (Xoo) transcriptionally activates rice (Oryza sativa) susceptibility gene Xa13 to cause bacterial blight disease. Xa13 encodes an indispensable plasma membrane protein of the MtN3/saliva family, which is prevalent in eukaryotes with unknown biochemical function. We show that the XA13 protein cooperates with two other proteins, COPT1 and COPT5, to promote removal of copper from xylem vessels, where Xoo multiplies and spreads to cause disease. Copper, an essential micronutrient of plants and an important element for a number of pesticides in agriculture, suppresses Xoo growth. Xoo strain PXO99 is more sensitive to copper than other strains; its infection of rice is associated with activation of XA13, COPT1, and COPT5, which modulate copper redistribution in rice. The involvement of XA13 in copper redistribution has led us to propose a mechanism of bacterial virulence.

Yuan, Meng; Chu, Zhaohui; Li, Xianghua; Xu, Caiguo; Wang, Shiping

2010-01-01

21

Suppression of the Bacterial Spot Pathogen Xanthomonas euvesicatoria on Tomato Leaves by an Attenuated Mutant of Xanthomonas perforans  

Microsoft Academic Search

A bacteriocin-producing strain of the bacterial spot of tomato plant pathogen, Xanthomonas perforans, with attenuated pathogenicity was deployed for biocontrol of a bacteriocin-sensitive strain of the genetically closely related bacterial spot of tomato plant pathogen, X. euvesicatoria. The attenuated mutant (91-118opgHbcnB) of X. perforans was tested in leaf tissue and shown to significantly inhibit internal populations of the wild-type X.

A. P. Hert; M. Marutani; M. T. Momol; P. D. Roberts; S. M. Olson; J. B. Jones

2009-01-01

22

A SNP Haplotype Associated with a gene resistant to Xanthomonas axonopodis pv. malvacearum in Upland Cotton (Gossyium hirsutum L.)  

Technology Transfer Automated Retrieval System (TEKTRAN)

An F5 population of 285 families with each tracing back to a different F2 plant , derived from a cotton bacterial blight resistant line ‘DeltaOpal’ and a susceptible line ‘DP388’, was artificially inoculated with bacterial blight race 18 (Xanthomonas campestris pv. Malvacearum) to assay their resist...

23

Characterization of the pigment xanthomonadin in the bacterial genus Xanthomonas using micro- and resonance Raman spectroscopy  

NASA Astrophysics Data System (ADS)

We used micro- and resonance Raman spectroscopy with 785 nm and 514.5 nm laser excitation, respectively, to characterize a plant pathogenic bacteria, Xanthomonas axonopodis pv. dieffenbachiae D150. The bacterial genus Xathomonas is closely related to bacterial genus Stenotrophomonas that causes an infection in humans. This study has identified for the first time the unique Raman spectra of the carotenoid-like pigment xanthomonadin of the Xanthomonas strain. Xanthomonadin is a brominated aryl-polyene pigment molecule similar to carotenoids. Further studies were conducted using resonance Raman spectroscopy with 514.5 nm laser excitation on several strains of the bacterial genus Xanthomonas isolated from numerous plants from various geographical locations. The current study revealed that the Raman bands representing the vibrations (v1, v2, v3) of the polyene chain of xanthomonadin are 1003-1005 (v3), 1135-1138 (v2), and 1530 (v1). Overtone bands representing xanthomonadin were identified as 2264-2275 (2v2), and combinational bands at 2653-2662 (v1+ v2). The findings from this study validate our previous finding that the Raman fingerprints of xanthomonadin are unique for the genus Xanthomonas. This facilitates rapid identification (~5 minutes) of Xanthomonas spp. from bacterial culture plates. The xanthomonadin marker is different from Raman markers of many other bacterial genus including Agrobacterium, Bacillus, Clavibacter, Enterobacter, Erwinia, Microbacterium, Paenibacillus, and Ralstonia. This study also identified Xanthomonas spp. from bacterial strains isolated from a diseased wheat sample on a culture plate.

Paret, Mathews L.; Sharma, Shiv K.; Misra, Anupam K.; Acosta, Tayro; deSilva, Asoka S.; Vowell, Tomie; Alvarez, Anne M.

2012-05-01

24

Epidemiological study of hazelnut bacterial blight in central Italy by using laboratory analysis and geostatistics.  

PubMed

Incidence of Xanthomonas arboricola pv. corylina, the causal agent of hazelnut bacterial blight, was analyzed spatially in relation to the pedoclimatic factors. Hazelnut grown in twelve municipalities situated in the province of Viterbo, central Italy was studied. A consistent number of bacterial isolates were obtained from the infected tissues of hazelnut collected in three years (2010-2012). The isolates, characterized by phenotypic tests, did not show any difference among them. Spatial patterns of pedoclimatic data, analyzed by geostatistics showed a strong positive correlation of disease incidence with higher values of rainfall, thermal shock and soil nitrogen; a weak positive correlation with soil aluminium content and a strong negative correlation with the values of Mg/K ratio. No correlation of the disease incidence was found with soil pH. Disease incidence ranged from very low (<1%) to very high (almost 75%) across the orchards. Young plants (4-year old) were the most affected by the disease confirming a weak negative correlation of the disease incidence with plant age. Plant cultivars did not show any difference in susceptibility to the pathogen. Possible role of climate change on the epidemiology of the disease is discussed. Improved management practices are recommended for effective control of the disease. PMID:23424654

Lamichhane, Jay Ram; Fabi, Alfredo; Ridolfi, Roberto; Varvaro, Leonardo

2013-02-12

25

PATHOGENICITY OF XANTHOMONAS AXONOPODIS PV. GLYCINES, THE CAUSATIVE AGENT OF BACTERIAL PUSTULE IN SOYEANS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Xanthomonas axonopodis pv. glycines is the casual agent of bacterial pustule of soybean (Glycine max [L.] Merr). Bacterial pustule is a prevalent disease in many soybean-growing areas, especially in countries such as Brazil, China and India where it can cause yield losses of up to 40%. X. axonopodis...

26

Sustainable control of pea bacterial blight : approaches for durable genetic resistance and biocontrol by endophytic bacteria  

Microsoft Academic Search

Key-words: bacterial blight, biological control, biodiversity, endophytic bacteria, L-form, pea, PDRl retrotransposon, Pisum sativum, Pisum abyssinicum, Pseudomonas syringae pv. pisi, race specific resistance, race non-specific resistance, Spanish landraces.<\\/font>Pea bacterial blight (Pseudomonas syringae pv. pisi) occurs worldwide and can cause severe damage under cool and wet conditions particularly at the seedling stage in wintersown crops. Seven Ps. syr. pv. pisi races

M. Elvira-Recuenco

2000-01-01

27

Biological control of bacterial spot of tomato using hrp mutants of Xanthomonas campestris pv. vesicatoria  

Microsoft Academic Search

Xanthomonas campestris pv. vesicatoria strain 75-3 hrpG, hrpX, hrpF and hrpE1 mutants were evaluated for control of bacterial spot of tomato under both greenhouse and field conditions. In greenhouse studies, the 75-3 hrp mutants were spray-inoculated onto tomato foliage 48h prior to inoculation of the wild-type pathogen, X. campestris pv. vesicatoria 75-3, and bacterial spot severity was assessed 10 days

W. P. Moss; J. M. Byrne; H. L. Campbell; P. Ji; U. Bonas; J. B. Jones; M. Wilson

2007-01-01

28

BACTERIAL RESISTANCE IMPROVEMENT IN DRY BEANS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Common bacterial blight (CBB) (Xanthomonas axonopodis pv. phaseoli) and halo blight (HB) (Pseudomonas savastanoi pv. phaseolicola) are serious seedborne diseases of dry beans. These diseases are widely distributed throughout the bean producing areas in South Africa and can cause severe yield and see...

29

Involvement of OsJAZ8 in jasmonate-induced resistance to bacterial blight in rice.  

PubMed

The plant hormone jasmonic acid (JA) has a crucial role in both host immunity and development in plants. Here, we report the importance of JA signaling in the defense system of rice. Exogenous application of JA conferred resistance to bacterial blight caused by Xanthomonas oryzae pv. oryzae (Xoo) in rice. Expression of OsJAZ8, a rice jasmonate ZIM-domain protein, was highly up-regulated by JA. OsJAZ8 interacted with a putative OsCOI1, which is a component of the SCF(COI1) E3 ubiquitin ligase complex, in a coronatine-dependent manner. OsJAZ8 also formed heterodimers with other OsJAZ proteins but did not form homodimer. JA treatment caused OsJAZ8 degradation and this degradation was dependent on the 26S proteasome pathway. Furthermore, the JA-dependent OsJAZ8 degradation was mediated by the Jas domain. Transgenic rice plants overexpressing OsJAZ8?C, which lacks the Jas domain, exhibited a JA-insensitive phenotype. A large-scale analysis using a rice DNA microarray revealed that overexpression of OsJAZ8?C altered the expression of JA-responsive genes, including defense-related genes, in rice. Furthermore, OsJAZ8?C negatively regulated the JA-induced resistance to Xoo in rice. On the basis of these data, we conclude that JA plays an important role in resistance to Xoo, and OsJAZ8 acts as a repressor of JA signaling in rice. PMID:23104764

Yamada, Shoko; Kano, Akihito; Tamaoki, Daisuke; Miyamoto, Ayumi; Shishido, Hodaka; Miyoshi, Seika; Taniguchi, Shiduku; Akimitsu, Kazuya; Gomi, Kenji

2012-10-26

30

Suppression of the Bacterial Spot Pathogen Xanthomonas euvesicatoria on Tomato Leaves by an Attenuated Mutant of Xanthomonas perforans?  

PubMed Central

A bacteriocin-producing strain of the bacterial spot of tomato plant pathogen, Xanthomonas perforans, with attenuated pathogenicity was deployed for biocontrol of a bacteriocin-sensitive strain of the genetically closely related bacterial spot of tomato plant pathogen, X. euvesicatoria. The attenuated mutant (91-118?opgH?bcnB) of X. perforans was tested in leaf tissue and shown to significantly inhibit internal populations of the wild-type X. euvesicatoria strain although significantly less than the wild-type 91-118 strain, whereas in a phyllosphere inhibition assay, the mutant strain reduced epiphytic populations comparably to 91-118. Thus, the attenuated mutant limited the sensitive bacterium more efficiently on the leaf surface than inside the leaf. In field experiments, weekly application of 91-118?opgH?bcnB significantly reduced X. euvesicatoria populations compared to the growers’ standard control (copper hydroxide and mancozeb applied weekly and acibenzolar-S-methyl applied every 2 weeks). The biological control agent, 91-118?opgH?bcnB, applied every 2 weeks also significantly reduced X. euvesicatoria populations in one season but was not significantly different from the growers’ standard control. Potentially, attenuated pathogenic strains could be deployed as biological control agents in order to improve disease control of foliar plant pathogens.

Hert, A. P.; Marutani, M.; Momol, M. T.; Roberts, P. D.; Olson, S. M.; Jones, J. B.

2009-01-01

31

Suppression of the bacterial spot pathogen Xanthomonas euvesicatoria on tomato leaves by an attenuated mutant of Xanthomonas perforans.  

PubMed

A bacteriocin-producing strain of the bacterial spot of tomato plant pathogen, Xanthomonas perforans, with attenuated pathogenicity was deployed for biocontrol of a bacteriocin-sensitive strain of the genetically closely related bacterial spot of tomato plant pathogen, X. euvesicatoria. The attenuated mutant (91-118DeltaopgHDeltabcnB) of X. perforans was tested in leaf tissue and shown to significantly inhibit internal populations of the wild-type X. euvesicatoria strain although significantly less than the wild-type 91-118 strain, whereas in a phyllosphere inhibition assay, the mutant strain reduced epiphytic populations comparably to 91-118. Thus, the attenuated mutant limited the sensitive bacterium more efficiently on the leaf surface than inside the leaf. In field experiments, weekly application of 91-118DeltaopgHDeltabcnB significantly reduced X. euvesicatoria populations compared to the growers' standard control (copper hydroxide and mancozeb applied weekly and acibenzolar-S-methyl applied every 2 weeks). The biological control agent, 91-118DeltaopgHDeltabcnB, applied every 2 weeks also significantly reduced X. euvesicatoria populations in one season but was not significantly different from the growers' standard control. Potentially, attenuated pathogenic strains could be deployed as biological control agents in order to improve disease control of foliar plant pathogens. PMID:19286785

Hert, A P; Marutani, M; Momol, M T; Roberts, P D; Olson, S M; Jones, J B

2009-03-13

32

Development of candidate gene markers associated to common bacterial blight resistance in common bean.  

PubMed

Common bacterial blight (CBB), caused by Xanthomonas axonopodis pv. phaseoli (Xap), is a major yield-limiting factor of common bean (Phaseolus vulgaris L.) production around the world. Two major CBB-resistant quantitative trait loci (QTL), linked to the sequence characterized amplified region markers BC420 and SU91, are located at chromosomes 6 and 8, respectively. Using map-based cloning approach, four bacterial artificial chromosome (BAC) clones from the BC420-QTL locus and one BAC clone containing SU91 were sequenced by Roche 454 technique and subsequently assembled using merged assemblies from three different programs. Based on the quality of the assembly, only the sequences of BAC 32H6 and 4K7 were used for candidate gene marker (CGM) development and candidate gene (CG) selection. For the BC420-QTL locus, 21 novel genes were predicted in silico by FGENESH using Medicago gene model, whereas 16 genes were identified in the SU91-QTL locus. For each putative gene, one or more primer pairs were designed and tested in the contrasting near isogenic lines. Overall, six and nine polymorphic markers were found in the SU91- and BC420-QTL loci, respectively. Afterwards, association mapping was conducted in a breeding population of 395 dry bean lines to discover marker-trait associations. Two CGMs per each locus showed better association with CBB resistance than the BC420 and SU91 markers, which include BC420-CG10B and BC420-CG14 for BC420_QTL locus, and SU91-CG10 and SU91-CG11 for SU91_QTL locus. The strong associations between CBB resistance and the CGs 10 and 14 from BC420_QTL locus and the CGs 10 and 11 from SU91_QTL locus indicate that the genes 10 and 14 from the BC420 locus are potential CGs underlying the BC420_QTL locus, whereas the genes 10 and 11 from the SU91 locus are potential CGs underlying the SU91_QTL locus. The superiority of SU91-CG11 was further validated in a recombinant inbred line population Sanilac × OAC 09-3. Thus, co-dominant CGMs, BC420-CG14 and SU91-CG11, are recommended to replace BC420 and SU91 for marker-assisted selection of common bean with resistance to CBB. PMID:22798059

Shi, Chun; Yu, Kangfu; Xie, Weilong; Perry, Gregory; Navabi, Alireza; Pauls, K Peter; Miklas, Phillip N; Fourie, Deidré

2012-07-14

33

Recent progress in the characterization of molecular determinants in the Xanthomonas axonopodis pv. manihotis –cassava interaction  

Microsoft Academic Search

Cassava bacterial blight, caused by Xanthomonas axonopodis pv. manihotis (Xam), is a widespread disease that affects cassava (Manihot esculenta Crantz). Studies on the pathogen population structure, pathogen diagnosis, identification and expression of plant genes involved in resistance have been carried out. Different molecular techniques were developed to assess the genetic diversity among the Xampopulations. Characterization of Xam population dynamics over

Valérie Verdier; Silvia Restrepo; Gloria Mosquera; Véronique Jorge; Camilo Lopez

2004-01-01

34

High-Quality Draft Genome Sequences of Two Xanthomonas citri pv. malvacearum Strains  

PubMed Central

We report high-quality draft genome sequences of two strains (race 18 and 20) of Xanthomonas citri pv. malvacearum, the causal agent of bacterial blight of cotton. Comparative genomics will help to decipher mechanisms provoking disease and triggering defense responses and to develop new molecular tools for epidemiological surveillance.

Cunnac, Sebastien; Bolot, Stephanie; Forero Serna, Natalia; Ortiz, Erika; Szurek, Boris; Noel, Laurent D.; Arlat, Matthieu; Jacques, Marie-Agnes; Gagnevin, Lionel; Carrere, Sebastien; Nicole, Michel

2013-01-01

35

An efficient method for visualization and growth of fluorescent Xanthomonas oryzae pv. oryzae in planta  

Microsoft Academic Search

BACKGROUND: Xanthomonas oryzae pv. oryzae, the causal agent of bacterial blight disease, is a serious pathogen of rice. Here we describe a fluorescent marker system to study virulence and pathogenicity of X. oryzae pv. oryzae. RESULTS: A fluorescent X. oryzae pv. oryzae Philippine race 6 strain expressing green fluorescent protein (GFP) (PXO99GFP) was generated using the gfp gene under the

Sang-Wook Han; Chang-Jin Park; Sang-Won Lee; Pamela C Ronald

2008-01-01

36

Rubber-degrading enzyme from a bacterial culture. [Xanthomonas sp  

SciTech Connect

Rubber-degrading activity was found in the extracellular culture medium of Xanthomonas sp. strain 35Y which was grown on natural rubber latex. Natural rubber in the latex state was degraded by the crude enzyme, and two fractions were separately observed by gel permeation chromatography of the reaction products. One fraction was of higher molecular weight (HMW) with a very wide MW distribution from 10{sup 3} to 10{sup 5}, and the other fraction was of lower molecular weight (LMW) with a MW of a few hundred. {sup 1}H-nuclear magnetic resonance spectra of the partially purified fractions were those expected of cis-1,4-polyisoprene mixtures with the structure OHC-CH{sub 2}-(-CH{sub 2}-C(-CH{sub 3})=CH-CH{sub 2}-){sub n}-CH{sub 2}-C(=O)-CH{sub 3}, with average values of n of about 113 and 2 for HMW and LMW fractions, respectively. The LMW fraction consisted mostly of one component in gas-liquid chromatography as well as in gel permeation chromatography, and the main component was identified as 12-oxo-4,8-dimethyl trideca-4,8-diene-1-al (acetonyl diprenyl acetoaldehyde, A{sub L}P{sub 2}A{sub t}) by {sup 13}C-nuclear magnetic resonance and gas chromatography-mass spectra. Not only the lattices of natural and synthetic isoprene rubber, but also some kinds of low-MW polyisoprene compounds of cis-1,4 type, were degraded by the crude enzyme. The rubber-degrading reaction was found to be at least partly oxygenase catalyzed from the incorporation of {sup 18}O into A{sub L}P{sub 2}A{sub t} under an {sup 18}O{sub 2} atmosphere.

Tsuchii, A.; Takeda, K. (Fermentation Research Institute, Tsukuba (Japan))

1990-01-01

37

Association mapping of common bacterial blight resistance QTL in Ontario bean breeding populations  

PubMed Central

Background Common bacterial blight (CBB), incited by Xanthomonas axonopodis pv. phaseoli (Xap), is a major yield-limiting factor of common bean (Phaseolus vulgaris L.) production around the world. Host resistance is practically the most effective and environmentally-sound approach to control CBB. Unlike conventional QTL discovery strategies, in which bi-parental populations (F2, RIL, or DH) need to be developed, association mapping-based strategies can use plant breeding populations to synchronize QTL discovery and cultivar development. Results A population of 469 dry bean lines of different market classes representing plant materials routinely developed in a bean breeding program were used. Of them, 395 lines were evaluated for CBB resistance at 14 and 21 DAI (Days After Inoculation) in the summer of 2009 in an artificially inoculated CBB nursery in south-western Ontario. All lines were genotyped using 132 SNPs (Single Nucleotide Polymorphisms) evenly distributed across the genome. Of the 132 SNPs, 26 SNPs had more than 20% missing data, 12 SNPs were monomorphic, and 17 SNPs had a MAF (Minor Allelic Frequency) of less than 0.20, therefore only 75 SNPs were used for association study, based on one SNP per locus. The best possible population structure was to assign 36% and 64% of the lines into Andean and Mesoamerican subgroups, respectively. Kinship analysis also revealed complex familial relationships among all lines, which corresponds with the known pedigree history. MLM (Mixed Linear Model) analysis, including population structure and kinship, was used to discover marker-trait associations. Eighteen and 22 markers were significantly associated with CBB rating at 14 and 21 DAI, respectively. Fourteen markers were significant for both dates and the markers UBC420, SU91, g321, g471, and g796 were highly significant (p ? 0.001). Furthermore, 12 significant SNP markers were co-localized with or close to the CBB-QTLs identified previously in bi-parental QTL mapping studies. Conclusions This study demonstrated that association mapping using a reasonable number of markers, distributed across the genome and with application of plant materials that are routinely developed in a plant breeding program can detect significant QTLs for traits of interest.

2011-01-01

38

EPISTATIC INTERACTION BETWEEN TWO MAJOR QTL CONDITIONING RESISTANCE TO COMMON BACTERIAL BLIGHT IN COMMON BEAN  

Technology Transfer Automated Retrieval System (TEKTRAN)

Resistance to common bacterial blight in common bean is a complex trait that is quantitatively inherited. Combining QTL is the current strategy for improving resistance, but interactions among different QTL are unknown. We examined the interaction between two independent QTL present in dry bean bre...

39

Factors influencing efficacy of plastic shelters for control of bacterial blight of lilac  

Technology Transfer Automated Retrieval System (TEKTRAN)

Plastic shelters are thought to manage bacterial blight by protecting plants from rain and/or frost. In February to April 2008 and 2009, we studied the contribution of frost protection to efficacy of this cultural control practice. Lilacs in 1-gallon pots were exposed to four treatments: 1) plants...

40

EMERGENCE OF BACTERIAL BLIGHT OF CRUCIFERS IN CALIFORNIA AND THE U.S.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Since its initial appearance in 1995 on broccoli raab (Brassica rapa subsp. rapa) in the Salinas Valley of California, Pseudomonas syringae pv. alisalensis has been shown to cause bacterial blights on a variety of crucifers in California and other states. In addition to published reports of outbreak...

41

Development of an engineered ‘bioluminescent’ reporter phage for the detection of bacterial blight of crucifers  

Technology Transfer Automated Retrieval System (TEKTRAN)

Bacterial blight, caused by the phytopathogen Pseudomonas cannabina pv. alisalensis, is an emerging disease afflicting important members of the Brassica family. The disease is often misdiagnosed as peppery leaf spot, a much less severe disease caused by the closely related pathogen Pseudomonas syrin...

42

Registration of common bacterial blight resistant cranberry dry bean germplasm line USCR-CBB-20  

Technology Transfer Automated Retrieval System (TEKTRAN)

Common bacterial blight is a serious disease of dry edible beans in warm humid climates. The disease is most prominent east of the continental divide in the U.S. Large seeded dry beans from the Andean gene pool, such as those in the cranberry bean market class are very susceptible to this disease. ...

43

BACTERIAL BLIGHT ON ARUGULA, A NEW DISEASE CAUSED BY PSEUDOMONAS SYRINGAE PV. ALISALENSIS IN CALIFORNIA.  

Technology Transfer Automated Retrieval System (TEKTRAN)

A novel bacterial blight of arugula Eruca sativa was seen for the first time in coastal California in 1995. Bacteria isolated from infected tissue were analyzed using standard biochemical and physiological tests including the standard LOPAT tests and fatty acid methyl ester analysis. Results from th...

44

Severe outbreak of bacterial panicle blight across Texas Rice Belt in 2010  

Technology Transfer Automated Retrieval System (TEKTRAN)

Bacterial panicle blight symptoms have been observed in rice fields in Texas for many years, but it was not until 1996 that Burkholderia glumae was identified as the causal agent. Although it is generally considered a minor disease, there have been years where significant losses to yield and milling...

45

Genetic analysis of resistance to bacterial leaf streak caused by Xanthomonas campestris pv. undulosa in bread wheat  

Microsoft Academic Search

The inheritance of resistance to bacterial leaf streak or black chaff of wheat was studied under field conditions, with an artificial epidemic of Xanthomonas campestris pv. undulosa. A complete series of crosses between five parents, differing in reaction to X. c. pv. undulosa, was generated. Disease was recorded at two different stages of growth. No evidence of cytoplasmic effect was

Etienne Duveiller; Maarten van Ginkel; Marja Thijssen

1992-01-01

46

Quantifying the effect of bacterial antagonists on the relationship between phyllosphere population sizes of Xanthomonas translucens pv. translucens and subsequent bacterial leaf streak severity on wheat seedlings  

Microsoft Academic Search

The influence of bacterial antagonists on the relationship between leaf-associated population sizes of Xanthomonas translucens pv. translucens (Xtt) and subsequent bacterial leaf streak (BLS) severity on wheat seedlings was investigated when antagonists were challenged with the pathogen. Bacterial antagonists (108CFU\\/ml) were inoculated individually onto 10-day-old wheat seedlings maintained in a growth chamber. Antagonists were challenged 48h later with a single

K. D. Stromberg; L. L. Kinkel; K. J. Leonard

2004-01-01

47

Induction and selection of mutations for resistance against bacterial leaf blight in rice  

Microsoft Academic Search

Dry seed lots of a rice cultivar, Harebare, susceptible for bacterial leaf blight (BLB), were exposed to thermal neutrons with and without pre-treatment of seed for boron-enrichment, and to gamma-rays. M1 plants of each of the treatments were grown and their seeds were separately harvested. M2 populations were raised in rice fields of a farmer in a region where BLB

H. Nakai; M. Kobayashi; M. Saito

1985-01-01

48

[Molecular mapping of a bacterial blight resistance gene Xa-25 in rice].  

PubMed

Xa-25 was a bacterial blight resistance gene identified in a somaclonal mutant HX-3. A doubled-haploid (DH) population including 129 stable lines was derived from anther culture of a typical japanica 02428 and a typical indica HX-3 cross. The bacterial blight strain Zhe173, a typical bacterial blight strain in Yangtze River valley, was used to test the resistance or susceptible of the DH population lines, and the results showed that the resistance lines and susceptible lines were 62 and 67, respectively. A total of 300 SSR primer pairs covering 12 rice chromosomes were used for polymorphism survey of 02428 and HX-3. Among these primers, 74 showed polymorphism between the parents. Using these polymorphic SSR markers, bulked segregant analysis was conducted on the DH population. As the result, Xa-25 was located at the terminal region of the long arm of chromosome 4 between the two SSR markers RM6748 and RM1153, the map distance between Xa-25 and the two SSR markers was 9.3 cM and 3.0 cM, respectively. PMID:15759866

Gao, Dong-Ying; Liu, Ai-Min; Zhou, Yi-Hong; Cheng, Yan-Jun; Xiang, Yang-Hai; Sun, Li-Hua; Zhai, Wen-Xue

2005-02-01

49

Abscisic Acid Promotes Susceptibility to the Rice Leaf Blight Pathogen Xanthomonas oryzae pv oryzae by Suppressing Salicylic Acid-Mediated Defenses  

PubMed Central

The plant hormone abscisic acid (ABA) is involved in a wide variety of plant processes, including the initiation of stress-adaptive responses to various environmental cues. Recently, ABA also emerged as a central factor in the regulation and integration of plant immune responses, although little is known about the underlying mechanisms. Aiming to advance our understanding of ABA-modulated disease resistance, we have analyzed the impact, dynamics and interrelationship of ABA and the classic defense hormone salicylic acid (SA) during progression of rice infection by the leaf blight pathogen Xanthomonas oryzae pv. oryzae (Xoo). Consistent with ABA negatively regulating resistance to Xoo, we found that exogenously administered ABA renders rice hypersusceptible to infection, whereas chemical and genetic disruption of ABA biosynthesis and signaling, respectively, led to enhanced Xoo resistance. In addition, we found successful Xoo infection to be associated with extensive reprogramming of ABA biosynthesis and response genes, suggesting that ABA functions as a virulence factor for Xoo. Interestingly, several lines of evidence indicate that this immune-suppressive effect of ABA is due at least in part to suppression of SA-mediated defenses that normally serve to limit pathogen growth. Resistance induced by the ABA biosynthesis inhibitor fluridone, however, appears to operate in a SA-independent manner and is likely due to induction of non-specific physiological stress. Collectively, our findings favor a scenario whereby virulent Xoo hijacks the rice ABA machinery to cause disease and highlight the importance of ABA and its crosstalk with SA in shaping the outcome of rice-Xoo interactions.

Xu, Jing; Audenaert, Kris

2013-01-01

50

[Polyvalence of bacteriophages isolated from fruit trees, affected by bacterial fire blight].  

PubMed

Phage populations appearing as a result of a pathogenic process caused by Erwinia amylovora have been discovered and described. They accompany bacterial fire blight development in the process of quince, pear and apple trees vegetation in Zakarpattya region of Ukraine. Phage isolates of the affected pear and quince include polyvalent virulent phages able to develop on bacterial strains associated with plants--E. amylovora. E. "horticola" and Pantoea agglomerans. E. amylovora isolated from the plant tissues affected by the fire blight and detected at the same time as phages proved to be resistant to the viral infection. It is hard to explain now this characteristic however it was noticed that resistance to phages can change drastically in case of dissociation, lysogenization and mutagenesis of erwinia in laboratory conditions. Phage population study shows that they are heterogeneous and can obviously include not only polyvalent but also specific viruses. Further studies of biology and molecular genetics of pure lines of isolated phages will help to get closer to understanding the place and role of bacteriophages in the complicated network of relations between bacterial pathogens and plants. PMID:23720968

Tovkach, F I; Moroz, S N; Korol', N A; Fa?diuk, Iu V; Kushkina, A I

51

Quantitative Measurements of Xanthomonas Oryzae pv. Oryzae Distribution in Rice Using Fluorescent-Labeling  

Microsoft Academic Search

The rice host sensor, XA21, confers robust resistance to most strains of Xanthomonas oryzae pv. oryzae (Xoo), the casual agent of bacterial blight disease. Using in planta fluorescence imaging of Xoo strain PXO99Az expressing a green fluorescent protein (Xoo-gfp) we show that XA21 restricts Xoo spread at the point of infection. This noninvasive and quantitative method to measure spatial distribution

Kazunari Nozue; Chang-Jin Park; Pamela C. Ronald

2011-01-01

52

Epidemiological effect of gene deployment strategies on bacterial blight of rice.  

PubMed

ABSTRACT Experiments were conducted in farmers' fields at two locations of the irrigated lowlands of Laguna province in southern Luzon island, Philippines, during the wet seasons of 1993 and 1994. Nine rice populations were studied including pure stands, two-component mixtures, two-gene combinations of backcrossed lines containing varying combinations of the bacterial blight resistance genes Xa-4, xa-5, and Xa-10, and a non-isogenic cultivar containing Xa-4 and partial resistance to bacterial blight. The area under the disease progress curve (AUDPC) of both gene combinations studied was significantly less than the single most effective gene of each combination deployed singly. A mixture of a susceptible and a resistant line expressed an AUDPC significantly less than the mean of its component pure stands, but two other mixtures did not. The cultivar IR20, which contains both Xa-4 and partial resistance, reduced the AUDPC by about two-thirds as compared with IR-BB4, which contains Xa-4 and little or no partial resistance. PMID:18945155

Ahmed, H U; Finckh, M R; Alfonso, R F; Mundt, C C

1997-01-01

53

Genomic and phenotypic characterization of Xanthomonas cynarae sp. nov., a new species that causes bacterial bract spot of artichoke (Cynara scolymus L.)  

Microsoft Academic Search

A bacterial disease of artichoke (Cynara scolymus L.) was first observed in 1954 in Brittany and the Loire Valley, France. This disease causes water-soaked spots on bracts and depreciates marketability of the harvest. Ten strains of the pathogen causing bacterial spot of artichoke, previously identified as a member of the genus Xanthomonas, were characterized and compared with type and pathotype

Louis Gardan; Charles Manceau; Jean-Luc Tanguy; Yves Tirilly

54

First report of bacterial blight of cabbage (Brassica oleracea var. capitata L.) caused by Pseudomonas cannabina pv. alisalensis in California  

Technology Transfer Automated Retrieval System (TEKTRAN)

A novel bacterial leaf blight was seen in field grown cabbage (Brassica oleracea var. capitata L.) in Monterey County, California in 2006. Koch’s postulates were completed and etiology of the pathogen was determined. Physiological and molecular characterization showed that the pathogen was Pseudomon...

55

FIRST REPORT OF BACTERIAL BLIGHT OF RUTABAGA (BRASSICA NAPUS VAR. NAPOBRASSICA) CAUSED BY PSEUDOMONAS SYRINGAE PV. ALISALENSIS IN CALIFORNIA  

Technology Transfer Automated Retrieval System (TEKTRAN)

A novel bacterial blight on commercial organically grown rutabaga (Brassica napus var. napobrassica) was seen for the first time in coastal California in 2005. Koch’s postulates were completed and the etiology of the pathogen was elucidated. Characterization showed that pathogen was Pseudomonas syri...

56

ROLE OF 2,4-DIACETYLPHLOROGLUCINOL FOR PLANT DISEASE CONTROL: ITS IMPORTANCE TO RICE BACTERIAL BLIGHT SUPPRESSION IN INDIA.  

Technology Transfer Automated Retrieval System (TEKTRAN)

We have used established methods for assembling and characterizing plant-associated bacteria from parts of Andhra Pradesh, Karnataka, Kerala, Maharashtra and Tamil Nadu states of India. This present investigation is on Pseudomonas strains as biocontrol agents of bacterial blight of rice but the emph...

57

Bacterial panicle blight resistance QTL in rice (Oryza sativa L.) and their association with resistance to other diseases  

Technology Transfer Automated Retrieval System (TEKTRAN)

Bacterial panicle blight (BPB) of rice (Oryza sativa L.) occurs when the bacterium Burkholderia glumae infects and colonizes emerging and flowering panicles, causing kernels to abort. To identify quantitative trait loci (QTL) for BPB resistance, a population of 300 recombinant inbred lines (RILs) d...

58

Effervescent fast-disintegrating bacterial formulation for biological control of rice sheath blight.  

PubMed

A lack of effective, easily applied and stable formulation has been a major obstacle to widespread use of biocontrol agents for control of rice sheath blight. In this study, effervescent fast-disintegrating granules containing endospores of Bacillus megaterium were developed for use either by broadcast or spray application. The formulation composed of lactose, polyvinyl pyrrolidone K-30 (PVP, K-30) and effervescent base (citric acid, tartaric acid and sodium bicarbonate). The number of living bacteria in effervescent granules that performed mycelial growth inhibition was in the range of 10(9) CFU/g after 12 months storage at room temperature. The number of viable bacteria after applying into the water and spraying on the rice seedling for 7 days in the greenhouse tests were also satisfactory high (10(9) CFU/g of granules and 10(6) CFU/g of plant, respectively). The scanning electron microscope (SEM) was used to observe bacterial antagonist on the surface of leaf sheath and leaf blade after spraying with formulation. Effervescent formulation applied either broadcasting or spraying reduced incidence of sheath blight disease in the greenhouse experiments. PMID:17428569

Wiwattanapatapee, R; Chumthong, A; Pengnoo, A; Kanjanamaneesathian, M

2007-02-02

59

TaCPK2-A, a calcium-dependent protein kinase gene that is required for wheat powdery mildew resistance enhances bacterial blight resistance in transgenic rice  

PubMed Central

Calcium-dependent protein kinases (CPKs) are important Ca2+ signalling components involved in complex immune and stress signalling networks; but the knowledge of CPK gene functions in the hexaploid wheat is limited. Previously, TaCPK2 was shown to be inducible by powdery mildew (Blumeria graminis tritici, Bgt) infection in wheat. Here, its functions in disease resistance are characterized further. This study shows the presence of defence-response and cold-response cis-elements on the promoters of the A subgenome homoeologue (TaCPK2-A) and D subgenome homoeologue (TaCPK2-D), respectively. Their expression patterns were then confirmed by quantitative real-time PCR (qRT-PCR) using genome-specific primers, where TaCPK2-A was induced by Bgt treatment while TaCPK2-D mainly responded to cold treatment. Downregulation of TaCPK2-A by virus-induced gene silencing (VIGS) causes loss of resistance to Bgt in resistant wheat lines, indicating that TaCPK2-A is required for powdery mildew resistance. Furthermore, overexpression of TaCPK2-A in rice enhanced bacterial blight (Xanthomonas oryzae pv. oryzae, Xoo) resistance. qRT-PCR analysis showed that overexpression of TaCPK2-A in rice promoted the expression of OsWRKY45-1, a transcription factor involved in both fungal and bacterial resistance by regulating jasmonic acid and salicylic acid signalling genes. The opposite effect was found in wheat TaCPK2-A VIGS plants, where the homologue of OsWRKY45-1 was significantly repressed. These data suggest that modulation of WRKY45-1 and associated defence-response genes by CPK2 genes may be the common mechanism for multiple disease resistance in grass species, which may have undergone subfunctionalization in promoters before the formation of hexaploid wheat.

Geng, Shuaifeng; Li, Aili; Tang, Lichuan; Lan, Xiujin; Mao, Long

2013-01-01

60

TaCPK2-A, a calcium-dependent protein kinase gene that is required for wheat powdery mildew resistance enhances bacterial blight resistance in transgenic rice.  

PubMed

Calcium-dependent protein kinases (CPKs) are important Ca2+ signalling components involved in complex immune and stress signalling networks; but the knowledge of CPK gene functions in the hexaploid wheat is limited. Previously, TaCPK2 was shown to be inducible by powdery mildew (Blumeria graminis tritici, Bgt) infection in wheat. Here, its functions in disease resistance are characterized further. This study shows the presence of defence-response and cold-response cis-elements on the promoters of the A subgenome homoeologue (TaCPK2-A) and D subgenome homoeologue (TaCPK2-D), respectively. Their expression patterns were then confirmed by quantitative real-time PCR (qRT-PCR) using genome-specific primers, where TaCPK2-A was induced by Bgt treatment while TaCPK2-D mainly responded to cold treatment. Downregulation of TaCPK2-A by virus-induced gene silencing (VIGS) causes loss of resistance to Bgt in resistant wheat lines, indicating that TaCPK2-A is required for powdery mildew resistance. Furthermore, overexpression of TaCPK2-A in rice enhanced bacterial blight (Xanthomonas oryzae pv. oryzae, Xoo) resistance. qRT-PCR analysis showed that overexpression of TaCPK2-A in rice promoted the expression of OsWRKY45-1, a transcription factor involved in both fungal and bacterial resistance by regulating jasmonic acid and salicylic acid signalling genes. The opposite effect was found in wheat TaCPK2-A VIGS plants, where the homologue of OsWRKY45-1 was significantly repressed. These data suggest that modulation of WRKY45-1 and associated defence-response genes by CPK2 genes may be the common mechanism for multiple disease resistance in grass species, which may have undergone subfunctionalization in promoters before the formation of hexaploid wheat. PMID:23918959

Geng, Shuaifeng; Li, Aili; Tang, Lichuan; Yin, Lingjie; Wu, Liang; Lei, Cailin; Guo, Xiuping; Zhang, Xin; Jiang, Guanghuai; Zhai, Wenxue; Wei, Yuming; Zheng, Youliang; Lan, Xiujin; Mao, Long

2013-08-01

61

Xa3 , conferring resistance for rice bacterial blight and encoding a receptor kinase-like protein, is the same as Xa26  

Microsoft Academic Search

Xa3-mediated resistance for rice bacterial blight, one of the most devastating rice diseases worldwide, is influenced by genetic background. Xa3 is genetically tightly linked to Xa26, another gene for bacterial blight resistance. Xa26 belongs to a clustered multigene family encoding leucine-rich repeat (LRR) receptor kinase-like proteins. To characterize Xa3, we fine mapped it using a population segregating for only one

Yi Xiang; Yinglong Cao; Caiguo Xu; Xianghua Li; Shiping Wang

2006-01-01

62

A major QTL for common bacterial blight resistance derives from the common bean great northern landrace cultivar Montana No.5  

Microsoft Academic Search

Knowledge of the evolutionary origin and sources of pest resistance genes will facilitate gene deployment and development\\u000a of crop cultivars with durable resistance. Our objective was to determine the source of common bacterial blight (CBB) resistance\\u000a in the common bean Great Northern Nebraska #1 (GN#1) and GN#1 Selection 27 (GN#1 Sel 27). Several great northern cultivars\\u000a including GN#1, GN#1 Sel

Phillip N. Miklas; Dermot P. Coyne; Kenneth F. Grafton; Nedim Mutlu; Jim Reiser; Dale T. Lindgren; Shree P. Singh

2003-01-01

63

Pathovars of Pseudomonas syringae Causing Bacterial Brown Spot and Halo Blight in Phaseolus vulgaris L. Are Distinguishable by Ribotyping  

Microsoft Academic Search

Ribotyping was evaluated as a method to differentiate between Pseudomonas syringae pv. phaseolicola and pv. syringae strains causing bacterial brown spot and halo blight diseases in Phaseolus vulgaris L. Ribotyping, with restriction enzymes BglI and SalI and using the Escherichia coli rrnB operon as the probe, differentiated 11 and 14 ribotypes, respectively, and a combination of data from both procedures

ANA J. GONZALEZ; ELENA LANDERAS; M. CARMEN MENDOZA

2000-01-01

64

Characterization of hypersensitive resistance to bacterial spot race T3 (Xanthomonas perforans) from tomato accession PI 128216.  

PubMed

Bacterial spot of tomato is caused by four species of Xanthomonas. The accession PI 128216 (Solanum pimpinellifolium) displays a hypersensitive reaction (HR) to race T3 strains (predominantely Xanthomonas perforans). We developed an inbred backcross (IBC) population (BC(2)S(5), 178 families) derived from PI 128216 and OH88119 (S. lycopersicum) as the susceptible recurrent parent for simultaneous introgression and genetic analysis of the HR response. These IBC families were evaluated in the greenhouse for HR to race T3 strain Xcv761. The IBC population was genotyped with molecular markers distributed throughout the genome in order to identify candidate loci conferring resistance. We treated the IBC population as a hypothesis forming generation to guide validation in subsequent crosses. Nonparametric analysis identified an association between HR and markers clustered on chromosome 11 (P < 0.05 to 0.0001) and chromosome 6 (0.04 > P > 0.002). Further analysis of the IBC population suggested that markers on chromosome 6 and 11 failed to assort independently, a phenomenon known as gametic phase disequilibrium. Therefore, to validate marker-trait linkages, resistant IBC plants were crossed with OH88119 and BC(3)F(2) progeny were evaluated for HR in the greenhouse. In these subsequent populations, the HR response was associated with the chromosome 11 markers (P < 0.0002) but not with the markers on chromosome 6 (P > 0.25). Independent F(2) families were developed by crossing resistant IBC lines to OH8245, OH88119, and OH7530. These populations were genotyped, organized into classes based on chromosome 11 markers, and evaluated for resistance in the field. The PI 128216 locus on chromosome 11 provided resistance that was dependent on gene dosage and genetic background. These results define a single locus, Rx-4, from PI 128216, which provides resistance to bacterial spot race T3, has additive gene action, and is located on chromosome 11. PMID:19671005

Robbins, Matthew D; Darrigues, Audrey; Sim, Sung-Chur; Masud, Mohammed Abu Taher; Francis, David M

2009-09-01

65

Metabolite profiles of rice cultivars containing bacterial blight-resistant genes are distinctive from susceptible rice.  

PubMed

The metabolic changes of bacterial blight-resistant line C418/Xa23 generated by molecular marker-assisted selection (n= 12), transgenic variety C418-Xa21 generated by using the Agrobacterium-mediated system (n= 12), and progenitor cultivar C418 (n= 12) were monitored using gas chromatography/mass spectrometry. The validation, discrimination, and establishment of correlative relationships between metabolite signals were performed by cluster analysis, principal component analysis, and partial least squares-discriminant analysis. Significant and unintended changes were observed in 154 components in C418/Xa23 and 48 components in C418-Xa21 compared with C418 (P< 0.05, Fold change > 2.0). The most significant decreases detected (P< 0.001) in both C418/Xa23 and C418-Xa21 were in three amino acids: glycine, tyrosine, and alanine, and four identified metabolites: malic acid, ferulic acid, succinic acid, and glycerol. Linoleic acid was increased specifically in C418/Xa23 which was derived from traditional breeding. This line, possessing a distinctive metabolite profile as a positive control, shows more differences vs. the parental than the transgenic line. Only succinic acid that falls outside the boundaries of natural variability between the two non-transgenic varieties C418 and C418/Xa23 should be further investigated with respect to safety or nutritional impact. PMID:22687573

Wu, Jiao; Yu, Haichuan; Dai, Haofu; Mei, Wenli; Huang, Xin; Zhu, Shuifang; Peng, Ming

2012-06-11

66

Are the Dominant and Recessive Plant Disease Resistance Genes Similar?: A Case Study of Rice R Genes and Xanthomonas oryzae pv. oryzae Races  

Microsoft Academic Search

The resistance of rice to its bacterial blight pathogen Xanthomonas oryzae pv. oryzae (Xoo) has both qualitative and quantitative components that were investigated using three near-isogenic line sets for four resistance (R) genes (Xa4, xa5, xa13, and Xa21) and 12 Xoo races. Our results indicate that these two resistance components of rice plants were associated with the properties of the

Zhi-Kang Li; Alma Sanchez; E. Angeles; Sukhwider Singh; Jessica Domingo; Ning Huang; Gurdev S. Khush

67

A plant natriuretic peptide-like gene in the bacterial pathogen Xanthomonas axonopodis may induce hyper-hydration in the plant host: a hypothesis of molecular mimicry  

Microsoft Academic Search

BACKGROUND: Plant natriuretic peptides (PNPs) are systemically mobile molecules that regulate homeostasis at nanomolar concentrations. PNPs are up-regulated under conditions of osmotic stress and PNP-dependent processes include changes in ion transport and increases of H2O uptake into protoplasts and whole tissue. PRESENTATION OF THE HYPOTHESIS: The bacterial citrus pathogen Xanthomonas axonopodis pv. Citri str. 306 contains a gene encoding a

Victoria Nembaware; Cathal Seoighe; Muhammed Sayed; Chris Gehring

2004-01-01

68

Blighted Ovum  

MedlinePLUS

... be reprinted for personal, noncommercial use only. Blighted ovum: What causes it? By Mayo Clinic staff Original ... your e-mail address Sign up Question Blighted ovum: What causes it? What causes a blighted ovum? ...

69

Pathovars of Pseudomonas syringae Causing Bacterial Brown Spot and Halo Blight in Phaseolus vulgaris L. Are Distinguishable by Ribotyping  

PubMed Central

Ribotyping was evaluated as a method to differentiate between Pseudomonas syringae pv. phaseolicola and pv. syringae strains causing bacterial brown spot and halo blight diseases in Phaseolus vulgaris L. Ribotyping, with restriction enzymes BglI and SalI and using the Escherichia coli rrnB operon as the probe, differentiated 11 and 14 ribotypes, respectively, and a combination of data from both procedures yielded 19 combined ribotypes. Cluster analysis of the combined ribotypes differentiated the pathovars phaseolicola and syringae, as well as different clonal lineages within these pathovars. The potential of ribotyping to screen for correlations between lineages and factors such as geographical region and/or bean varieties is also reported.

Gonzalez, Ana J.; Landeras, Elena; Mendoza, M. Carmen

2000-01-01

70

Mechanistically compatible mixtures of bacterial antagonists improve biological control of fire blight of pear.  

PubMed

Mixtures of biological control agents can be superior to individual agents in suppressing plant disease, providing enhanced efficacy and reliability from field to field relative to single biocontrol strains. Nonetheless, the efficacy of combinations of Pseudomonas fluorescens A506, a commercial biological control agent for fire blight of pear, and Pantoea vagans strain C9-1 or Pantoea agglomerans strain Eh252 rarely exceeds that of individual strains. A506 suppresses growth of the pathogen on floral colonization and infection sites through preemptive exclusion. C9-1 and Eh252 produce peptide antibiotics that contribute to disease control. In culture, A506 produces an extracellular protease that degrades the peptide antibiotics of C9-1 and Eh252. We hypothesized that strain A506 diminishes the biological control activity of C9-1 and Eh252, thereby reducing the efficacy of biocontrol mixtures. This hypothesis was tested in five replicated field trials comparing biological control of fire blight using strain A506 and A506 aprX::Tn5, an extracellular protease-deficient mutant, as individuals and combined with C9-1 or Eh252. On average, mixtures containing A506 aprX::Tn5 were superior to those containing the wild-type strain, confirming that the extracellular protease of A506 diminished the biological control activity of C9-1 and Eh252 in situ. Mixtures of A506 aprX::Tn5 and C9-1 or Eh252 were superior to oxytetracycline or single biocontrol strains in suppressing fire blight of pear. These experiments demonstrate that certain biological control agents are mechanistically incompatible, in that one strain interferes with the mechanism by which a second strain suppresses plant disease. Mixtures composed of mechanistically compatible strains of biological control agents can suppress disease more effectively than individual biological control agents. PMID:20839962

Stockwell, V O; Johnson, K B; Sugar, D; Loper, J E

2011-01-01

71

Particle-bombardment-mediated co-transformation of elite Chinese rice cultivars with genes conferring resistance to bacterial blight and sap-sucking insect pests  

Microsoft Academic Search

.   Transgenic rice plants were generated using particle bombardment to simultaneously introduce the rice Xa21 gene effective against bacterial blight and the Galanthus nivalis agglutinin (snowdrop lectin; gna) gene effective against sap-sucking insect pests, specifically the brown plant hopper. Using three plasmids, we co-transformed\\u000a 5- to 10-d-old, mature seed-derived rice (Oryza sativa L.) callus of two elite Chinese rice cultivars,

Kexuan Tang; Porntip Tinjuangjun; Yanan Xu; Xiaofen Sun; John A. Gatehouse; Pamela C. Ronald; Huaxiong Qi; Xinggui Lu; Paul Christou; Ajay Kohli

1999-01-01

72

Antisense Suppression of a (+)-?-Cadinene Synthase Gene in Cotton Prevents the Induction of This Defense Response Gene during Bacterial Blight Infection But Not Its Constitutive Expression1[w  

PubMed Central

In cotton (Gossypium hirsutum) the enzyme (+)-?-cadinene synthase (CDNS) catalyzes the first committed step in the biosynthesis of cadinane-type sesquiterpenes, such as gossypol, that provide constitutive and inducible protection against pests and diseases. A cotton cDNA clone encoding CDNS (cdn1-C4) was isolated from developing embryos and functionally characterized. Southern analysis showed that CDNS genes belong to a large multigene family, of which five genomic clones were studied, including three pseudogenes and one gene that may represent another subfamily of CDNS. CDNS expression was shown to be induced in cotton infected with either the bacterial blight or verticillium wilt pathogens. Constructs for the constitutive or seed-specific antisense suppression of cdn1-C4 were introduced into cotton by Agrobacterium-mediated transformation. Gossypol levels were not reduced in the seeds of transformants with either construct, nor was the induction of CDNS expression affected in stems of the constitutive antisense plants infected with Verticillium dahliae Kleb. However, the induction of CDNS mRNA and protein in response to bacterial blight infection of cotyledons was completely blocked in the constitutive antisense plants. These results suggest that cdn1-C4 may be involved specifically in the bacterial blight response and that the CDNS multigene family comprises a complex set of genes differing in their temporal and spatial regulation and responsible for different branches of the cotton sesquiterpene pathway.

Townsend, Belinda J.; Poole, Andrew; Blake, Christopher J.; Llewellyn, Danny J.

2005-01-01

73

The Rice Bacterial Pathogen Xanthomonas oryzae pv. oryzae Produces 3-Hydroxybenzoic Acid and 4-Hydroxybenzoic Acid via XanB2 for Use in Xanthomonadin, Ubiquinone, and Exopolysaccharide Biosynthesis.  

PubMed

Xanthomonas oryzae pv. oryzae, the causal agent of rice bacterial blight, produces membrane-bound yellow pigments, referred to as xanthomonadins. Xanthomonadins protect the pathogen from photodamage and host-induced perioxidation damage. They are also required for epiphytic survival and successful host plant infection. Here, we show that XanB2 encoded by PXO_3739 plays a key role in xanthomonadin and coenzyme Q8 biosynthesis in X. oryzae pv. oryzae PXO99A. A xanB2 deletion mutant exhibits a pleiotropic phenotype, including xanthomonadin deficiency, producing less exopolysaccharide (EPS), lower viability and H2O2 resistance, and lower virulence. We further demonstrate that X. oryzae pv. oryzae produces 3-hydroxybenzoic acid (3-HBA) and 4-hydroxybenzoic acid (4-HBA) via XanB2. 3-HBA is associated with xanthomonadin biosynthesis while 4-HBA is mainly used as a precursor for coenzyme Q (CoQ)8 biosynthesis. XanB2 is the alternative source of 4-HBA for CoQ8 biosynthesis in PXO99A. These findings suggest that the roles of XanB2 in PXO99A are generally consistent with those in X. campestris pv. campestris. The present study also demonstrated that X. oryzae pv. oryzae PXO99A has evolved several specific features in 3-HBA and 4-HBA signaling. First, our results showed that PXO99A produces less 3-HBA and 4-HBA than X. campestris pv. campestris and this is partially due to a degenerated 4-HBA efflux pump. Second, PXO99A has evolved unique xanthomonadin induction patterns via 3-HBA and 4-HBA. Third, our results showed that 3-HBA or 4-HBA positively regulates the expression of gum cluster to promote EPS production in PXO99A. Taken together, the results of this study indicate that XanB2 is a key metabolic enzyme linking xanthomonadin, CoQ, and EPS biosynthesis, which are collectively essential for X. oryzae pv. oryzae pathogenesis. PMID:23718125

Zhou, Lian; Huang, Tin-Wei; Wang, Jia-Yuan; Sun, Shuang; Chen, Gongyou; Poplawsky, Alan; He, Ya-Wen

2013-10-01

74

Induced adaptive and cross-protection responses against oxidative stress killing in a bacterial phytopathogen, Xanthomonas oryzae pv. oryzae  

Microsoft Academic Search

In Xanthomonas oryzae pv. oryzae, exposure to a sub-lethal concentration of H2O2 conferred protection to subsequent challenges with a killing concentration of H2O2 (30 mM, adaptive response). No adaptive response to tert-butylhydroperoxides (tBOOH) or the superoxide generator menadione was observed. However, exposure to sub-lethal concentrations of tBOOH or N-ethylmaleimide (a thiol reagent) induced cross-protection to low 30 mM lethal levels

Skorn Mongkolsuk; Paiboon Vattanaviboon; Wipa Praituan

1997-01-01

75

Role of the FeoB protein and siderophore in promoting virulence of Xanthomonas oryzae pv. oryzae on rice.  

PubMed

Xanthomonas oryzae pv. oryzae causes bacterial blight, a serious disease of rice. Our analysis revealed that the X. oryzae pv. oryzae genome encodes genes responsible for iron uptake through FeoB (homolog of the major bacterial ferrous iron transporter) and a siderophore. A mutation in the X. oryzae pv. oryzae feoB gene causes severe virulence deficiency, growth deficiency in iron-limiting medium, and constitutive production of a siderophore. We identified an iron regulated xss gene cluster, in which xssABCDE (Xanthomonas siderophore synthesis) and xsuA (Xanthomonas siderophore utilization) genes encode proteins involved in biosynthesis and utilization of X. oryzae pv. oryzae siderophore. Mutations in the xssA, xssB, and xssE genes cause siderophore deficiency and growth restriction under iron-limiting conditions but are virulence proficient. An xsuA mutant displayed impairment in utilization of native siderophore, suggesting that XsuA acts as a specific receptor for a ferric-siderophore complex. Histochemical and fluorimetric assays with gusA fusions indicate that, during in planta growth, the feoB gene is expressed and that the xss operon is not expressed. This study represents the first report describing a role for feoB in virulence of any plant-pathogenic bacterium and the first functional characterization of a siderophore-biosynthetic gene cluster in any xanthomonad. PMID:20382771

Pandey, Alok; Sonti, Ramesh V

2010-04-09

76

A mutation in the Xanthomonas oryzae pv. oryzae wxoD gene affects xanthan production and chemotaxis.  

PubMed

Xanthomonas oryzae pv. oryzae causes bacterial blight in rice (Oryza sativa L.). The effect of a mutation in the wxoD gene, that encodes a putative O-antigen acetylase, on xanthan production as well as bacterial chemotaxis was investigated. The mutation increased xanthan production by 52 %. The mutant strain was non-motile on semi-solid agar swarm plates. In addition, several genes involved in chemotaxis, including the cheW, cheV, cheR, and cheD genes, were down-regulated by a mutation in the wxoD gene. Thus, the mutation in the wxoD gene affects xanthan production as well as bacterial chemotaxis. However, the wxoD gene is not essential for the virulence of X. oryzae. PMID:23881323

Nam, Jae-Young; Kim, Hong-Il; Lee, Chang-Soo; Park, Young-Jin

2013-07-24

77

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 Central

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.

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

2012-01-01

78

Comparison of the genomes of two Xanthomonas pathogens with differing host specificities  

Microsoft Academic Search

The genus Xanthomonas is a diverse and economically important group of bacterial phytopathogens, belonging to the gamma-subdivision of the Proteobacteria. Xanthomonas axonopodis pv. citri (Xac) causes citrus canker, which affects most commercial citrus cultivars, resulting in significant losses worldwide. Symptoms include canker lesions, leading to abscission of fruit and leaves and general tree decline. Xanthomonas campestris pv. campestris (Xcc) causes

A. C. R. da Silva; J. A. Ferro; F. C. Reinach; C. S. Farah; L. R. Furlan; R. B. Quaggio; C. B. Monteiro-Vitorello; M. A. Van Sluys; N. F. Almeida; L. M. C. Alves; A. M. do Amaral; M. C. Bertolini; L. E. A. Camargo; G. Camarotte; F. Cannavan; J. Cardozo; F. Chambergo; L. P. Ciapina; R. M. B. Cicarelli; L. L. Coutinho; J. R. Cursino-Santos; H. El-Dorry; J. B. Faria; A. J. S. Ferreira; R. C. C. Ferreira; M. I. T. Ferro; E. F. Formighieri; M. C. Franco; C. C. Greggio; A. Gruber; A. M. Katsuyama; L. T. Kishi; R. P. Leite; E. G. M. Lemos; M. V. F. Lemos; E. C. Locali; A. M. B. N. Madeira; N. M. Martinez-Rossi; E. C. Martins; J. Meidanis; C. F. M. Menck; C. Y. Miyaki; D. H. Moon; L. M. Moreira; M. T. M. Novo; V. K. Okura; M. C. Oliveira; V. R. Oliveira; H. A. Pereira; A. Rossi; J. A. D. Sena; C. Silva; R. F. de Souza; L. A. F. Spinola; M. A. Takita; E. C. Teixeira; R. I. D. Tezza; M. Trindade dos Santos; D. Truffi; S. M. Tsai; F. F. White; J. C. Setubal; J. P. Kitajima

2002-01-01

79

First Report of Bacterial Leaf Blight on Broccoli and Cabbage Caused by Pseudomonas syringae pv. alisalensis in South Carolina  

Technology Transfer Automated Retrieval System (TEKTRAN)

In May 2009, leaf spot and leaf blight symptoms were observed on broccoli (B. oleracea var. italica) and cabbage (Brassica oleracea var. capitata) on several farms in Lexington County, the major brassica-growing region of South Carolina. Affected areas ranged from scattered disease foci within fiel...

80

Identification, fermentation, and bioactivity against Xanthomonas oryzae of antimicrobial metabolites isolated from Phomopsis longicolla S1B4.  

PubMed

Bacterial blight, an important and potentially destructive bacterial disease in rice, is caused by Xanthomonas oryzae. Recently, this organism has developed resistance to available antibiotics, prompting scientists to find a suitable alternative. This study focused on secondary metabolites of Phomopsis longicolla to target X. oryzae. Five bioactive compounds were isolated by activity-guided fractionation from ethyl acetate extracts of mycelia and were identified by LC/MS and NMR spectroscopy as dicerandrol A, dicerandrol B, dicerandrol C, deacetylphomoxanthone B, and fusaristatin A. This is the first time fusaristatin A has been isolated from Phomopsis sp. Deacetylphomoxanthone B showed a higher antibacterial effect against X. oryzae KACC 10331 than the positive control (2,4-diacetyphloroglucinol). Dicerandrol A also showed high antimicrobial activity against Grampositive bacteria (Staphylococcus aureus, Bacillus subtilis) and yeast (Candida albicans). In addition, high production yields of these compounds were obtained at the stationary and death phases. PMID:20372017

Lim, Chaesung; Kim, Jiyoung; Choi, Jung Nam; Ponnusamy, Kannan; Jeon, Yultaek; Kim, Soo-Un; Kim, Jeong Gu; Lee, Choonghwan

2010-03-01

81

Productivity and biochemical properties of green tea in response to full-length and functional fragments of HpaG Xooc , a harpin protein from the bacterial rice leaf streak pathogen Xanthomonas oryzae pv. oryzicola  

Microsoft Academic Search

Harpin proteins from plant pathogenic bacteria can stimulate hypersensitive cell death (HCD), drought tolerance, defence responses\\u000a against pathogens and insects in plants, as well as enhance plant growth. Recently, we identified nine functional fragments\\u000a of HpaGXooc, a harpin protein from Xanthomonas oryzae pv. oryzicola, the pathogen that causes bacterial leaf streak in rice. Fragments HpaG1–94, HpaG10–42, and HpaG62–138, which contain

Xiaojing Wu; Tingquan Wu; Juying Long; Qian Yin; Yong Zhang; Lei Chen; Ruoxue Liu; Tongchun Gao; Hansong Dong

2007-01-01

82

Comparative Transcriptome Profiling Reveals Different Expression Patterns in Xanthomonas oryzae pv. oryzae Strains with Putative Virulence-Relevant Genes  

PubMed Central

Xanthomonas oryzae pv. oryzae (Xoo) is the causal agent of rice bacterial blight, which is a major rice disease in tropical Asian countries. An attempt has been made to investigate gene expression patterns of three Xoo strains on the minimal medium XOM2, PXO99 (P6) and PXO86 (P2) from the Philippines, and GD1358 (C5) from China, which exhibited different virulence in 30 rice varieties, with putative virulence factors using deep sequencing. In total, 4,781 transcripts were identified in this study, and 1,151 and 3,076 genes were differentially expressed when P6 was compared with P2 and with C5, respectively. Our results indicated that Xoo strains from different regions exhibited distinctly different expression patterns of putative virulence-relevant genes. Interestingly, 40 and 44 genes involved in chemotaxis and motility exhibited higher transcript alterations in C5 compared with P6 and P2, respectively. Most other genes associated with virulence, including exopolysaccharide (EPS) synthesis, Hrp genes and type III effectors, including Xanthomonas outer protein (Xop) effectors and transcription activator-like (TAL) effectors, were down-regulated in C5 compared with P6 and P2. The data were confirmed by real-time quantitative RT-PCR, tests of bacterial motility, and enzyme activity analysis of EPS and xylanase. These results highlight the complexity of Xoo and offer new avenues for improving our understanding of Xoo-rice interactions and the evolution of Xoo virulence.

Zhang, Fan; Du, Zhenglin; Huang, Liyu; Cruz, Casiana Vera; Zhou, Yongli; Li, Zhikang

2013-01-01

83

New genes of Xanthomonas citri subsp. citri involved in pathogenesis and adaptation revealed by a transposon-based mutant library  

Microsoft Academic Search

BACKGROUND: Citrus canker is a disease caused by the phytopathogens Xanthomonas citri subsp. citri, Xanthomonas fuscans subsp. aurantifolli and Xanthomonas alfalfae subsp. citrumelonis. The first of the three species, which causes citrus bacterial canker type A, is the most widely spread and severe, attacking all citrus species. In Brazil, this species is the most important, being found in practically all

Marcelo L Laia; Leandro M Moreira; Juliana Dezajacomo; Joice B Brigati; Cristiano B Ferreira; Ana CR Silva; Jesus A Ferro; Julio CF Oliveira

2009-01-01

84

FIRE BLIGHT  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fire blight, caused by the bacterium Erwinia amylovora, is a destructive disease of apple, pears and woody ornamentals of the rose family. The disease is indigenous to North America and has been studied for more than one century. E. amylovora can infect blossoms, stems, immature fruits, woody branch...

85

Comparative genomic and transcriptome analyses of pathotypes of Xanthomonas citri subsp. citri provide insights into mechanisms of bacterial virulence and host range  

PubMed Central

Background Citrus bacterial canker is a disease that has severe economic impact on citrus industries worldwide and is caused by a few species and pathotypes of Xanthomonas. X. citri subsp. citri strain 306 (XccA306) is a type A (Asiatic) strain with a wide host range, whereas its variant X. citri subsp. citri strain Aw12879 (Xcaw12879, Wellington strain) is restricted to Mexican lime. Results To characterize the mechanism for the differences in host range of XccA and Xcaw, the genome of Xcaw12879 that was completed recently was compared with XccA306 genome. Effectors xopAF and avrGf1 are present in Xcaw12879, but were absent in XccA306. AvrGf1 was shown previously for Xcaw to cause hypersensitive response in Duncan grapefruit. Mutation analysis of xopAF indicates that the gene contributes to Xcaw growth in Mexican lime but does not contribute to the limited host range of Xcaw. RNA-Seq analysis was conducted to compare the expression profiles of Xcaw12879 and XccA306 in Nutrient Broth (NB) medium and XVM2 medium, which induces hrp gene expression. Two hundred ninety two and 281 genes showed differential expression in XVM2 compared to in NB for XccA306 and Xcaw12879, respectively. Twenty-five type 3 secretion system genes were up-regulated in XVM2 for both XccA and Xcaw. Among the 4,370 common genes of Xcaw12879 compared to XccA306, 603 genes in NB and 450 genes in XVM2 conditions were differentially regulated. Xcaw12879 showed higher protease activity than XccA306 whereas Xcaw12879 showed lower pectate lyase activity in comparison to XccA306. Conclusions Comparative genomic analysis of XccA306 and Xcaw12879 identified strain specific genes. Our study indicated that AvrGf1 contributes to the host range limitation of Xcaw12879 whereas XopAF contributes to virulence. Transcriptome analyses of XccA306 and Xcaw12879 presented insights into the expression of the two closely related strains of X. citri subsp. citri. Virulence genes including genes encoding T3SS components and effectors are induced in XVM2 medium. Numerous genes with differential expression in Xcaw12879 and XccA306 were identified. This study provided the foundation to further characterize the mechanisms for virulence and host range of pathotypes of X. citri subsp. citri.

2013-01-01

86

Latent infections of in vitro anthurium caused by Xanthomonas campestris pv. dieffenbachiae  

Microsoft Academic Search

Latent infections of tissue-cultured Anthurium andraeanum Lind. caused by the blight pathogen, Xanthomonas campestris pv. dieffenbachiae (McCulloch & Pirone) Dye, were examined. The pathogen survived in or on callus for over 4 months without producing symptoms in callus or turbidity in the medium. The pathogen survived for more than 1 year on or within stage II shoots without producing symptoms

D. J. Norman; A. M. Alvarez

1994-01-01

87

Enhanced resistance to blast fungus and bacterial blight in transgenic rice constitutively expressing OsSBP, a rice homologue of mammalian selenium-binding proteins.  

PubMed

The rice Oryza sativa selenium-binding protein homologue (OsSBP) gene encodes a homologue of mammalian selenium-binding proteins, and it has been isolated as one of the genes induced by treating a plant with a cerebroside elicitor from rice blast fungus. The possible role of OsSBP in plant defense was evaluated by using a transgenic approach. Plants overexpressing OsSBP showed enhanced resistance to a virulent strain of rice blast fungus as well as to rice bacterial blight. The expression of defense-related genes and the accumulation of phytoalexin after infection by rice blast fungus were accelerated in the OsSBP overexpressors. A higher level of H(2)O(2) accumulation and reduced activity of such scavenging enzymes as ascorbate peroxidase and catalase were seen when the OsSBP-overexpressing plants were treated with the protein phosphatase 1 inhibitor, calyculin A. These results suggest that the upregulation of OsSBP expression conferred enhanced tolerance to different pathogens, possibly by increasing plant sensitivity to endogenous defense responses. Additionally, the OsSBP protein might have a role in modulating the defense mechanism to biotic stress in rice. PMID:15118317

Sawada, Kazutoshi; Hasegawa, Morifumi; Tokuda, Lena; Kameyama, Junko; Kodama, Osamu; Kohchi, Takayuki; Yoshida, Kazuya; Shinmyo, Atsuhiko

2004-04-01

88

Analysis of pathogenicity mutants of a bacteriocin producing Xanthomonas perforans  

Microsoft Academic Search

Since the initial discovery of Xanthomonas perforans on tomato in 1991, it has completely displaced Xanthomonas euvesicatoria as the bacterial spot of tomato pathogen in Florida. Previous research has shown that X. perforans produces at least three different bacteriocin-like compounds (BcnA, BcnB, BcnC) antagonistic toward X. euvesicatoria strains. In this study pathogenicity-attenuated, bacteriocin-producing mutants of X. perforans were created to

A. P. Hert; M. Marutani; M. T. Momol; P. D. Roberts; J. B. Jones

2009-01-01

89

First Report of Bacterial Blight on Conventionally and Organically Grown Arugula in Nevada Caused by Pseudomonas syringae pv. alisalensis.  

Technology Transfer Automated Retrieval System (TEKTRAN)

A novel bacterial leaf spot was detected in commercial organic and conventional plantings of the arugula (Eruca vesicaria spp. sativa) cv. My Way in 2007. Koch’s postulates were completed and etiology of the pathogen was determined. Physiological and molecular characterization showed that the pathog...

90

Ketoglutarate Transport Protein KgtP Is Secreted through the Type III Secretion System and Contributes to Virulence in Xanthomonas oryzae pv. oryzae  

PubMed Central

The phytopathogenic prokaryote Xanthomonas oryzae pv. oryzae is the causal agent of bacterial leaf blight (BB) of rice and utilizes a type III secretion system (T3SS) to deliver T3SS effectors into rice cells. In this report, we show that the ketoglutarate transport protein (KgtP) is secreted in an HpaB-independent manner through the T3SS of X. oryzae pv. oryzae PXO99A and localizes to the host cell membrane for ?-ketoglutaric acid export. kgtP contained an imperfect PIP box (plant-inducible promoter) in the promoter region and was positively regulated by HrpX and HrpG. A kgtP deletion mutant was impaired in bacterial virulence and growth in planta; furthermore, the mutant showed reduced growth in minimal media containing ?-ketoglutaric acid or sodium succinate as the sole carbon source. The reduced virulence and the deficiency in ?-ketoglutaric acid utilization by the kgtP mutant were restored to wild-type levels by the presence of kgtP in trans. The expression of OsIDH, which is responsible for the synthesis of ?-ketoglutaric acid in rice, was enhanced when KgtP was present in the pathogen. To our knowledge, this is the first report demonstrating that KgtP, which is regulated by HrpG and HrpX and secreted by the T3SS in Xanthomonas oryzae pv. oryzae, transports ?-ketoglutaric acid when the pathogen infects rice.

Guo, Wei; Cai, Lu-Lu; Zou, Hua-Song; Ma, Wen-Xiu; Liu, Xi-Ling; Zou, Li-Fang; Li, Yu-Rong

2012-01-01

91

Metabolic changes of Phomopsis longicolla fermentation and its effect on antimicrobial activity against Xanthomonas oryzae.  

PubMed

Bacterial blight, an important and potentially destructive bacterial disease in rice caused by Xanthomonas oryzae pv. oryzae (Xoo), has recently developed resistance to the available antibiotics. In this study, mass spectrometry (MS)-based metabolite profiling and multivariate analysis were employed to investigate the correlation between time-dependent metabolite changes and antimicrobial activities against Xoo over the course of Phomopsis longicolla S1B4 fermentation. Metabolites were clearly differentiated based on fermentation time into phase 1 (days 4-8) and phase 2 (days 10-20) in the principal component analysis (PCA) plot. The multivariate statistical analysis showed that the metabolites contributing significantly for phases 1 and 2 were deacetylphomoxanthone B, monodeacetylphomoxanthone B, fusaristatin A, and dicerandrols A, B, and C as identified by liquid chromatography-mass spectrometry (LC-MS), and dimethylglycine, isobutyric acid, pyruvic acid, ribofuranose, galactofuranose, fructose, arabinose, hexitol, myristic acid, and propylstearic acid were identified by gas chromatography-mass spectrometry (GC-MS)-based metabolite profiling. The most significantly different secondary metabolites, especially deacetylphomoxanthone B, monodeacetylphomoxanthone B, and dicerandrol A, B and C, were positively correlated with antibacterial activity against Xoo during fermentation. PMID:23412059

Choi, Jung Nam; Kim, Jiyoung; Ponnusamy, Kannan; Lim, Chaesung; Kim, Jeong Gu; Muthaiya, Maria John; Lee, Choonghwan

2013-02-01

92

Draft Genome Sequence of the Xanthomonas cassavae Type Strain CFBP 4642.  

PubMed

We report the draft genome sequence of the Xanthomonas cassavae type strain CFBP 4642, the causal agent of bacterial necrosis on cassava plants. These data will allow the comparison of this nonvascular pathogen with the vascular pathogen Xanthomonas axonopodis pv. manihotis, both infecting the same host, which will facilitate the development of diagnostic tools. PMID:23990580

Bolot, Stéphanie; Munoz Bodnar, Alejandra; Cunnac, Sébastien; Ortiz, Erika; Szurek, Boris; Noël, Laurent D; Arlat, Matthieu; Jacques, Marie-Agnès; Gagnevin, Lionel; Portier, Perrine; Fischer-Le Saux, Marion; Carrere, Sébastien; Koebnik, Ralf

2013-08-29

93

Characterization and genetic analysis of a novel rice spotted-leaf mutant HM47 with broad-spectrum resistance to Xanthomonas oryzae pv. oryzae.  

PubMed

A stable inherited rice spotted-leaf mutant HM47 derived from an EMS-induced IR64 mutant bank was identified. The mutant expressed hypersensitive response (HR)-like symptoms throughout its whole life from the first leaf to the flag leaf, without pathogen invasion. Initiation of the lesions was induced by light under natural summer field conditions. Expression of pathogenesis-related genes including PAL, PO-C1, POX22.3 and PBZ1 was enhanced significantly in association with cell death and accumulation of H2 O2 at and around the site of lesions in the mutant in contrast to that in the wild-type (WT). Disease reaction to Xanthomonas oryzae pv. oryzae from the Philippines and China showed that HM47 is a broad-spectrum disease-resistant mutant with enhanced resistance to multiple races of bacterial blight pathogens tested. An F2 progeny test showed that bacterial blight resistance to race HB-17 was co-segregated with the expression of lesions. Genetic analysis indicated that the spotted-leaf trait was controlled by a single recessive gene, tentatively named spl(HM47) , flanked by two insertion/deletion markers in a region of approximately 74 kb on the long arm of chromosome 4. Ten open reading frames are predicted, and all of them are expressed proteins. Isolation and validation of the putative genes are currently underway. PMID:23210861

Feng, Bao-Hua; Yang, Yang; Shi, Yong-Feng; Shen, Hai-Chao; Wang, Hui-Mei; Huang, Qi-Na; Xu, Xia; Lü, Xiang-Guang; Wu, Jian-Li

2013-02-04

94

Screening of potential bacterial antagonists for control of sheath blight in rice and development of suitable bacterial formulations for effective application  

Microsoft Academic Search

Soil samples were taken from paddy rice fields in 14 provinces in the southern part of Thailand. Bacteria were isolated from\\u000a these soils using the soil dilution plate method on King’s B medium and Thornton’s standardised medium. Isolation yielded\\u000a 323 bacterial isolates which were subsequently tested for their effectiveness in inhibiting mycelial growth of Rhizoctonia solani, the causal agent of

Mana Kanjanamaneesathian; Chirasak Kusonwiriyawong; Ashara Pengnoo; Ladda Nilratana

1998-01-01

95

MultiLocus Sequence Analysis- and Amplified Fragment Length Polymorphism-based characterization of xanthomonads associated with bacterial spot of tomato and pepper and their relatedness to Xanthomonas species.  

PubMed

MultiLocus Sequence Analysis (MLSA) and Amplified Fragment Length Polymorphism (AFLP) were used to measure the genetic relatedness of a comprehensive collection of xanthomonads pathogenic to solaneous hosts to Xanthomonas species. The MLSA scheme was based on partial sequences of four housekeeping genes (atpD, dnaK, efp and gyrB). Globally, MLSA data unambiguously identified strains causing bacterial spot of tomato and pepper at the species level and was consistent with AFLP data. Genetic distances derived from both techniques showed a close relatedness of (i) X. euvesicatoria, X. perforans and X. alfalfae and (ii) X. gardneri and X. cynarae. Maximum likelihood tree topologies derived from each gene portion and the concatenated data set for species in the X. campestris 16S rRNA core (i.e. the species cluster comprising all strains causing bacterial spot of tomato and pepper) were not congruent, consistent with the detection of several putative recombination events in our data sets by several recombination search algorithms. One recombinant region in atpD was identified in most strains of X. euvesicatoria including the type strain. PMID:22336775

Hamza, A A; Robene-Soustrade, I; Jouen, E; Lefeuvre, P; Chiroleu, F; Fisher-Le Saux, M; Gagnevin, L; Pruvost, O

2012-02-13

96

The xrvA gene of Xanthomonas oryzae pv. oryzae, encoding an H-NS-like protein, regulates virulence in rice.  

PubMed

Xanthomonas oryzae pv. oryzae (Xoo) causes bacterial blight disease in rice, one of the most serious rice diseases. The xrvA gene from Xoo strain 1,3751 encodes a protein containing a histone-like nucleoid-structuring protein (H-NS) domain. The expression of xrvA in strain 1,3751 was enhanced in XOM2 minimal medium. Mutation of the xrvA gene of strain 1,3751 led to a significant reduction in virulence in the host plant rice, a delayed hypersensitive response in the nonhost castor-oil plant, a decrease in extracellular polysaccharide and diffusible signal factor production, and an increase in intracellular glycogen accumulation. Northern hybridization analyses revealed that the virulence-associated genes hrpG, hrpX, rpfC, rpfF, rpfG and gumB were downregulated in the xrvA mutant compared to the wild-type and complemented strains. Interestingly, increase of copy number of xrvA in the wild-type strain 1,3751 resulted in a strain showing similar phenotypes as the xrvA mutant and a reduction of the expression of gumB, hrpX, rpfC, rpfF and rpfG. These findings indicate that the xrvA gene, which is highly conserved in the sequenced strains of Xanthomonas, encodes an important regulatory factor for the virulence of Xoo. PMID:19423625

Feng, Jia-Xun; Song, Zhi-Zhong; Duan, Cheng-Jie; Zhao, Shuai; Wu, Ying-Qiao; Wang, Chao; Dow, J Maxwell; Tang, Ji-Liang

2009-05-07

97

A Cell Wall-Degrading Esterase of Xanthomonas oryzae Requires a Unique Substrate Recognition Module for Pathogenesis on Rice[W  

PubMed Central

Xanthomonas oryzae pv oryzae (Xoo) causes bacterial blight, a serious disease of rice (Oryza sativa). LipA is a secretory virulence factor of Xoo, implicated in degradation of rice cell walls and the concomitant elicitation of innate immune responses, such as callose deposition and programmed cell death. Here, we present the high-resolution structural characterization of LipA that reveals an all-helical ligand binding module as a distinct functional attachment to the canonical hydrolase catalytic domain. We demonstrate that the enzyme binds to a glycoside ligand through a rigid pocket comprising distinct carbohydrate-specific and acyl chain recognition sites where the catalytic triad is situated 15 Å from the anchored carbohydrate. Point mutations disrupting the carbohydrate anchor site or blocking the pocket, even at a considerable distance from the enzyme active site, can abrogate in planta LipA function, exemplified by loss of both virulence and the ability to elicit host defense responses. A high conservation of the module across genus Xanthomonas emphasizes the significance of this unique plant cell wall–degrading function for this important group of plant pathogenic bacteria. A comparison with the related structural families illustrates how a typical lipase is recruited to act on plant cell walls to promote virulence, thus providing a remarkable example of the emergence of novel functions around existing scaffolds for increased proficiency of pathogenesis during pathogen-plant coevolution.

Aparna, Gudlur; Chatterjee, Avradip; Sonti, Ramesh V.; Sankaranarayanan, Rajan

2009-01-01

98

A transposon insertion in the gumG homologue of Xanthomonas oryzae pv. oryzae causes loss of extracellular polysaccharide production and virulence.  

PubMed

Xanthomonas oryzae pv. oryzae causes a serious disease of rice called bacterial leaf blight. It produces copious amounts of extracellular polysaccharide (EPS). An EPS- and virulence-deficient mutant of X. oryzae pv. oryzae was isolated by Tn5 mutagenesis. The mutant allele in this strain was cloned by transposon tagging in the Escherichia coli vector pBluescript and the DNA sequences flanking the transposon insertion site were determined. Computer-based similarity searches in the DNA database using the BLAST algorithm showed these sequences to be 78% identical at the nucleotide level to a gene, gumG, in the gum cluster, which is required for EPS biosynthesis in Xanthomonas campestris pv. campestris. A 36-kb X. oryzae pv. oryzae genomic clone containing the putative EPS biosynthetic gene cluster of X. oryzae pv. oryzae restored both EPS production and virulence proficiency to the gumGXo::Tn5 mutant. The results suggest that EPS is an important virulence factor of X. oryzae pv. oryzae. PMID:10481086

Dharmapuri, S; Sonti, R V

1999-10-01

99

Biosynthesis of Silver Nanoparticles by Phytopathogen Xanthomonas oryzae pv. oryzae Strain BXO8.  

PubMed

Extracellular biogenic synthesis of silver nanoparticles with various shapes using the rice bacterial blight bacterium Xanthomonas oryzae pv. oryzae BXO8 is reported. The synthesized silver nanoparticles were characterized by UV-Vis spectroscopy, powder X-ray diffractometry (XRD), scanning electron microscopy, energy dispersive X-ray spectrometry, and highresolution transmission electron microscopy (HR-TEM). Based on the evidence of HR-TEM, the synthesized particles were found to be spherical, with anisotropic structures such as triangles and rods, with an average size of 14.86 nm. The crystalline nature of silver nanoparticles was evident from the bright circular spots in the SAED pattern, clear lattice fringes in the high-resolution TEM images, and peaks in the XRD pattern. The FTIR spectrum showed that biomolecules containing amide and carboxylate groups are involved in the reduction and stabilization of the silver nanoparticles. Using such a biological method for the synthesis of silver nanoparticles is a simple, viable, cost-effective, and environmentally friendly process, which can be used in antimicrobial therapy. PMID:23751558

Narayanan, Kannan Badri; Sakthivel, Natarajan

2013-09-28

100

Involvement of bacterial TonB-dependent signaling in the generation of an oligogalacturonide damage-associated molecular pattern from plant cell walls exposed to Xanthomonas campestris pv. campestris pectate lyases  

PubMed Central

Background Efficient perception of attacking pathogens is essential for plants. Plant defense is evoked by molecules termed elicitors. Endogenous elicitors or damage-associated molecular patterns (DAMPs) originate from plant materials upon injury or pathogen activity. While there are comparably well-characterized examples for DAMPs, often oligogalacturonides (OGAs), generated by the activity of fungal pathogens, endogenous elicitors evoked by bacterial pathogens have been rarely described. In particular, the signal perception and transduction processes involved in DAMP generation are poorly characterized. Results A mutant strain of the phytopathogenic bacterium Xanthomonas campestris pv. campestris deficient in exbD2, which encodes a component of its unusual elaborate TonB system, had impaired pectate lyase activity and caused no visible symptoms for defense on the non-host plant pepper (Capsicum annuum). A co-incubation of X. campestris pv. campestris with isolated cell wall material from C. annuum led to the release of compounds which induced an oxidative burst in cell suspension cultures of the non-host plant. Lipopolysaccharides and proteins were ruled out as elicitors by polymyxin B and heat treatment, respectively. After hydrolysis with trifluoroacetic acid and subsequent HPAE chromatography, the elicitor preparation contained galacturonic acid, the monosaccharide constituent of pectate. OGAs were isolated from this crude elicitor preparation by HPAEC and tested for their biological activity. While small OGAs were unable to induce an oxidative burst, the elicitor activity in cell suspension cultures of the non-host plants tobacco and pepper increased with the degree of polymerization (DP). Maximal elicitor activity was observed for DPs exceeding 8. In contrast to the X. campestris pv. campestris wild type B100, the exbD2 mutant was unable to generate elicitor activity from plant cell wall material or from pectin. Conclusions To our knowledge, this is the second report on a DAMP generated by bacterial features. The generation of the OGA elicitor is embedded in a complex exchange of signals within the framework of the plant-microbe interaction of C. annuum and X. campestris pv. campestris. The bacterial TonB-system is essential for the substrate-induced generation of extracellular pectate lyase activity. This is the first demonstration that a TonB-system is involved in bacterial trans-envelope signaling in the context of a pathogenic interaction with a plant.

2012-01-01

101

Plant Disease Lesson: Bacterial spot of pepper and tomato  

NSDL National Science Digital Library

This plant disease lesson on Bacterial spot of pepper and tomato (caused by Xanthomonas axonopodis (syn. campestris) pathovar vesicatoria, Xanthomonas vesicatoria, Xanthomonas gardneri) includes information on symptoms and signs, pathogen biology, disease cycle and epidemiology, disease management, and the significance of the disease. Selected references are listed and a glossary is also available for use with this resource.

David F. Ritchie (North Carolina State University;)

2000-10-27

102

Comparison of Genomes of Three Xanthomonas oryzae Bacteriophages  

PubMed Central

Background Xp10 and OP1 are phages of Xanthomonas oryzae pv. oryzae (Xoo), the causative agent of bacterial leaf blight in rice plants, which were isolated in 1967 in Taiwan and in 1954 in Japan, respectively. We recently isolated the Xoo phage Xop411. Results The linear Xop411 genome (44,520 bp, 58 ORFs) sequenced here is 147 bp longer than that of Xp10 (60 ORFs) and 735 bp longer than that of OP1 (59 ORFs). The G+C contents of OP1 (51%) and Xop411 and Xp10 (52% each) are less than that of the host (65%). The 9-bp 3'-overhangs (5'-GGACAGTCT-3') in Xop411 and Xp10 are absent from OP1. More of the deduced Xop411 proteins share higher degrees of identity with Xp10 than with OP1 proteins, while the right end of the genomes of Xp10 and OP1, containing all predicted promoters, share stronger homology. Xop411, Xp10, and OP1 contain 8, 7, and 6 freestanding HNH endonuclease genes, respectively. These genes can be classified into five groups depending on their possession of the HNH domain (HNN or HNH type) and/or AP2 domain in intact or truncated forms. While the HNN-AP2 type endonuclease genes dispersed in the genome, the HNH type endonuclease genes, each with a unique copy, were located within the same genome context. Mass spectrometry and N-terminal sequencing showed nine Xop411 coat proteins, among which three were identified, six were assigned as coat proteins (4) and conserved phage proteins (2) in Xp10. The major coat protein, in which only the N-terminal methionine is removed, appears to exist in oligomeric forms containing 2 to 6 subunits. The three phages exhibit different patterns of domain duplication in the N-terminus of the tail fiber, which are involved in determination of the host range. Many short repeated sequences are present in and around the duplicated domains. Conclusion Geographical separation may have confined lateral gene transfer among the Xoo phages. The HNN-AP2 type endonucleases were more likely to transfer their genes randomly in the genome and may degenerate after successful transmission. Some repeated sequences may be involved in duplication/loss of the domains in the tail fiber genes.

Lee, Chia-Ni; Hu, Rouh-Mei; Chow, Teh-Yuan; Lin, Juey-Wen; Chen, Hui-Yi; Tseng, Yi-Hsiung; Weng, Shu-Fen

2007-01-01

103

Ascochyta blight of peas  

Technology Transfer Automated Retrieval System (TEKTRAN)

Identification, taxonomy & nomenclature, epidemiology, symptoms, host ranges, and management are described for three fungal pathogens which collectively and individually cause Ascochyta blight of field pea (Pisum sativum): Ascochyta pisi, Ascochyta pinodes, and Ascochyta pinodella. The first two are...

104

Studies on fire blight  

Microsoft Academic Search

Part 1<\\/strong><\\/strong>Effects of water potential and temperature on multiplication of and pressure by Erwinia amylovora in host plantsAnalysis of field data from Eve Billing, England, on the duration of the incubation period of fire blight revealed that temperature and rainfall were positively and interactively correlated with the development rate of fire blight. Values of standard regression coefficients suggest that temperature

H. J. Schouten

1991-01-01

105

XopR, a type III effector secreted by Xanthomonas oryzae pv. oryzae, suppresses microbe-associated molecular pattern-triggered immunity in Arabidopsis thaliana.  

PubMed

Xanthomonas oryzae pv. oryzae is the causal agent of bacterial blight of rice. The XopR protein, secreted into plant cells through the type III secretion apparatus, is widely conserved in xanthomonads and is predicted to play important roles in bacterial pathogenicity. Here, we examined the function of XopR by constructing transgenic Arabidopsis thaliana plants expressing it under control of the dexamethasone (DEX)-inducible promoter. In the transgenic plants treated with DEX, slightly delayed growth and variegation on leaves were observed. Induction of four microbe-associated molecular pattern (MAMP)-specific early-defense genes by a nonpathogenic X. campestris pv. campestris hrcC deletion mutant were strongly suppressed in the XopR-expressing plants. XopR expression also reduced the deposition of callose, an immune response induced by flg22. When transiently expressed in Nicotiana benthamiana, a XopR::Citrine fusion gene product localized to the plasma membrane. The deletion of XopR in X. oryzae pv. oryzae resulted in reduced pathogenicity on host rice plants. Collectively, these results suggest that XopR inhibits basal defense responses in plants rapidly after MAMP recognition. PMID:22204644

Akimoto-Tomiyama, Chiharu; Furutani, Ayako; Tsuge, Seiji; Washington, Erica J; Nishizawa, Yoko; Minami, Eiichi; Ochiai, Hirokazu

2012-04-01

106

Molecular genetics of Erwinia amylovora involved in the development of fire blight  

Microsoft Academic Search

The bacterial plant pathogen, Erwinia amylovora, causes the devastating disease known as fire blight in some Rosaceous plants like apple, pear, quince, raspberry and several ornamentals. Knowledge of the factors affecting the development of fire blight has mushroomed in the last quarter century. On the molecular level, genes encoding a Hrp type III secretion system, genes encoding enzymes involved in

Chang-Sik Oh; Steven V. Beer

2005-01-01

107

Identification of ta-siRNAs and cis-nat-siRNAs in cassava and their roles in response to cassava bacterial blight.  

PubMed

Trans-acting small interfering RNAs (ta-siRNAs) and natural cis-antisense siRNAs (cis-nat-siRNAs) are recently discovered small RNAs (sRNAs) involved in post-transcriptional gene silencing. ta-siRNAs are transcribed from genomic loci and require processing by microRNAs (miRNAs). cis-nat-siRNAs are derived from antisense RNAs produced by the simultaneous transcription of overlapping antisense genes. Their roles in many plant processes, including pathogen response, are mostly unknown. In this work, we employed a bioinformatic approach to identify ta-siRNAs and cis-nat-siRNAs in cassava from two sRNA libraries, one constructed from healthy cassava plants and one from plants inoculated with the bacterium Xanthomonas axonopodis pv. manihotis (Xam). A total of 54 possible ta-siRNA loci were identified in cassava, including a homolog of TAS3, the best studied plant ta-siRNA. Fifteen of these loci were induced, while 39 were repressed in response to Xam infection. In addition, 15 possible cis-natural antisense transcript (cis-NAT) loci producing siRNAs were identified from overlapping antisense regions in the genome, and were found to be differentially expressed upon Xam infection. Roles of sRNAs were predicted by sequence complementarity and our results showed that many sRNAs identified in this work might be directed against various transcription factors. This work represents a significant step toward understanding the roles of sRNAs in the immune response of cassava. PMID:23665476

Quintero, Andrés; Pérez-Quintero, Alvaro L; López, Camilo

2013-05-07

108

Rootstock-regulated gene expression patterns associated with fire blight resistance in apple  

Technology Transfer Automated Retrieval System (TEKTRAN)

Background: Desirable apple varieties are clonally propagated by grafting vegetative scions onto rootstocks. Rootstocks influence many phenotypic traits of the scion, including resistance to pathogens such as Erwinia amylovora, which causes fire blight, the most serious bacterial disease of apple....

109

Fire Blight: Its Nature, Prevention, and Control. A Practical Guide to Integrated Disease Management.  

National Technical Information Service (NTIS)

Fire blight is a serious bacterial disease of apples, pears, quinces, and several plants in the rose family (Rosaceae), including hawthorn, cotoneaster, firethorn (pyracantha), mountainash, blackberry, and raspberry. Outbreaks of this disease are usually ...

T. van der Zwet S. V. Beer

1992-01-01

110

Potential for Control of Seedling Blight of Wheat Caused by Fusarium graminearum and Related Species Using the Bacterial Endophyte Bacillus mojavensis  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fusarium infected-wheat seed decreases germination, seedling emergence, and causes post emergence seedling death, and can contribute to wheat scab and ear rot of maize, with consequent production of mycotoxins such as deoxynivalenol and zearalenone. A patented endophytic bacterial strain, Bacillus ...

111

A Novel Manganese Efflux System, YebN, Is Required for Virulence by Xanthomonas oryzae pv. oryzae  

PubMed Central

Manganese ions (Mn2+) play a crucial role in virulence and protection against oxidative stress in bacterial pathogens. Such pathogens appear to have evolved complex mechanisms for regulating Mn2+ uptake and efflux. Despite numerous studies on Mn2+ uptake, however, only one efflux system has been identified to date. Here, we report on a novel Mn2+ export system, YebN, in Xanthomonas oryzae pv. oryzae (Xoo), the causative agent of bacterial leaf blight. Compared with wild-type PXO99, the yebN mutant was highly sensitive to Mn2+ and accumulated high concentrations of intracellular manganese. In addition, we found that expression of yebN was positively regulated by Mn2+ and the Mn2+-dependent transcription regulator, MntR. Interestingly, the yebN mutant was more tolerant to methyl viologen and H2O2 in low Mn2+ medium than PXO99, but more sensitive in high Mn2+ medium, implying that YebN plays an important role in Mn2+ homoeostasis and detoxification of reactive oxygen species (ROS). Notably, deletion of yebN rendered Xoo sensitive to hypo-osmotic shock, suggesting that YebN may protect against such stress. That mutation of yebN substantially reduced the Xoo growth rate and lesion formation in rice implies that YebN could be involved in Xoo fitness in host. Although YebN has two DUF204 domains, it lacks homology to any known metal transporter. Hence, this is the first report of a novel metal export system that plays essential roles in hypo-osmotic and oxidative stress, and virulence. Our results lay the foundations for elucidating the complex and fascinating relationship between metal homeostasis and host-pathogen interactions.

Li, Chunxia; Tao, Jun; Mao, Daqing; He, Chaozu

2011-01-01

112

Disease Alert: Stemphylium Blight  

Technology Transfer Automated Retrieval System (TEKTRAN)

Lentil leaves showing symptoms of Stemphylium blight were collected from a lentil field northeast of Garfield (near Idaho border) on July 8, 2013, and incubation of the diseased leaves showed typical spores of the pathogen Stemphylium botryosum or other Stemphylium sp. The field was planted with ‘Mo...

113

Ascochyta blight of chickpea  

Technology Transfer Automated Retrieval System (TEKTRAN)

Ascochyta blight of chickpea is caused by the necrotrophic pathogen Ascochyta rabiei. The disease is a serious yield constraint of chickpea worldwide. The pathogen causes necrotic lesions on leaves, stems, flowers, pod and seeds under cool and humid conditions. The pathogen survives in crop debri...

114

Distribution and biological role of the oligopeptide-binding protein (OppA) in Xanthomonas species  

PubMed Central

In this study we investigated the prevalence of the oppA gene, encoding the oligopeptide binding protein (OppA) of the major bacterial oligopeptide uptake system (Opp), in different species of the genus Xanthomonas. The oppA gene was detected in two Xanthomonas axonopodis strains among eight tested Xanthomonas species. The generation of an isogenic oppA-knockout derivative of the Xac 306 strain, showed that the OppA protein neither plays a relevant role in oligopeptide uptake nor contributes to the infectivity and multiplication of the bacterial strain in leaves of sweet orange (Citrus sinensis) and Rangpur lime (Citrus limonia). Taken together these results suggest that the oppA gene has a recent evolutionary history in the genus and does not contribute in the physiology or pathogenesis of X. axonopodis.

2010-01-01

115

Biological control of post-harvest late blight of potatoes  

Technology Transfer Automated Retrieval System (TEKTRAN)

Introduction of US-8 genotypes of Phytophthora infestans has coincided with an increase in severity of potato late blight in North America. As alternatives to chemical fungicides, 18 bacterial strains patented as biological control agents (BCA) of both sprouting and Fusarium dry rot were cultivated...

116

Novel genomic locus with atypical G+C content that is required for extracellular polysaccharide production and virulence in Xanthomonas oryzae pv. oryzae.  

PubMed

Three exopolysaccharide (EPS)- and virulence-deficient mutants of Xanthomonas oryzae pv. oryzae, the causal agent of bacterial leaf blight of rice, were isolated by Tn5 mutagenesis. These insertions are not located within the gum gene cluster. A 40-kb cosmid clone that restored EPS production and virulence to all three mutants was isolated, and the three transposon insertions were localized to contiguous 4.3- and 3.5-kb EcoRI fragments that are included in this clone. Sequence data indicate that two of the transposon insertions are in genes that encode a putative sugar nucleotide epimerase and a putative glycosyl transferase, respectively; the third insertion is located between the glycosyl transferase gene and a novel open reading frame (ORF). A 5.5-kb genomic region in which these three ORFs are located has a G+C content of 5-1.7%, quite different from the G+C content of approximately 65.0% that is typical of X. oryzae pv. oryzae. Homologues of this locus have not yet been reported in any other xanthomonad. PMID:11763133

Dharmapuri, S; Yashitola, J; Vishnupriya, M R; Sonti, R V

2001-11-01

117

Xanthomonas axonopodis pv. citri uses a plant natriuretic peptide-like protein to modify host homeostasis  

Microsoft Academic Search

Plant natriuretic peptides (PNPs) are a class of extracellular, systemically mobile molecules that elicit a number of plant responses important in homeostasis and growth. The bacterial citrus pathogen, Xanthomonas axonopodis pv. citri, also contains a gene encoding a PNP-like protein, XacPNP, that shares significant sequence similarity and identical domain organization with plant PNPs but has no homologues in other bacteria.

Natalia Gottig; Betiana S. Garavaglia; Lucas D. Daurelio; Alex Valentine; Chris Gehring; Elena G. Orellano; Jorgelina Ottado

2008-01-01

118

The bacterial effector DspA/E is toxic in Arabidopsis thaliana and is required for multiplication and survival of fire blight pathogen.  

PubMed

The type III effector DspA/E is an essential pathogenicity factor of the phytopathogenic bacterium Erwinia amylovora. We showed that DspA/E was required for transient bacterial growth in nonhost Arabidopsis thaliana leaves, as an E.?amylovora dspA/E mutant was unable to grow. We expressed DspA/E in A.?thaliana transgenic plants under the control of an oestradiol-inducible promoter, and found that DspA/E expressed in?planta restored the growth of a dspA/E mutant. DspA/E expression in these transgenic plants led to the modulation by at least two-fold of the expression of 384 genes, mostly induced (324 genes). Both induced and repressed genes contained high proportions of defence genes. DspA/E expression ultimately resulted in plant cell death without requiring a functional salicylic acid signalling pathway. Analysis of A.?thaliana transgenic seedlings expressing a green fluorescent protein (GFP):DspA/E fusion indicated that the fusion protein could only be detected in a few cells per seedling, suggesting the degradation or absence of accumulation of DspA/E in plant cells. Consistently, we found that DspA/E repressed plant protein synthesis when injected by E.?amylovora or when expressed in transgenic plants. Thus, we conclude that DspA/E is toxic to A.?thaliana: it promotes modifications, among which the repression of protein synthesis could be determinant in the facilitation of necrosis and bacterial growth. PMID:23634775

Degrave, Alexandre; Moreau, Manon; Launay, Alban; Barny, Marie-Anne; Brisset, Marie-Noëlle; Patrit, Oriane; Taconnat, Ludivine; Vedel, Regine; Fagard, Mathilde

2013-03-12

119

Integrated biological control of bacterial speck and spot of tomato under field conditions using foliar biological control agents and plant growth-promoting rhizobacteria  

Microsoft Academic Search

Integration of foliar bacterial biological control agents and plant growth promoting rhizobacteria (PGPR) was investigated to determine whether biological control of bacterial speck of tomato, caused by Pseudomonas syringae pv. tomato, and bacterial spot of tomato, caused by Xanthomonas campestris pv. vesicatoria and Xanthomonas vesicatoria, could be improved. Three foliar biological control agents and two selected PGPR strains were employed

P. Ji; H. L. Campbell; J. W. Kloepper; J. B. Jones; T. V. Suslow; M. Wilson

2006-01-01

120

Integrated biological control of bacterial speck and spot of tomato under Weld conditions using foliar biological control agents and plant growth-promoting rhizobacteria  

Microsoft Academic Search

Integration of foliar bacterial biological control agents and plant growth promoting rhizobacteria (PGPR) was investigated to deter- mine whether biological control of bacterial speck of tomato, caused by Pseudomonas syringae pv. tomato, and bacterial spot of tomato, caused by Xanthomonas campestris pv. vesicatoria and Xanthomonas vesicatoria, could be improved. Three foliar biological control agents and two selected PGPR strains were

P. Ji; H. L. Campbell; J. W. Kloepper; J. B. Jones; T. V. Suslow; M. Wilson

2006-01-01

121

Restoration of pathogenicity of avirulent Xanthomonas oryzae pv. oryzae and X. campestris pathovars by reciprocal complementation with the hrpXo and hrpXc genes and identification of HrpX function by sequence analyses.  

PubMed

The molecular basis of pathogenesis by Xanthomonas oryzae pv. oryzae has been partly elucidated by the identification of a gene, hrpXo, required for bacterial blight on rice. A mutation in hrpXo results in the loss of pathogenicity on rice and the loss of hypersensitivity on nonhosts such as Datura stramonium and radishes. Pathogenicity and its ability to cause the hypersensitive reaction is restored by complementing the mutant with the heterologous hrpXc gene derived from X. campestris pv. campestris. Conversely, hrpXo complements nonpathogenic mutants of X. campestris pv. campestris and X. campetstris pv, armoraciae. Mutants bearing the heterologous hrpX gene are restored in their abilities to cause diseases typical of their chromosomal background and not the hypersensitive reaction on their respective hosts. The hrpXo and hrpXc genes are therefore functionally equivalent, and this functional equivalence extends into X. campestris pv. armoraciae and possibly into other X. campestris pathovars, since this gene is highly conserved among eight other pathovars tested. Sequence analyses of hrpXo revealed an open reading frame of 1,452 bp with a coding capacity for a protein of 52.3 kDa. The protein contains a consensus domain for possible protein myristoylation whose consequence may result in a loss of recognition by host defense and surveillance systems. PMID:8458844

Kamdar, H V; Kamoun, S; Kado, C I

1993-04-01

122

Isolation of the chitinolytic bacteria Xanthomonas maltophilia and Serratia marcescens as biological control agents for summer patch disease of turfgrass  

Microsoft Academic Search

A mycelial baiting method was used to isolate chitinolytic bacteria from soils known to harbor Magnaporthe poae, the causal agent of summer patch on Kentucky bluegrass. Two bacterial isolates, identified as Xanthomonas maltophilia 34S1 and Serratia marcescens 9M5, suppressed summer patch symptom development in Kentucky bluegrass cv. Baron by more than 70 and 50%, respectively, when compared to untreated control

Donald Y. Kobayashi; Mirta Guglielmoni; Bruce B. Clarke

1995-01-01

123

Correlations between disease severity, glucosinolate profiles and total phenolics and Xanthomonas campestris pv. campestris inoculation of different Brassicaceae  

Microsoft Academic Search

Many Brassicaceae species are economically important crops and Xanthomonas campestris pv. campestris (Xcc), the causal agent of black rot, is considered one of the most important necrotrophic plant bacterial diseases occurring worldwide on these and many other crops. Therefore identifying resistance mechanisms and genes is crucial. Researchers continue to investigate the role of phytochemicals (plant secondary metabolites) in protecting plants

Alfredo Aires; Carla S. P. Dias; Rosa Carvalho; Maria Helena Oliveira; António A. Monteiro; Manuel Vieira Simões; Eduardo A. S. Rosa; Richard N. Bennett; Maria José Saavedra

2011-01-01

124

Construction of a genetic linkage map for identification of molecular markers associated with resistance to Xanthomonas arboriciola pv. pruni in peach [Prunus persica (L.) Batsch  

Technology Transfer Automated Retrieval System (TEKTRAN)

Bacterial spot, caused by Xanthomonas campestris pv. pruni, is a serious disease that can affect peach fruit quality and production. The molecular basis of its tolerance and susceptibility is yet to be understood. To study the genetics of the peach in response to bacterial spot, an F2 population of ...

125

Late blight in the United States  

Technology Transfer Automated Retrieval System (TEKTRAN)

This book chapter is specific to late blight in the United States and will include a review and discussion of the history of late blight on potato and tomato crops, changes in grower attitudes towards late blight, present status of the disease in the US, methods for identification, management, and c...

126

Identification of Genes Required for Nonhost Resistance to Xanthomonas oryzae pv. oryzae Reveals Novel Signaling Components  

Microsoft Academic Search

BackgroundNonhost resistance is a generalized, durable, broad-spectrum resistance exhibited by plant species to a wide variety of microbial pathogens. Although nonhost resistance is an attractive breeding strategy, the molecular basis of this form of resistance remains unclear for many plant-microbe pathosystems, including interactions with the bacterial pathogen of rice, Xanthomonas oryzae pv. oryzae (Xoo).Methods and FindingsVirus-induced gene silencing (VIGS) and

Wen Li; You-Ping Xu; Zhi-Xin Zhang; Wen-Yuan Cao; Fei Li; Xueping Zhou; Gong-You Chen; Xin-Zhong Cai

2012-01-01

127

Plant Disease Lesson: Early blight  

NSDL National Science Digital Library

This plant disease lesson on early blight (caused by the fungus Alternaria solani) includes information on symptoms and signs, pathogen biology, disease cycle and epidemiology, disease management, and the significance of the disease. Selected references are listed and a glossary is also available for use with this resource.

Greg Kemmitt (Dow AgroSciences;)

2002-08-09

128

GENES CONDITIONING HALO BLIGHT RESISTANCE TO RACES 1, 7, AND 9 OCCUR IN A TIGHT CLUSTER  

Technology Transfer Automated Retrieval System (TEKTRAN)

Halo blight is a seed-borne bacterial disease (caused by Pseudomonas syringae pv. phaseolicola) that infects common bean (Phaseolus vulgaris L.) worldwide. Genetic resistance is the most effective control method. A host/pathogen differential series identifies five resistance genes. Our goal is to f...

129

BACILLUS SPECIES NRRL B-30212 FOR REDUCING FUSARIUM HEAD BLIGHT IN CEREALS  

Technology Transfer Automated Retrieval System (TEKTRAN)

We have discovered 4 yeasts and 3 bacteria that are superior antagonists of Fusarium graminearum, the primary causal agent of Fusarium head blight of wheat and barley in the United States. Previous patents have been issued regarding the yeast strains and two of the bacterial strains. In this pate...

130

QTLS FOR PANICLE BLIGHT RESISTANCE AND THEIR ASSOCIATION WITH RESISTANCE TO OTHER DISEASES  

Technology Transfer Automated Retrieval System (TEKTRAN)

After the discovery of the bacterial pathogen Burkholderia glumae as the cause of panicle blight disease in rice, an inoculated nursery screening procedure was established at the LSU Agricultural Center Rice Research Station in Crowley, LA for identifying genetically resistant germplasm. Major genes...

131

Computational Identification of Candidate Genes Involved in Response to Fire Blight in Apples  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fire blight (Erwinia amylovora) is a destructive bacterial disease affecting plants in the Rosaceae including apple, pear, and quince. The disease is common in North America, and kills blossoms, shoots, limbs, and, sometimes, entire trees. Bioinformatics tools were used in collaboration with a NRI-f...

132

Identification and fine-mapping of Xa33, a novel gene for resistance to Xanthomonas oryzae pv. oryzae.  

PubMed

Broadening of the genetic base for identification and transfer of genes for resistance to insect pests and diseases from wild relatives of rice is an important strategy in resistance breeding programs across the world. An accession of Oryza nivara, International Rice Germplasm Collection (IRGC) accession number 105710, was identified to exhibit high level and broad-spectrum resistance to Xanthomonas oryzae pv. oryzae. In order to study the genetics of resistance and to tag and map the resistance gene or genes present in IRGC 105710, it was crossed with the bacterial blight (BB)-susceptible varieties 'TN1' and 'Samba Mahsuri' (SM) and then backcrossed to generate backcross mapping populations. Analysis of these populations and their progeny testing revealed that a single dominant gene controls resistance in IRGC 105710. The BC(1)F(2) population derived from the cross IRGC 105710/TN1//TN1 was screened with a set of 72 polymorphic simple-sequence repeat (SSR) markers distributed across the rice genome and the resistance gene was coarse mapped on chromosome 7 between the SSR markers RM5711 and RM6728 at a genetic distance of 17.0 and 19.3 centimorgans (cM), respectively. After analysis involving 49 SSR markers located between the genomic interval spanned by RM5711 and RM6728, and BC(2)F(2) population consisting of 2,011 individuals derived from the cross IRGC 105710/TN1//TN1, the gene was fine mapped between two SSR markers (RMWR7.1 and RMWR7.6) located at a genetic distance of 0.9 and 1.2 cM, respectively, from the gene and flanking it. The linkage distances were validated in a BC(1)F(2) mapping population derived from the cross IRGC 105710/SM//2 × SM. The BB resistance gene present in the O. nivara accession was identified to be novel based on its unique map location on chromosome 7 and wider spectrum of BB resistance; this gene has been named Xa33. The genomic region between the two closely flanking SSR markers was in silico analyzed for putatively expressed candidate genes. In total, eight genes were identified in the region and a putative gene encoding serinethreonine kinase appears to be a candidate for the Xa33 gene. PMID:21970567

Kumar, P Natraj; Sujatha, K; Laha, G S; Rao, K Srinivasa; Mishra, B; Viraktamath, B C; Hari, Y; Reddy, C S; Balachandran, S M; Ram, T; Madhav, M Sheshu; Rani, N Shobha; Neeraja, C N; Reddy, G Ashok; Shaik, H; Sundaram, R M

2012-02-01

133

Ectopic expression of Hrf1 enhances bacterial resistance via regulation of diterpene phytoalexins, silicon and reactive oxygen species burst in rice.  

PubMed

Harpin proteins as elicitor derived from plant gram negative bacteria such as Xanthomonas oryzae pv. oryzae (Xoo), Erwinia amylovora induce disease resistance in plants by activating multiple defense responses. However, it is unclear whether phytoalexin production and ROS burst are involved in the disease resistance conferred by the expression of the harpin(Xoo) protein in rice. In this article, ectopic expression of hrf1 in rice enhanced resistance to bacterial blight. Accompanying with the activation of genes related to the phytoalexin biosynthesis pathway in hrf1-transformed rice, phytoalexins quickly and consistently accumulated concurrent with the limitation of bacterial growth rate. Moreover, the hrf1-transformed rice showed an increased ability for ROS scavenging and decreased hydrogen peroxide (H(2)O(2)) concentration. Furthermore, the localization and relative quantification of silicon deposition in rice leaves was detected by scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometer (EDS). Finally, the transcript levels of defense response genes increased in transformed rice. These results show a correlation between Xoo resistance and phytoalexin production, H(2)O(2), silicon deposition and defense gene expression in hrf1-transformed rice. These data are significant because they provide evidence for a better understanding the role of defense responses in the incompatible interaction between bacterial disease and hrf1-transformed plants. These data also supply an opportunity for generating nonspecific resistance to pathogens. PMID:22970151

Li, Wenqi; Shao, Min; Zhong, Weigong; Yang, Jie; Okada, Kazunori; Yamane, Hisakazu; Zhang, Lei; Wang, Guang; Wang, Dong; Xiao, Shanshan; Chang, Shanshan; Qian, Guoliang; Liu, Fengquan

2012-09-06

134

Glutamate transport and xanthan gum production in the plant pathogen Xanthomonas axonopodis pv. citri.  

PubMed

L-glutamate plays a central role in nitrogen metabolism in all living organisms. In the genus Xanthomonas, the nitrogen nutrition is an important factor involved in the xanthan gum production, an important exopolysaccharide with various industrial and biotechnological applications. In this report, we demonstrate that the use of L-glutamate by the phytopathogen Xanthomonas axonopodis pv. citri as a nitrogen source in defined medium significantly increases the production of xanthan gum. This increase is dependent on the L-glutamate concentration. In addition, we have also characterized a glutamate transport system that is dependent on a proton gradient and on ATP and is modulated by amino acids that are structurally related to glutamate. This is the first biochemical characterization of an energy substrate transport system observed in a bacterial phytopathogen with a broad economic and industrial impact due to xanthan gum production. PMID:23719672

Rojas, Robert; Nishidomi, Sabrina; Nepomuceno, Roberto; Oshiro, Elisa; de Cassia Café Ferreira, Rita

2013-05-30

135

Marker-assisted Selection for Combining Resistance to Bacterial Spot and Bacterial Speck in Tomato  

Microsoft Academic Search

ADDITIONAL INDEX WORDS. Xanthomonas euvesicatoria, X. vesicatoria, X. perforans, X. gardneri, Pseudomonas syringae pv. tomato, plant breeding, DNA isolation method ABSTRACT. The lack of resistance to bacterial diseases increases both the fi nancial cost and environmental impact of tomato (Lycopersicon esculentum Mill.) production while reducing yield and quality. Because several bacterial diseases can be present in the same fi eld,

Wencai Yang; David M. Francis

2005-01-01

136

Antibiosis Contributes to Biological Control of Fire Blight by Pantoea agglomerans Strain Eh252 in Orchards.  

PubMed

ABSTRACT Fire blight, caused by Erwinia amylovora, is the most serious bacterial disease of pear and apple trees. Biological control with strains of Pantoea agglomerans (syn. Erwinia herbicola) may provide an effective disease management strategy for fire blight. Most strains of P. agglomerans evaluated for suppression of fire blight produce compounds that inhibit the growth of E. amylovora in culture. The role of these inhibitory compounds in fire blight suppression in orchard environments has not been studied. In seven field trials in Oregon, we compared the population dynamics and disease suppression with P. agglomerans Eh252, a strain that produces a single antibiotic, with its near-isogenic antibiotic-deficient derivative, strain 10:12. Water or suspensions of Eh252 or 10:12 (1 x 10(8) CFU/ml) were applied at 30 and 70% bloom to pear or apple trees. Aqueous suspensions of freeze-dried cells of E. amylovora (3 x 10(5) CFU/ml) were applied at full bloom. Additional trees were treated with streptomycin or oxytetracycline at 30 and 70% bloom and in some experiments, 1 day after application of the pathogen. Population sizes of Eh252 or 10:12 on pear blossoms were estimated by spreading dilutions of blossom washes on culture media. Average population sizes of Eh252 and 10:12 on blossoms ranged from 10(5) to 10(7) CFU, and in five of six trials, the relative area under the population curve of Eh252 was not significantly different than that of its derivative 10:12. Both Eh252 and 10:12 reduced the growth of the pathogen on blossoms compared with inoculated water-treated controls. Eh252 significantly decreased the incidence of fire blight in six of seven field trials compared with the incidence on water-treated trees, and 10:12 similarly reduced the incidence of fire blight in four of seven trials. In three of seven field trials, trees treated with Eh252 had a significantly lower incidence of fire blight compared with trees treated 3 with 10:12. Overall,3 Eh252 reduced the incidence of fire blight by 55 +/- 8%, 10:12 by 30 +/- 6%, streptomycin by 75 +/- 4%, and oxytetracycline by 16 +/- 14%. The effectiveness of strain 10:12 compared with water treatment indicates that other mechanisms (e.g., competitive exclusion or habitat modification) also contribute to disease suppression by P. agglomerans. The increased suppression of fire blight by the parental strain Eh252 compared with the antibiotic-deficient mutant 10:12 indicates that antibiosis is an important mechanism of biological control of fire blight. PMID:18944246

Stockwell, V O; Johnson, K B; Sugar, D; Loper, J E

2002-11-01

137

Iron homeostasis and fire blight susceptibility in transgenic pear plants overexpressing a pea ferritin gene.  

PubMed

The bacterial pathogen Erwinia amylovora causes the devastating disease known as fire blight in some rosaceous plants including apple and pear. One of the pathogenicity factors affecting fire blight development is the production of a siderophore, desferrioxamine, which overcomes the limiting conditions in plant tissues and also protects bacteria against active oxygen species. In this paper we examine the effect of an iron chelator protein encoded by the pea ferritin gene on the fire blight susceptibility of pear (Pyrus communis). Transgenic pear clones expressing this gene controlled either by the constitutive promoter CaMV 35S or by the inducible promoter sgd24 promoter were produced. The transgenic clones produced were analysed by Q-RT-PCR to determine the level of expression of the pea transgene. A pathogen-inducible pattern of expression of the pea transgene was observed in sgd24-promoter transformants. Adaptation to iron deficiency in vitro was tested in some transgenic clones and different iron metabolism parameters were measured. No strong effect on iron and chlorophyll content, root reductase activity and fire blight susceptibility was detected in the transgenic lines tested. No transformants showed a significant reduction in susceptibility to fire blight in greenhouse conditions when inoculated with E. amylovora. PMID:21421420

Djennane, Samia; Cesbron, Colette; Sourice, Sophie; Cournol, Raphael; Dupuis, Fabrice; Eychenne, Magali; Loridon, Karine; Chevreau, Elisabeth

2011-02-01

138

The noncanonical type III secretion system of Xanthomonas translucens pv. graminis is essential for forage grass infection.  

PubMed

Xanthomonas translucens pv. graminis (Xtg) is a gammaproteobacterium that causes bacterial wilt on a wide range of forage grasses. To gain insight into the host-pathogen interaction and to identify the virulence factors of Xtg, we compared a draft genome sequence of one isolate (Xtg29) with other Xanthomonas spp. with sequenced genomes. The type III secretion system (T3SS) encoding a protein transport system for type III effector (T3E) proteins represents one of the most important virulence factors of Xanthomonas spp. In contrast with other Xanthomonas spp. assigned to clade 1 on the basis of phylogenetic analyses, we identified an hrp (hypersensitive response and pathogenicity) gene cluster encoding T3SS components and a representative set of 35 genes encoding putative T3Es in the genome of Xtg29. The T3SS was shown to be divergent from the hrp gene clusters of other sequenced Xanthomonas spp. Xtg mutants deficient in T3SS regulating and structural genes were constructed to clarify the role of the T3SS in forage grass colonization. Italian ryegrass infection with these mutants led to significantly reduced symptoms (P < 0.05) relative to plants infected with the wild-type strain. This showed that the T3SS is required for symptom evocation. In?planta multiplication of the T3SS mutants was not impaired significantly relative to the wild-type, indicating that the T3SS is not required for survival until 14 days post-infection. This study represents the first major step to understanding the bacterial colonization strategies deployed by Xtg and may assist in the identification of resistance (R) genes in forage grasses. PMID:23578314

Wichmann, Fabienne; Vorhölter, Frank-Jörg; Hersemann, Lena; Widmer, Franco; Blom, Jochen; Niehaus, Karsten; Reinhard, Sonja; Conradin, Constanze; Kölliker, Roland

2013-04-11

139

HISTOLOGY AND PHYSIOLOGY OF FUSARIUM HEAD BLIGHT  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fusarium head blight re-emerged as a devastating disease of wheat and barley in the 1990s in the midwestern U.S. Research efforts to control the disease have been hampered by limited knowledge of how the fungal head blight pathogens infect and damage head tissue and what natural defenses the plant h...

140

Fingerprinting Closely Related Xanthomonas Pathovars with Random Nonamer Oligonucleotide Microarrays  

PubMed Central

Current bacterial DNA-typing methods are typically based on gel-based fingerprinting methods. As such, they access a limited complement of genetic information and many independent restriction enzymes or probes are required to achieve statistical rigor and confidence in the resulting pattern of DNA fragments. Furthermore, statistical comparison of gel-based fingerprints is complex and nonstandardized. To overcome these limitations of gel-based microbial DNA fingerprinting, we developed a prototype, 47-probe microarray consisting of randomly selected nonamer oligonucleotides. Custom image analysis algorithms and statistical tools were developed to automatically extract fingerprint profiles from microarray images. The prototype array and new image analysis algorithms were used to analyze 14 closely related Xanthomonas pathovars. Of the 47 probes on the prototype array, 10 had diagnostic value (based on a chi-squared test) and were used to construct statistically robust microarray fingerprints. Analysis of the microarray fingerprints showed clear differences between the 14 test organisms, including the separation of X. oryzae strains 43836 and 49072, which could not be resolved by traditional gel electrophoresis of REP-PCR amplification products. The proof-of-application study described here represents an important first step to high-resolution bacterial DNA fingerprinting with microarrays. The universal nature of the nonamer fingerprinting microarray and data analysis methods developed here also forms a basis for method standardization and application to the forensic identification of other closely related bacteria.

Kingsley, Mark T.; Straub, Timothy M.; Call, Douglas R.; Daly, Don S.; Wunschel, Sharon C.; Chandler, Darrell P.

2002-01-01

141

Genetic Diversity and Pathogenicity of Xanthomonas axonopodis Strains Inducing Citrus Canker Disease in Iran and South Korea  

Microsoft Academic Search

For the first time in 1989 citrus bacterial canker disease has seen on Citrus\\u000a aurantiifolia in southern Iran. A total of 43 strains from affected citrus trees, ten strains from South Korea and representative from\\u000a all known five pathotypes of Xanthomonas axonopodis pathogenic on citrus trees were used in this study. Isolated strains from Iran were indistinguishable by phenotypic, FAMEs,

G. Khodakaramian; J. Swings

2011-01-01

142

Transgenic Sweet Orange ( Citrus sinensis L. Osbeck) Expressing the attacin A Gene for Resistance to Xanthomonas citri subsp. citri  

Microsoft Academic Search

Genetic transformation with genes that code for antimicrobial peptides has been an important strategy used to control bacterial\\u000a diseases in fruit crops, including apples, pears, and citrus. Asian citrus canker (ACC) caused by Xanthomonas citri subsp. citri Schaad et al. (Xcc) is a very destructive disease, which affects the citrus industry in most citrus-producing areas of the world. Here, we

Suane Coutinho Cardoso; Janaynna Magalhães Barbosa-Mendes; Raquel Luciana Boscariol-Camargo; Rock Seille Carlos Christiano; Armando Bergamin Filho; Maria Lúcia Carneiro Vieira; Beatriz Madalena Januzzi Mendes; Francisco de Assis Alves Mourão Filho

2010-01-01

143

Effects of agitator configuration and rotational speed on the production of extracellular polysaccharide by Xanthomonas cucurbitae PCSIR B52  

Microsoft Academic Search

A strain of Xanthomonas cucurbitae PCSIR B-52, efficiently produced extracellular polysaccharide using partially deproteinized low-acid cheese whey without hydrolysis. The effects of the agitator configuration and rotational speed on the viscosity of the fermented broth and the productivity of extracellular polysaccharide based on bacterial growth were evaluated in a batch process. Agitation was performed by a six-bladed disc turbine impeller

Shahjahan Baig; Hafiz Sameer Ahmad

1995-01-01

144

Enhancing effect of 4-hydroxy-3-nitrophenylacetic acid on transcription of the ice nucleation-active gene of Xanthomonas campestris.  

PubMed

Cultivation of an ice nucleation-active strain of Xanthomonas campestris in the presence (1 ppm) of 4-hydroxy-3-nitrophenylacetic acid resulted in enhancement of its ice-nucleation activity. Both the ice-nucleation-active protein, InaX, and its mRNA were effectively expressed in the bacterial cells cultured in the presence of this compound. This indicates that this compound stimulated the biosynthesis of the ice-nucleation-active protein. PMID:7765721

Watanabe, M; Watanabe, J; Michigami, Y

1994-12-01

145

Infective Endocarditis due to Stenotrophomonas (Xanthomonas) maltophilia  

Microsoft Academic Search

Stenotrophomonas maltophilia (formerly Xanthomonas maltophilia) is a gram-negative bacillus increasingly associated with serious nosocomial infections. Here, the case of a 69-year-old female patient who developed prosthetic valve endocarditis associated with this organism is described. A review of the literature revealed only 18 previous reports; eight involved native valves, the remainder prosthetic valves. Most cases were associated with risk factors, including

R. G. Munter; A. M. Yinnon; Y. Schlesinger; C. Hershko

1998-01-01

146

Infective endocarditis due to Stenotrophomonas (Xanthomonas) maltophilia  

Microsoft Academic Search

Stenotrophomonas maltophilia (formerlyXanthomonas maltophilia) is a gram-negative bacillus increasingly associated with serious nosocomial infections. Here, the case of a 69-year-old female patient who developed prosthetic valve endocarditis associated with this organism is described. A review of the literature revealed only 18 previous reports; eight involved native valves, the remainder prosthetic valves. Most cases were associated with risk factors, including intravenous

R. G. Munter; A. M. Yinnon; Y. Schlesinger; C. Hershko

1998-01-01

147

Genetic engineering to contain the Vitreoscilla hemoglobin gene enhances degradation of benzoic acid by Xanthomonas maltophilia  

SciTech Connect

Xanthomonas maltophilia was transformed with the gene encoding Vitreoscilla (bacterial) hemoglobin, vgb, and the growth of the engineered strain was compared with that of the untransformed strain using benzoic acid as the sole carbon source. In general, growth of the engineered strain was greater than that of the untransformed strain; this was true for experiments using both overnight cultures and log phase cells as inocula, but particularly for the latter. In both cases the engineered strain was also more efficiency than the untransformed strain in converting benzoic acid into biomass.

Liu, S.C.; Webster, D.A.; Wei, M.L.; Stark, B.C. [Illinois Inst. of Technology, Chicago, IL (United States)

1996-01-05

148

Bacterial Spot of Tomato and Pepper?  

Microsoft Academic Search

INTRODUCTION: Bacterial spot, caused by a group of xanthomonads (Xanthomonas spp.), is a serious disease on tomato and pepper worldwide. It can be destructive to tomato and pepper seedlings and can result in total crop loss in warm and humid areas due to persistence of the causal bacterium and weather conditions favorable to the disease. Repeated chemical application for control

Xiaoan Sun; Misty C. Nielsen; John W. Miller

149

Genetic variation in bean bacterial pathogens  

Microsoft Academic Search

In this review, genetic variation has been reported in bacterial pathogens of Phaseolus vulgaris L., Xanthomonas phaseoli, Pseudomonas phaseolicola, corynebacterium flaccumfaciens, and Pseudomonas syringae based on degrees of virulence and cultural characteristics. P. phaseolicola, which was reported as consisting of 2 races, was found to comprise numerous strains. A correlation between appearance on special culture medium and virulence was reported

M. L. Schuster; D. P. Coyne

1975-01-01

150

Citrus Proteins for Use in Field Detection of Citrus Blight Using Immunological Techniques.  

National Technical Information Service (NTIS)

The invention relates to purified and isolated citrus blight leaf proteins which are specific indicators of the presence of citrus blight. The isolated and purified citrus blight leaf proteins are extracted from citrus blighted leaves and have a molecular...

M. G. Bausher

1991-01-01

151

BIOLOGICAL CONTROL OF POST HARVEST LATE BLIGHT OF POTATOES IN STORAGE BY BACTERIA SUPPRESSIVE TO FUNGAL DRY ROT AND SPROUTING  

Technology Transfer Automated Retrieval System (TEKTRAN)

Introduction of US-8 genotypes of Phytophthora infestans has coincided with an increase in severity of potato late blight in North America. As alternatives to chemical fungicides, 18 bacterial strains patented as biological control agents (BCA) of both sprouting and Fusarium dry rot were cultivated...

152

Fire blight of pome fruits in Jordan: disease development and response of different fruit cultivars to the disease  

Microsoft Academic Search

Sixty-nine different bacterial isolates obtained from pome fruit (apple Malus domestica, pear Pyrus communis, and quince Cydonia oblonga) and Firethorn (Pyracantha sp.), suspected of being infected with fire blight and collected from different pome fruit growing areas in Jordan during the 1999 growing season, were biochemically, physiologically and pathologically tested for the disease. Results of the tests indicated that the

M. S Al-Dahmashi; H Khlaif

2004-01-01

153

TRANSGENIC EXPRESSION OF THE ERWINIA AMYLOVORA (FIRE BLIGHT) EFFECTOR PROTEIN EOP1 SUPRESSES HOST BASAL DEFENSE MECHANISMS IN MALUS (APPLE)  

Technology Transfer Automated Retrieval System (TEKTRAN)

Erwinia amylovora (Ea) is the causative agent of fire blight, a devastating disease of apple and pear. Like many other plant and animal bacterial pathogens Ea utilizes a type three secretion system (TTSS) to deliver effector proteins into plant host cells. Once inside the host cell, effector protei...

154

The Phytoalexin-Inducible Multidrug Efflux Pump AcrAB Contributes to Virulence in the Fire Blight Pathogen, Erwinia amylovora  

Microsoft Academic Search

The enterobacterium Erwinia amylovora causes fire blight on members of the family Rosaceae, with economic impor- tance on apple and pear. During pathogenesis, the bacte- rium is exposed to a variety of plant-borne antimicrobial compounds. In plants of Rosaceae, many constitutively syn- thesized isoflavonoids affecting microorganisms were iden- tified. Bacterial multidrug efflux transporters which medi- ate resistance toward structurally unrelated

Antje Burse; Helge Weingart; Matthias S. Ullrich

2004-01-01

155

Effect of phosphorus on bacterial leaf spot disease incidence, and chemical composition and storage quality of Piper betle leaves  

Microsoft Academic Search

Biochemical analysis of betel leaves infected by leaf spot and blight caused byXanthomonas campestris pv.betlicola showed a decrease in moisture, chlorophyll, protein, phenol and total carbohydrate contents as compared with healthy leaves.\\u000a The decrease in these five parameters was 31-42%, 29-70%, 20-79%, 30-53% and 53-87%, respectively. Application of 100 kg P2O5\\/ha gave maximum height of vine, number of leaves per

A. R. Wasnikar; S. K. Khatik; M. L. Nayak; S. K. Vishwakarma; L. K. Punekar

1993-01-01

156

Xanthomonas oryzae pv. oryzae Type III Effector XopN Targets OsVOZ2 and a Putative Thiamine Synthase as a Virulence Factor in Rice  

PubMed Central

Xanthomonasoryzae pv. oryzae (Xoo) is spread systemically through the xylem tissue and causes bacterial blight in rice. We evaluated the roles of Xanthomonas outer proteins (Xop) in the Xoo strain KXO85 in a Japonica-type rice cultivar, Dongjin. Five xop gene knockout mutants (xopQKXO85, xopXKXO85, xopP1KXO85, xopP2KXO85, and xopNKXO85) were generated by EZ-Tn5 mutagenesis, and their virulence was assessed in 3-month-old rice leaves. Among these mutants, the xopNKXO85 mutant appeared to be less virulent than the wild-type KXO85; however, the difference was not statistically significant. In contrast, the xopNKXO85 mutant exhibited significantly less virulence in flag leaves after flowering than the wild-type KXO85. These observations indicate that the roles of Xop in Xoo virulence are dependent on leaf stage. We chose the xopN gene for further characterization because the xopNKXO85 mutant showed the greatest influence on virulence. We confirmed that XopNKXO85 is translocated into rice cells, and its gene expression is positively regulated by HrpX. Two rice proteins, OsVOZ2 and a putative thiamine synthase (OsXNP), were identified as targets of XopNKXO85 by yeast two-hybrid screening. Interactions between XopNKXO85 and OsVOZ2 and OsXNP were further confirmed in planta by bimolecular fluorescence complementation and in vivo pull-down assays. To investigate the roles of OsVOZ2 in interactions between rice and Xoo, we evaluated the virulence of the wild-type KXO85 and xopNKXO85 mutant in the OsVOZ2 mutant line PFG_3A-07565 of Dongjin. The wild-type KXO85 and xopNKXO85 mutant were significantly less virulent in the mutant rice line. These results indicate that XopNKXO85 and OsVOZ2 play important roles both individually and together for Xoo virulence in rice.

Cheong, Hoon; Kim, Chi-Yeol; Jeon, Jong-Seong; Lee, Byoung-Moo; Sun Moon, Jae; Hwang, Ingyu

2013-01-01

157

Analysis of Fire Blight Shoot Infection Epidemics on Apple  

Microsoft Academic Search

Biggs, A. R., Turechek, W. W., and Gottwald, T. R. 2008. Analysis of fire blight shoot infection epidemics on apple. Plant Dis. 92:1349-1356. Fire blight incidence and spread of the shoot blight phase of the disease was studied in four apple cultivars in replicated blocks over 4 years (1994 to 1997). Cv. York was highly susceptible, followed by 'Fuji' and

Alan R. Biggs; William W. Turechek; Tim R. Gottwald

2008-01-01

158

COMPARATIVE MAPPING OF LATE-BLIGHT RESISTANCE LOCI IN SOLANUM  

Technology Transfer Automated Retrieval System (TEKTRAN)

Phytophthora infestans is the casual agent of late blight and continues to be a major threat to potato production worldwide. There are no curative control agents available and resistance genes offer promise in controlling late-blight epidemics. To date, the sole source of late-blight resistance ha...

159

Method for improving specific Xanthan productivity during continuous fermentation. [Xanthomonas sp. , Xanthomonas campestris  

SciTech Connect

The heteropolysaccharides produced by the action of Xanthomonas bacteria on carbohydrate media have a potential application as film forming agents and as thickeners for oil field drilling fluids, fracturing liquids, and emulsifying, stabilizing, and sizing agents. Heteropolysaccharides, particularly xanthan gum, have significant potential as mobility control agents in micellar polymer flooding. Xanthan gum has excellent viscosifying properties at low concentration; it is resistant to shear degradation and exhibits only minimal losses in viscosity as a function of temperature, pH, and ionic strength. During continuous culture, the concentration of biomass is set by the concentration of the limiting nutrient being fed with the medium and biomass concentration is varied by raising or lowering the limiting nutrient concentration. By growing a species of the genus Xanthomonas such as Xanthomonas campestris, in continuous culture in a medium containing glucose, mineral salts, and NH/sub 4/Cl and either glutamate or glutamate plus yeast extract, the specific productivity is improved by first operating and then raising the cell concentration. 16 claims.

Weisrock, W.P.

1982-01-19

160

Method for improving specific xanthan productivity during continuous fermentation. [Xanthomonas sp. , Xanthomonas campestris  

SciTech Connect

The heteropolysaccharides produced by the action of Xanthomonas bacteria on carbohydrate media have a potential application as film forming agents and as thickeners for oil field drilling fluids, fracturing liquids, and emulsifying, stabilizing, and sizing agents. Heteropolysaccharides, particularly xanthan gum, have significant potential as mobility control agents in micellar polymer flooding. Xanthan gum has excellent viscosifying properties at low concentration; it is resistant to shear degradation and exhibits only minimal losses in viscosity as a function of temperature, pH, and ionic strength. During continuous culture, the concentration of biomass is set by the concentration of the limiting nutrient being fed with the medium and biomass concentration is varied by raising or lowering the limiting nutrient concentration. By growing a species of the genus Xanthomonas such as Xanthomonas campestris, in continuous culture in a medium containing glucose, mineral salts, and NH/sub 4/Cl and either glutamate or glutamate plus yeast extract, the specific productivity is improved by first operating and then raising the cell concentration. 16 claims.

Weisrock, W.P.

1982-01-19

161

A multilocus sequence analysis of the genus Xanthomonas  

Microsoft Academic Search

A multilocus sequence analysis (MLSA) of strains representing all validly published Xanthomonas spp. (119 strains) was conducted using four genes; dnaK, fyuA, gyrB and rpoD, a total of 440 sequences. Xanthomonas spp. were divided into two groups similar to those indicated in earlier 16S rDNA comparative analyses, and they possibly represent distinct genera. The analysis clearly differentiated most species that

J. M. Young; D.-C. Park; H. M. Shearman; E. Fargier

2008-01-01

162

Mutations in the N-terminal coding region of the harpin protein Hpa1 from Xanthomonas oryzae cause loss of hypersensitive reaction induction in tobacco  

Microsoft Academic Search

Harpins encoded by many gram-negative phytopathogenic bacterial hrp genes induce hypersensitive response (HR) and associated defense responses on nonhost plants. Hpa1Xoo and Hpa1Xoc, two harpin proteins from Xanthomonas oryzae pathovars, induce HR when infiltrated into tobacco leaves. N- and C-terminal mutations of Hpa1Xoo and Hpa1Xoc, respectively, were tested for their ability to elicit HR on tobacco. Deletion of codons for

Xiao-yu Wang; Cong-feng Song; Wei-guo Miao; Zhao-lin Ji; Xiben Wang; Yan Zhang; Jia-huan Zhang; John S. Hu; Wayne Borth; Jin-sheng Wang

2008-01-01

163

Effect of Soil–matric Potential and Phylloplanes of Rotation-crops on the Survival of a Bioluminescent Xanthomonas campestris pv. campestris  

Microsoft Academic Search

The survival of the bacterial pathogen, Xanthomonas campestris pv. campestris (Xcc), was studied in plant debris-infested soil with different matric potentials (0, -10, -30, -50, -100, -200, and -900?kPa), and on the phylloplane of crops used for rotation with cabbage. Populations of cellulolytic and proteolytic microorganisms were studied in relation to soil matric potential and Xcc. The survival of Xcc

Renée S. Arias; Scot C. Nelson; Anne M. Alvarez

2000-01-01

164

AsnB, regulated by diffusible signal factor and global regulator Clp, is involved in aspartate metabolism, resistance to oxidative stress and virulence in Xanthomonas oryzae pv. oryzicola.  

PubMed

Xanthomonas oryzae pv. oryzicola (Xoc) causes bacterial leaf streak in rice, which is a destructive disease worldwide. Xoc virulence factors are regulated by diffusible signal factor (DSF) and the global regulator Clp. In this study, we have demonstrated that asnB (XOC_3054), encoding an asparagine synthetase, is a novel virulence-related gene regulated by both DSF and Clp in Xoc. A sequence analysis revealed that AsnB is highly conserved in Xanthomonas. An asnB mutation in Xoc dramatically impaired pathogen virulence and growth rate in host rice, but did not affect the ability to trigger the hypersensitive response in nonhost (plant) tobacco. Compared with the wild-type strain, the asnB deletion mutant was unable to grow in basic MMX (-) medium (a minimal medium without ammonium sulphate as the nitrogen source) with or without 10 tested nitrogen sources, except asparagine. The disruption of asnB impaired pathogen resistance to oxidative stress and reduced the transcriptional expression of oxyR, katA and katG, which encode three important proteins responsible for hydrogen peroxide (H(2)O(2)) sensing and detoxification in Xanthomonas in the presence of H(2)O(2), and nine important known Xoc virulence-related genes in plant cell-mimicking medium. Furthermore, the asnB mutation did not affect extracellular protease activity, extracellular polysaccharide production, motility or chemotaxis. Taken together, our results demonstrate the role of asnB in Xanthomonas for the first time. PMID:23157387

Qian, Guoliang; Liu, Chunhui; Wu, Guichun; Yin, Fangqun; Zhao, Yancun; Zhou, Yijing; Zhang, Yanbing; Song, Zhiwei; Fan, Jiaqin; Hu, Baishi; Liu, Fengquan

2012-11-16

165

Volatile organic compounds produced by the phytopathogenic bacterium Xanthomonas campestris pv. vesicatoria 85-10  

PubMed Central

Summary Xanthomonas campestris is a phytopathogenic bacterium and causes many diseases of agricultural relevance. Volatiles were shown to be important in inter- and intraorganismic attraction and defense reactions. Recently it became apparent that also bacteria emit a plethora of volatiles, which influence other organisms such as invertebrates, plants and fungi. As a first step to study volatile-based bacterial–plant interactions, the emission profile of Xanthomonas c. pv. vesicatoria 85-10 was determined by using GC/MS and PTR–MS techniques. More than 50 compounds were emitted by this species, the majority comprising ketones and methylketones. The structure of the dominant compound, 10-methylundecan-2-one, was assigned on the basis of its analytical data, obtained by GC/MS and verified by comparison of these data with those of a synthetic reference sample. Application of commercially available decan-2-one, undecan-2-one, dodecan-2-one, and the newly synthesized 10-methylundecan-2-one in bi-partite Petri dish bioassays revealed growth promotions in low quantities (0.01 to 10 ?mol), whereas decan-2-one at 100 ?mol caused growth inhibitions of the fungus Rhizoctonia solani. Volatile emission profiles of the bacteria were different for growth on media (nutrient broth) with or without glucose.

Weise, Teresa; Kai, Marco; Gummesson, Anja; Troeger, Armin; von Reuss, Stephan; Piepenborn, Silvia; Kosterka, Francine; Sklorz, Martin; Zimmermann, Ralf; Francke, Wittko

2012-01-01

166

Evolutionary and Experimental Assessment of Novel Markers for Detection of Xanthomonas euvesicatoria in Plant Samples  

PubMed Central

Background Bacterial spot-causing xanthomonads (BSX) are quarantine phytopathogenic bacteria responsible for heavy losses in tomato and pepper production. Despite the research on improved plant spraying methods and resistant cultivars, the use of healthy plant material is still considered as the most effective bacterial spot control measure. Therefore, rapid and efficient detection methods are crucial for an early detection of these phytopathogens. Methodology In this work, we selected and validated novel DNA markers for reliable detection of the BSX Xanthomonas euvesicatoria (Xeu). Xeu-specific DNA regions were selected using two online applications, CUPID and Insignia. Furthermore, to facilitate the selection of putative DNA markers, a customized C program was designed to retrieve the regions outputted by both databases. The in silico validation was further extended in order to provide an insight on the origin of these Xeu-specific regions by assessing chromosomal location, GC content, codon usage and synteny analyses. Primer-pairs were designed for amplification of those regions and the PCR validation assays showed that most primers allowed for positive amplification with different Xeu strains. The obtained amplicons were labeled and used as probes in dot blot assays, which allowed testing the probes against a collection of 12 non-BSX Xanthomonas and 23 other phytopathogenic bacteria. These assays confirmed the specificity of the selected DNA markers. Finally, we designed and tested a duplex PCR assay and an inverted dot blot platform for culture-independent detection of Xeu in infected plants. Significance This study details a selection strategy able to provide a large number of Xeu-specific DNA markers. As demonstrated, the selected markers can detect Xeu in infected plants both by PCR and by hybridization-based assays coupled with automatic data analysis. Furthermore, this work is a contribution to implement more efficient DNA-based methods of bacterial diagnostics.

Albuquerque, Pedro; Caridade, Cristina M. R.; Rodrigues, Arlete S.; Marcal, Andre R. S.; Cruz, Joana; Cruz, Leonor; Santos, Catarina L.; Mendes, Marta V.; Tavares, Fernando

2012-01-01

167

40 CFR 180.1261 - Xanthomonas campestris pv. vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Xanthomonas campestris pv. vesicatoria and Pseudomonas...Exemptions From Tolerances § 180.1261 Xanthomonas campestris pv. vesicatoria and Pseudomonas...tolerance is established for residues of Xanthomonas campestris pv. vesicatoria and...

2010-07-01

168

40 CFR 180.1261 - Xanthomonas campestris pv. vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages.  

Code of Federal Regulations, 2010 CFR

...2009-07-01 2009-07-01 false Xanthomonas campestris pv. vesicatoria and Pseudomonas...Exemptions From Tolerances § 180.1261 Xanthomonas campestris pv. vesicatoria and Pseudomonas...tolerance is established for residues of Xanthomonas campestris pv. vesicatoria and...

2009-07-01

169

Physical and functional repetition in a bacterial ice nucleation gene  

Microsoft Academic Search

Nucleation of a physical process is distinct from catalysis, and as the function of a protein it is highly unusual. The ability to nucleate ice formation in supercooled water is a property of some members of the bacterial genera Erwinia, Pseudomonas and Xanthomonas1-3. This property is implicated in the ability of bacteria to cause frost injury to plants. Orser et

Robert L. Green; Gareth J. Warren

1985-01-01

170

OCCURRENCE OF CITRUS BLIGHT IN COSTA RICA  

Technology Transfer Automated Retrieval System (TEKTRAN)

Technical Abstract: Since 1997, citrus blight (CB) symptoms were observed in several groves in the northern region of Costa Rica, the country=s most important citrus area (more than 25,000 ha.). The symptoms include a general decline of the tree canopy with wilt, off-color leaves, leaf drop, twig...

171

[Bacterial diseases of rape].  

PubMed

Bacterial destruction of the culture was described and its agents identified in the spring and winter rape crops. Typical symptoms are the following: browning of stem tissue and its mucilagization, chlorosis of leaves, yellowing and beginning of soft rot in the place of leaf stalks affixion to stems, loss of pigmentation (violet). Pathogenic properties of the collection strains and morphological, cultural, physiological, and biochemical properties of the agents of rape's bacterial diseases isolated by the authors have been investigated. It was found that all the isolates selected by the authors are highly or moderately aggressive towards different varieties of rape. According to the complex of phenotypic properties 44% of the total number of isolates selected by the authors are related to representatives of the genus Pseudomonas, 37% - to Xanthomonas and 19% - to Pectobacterium. PMID:23293826

Zakharova, O M; Mel'nychuk, M D; Dankevych, L A; Patyka, V P

172

Fortunella margarita Transcriptional Reprogramming Triggered by Xanthomonas citri subsp. citri  

PubMed Central

Background Citrus canker disease caused by the bacterial pathogen Xanthomonas citri subsp. citri (Xcc) has become endemic in areas where high temperature, rain, humidity, and windy conditions provide a favourable environment for the dissemination of the bacterium. Xcc is pathogenic on many commercial citrus varieties but appears to elicit an incompatible reaction on the citrus relative Fortunella margarita Swing (kumquat), in the form of a very distinct delayed necrotic response. We have developed subtractive libraries enriched in sequences expressed in kumquat leaves during both early and late stages of the disease. The isolated differentially expressed transcripts were subsequently sequenced. Our results demonstrate how the use of microarray expression profiling can help assign roles to previously uncharacterized genes and elucidate plant pathogenesis-response related mechanisms. This can be considered to be a case study in a citrus relative where high throughput technologies were utilized to understand defence mechanisms in Fortunella and citrus at the molecular level. Results cDNAs from sequenced kumquat libraries (ESTs) made from subtracted RNA populations, healthy vs. infected, were used to make this microarray. Of 2054 selected genes on a customized array, 317 were differentially expressed (P < 0.05) in Xcc challenged kumquat plants compared to mock-inoculated ones. This study identified components of the incompatible interaction such as reactive oxygen species (ROS) and programmed cell death (PCD). Common defence mechanisms and a number of resistance genes were also identified. In addition, there were a considerable number of differentially regulated genes that had no homologues in the databases. This could be an indication of either a specialized set of genes employed by kumquat in response to canker disease or new defence mechanisms in citrus. Conclusion Functional categorization of kumquat Xcc-responsive genes revealed an enhanced defence-related metabolism as well as a number of resistant response-specific genes in the kumquat transcriptome in response to Xcc inoculation. Gene expression profile(s) were analyzed to assemble a comprehensive and inclusive image of the molecular interaction in the kumquat/Xcc system. This was done in order to elucidate molecular mechanisms associated with the development of the hypersensitive response phenotype in kumquat leaves. These data will be used to perform comparisons among citrus species to evaluate means to enhance the host immune responses against bacterial diseases.

2011-01-01

173

Xylella Genomics and Bacterial Pathogenicity to Plants  

PubMed Central

Xylella fastidiosa, a pathogen of citrus, is the first plant pathogenic bacterium for which the complete genome sequence has been published. Inspection of the sequence reveals high relatedness to many genes of other pathogens, notably Xanthomonas campestris. Based on this, we suggest that Xylella possesses certain easily testable properties that contribute to pathogenicity. We also present some general considerations for deriving information on pathogenicity from bacterial genomics.

Dow, J. M.

2000-01-01

174

PGPR mediated management of stem blight of Phyllanthus amarus (Schum and Thonn) caused by Corynespora cassiicola (Berk and Curt) Wei  

Microsoft Academic Search

Bacillus subtilis (BSCBE4), Pseudomonas chlororaphis (PA23), endophytic P. fluorescens (ENPF1) inhibited the mycelial growth of stem blight pathogen Corynespora casiicola (Berk and Curt)Wei under in vitro. All these bacterial isolates produced both hydroxamate and carboxylate type of siderophores. But the siderophore production was maximum with the isolate ENPF1. Delivering of talc based formulation of BSCBE4 through seedling dip and foliar

S Mathiyazhagan; K Kavitha; S Nakkeeran; G Chandrasekar; K Manian; P Renukadevi; AS Krishnamoorthy; WGD Fernando

2004-01-01

175

Molecular mapping of hypersensitive resistance from tomato 'Hawaii 7981' to Xanthomonas perforans race T3.  

PubMed

Bacterial spot of tomato (Solanum lycopersicum) is caused by four species of Xanthomonas. The disease causes significant yield losses and a reduction in fruit quality. Physiological races have been described with tomato race 3 (T3) corresponding to strains of Xanthomonas perforans. The breeding line Hawaii 7981 (hereafter H7981) shows a hypersensitive reaction (HR) to race T3 strains conditioned by the interaction of the host resistance locus Xv3 and the bacterial effector avrXv3. The Xv3 gene is required for H7981-derived resistance to be effective under field conditions, though its expression is subject to genetic background. The segregation of HR in F(2) populations derived from H7981 crossed to processing tomato parents OH88119 and OH7870 was studied in 331 progeny, with the two independent crosses providing validation. We screened 453 simple-sequence repeat, insertion/deletion, and single-nucleotide polymorphism markers and identified 44 polymorphic markers each for the OH88119 and OH7870 populations covering 84.6 and 73.3% of the genome, respectively, within 20 centimorgans (cM). Marker-trait analysis using all polymorphic markers demonstrated that Xv3-mediated resistance maps to chromosome 11 in the two independent crosses. Allelism tests were conducted in crosses between lines carrying Xv3 derived from H7981, Rx-4 derived from plant introduction (PI) 128216, and resistance derived from PI 126932. These allelism tests suggested that the loci conditioning HR to race T3 strains are linked within 0.1 cM, are allelic, or are the same gene. PMID:21916626

Wang, Hui; Hutton, Samuel F; Robbins, Matthew D; Sim, Sung-Chur; Scott, Jay W; Yang, Wencai; Jones, Jeffrey B; Francis, David M

2011-10-01

176

Putative resistance gene markers associated with quantitative trait loci for fire blight resistance in Malus 'Robusta 5' accessions  

PubMed Central

Background Breeding of fire blight resistant scions and rootstocks is a goal of several international apple breeding programs, as options are limited for management of this destructive disease caused by the bacterial pathogen Erwinia amylovora. A broad, large-effect quantitative trait locus (QTL) for fire blight resistance has been reported on linkage group 3 of Malus ‘Robusta 5’. In this study we identified markers derived from putative fire blight resistance genes associated with the QTL by integrating further genetic mapping studies with bioinformatics analysis of transcript profiling data and genome sequence databases. Results When several defined E.amylovora strains were used to inoculate three progenies from international breeding programs, all with ‘Robusta 5’ as a common parent, two distinct QTLs were detected on linkage group 3, where only one had previously been mapped. In the New Zealand ‘Malling 9’ X ‘Robusta 5’ population inoculated with E. amylovora ICMP11176, the proximal QTL co-located with SNP markers derived from a leucine-rich repeat, receptor-like protein ( MxdRLP1) and a closely linked class 3 peroxidase gene. While the QTL detected in the German ‘Idared’ X ‘Robusta 5’ population inoculated with E. amylovora strains Ea222_JKI or ICMP11176 was approximately 6?cM distal to this, directly below a SNP marker derived from a heat shock 90 family protein gene ( HSP90). In the US ‘Otawa3’ X ‘Robusta5’ population inoculated with E. amylovora strains Ea273 or E2002a, the position of the LOD score peak on linkage group 3 was dependent upon the pathogen strains used for inoculation. One of the five MxdRLP1 alleles identified in fire blight resistant and susceptible cultivars was genetically associated with resistance and used to develop a high resolution melting PCR marker. A resistance QTL detected on linkage group 7 of the US population co-located with another HSP90 gene-family member and a WRKY transcription factor previously associated with fire blight resistance. However, this QTL was not observed in the New Zealand or German populations. Conclusions The results suggest that the upper region of ‘Robusta 5’ linkage group 3 contains multiple genes contributing to fire blight resistance and that their contributions to resistance can vary depending upon pathogen virulence and other factors. Mapping markers derived from putative fire blight resistance genes has proved a useful aid in defining these QTLs and developing markers for marker-assisted breeding of fire blight resistance.

2012-01-01

177

Determination of responses of different bean cultivars against races of Pseudomonas syringae pv phaseolicola , causal agent of halo blight of bean  

Microsoft Academic Search

Use of resistant plant varieties combined with other disease management practices is regarded as the most practical approach\\u000a to control of seed-borne bacterial disease agents. In this study, responses of different bean cultivars to nine different\\u000a races of Pseudomonas syringae pv phaseolicola, the causal agent of bacterial halo blight of common bean (Phaseolus vulgaris L.), were determined. During compatible interaction

?mam Adem Bozkurt; Soner Soylu

2011-01-01

178

Characterization of a variant of Xanthomonas citri subsp. citri that triggers a host-specific defense response.  

PubMed

Citrus is an economically important fruit crop that is severely afflicted by Asiatic citrus bacterial canker (CBC), a disease caused by the phytopathogen Xanthomonas citri subsp. citri (X. citri). To gain insight into the molecular epidemiology of CBC, 42 Xanthomonas isolates were collected from a range of Citrus spp. across 17 different orchards in Tucumán, Argentina and subjected to molecular, biochemical, and pathogenicity tests. Analysis of genome-specific X. citri markers and DNA polymorphisms based on repetitive elements-based polymerase chain reaction showed that all 42 isolates belonged to X. citri. Interestingly, pathogenicity tests showed that one isolate, which shares >90% genetic similarity to the reference strain X. citri T, has host range specificity. This new variant of X. citri subsp. citri, named X. citri A(T), which is deficient in xanthan production, induces an atypical, noncankerous chlorotic phenotype in Citrus limon and C. paradisi and weak cankerous lesions in C. aurantifolia and C. clementina leaves. In C. limon, suppression of canker development is concomitant with an oxidative burst; xanthan is not implicated in the phenotype induced by this interaction, suggesting that other bacterial factors would be involved in triggering the defense response. PMID:23268580

Chiesa, María A; Siciliano, María F; Ornella, Leonardo; Roeschlin, Roxana A; Favaro, María A; Delgado, Natalia Pino; Sendín, Lorena N; Orce, Ingrid G; Ploper, L Daniel; Vojnov, Adrian A; Vacas, José Gadea; Filippone, María P; Castagnaro, Atilio P; Marano, María R

2013-06-01

179

Five phylogenetically close rice SWEET genes confer TAL effector-mediated susceptibility to Xanthomonas oryzae pv. oryzae.  

PubMed

Bacterial plant-pathogenic Xanthomonas strains translocate transcription activator-like (TAL) effectors into plant cells to function as specific transcription factors. Only a few plant target genes of TAL effectors have been identified, so far. Three plant SWEET genes encoding putative sugar transporters are known to be induced by TAL effectors from rice-pathogenic Xanthomonas oryzae pv. oryzae (Xoo). We predict and validate that expression of OsSWEET14 is induced by a novel TAL effector, Tal5, from an African Xoo strain. Artificial TAL effectors (ArtTALs) were constructed to individually target 20 SWEET orthologs in rice. They were used as designer virulence factors to study which rice SWEET genes can support Xoo virulence. The Tal5 target box differs from those of the already known TAL effectors TalC, AvrXa7 and PthXo3, which also induce expression of OsSWEET14, suggesting evolutionary convergence on key targets. ArtTALs efficiently complemented an Xoo talC mutant, demonstrating that specific induction of OsSWEET14 is the key target of TalC. ArtTALs that specifically target individual members of the rice SWEET family revealed three known and two novel SWEET genes to support bacterial virulence. Our results demonstrate that five phylogenetically close SWEET proteins, which presumably act as sucrose transporters, can support Xoo virulence. PMID:23879865

Streubel, Jana; Pesce, Céline; Hutin, Mathilde; Koebnik, Ralf; Boch, Jens; Szurek, Boris

2013-07-24

180

Insights into xanthomonas axonopodis pv. citri biofilm through proteomics  

PubMed Central

Background Xanthomonas axonopodis pv. citri (X. a. pv. citri) causes citrus canker that can result in defoliation and premature fruit drop with significant production losses worldwide. Biofilm formation is an important process in bacterial pathogens and several lines of evidence suggest that in X. a. pv. citri this process is a requirement to achieve maximal virulence since it has a major role in host interactions. In this study, proteomics was used to gain further insights into the functions of biofilms. Results In order to identify differentially expressed proteins, a comparative proteomic study using 2D difference gel electrophoresis was carried out on X. a. pv. citri mature biofilm and planktonic cells. The biofilm proteome showed major variations in the composition of outer membrane proteins and receptor or transport proteins. Among them, several porins and TonB-dependent receptor were differentially regulated in the biofilm compared to the planktonic cells, indicating that these proteins may serve in maintaining specific membrane-associated functions including signaling and cellular homeostasis. In biofilms, UDP-glucose dehydrogenase with a major role in exopolysaccharide production and the non-fimbrial adhesin YapH involved in adherence were over-expressed, while a polynucleotide phosphorylase that was demonstrated to negatively control biofilm formation in E. coli was down-regulated. In addition, several proteins involved in protein synthesis, folding and stabilization were up-regulated in biofilms. Interestingly, some proteins related to energy production, such as ATP-synthase were down-regulated in biofilms. Moreover, a number of enzymes of the tricarboxylic acid cycle were differentially expressed. In addition, X. a. pv. citri biofilms also showed down-regulation of several antioxidant enzymes. The respective gene expression patterns of several identified proteins in both X. a. pv. citri mature biofilm and planktonic cells were evaluated by quantitative real-time PCR and shown to consistently correlate with those deduced from the proteomic study. Conclusions Differentially expressed proteins are enriched in functional categories. Firstly, proteins that are down-regulated in X. a. pv. citri biofilms are enriched for the gene ontology (GO) terms ‘generation of precursor metabolites and energy’ and secondly, the biofilm proteome mainly changes in ‘outer membrane and receptor or transport’. We argue that the differentially expressed proteins have a critical role in maintaining a functional external structure as well as enabling appropriate flow of nutrients and signals specific to the biofilm lifestyle.

2013-01-01

181

Factors affecting infection of citrus with Xanthomonas axonopodis pv citri.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Xanthomonas axonopodis pv citri (Xac) causes citrus canker and is now considered endemic in Florida. Factors affecting dispersal and infection of the bacteria need to be understood to help optimize disease management strategies. Wind (0-18 m/sec) was simulated outdoors using a fan to study infection...

182

Evaluation of spray programs containing famoxadone plus cymoxanil, acibenzolar- S-methyl, and Bacillus subtilis compared to copper sprays for management of bacterial spot on tomato  

Microsoft Academic Search

Bacterial spot caused by Xanthomonas euvesicatoria Jones et al. and Xanthomonas perforans Jones et al. is a major disease on fresh market commercial tomato in Florida. Fourteen field trials were conducted between 1999 and 2005 (10 in south Florida and four in north Florida) testing famoxadone plus cymoxanil (Tanos 50DF®, E.I. du Pont de Nemours and Company, Wilmington, DE), Bacillus subtilis strain

P. D. Roberts; M. T. Momol; L. Ritchie; S. M. Olson; J. B. Jones; B. Balogh

2008-01-01

183

Rhizoctonia web blight in: compendium of azalea and rhodendron diseases  

Technology Transfer Automated Retrieval System (TEKTRAN)

Rhizoctonia web blight, caused by several Rhizoctonia spp., is an important disease of evergreen azaleas and other ornamental plants in nurseries. The primary pathogens causing web blight are binucleate Rhizoctonia anastomosis groups (AG) (= Ceratobasidium D.P. Rogers, teleomorph). In southern AL an...

184

Functional genomic response of apple to fire blight  

Technology Transfer Automated Retrieval System (TEKTRAN)

The goal of this project is to use a functional genomic analysis to characterize the response of apple (Malus x domestica) to fire blight disease and in doing so, identify new opportunities for improving fire blight resistance. cDNA suppression subtractive hybridization and cDNA-AFLP analysis were ...

185

Timing of fungicide sprays to prevent azalea web blight symptoms  

Technology Transfer Automated Retrieval System (TEKTRAN)

Several fungicides will control web blight, but guidelines about when to spray have not been clearly understood. Previous research has shown that a maximum daily temperatures greater than 95°F and minimum daily temperatures less than 68°F slow web blight development, but weather conditions are not s...

186

Application of mycofungicide to control late blight of potato  

Microsoft Academic Search

Late blight of potato in northern Thailand is caused by Phytophthora infestans and leads to economic damage in large areas of potato planted. The pathogen infects all stages of plant growth which show symptoms of late blight, stem rot and tuber rot and can result in 100% yield loss even with the use of chemical fungicides. Laboratory based bi-culture antagonistic

Kasem Soytong

187

The 2009 late blight pandemic in eastern USA  

Technology Transfer Automated Retrieval System (TEKTRAN)

The tomato late blight pandemic of 2009 made late blight into a household term in much of the eastern United States. Many home gardeners and organic producers lost most, if not all, of their tomato crop, and their experiences were reported in the mainstream press. This article, which is written for ...

188

FIRST REPORT OF CITRUS BLIGHT IN COSTA RICA  

Technology Transfer Automated Retrieval System (TEKTRAN)

Citrus blight is a chronic decline disease of citrus which removes 5-10 percent of the trees from production annually in Florida and Brazil, respectively. In the northern citrus area of Costa Rica, trees are undergoing a decline having symptoms similar to the symptoms associated with citrus blight; ...

189

Effects of Mulch and Potato Hilling on Development of Foliar Blight (Phytophthora infestans) and Control of Tuber Blight Infection  

Technology Transfer Automated Retrieval System (TEKTRAN)

Foliar and tuber blight caused by Phytophthora infestans accounts for significant losses in potatoes in field and storage, however; limited research has documented the effect of cultural practices on late blight control. Field experiments were conducted for two years on Howard gravely loam soil in N...

190

RELATIONSHIP BETWEEN INCIDENCE OF LATE BLIGHT TUBER ROT, FOLIAGE BLIGHT CONTROL AND THE EFFECT OF WEATHER AND SOIL VARIABLES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Potato tubers are often infected by Phytophthora infestans mainly by inocula produced on leaves or stems. Because of the linkage between foliage and tuber infection, the main control of tuber blight has been by fungicide control of foliage late blight. This study investigated the relationship betwee...

191

Genetic differences between blight-causing Erwinia species with differing host specificities, identified by suppression subtractive hybridization.  

PubMed

PCR-based subtractive hybridization was used to isolate sequences from Erwinia amylovora strain Ea110, which is pathogenic on apples and pears, that were not present in three closely related strains with differing host specificities: E. amylovora MR1, which is pathogenic only on Rubus spp.; Erwinia pyrifoliae Ep1/96, the causal agent of shoot blight of Asian pears; and Erwinia sp. strain Ejp556, the causal agent of bacterial shoot blight of pear in Japan. In total, six subtractive libraries were constructed and analyzed. Recovered sequences included type III secretion components, hypothetical membrane proteins, and ATP-binding proteins. In addition, we identified an Ea110-specific sequence with homology to a type III secretion apparatus component of the insect endosymbiont Sodalis glossinidius, as well as an Ep1/96-specific sequence with homology to the Yersinia pestis effector protein tyrosine phosphatase YopH. PMID:16963554

Triplett, Lindsay R; Zhao, Youfu; Sundin, George W

2006-09-08

192

Potent and specific bactericidal effect of juglone (5-hydroxy-1,4-naphthoquinone) on the fire blight pathogen Erwinia amylovora.  

PubMed

A screening of plant quinones for inhibiting effects on the bacterial fire blight pathogen Erwinia amylovora was performed. The most active compound, juglone from walnuts, has a potent and specific bactericidal effect on E. amylovora and minimal inhibitory concentrations of only 2.5-10 ?M, with stronger effects at lower, but still physiological, pH values. In vitro tests with juglone and inoculated flowers of apple (Malus domestica) showed an efficacy of 67% in preventing infection. In two years of field tests juglone had variable degrees of efficacy ranging from 40 to 82%, seemingly due to environmental conditions. A phytotoxic reaction to juglone, which is known for its allelopathic effect on plants, was restricted to browning of petals; later fruit russeting was not observed. Juglone is a promising candidate for the development of a new environmentally friendly plant protectant to replace the antibiotic streptomycin currently used in fire blight control. PMID:23163769

Fischer, Thilo Christopher; Gosch, Christian; Mirbeth, Beate; Gselmann, Markus; Thallmair, Veronika; Stich, Karl

2012-11-29

193

Survival and Epiphytic Fitness of a Nonpathogenic Mutant of Xanthomonas campestris pv. Glycines  

PubMed Central

Xanthomonas campestris pv. glycines is the causal agent of bacterial pustule disease of soybeans. The objective of this work was to construct a nonpathogenic mutant derived from the pathogenic wild-type strain YR32 and to evaluate its effectiveness in preventing growth of its parent on the soybean phyllosphere. A mini-Tn5-derived transposon was used to generate nonpathogenic mutants. Southern hybridization and pulsed-field gel electrophoresis confirmed the presence of a single transposon in each of the nonpathogenic mutants. One of the nonpathogenic mutants, M715, failed to induce a hypersensitive response in tomato leaves. An ice nucleation gene (inaZ) carried in pJL1703 was introduced into strain YR32 as a reporter gene to demonstrate that the presence of M715 could reduce colonization of the soybean phyllosphere by YR32. de Wit serial replacement analysis showed that M715 competed equally with its wild-type parental strain, YR32. Epiphytic fitness analysis of YR32 in the greenhouse indicated that the population dynamics of strains YR32, YR32(pJL1703), and M715 were similar, although the density of the mutant was slightly less than that of its parent. The M715 mutant was able to survive for 16 days after inoculation on soybean leaves and maintained population densities of approximately 104 to 105 cells g (fresh weight) of leaf?1. Therefore, M715 shows promise as an effective biocontrol agent for bacterial pustule disease in soybeans.

Rukayadi, Yaya; Suwanto, Antonius; Tjahjono, Budi; Harling, Rob

2000-01-01

194

Linkage and mapping of resistance genes to Xanthomonas axonopodis pv. passiflorae in yellow passion fruit.  

PubMed

The cultivated passion fruit (Passiflora edulis f. flavicarpa) is a cross-pollinated species native to South America. In the current study, a segregating F1 population derived from a single cross between the clones IAPAR-06 and IAPAR-123 was used to construct AFLP-based linkage maps and to map resistance genes to bacterial spot caused by Xanthomonas axonopodis pv. passiflorae. Linkage analysis was performed by the 2-way pseudo-testcross mapping method using markers that segregated in a 1:1 ratio. The IAPAR-06 linkage map was constructed using 115 markers, 112 of which were allocated to 9 linkage groups (LG) covering 790.2 cM. The map of IAPAR-123 was constructed using 140 markers, 138 of which were allocated to 9 LG covering 488.9 cM. In both maps, clusters of markers were detected, indicating that the AFLP markers were not distributed at random. Bacterial resistance was assessed by measuring the diseased leaf area after wound-inoculating the leaves of F1 plants. Quantitative resistance loci (QRLs) mapping was carried out by composite interval mapping and 1 QRL was detected, which explained 15.8% of the total phenotypic variation. The possibility of considering these data for marker-assisted selection in passion fruit breeding programs is discussed. PMID:16462898

Lopes, Ricardo; Lopes, Maria Teresa Gomes; Carneiro, Monalisa Sampaio; Matta, Frederico de Pina; Camargo, Luis Eduardo Aranha; Vieira, Maria Lucia Carneiro

2006-01-01

195

[Cloning and characterization of an harpin-encoding gene from Xanthomonas axonopodis pv. glycines required for hypersensitive response on nonhost plant tobacco].  

PubMed

An hpa1 gene was cloned into an expression vector, pET30a(+), from the genomic DNA of Xanthomonas axonopodis pv. glycines (Xag), the causal agent of soybean bacterial pustule, with degenerated primers by polymerase amplification reaction (PCR). The gene product was extracted from the conjugate (BHR-3) of BL21 (DES) with the recombined vector pHR3 after the engineering strain was induced by IPTG in LB medium. The SDS-PAGE gel showed that the gene product was 15.1kD. The product was heat-stable (10 min at 100 degrees C), protease K sensitive, and able to trigger hypersensitive response (HR) in common tobacco, but was unable to elicit HR in NahG transgenic tobacco in which salicylic acid accumulation was abolished. Moreover, the HR elicitation of the protein in tobacco was dispelled by eukayotic metabolic inhibitors, actinomycin D, cycloheximide and LaCl3. The 402 bp hpa1 gene in this study putatively encoded a 133 ammonia acid protein of which glycine (G) was rich with 21.1%. Sequence comparison indicated that the hpa1 gene and its protein was 51.4% - 93.8% identity with those of Xanthomonas oryzae pv. oryzae and other Xanthomonas species and pathovars. Alignments of harpin proteins of Xanthomonas genus displayed that the glycine-rich region with GGG-GG motif was variable. The comparison also showed that the harpin-encoding gene of Xag (nominated here as hpa1(Xag)) did not possess any similarity with that of Erwinia amylovora, Pseudomonas syringae and Ralstonia solanacearum at nucleotide and protein levels. It is concluded that hpa1(Xag) gene encodes an harpin protein which elicits a typical HR in nonhost tobacco. PMID:16245857

Chen, Gong-You; Zhang, Bing; Wu, Xiao-Min; Zhao, Mei-Qin

2005-08-01

196

IDENTIFICATION OF SOURCES OF RESITANCE TO BACTERIAL ANGULAR LEAFSPOT DISEASE OF STRAWBERRY  

Technology Transfer Automated Retrieval System (TEKTRAN)

Bacterial angular leafspot disease (BALD) of cultivated strawberry, caused by the bacterium Xanthomonas fragariae, has become an increasingly serious disease problem. It is of particular concern because it is readily transmitted through asymptomatic nursery plants. Until now, there have been no s...

197

Antagonistic activity of Bacillus subtilis SB1 and its biocontrol effect on tomato bacterial wilt  

Technology Transfer Automated Retrieval System (TEKTRAN)

A potential biocontrol agent of bacterial wilt, Bacillus subtilis SB1, isolated from tomato roots, showed a broad-spectrum of antimicrobial activity in in vitro experiments. It inhibited the growth of many plant pathogens, including Ralstonia solanacearum, Xanthomonas oryzae pv. oryzae, Fusarium ox...

198

Structural-Functional Characterization and Physiological Significance of Ferredoxin-NADP+ Reductase from Xanthomonas axonopodis pv. citri  

PubMed Central

Xanthomonas axonopodis pv. citri is a phytopathogen bacterium that causes severe citrus canker disease. Similar to other phytopathogens, after infection by this bacterium, plants trigger a defense mechanism that produces reactive oxygen species. Ferredoxin-NADP+ reductases (FNRs) are redox flavoenzymes that participate in several metabolic functions, including the response to reactive oxygen species. Xanthomonas axonopodis pv. citri has a gene (fpr) that encodes for a FNR (Xac-FNR) that belongs to the subclass I bacterial FNRs. The aim of this work was to search for the physiological role of this enzyme and to characterize its structural and functional properties. The functionality of Xac-FNR was tested by cross-complementation of a FNR knockout Escherichia coli strain, which exhibit high susceptibility to agents that produce an abnormal accumulation of •O2-. Xac-FNR was able to substitute for the FNR in E. coli in its antioxidant role. The expression of fpr in X. axonopodis pv. citri was assessed using semiquantitative RT-PCR and Western blot analysis. A 2.2-fold induction was observed in the presence of the superoxide-generating agents methyl viologen and 2,3-dimethoxy-1,4-naphthoquinone. Structural and functional studies showed that Xac-FNR displayed different functional features from other subclass I bacterial FNRs. Our analyses suggest that these differences may be due to the unusual carboxy-terminal region. We propose a further classification of subclass I bacterial FNRs, which is useful to determine the nature of their ferredoxin redox partners. Using sequence analysis, we identified a ferredoxin (XAC1762) as a potential substrate of Xac-FNR. The purified ferredoxin protein displayed the typical broad UV-visible spectrum of [4Fe-4S] clusters and was able to function as substrate of Xac-FNR in the cytochrome c reductase activity. Our results suggest that Xac-FNR is involved in the oxidative stress response of Xanthomonas axonopodis pv. citri and performs its biological function most likely through the interaction with ferredoxin XAC1762.

Delprato, Maria Laura; Ceccarelli, Eduardo A.; Orellano, Elena G.

2011-01-01

199

A multilocus sequence analysis of the genus Xanthomonas.  

PubMed

A multilocus sequence analysis (MLSA) of strains representing all validly published Xanthomonas spp. (119 strains) was conducted using four genes; dnaK, fyuA, gyrB and rpoD, a total of 440 sequences. Xanthomonas spp. were divided into two groups similar to those indicated in earlier 16S rDNA comparative analyses, and they possibly represent distinct genera. The analysis clearly differentiated most species that have been established by DNA-DNA reassociation. A similarity matrix of the data indicated clear numerical differences that could form the basis for species differentiation in the future, as an alternative to DNA-DNA reassociation. Some species, X. cynarae, X. gardneri and X. hortorum, formed a single heterogeneous group that is in need of further investigation. X. gardneri appeared to be a synonym of X. cynarae. Recently proposed new species, X. alfalfae, X. citri, X. euvesicatoria, X. fuscans and X. perforans, were not clearly differentiated as species from X. axonopodis, and X. euvesicatoria and X. perforans are very probably synonyms. MLSA offers a powerful tool for further investigation of the classification of Xanthomonas. Based on the dataset produced, the method also offers a relatively simple way of identifying strains as members of known species, or of indicating their status as members of new species. PMID:18783906

Young, J M; Park, D-C; Shearman, H M; Fargier, E

2008-09-10

200

Regulation of the oxidative stress protective enzymes, catalase and superoxide dismutase in Xanthomonas — a review  

Microsoft Academic Search

Xanthomonas showed atypical regulation of catalase (Kat) and superoxide dismutase with respect to growth phase and response to various inducers. The highest levels of both enzymes were detected during early log phase of growth and declined as growth continued. This was in contrast to resistance levels to superoxides, H2O2 and organic peroxides, which reached maximum levels during stationary phase. Xanthomonas

Suvit Loprasert; Paiboon Vattanaviboon; Wipa Praituan; Sangpen Chamnongpol; Skorn Mongkolsuk

1996-01-01

201

Diagnosis of bacterial spot of tomato using spectral signatures  

Microsoft Academic Search

Ultraviolet, visible, and near-infrared reflectance spectroscopy was used to determine the disease severity of tomato (Lycopersicon esculentum) leaves infected with Xanthomonas perforans, the causal agent of bacterial leaf spot of tomato. Chemometric methods were used to identify significant wavelengths and create spectral-based prediction models. Significant wavelengths were identified through analysis of the B-matrix from partial least squares (PLS) regression, analysis

C. D. Jones; J. B. Jones; W. S. Lee

2010-01-01

202

[Microclimatic niche of rice sheath blight fungus].  

PubMed

By using the principles and methods of niche, the microclimatic niche of rice sheath blight fungus was analyzed. The results showed that the integrative effect of ecological factors light intensity, air temperature, and humidity was higher than the effect of each of the factors, and the combination of light intensity and air temperature had higher effect than the other combinations of the three factors. At the tillering, booting, heading, and waxing stages of rice, the microclimatic niche breadth of the fungus was 0.3112, 0.4012, 0.4326, and 0.7365, respectively, i.e., increased with rice growth, and the microclimatic niche occupied by the fungus was mainly with the low light intensity, low air temperature and high humidity as the prior microclimate type. PMID:19288727

Wang, Zi-ying; Tan, Gen-jia

2008-12-01

203

Hypersensitive response and acyl-homoserine lactone production of the fire blight antagonists Erwinia tasmaniensis and Erwinia billingiae.  

PubMed

Fire blight caused by the Gram-negative bacterium Erwinia amylovora can be controlled by antagonistic microorganisms. We characterized epiphytic bacteria isolated from healthy apple and pear trees in Australia, named Erwinia tasmaniensis, and the epiphytic bacterium Erwinia billingiae from England for physiological properties, interaction with plants and interference with growth of E. amylovora. They reduced symptom formation by the fire blight pathogen on immature pears and the colonization of apple flowers. In contrast to E. billingiae, E. tasmaniensis strains induced a hypersensitive response in tobacco leaves and synthesized levan in the presence of sucrose. With consensus primers deduced from lsc as well as hrpL, hrcC and hrcR of the hrp region of E. amylovora and of related bacteria, these genes were successfully amplified from E. tasmaniensis DNA and alignment of the encoded proteins to other Erwinia species supported a role for environmental fitness of the epiphytic bacterium. Unlike E. tasmaniensis, the epiphytic bacterium E. billingiae produced an acyl-homoserine lactone for bacterial cell-to-cell communication. Their competition with the growth of E. amylovora may be involved in controlling fire blight. PMID:21261861

Jakovljevic, Vladimir; Jock, Susanne; Du, Zhiqiang; Geider, Klaus

2008-09-01

204

Race-specificity of plant resistance to bacterial spot disease determined by repetitive motifs in a bacterial avirulence protein  

Microsoft Academic Search

ELUCIDATION of the genetic and molecular basis of plant disease resistance is a major objective in the investigation of plant-micro-bial interactions. Xanthomonas campestris pathovar vesicatoria (Xcv), the causal agent of bacterial spot disease of pepper and tomato, has been developed as a model host-pathogen system to study the genetic interactions that specify the expression of plant disease resistance1-6. Several plant

Karin Herbers; Jutta Conrads-Strauch; Ulla Bonas

1992-01-01

205

Reactions of Open-Pollinated Sweet Corn Cultivars to Stewart's Wilt, Common Rust, Northern Leaf Blight, and Southern Leaf Blight  

Microsoft Academic Search

Pataky, J. K., du Toit, L. J., Revilla, P., and Tracy, W. F. 1998. Reactions of open-pollinated sweet corn cultivars to Stewart's wilt, common rust, northern leaf blight, and southern leaf blight. Plant Dis. 82:939-944. Over 800 open-pollinated (OP) varieties of sweet corn were grown and named in the century prior to the development of hybrids, but only a few

J. K. Pataky; L. J. du Toit; P. Revilla; W. F. Tracy

1998-01-01

206

A highly-conserved single-stranded DNA-binding protein in Xanthomonas functions as a harpin-like protein to trigger plant immunity.  

PubMed

Harpins are produced by gram-negative phytopathogenic bacteria and typically elicit hypersensitive response (HR) in non-host plants. The characterization of harpins in Xanthomonas species is largely unexplored. Here we demonstrate that Xanthomonas produce a highly conserved single-stranded DNA-binding protein (SSB(X)) that elicits HR in tobacco as by harpin Hpa1. SSB(X), like Hpa1, is an acidic, glycine-rich, heat-stable protein that lacks cysteine residues. SSB(X)-triggered HR in tobacco, as by Hpa1, is characterized by the oxidative burst, the expression of HR markers (HIN1, HSR203J), pathogenesis-related genes, and callose deposition. Both SSB(X)- and Hpa1-induced HRs can be inhibited by general metabolism inhibitors actinomycin D, cycloheximide, and lanthanum chloride. Furthermore, those HRs activate the expression of BAK1 and BIK1 genes that are essential for induction of mitogen-activated protein kinase (MAPK) and salicylic acid pathways. Once applied to plants, SSB(X) induces resistance to the fungal pathogen Alternaria alternata and enhances plant growth. When ssb(X)was deleted in X. oryzae pv. oryzicola, the causal agent of bacterial leaf streak in rice, the resulting ssb(Xoc)mutant was reduced in virulence and bacterial growth in planta, but retained its ability to trigger HR in tobacco. Interestingly, ssb(Xoc)contains an imperfect PIP-box (plant-inducible promoter) and the expression of ssb(Xoc)is regulated by HrpX, which belongs to the AraC family of transcriptional activators. Immunoblotting evidence showed that SSB(x) secretion requires a functional type-III secretion system as Hpa1 does. This is the first report demonstrating that Xanthomonas produce a highly-conserved SSB(X) that functions as a harpin-like protein for plant immunity. PMID:23418541

Li, Yu-Rong; Ma, Wen-Xiu; Che, Yi-Zhou; Zou, Li-Fang; Zakria, Muhammad; Zou, Hua-Song; Chen, Gong-You

2013-02-13

207

The chemically inducible expression of Erwinia amylovora bacterial effectors EopB1 and HopCEa in apple  

Technology Transfer Automated Retrieval System (TEKTRAN)

Erwinia amylovora, the causal agent of fire blight disease, utilizes a type three secretion system to deliver effector proteins into plant host cells. To investigate the role of individual bacterial effector proteins, we have engineered an apple host that transgenically expresses the bacterial effe...

208

Genetic diversity and a PCR-based method for Xanthomonas axonopodis detection in passion fruit.  

PubMed

Xanthomonas axonopodis pv. passiflorae causes bacterial spot in passion fruit. It attacks the purple and yellow passion fruit as well as the sweet passion fruit. The diversity of 87 isolates of pv. passiflorae collected from across 22 fruit orchards in Brazil was evaluated using molecular profiles and statistical procedures, including an unweighted pair-group method with arithmetical averages-based dendrogram, analysis of molecular variance (AMOVA), and an assigning test that provides information on genetic structure at the population level. Isolates from another eight pathovars were included in the molecular analyses and all were shown to have a distinct repetitive sequence-based polymerase chain reaction profile. Amplified fragment length polymorphism technique revealed considerable diversity among isolates of pv. passiflorae, and AMOVA showed that most of the variance (49.4%) was due to differences between localities. Cluster analysis revealed that most genotypic clusters were homogeneous and that variance was associated primarily with geographic origin. The disease adversely affects fruit production and may kill infected plants. A method for rapid diagnosis of the pathogen, even before the disease symptoms become evident, has value for producers. Here, a set of primers (Xapas) was designed by exploiting a single-nucleotide polymorphism between the sequences of the intergenic 16S-23S rRNA spacer region of the pathovars. Xapas was shown to effectively detect all pv. passiflorae isolates and is recommended for disease diagnosis in passion fruit orchards. PMID:21077774

Munhoz, C F; Weiss, B; Hanai, L R; Zucchi, M I; Fungaro, M H P; Oliveira, A L M; Monteiro-Vitorello, C B; Vieira, M L C

2011-04-01

209

Quorum sensing modulation of a putative glycosyltransferase gene cluster essential for Xanthomonas campestris biofilm formation.  

PubMed

Findings from previous studies suggest that the quorum sensing signal DSF (diffusible signal factor) negatively regulates biofilm formation in Xanthomonas campestris pv. campestris (Xcc) by affecting the expression of manA encoding biofilm dispersion and an unknown factor(s). In this study, by analysing the double deletion mutant ?rpfF?manA, in which DSF biosynthesis gene rpfF and biofilm dispersal gene manA were deleted, we found that DSF modulated biofilm development by suppression of a mechanism essential for biofilm formation. Transposon mutagenesis of ?rpfF?manA and subsequent analyses led to the identification of a novel gene locus xagABC encoding a putative glycosyl transferase system. Genetic analysis revealed that the transcriptional expression of xagABC was negatively regulated by DSF through the RpfC/RpfG two-component regulatory system. Deletion of the xag genes resulted in decreased extracellular polysaccharide production, abolished Xcc biofilm formation and attenuated the bacterial resistance to oxidative stress. Furthermore, we provide evidence that xagABC and manA were differentially expressed in Xcc and the biofilm formed by overexpression of xagABC in wild-type Xcc could be dispersed by ManA. These results provide new insight into the molecular mechanisms by which Xcc switches between planktonic growth and biofilm lifestyle. PMID:20636376

Tao, Fei; Swarup, Sanjay; Zhang, Lian-Hui

2010-12-01

210

Identification of Genes in Xanthomonas campestris pv. vesicatoria Induced during Its Interaction with Tomato?  

PubMed Central

Xanthomonas campestris pv. vesicatoria is the causal agent of bacterial spot disease of tomato and pepper. The disease process is interactive and very intricate and involves a plethora of genes in the pathogen and in the host. In the pathogen, different genes are activated in response to the changing environment to enable it to survive, adapt, evade host defenses, propagate, and damage the host. To understand the disease process, it is imperative to broaden our understanding of the gene machinery that participates in it, and the most reliable way is to identify these genes in vivo. Here, we have adapted a recombinase-based in vivo expression technology (RIVET) to study the genes activated in X. campestris pv. vesicatoria during its interaction with one of its hosts, tomato. This is the first study that demonstrates the feasibility of this approach for identifying in vivo induced genes in a plant pathogen. RIVET revealed 61 unique X. campestris pv. vesicatoria genes or operons that delineate a picture of the different processes involved in the pathogen-host interaction. To further explore the role of some of these genes, we generated knockout mutants for 13 genes and characterized their ability to grow in planta and to cause disease symptoms. This analysis revealed several genes that may be important for the interaction of the pathogen with its host, including a citH homologue gene, encoding a citrate transporter, which was shown to be required for wild-type levels of virulence.

Tamir-Ariel, Dafna; Navon, Naama; Burdman, Saul

2007-01-01

211

Characterization of the Xanthomonas axonopodis pv. glycines Hrp pathogenicity island.  

PubMed

We sequenced an approximately 29-kb region from Xanthomonas axonopodis pv. glycines that contained the Hrp type III secretion system, and we characterized the genes in this region by Tn3-gus mutagenesis and gene expression analyses. From the region, hrp (hypersensitive response and pathogenicity) and hrc (hrp and conserved) genes, which encode type III secretion systems, and hpa (hrp-associated) genes were identified. The characteristics of the region, such as the presence of many virulence genes, low G+C content, and bordering tRNA genes, satisfied the criteria for a pathogenicity island (PAI) in a bacterium. The PAI was composed of nine hrp, nine hrc, and eight hpa genes with seven plant-inducible promoter boxes. The hrp and hrc mutants failed to elicit hypersensitive responses in pepper plants but induced hypersensitive responses in all tomato plants tested. The Hrp PAI of X. axonopodis pv. glycines resembled the Hrp PAIs of other Xanthomonas species, and the Hrp PAI core region was highly conserved. However, in contrast to the PAI of Pseudomonas syringae, the regions upstream and downstream from the Hrp PAI core region showed variability in the xanthomonads. In addition, we demonstrate that HpaG, which is located in the Hrp PAI region of X. axonopodis pv. glycines, is a response elicitor. Purified HpaG elicited hypersensitive responses at a concentration of 1.0 micro M in pepper, tobacco, and Arabidopsis thaliana ecotype Cvi-0 by acting as a type III secreted effector protein. However, HpaG failed to elicit hypersensitive responses in tomato, Chinese cabbage, and A. thaliana ecotypes Col-0 and Ler. This is the first report to show that the harpin-like effector protein of Xanthomonas species exhibits elicitor activity. PMID:12730176

Kim, Jung-Gun; Park, Byoung Keun; Yoo, Chang-Hyuk; Jeon, Eunkyung; Oh, Jonghee; Hwang, Ingyu

2003-05-01

212

Integrons in Xanthomonas: a source of species genome diversity.  

PubMed

Integrons are best known for assembling antibiotic resistance genes in clinical bacteria. They capture genes by using integrase-mediated site-specific recombination of mobile gene cassettes. Integrons also occur in the chromosomes of many bacteria, notably beta- and gamma-Proteobacteria. In a survey of Xanthomonas, integrons were found in all 32 strains representing 12 pathovars of two species. Their chromosomal location was downstream from the acid dehydratase gene, ilvD, suggesting that an integron was present at this site in the ancestral xanthomonad. There was considerable sequence and structural diversity among the extant integrons. The majority of integrase genes were predicted to be inactivated by frameshifts, stop codons, or large deletions, suggesting that the associated gene cassettes can no longer be mobilized. In support, groups of strains with the same deletions or stop codons/frameshifts in their integrase gene usually contained identical arrays of gene cassettes. In general, strains within individual pathovars had identical cassettes, and these exhibited no similarity to cassettes detected in other pathovars. The variety and characteristics of contemporary gene cassettes suggests that the ancestral integron had access to a diverse pool of these mobile elements, and that their genes originated outside the Xanthomonas genome. Subsequent inactivation of the integrase gene in particular lineages has largely fixed the gene cassette arrays in particular pathovars during their differentiation and specialization into ecological niches. The acquisition of diverse gene cassettes by different lineages within Xanthomonas has contributed to the species-genome diversity of the genus. The role of gene cassettes in survival on plant surfaces is currently unknown. PMID:15755815

Gillings, Michael R; Holley, Marita P; Stokes, H W; Holmes, Andrew J

2005-03-08

213

ROLE OF CROP DEBRIS AND WEEDS IN THE EPIDEMIOLOGY OF BACTERIAL LEAF SPOT OF LETTUCE IN CALIFORNIA  

Technology Transfer Automated Retrieval System (TEKTRAN)

Bacterial leaf spot of lettuce (BLS), caused by Xanthomonas campestris pv. vitians, has increased in importance in California over the past 5 years. The pathogen can be seedborne, but it was not recovered from selected commercial lettuce seed lots planted during this time. Survival of X. campestri...

214

Association mapping of quantitative trait loci responsible for resistance to Bacterial Leaf Streak and Spot Blotch in spring wheat landraces  

Technology Transfer Automated Retrieval System (TEKTRAN)

Bacterial leaf streak (BLS), caused by Xanthomonas translucens pv. undulosa, and spot blotch (SB), caused by Cochliobolus sativus are two major diseases of wheat (Triticum aestivum L.). Planting resistant cultivars is the best approach to manage these diseases and identifying new sources of resistan...

215

Epidemiology of fire blight of floricane fruiting red raspberry caused by Erwinia amylovora  

Microsoft Academic Search

Current information on the epidemiology of fire blight of raspberry (Rubus idaeus), caused by Erwinia amylovora, is sparse and based on the assumption of a similarity to fire blight of apple (Malus ×domestica) and pear (Pyrus communis). To test this assumption, epidemiological studies of raspberry fire blight were conducted in controlled environment and in a planting of raspberry selection K81-6,

P. G. Braun; P. D. Hildebrand

2006-01-01

216

Isolation and Identification of Endophytic Bacteria Antagonistic to Camellia Oleifera Leaf Blight Base on Informatics  

Microsoft Academic Search

Leaf blight is a common Camellia oleifera disease caused by Pestalotiopsis microspora. The damaged young leaves show blight symptom, resulting in yield reduction. This study was to isolate antagonistic bacteria from Camellia oleifera tissue for control of the leaf blight. Antagonistic bacteria was screened from 175 endophytic bacterias by confront culture method. The results of the study showed that the

He Li; Guoying Zhou; Junang Liu

2009-01-01

217

Chemical and Cultural Approaches to Enhance Host Resistance to Fire Blight: Growth Regulators  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fire blight caused by the bacterium Erwinia amylovora [(Burrill) Winslow et al.] is one of the most destructive diseases in apple. Infection is initiated in the spring on flowers and with a second stage in late spring and summer termed shoot blight. Vigorous succulent growth favors fire blight inf...

218

Evaluation of the Biolog Substrate Utilization System To Identify and Assess Metabolic Variation among Strains of Xanthomonas campestris pv. Citri  

PubMed Central

Metabolic fingerprints of 148 strains of Xanthomonas campestris pv. citri originating from 24 countries and associated with various forms of citrus bacterial canker disease (CBCD) were obtained by using the Biolog substrate utilization system. Metabolic profiles were used to attempt strain identification. Only 6.8% of the studied strains were correctly identified when the commercial Microlog 2N data base was used alone. When the data base was supplemented with data from 54 strains of X. campestris pv. citri (40 CBCD-A strains, 8 CBCD-B strains, and 6 CBCD-C strains) and data from 43 strains of X. campestris associated with citrus bacterial spot disease, the percentage of correct identifications was 70%. Thus, it is recommended that users supplement the commercial data base with additional data prior to using the program for identification purposes. The utilization of Tween 40 in conjunction with other tests can help to differentiate strains associated with CBCD and citrus bacterial spot disease. These results confirmed the separation of X. campestris pv. citri into different subgroups (strains associated with Asiatic citrus canker [CBCD-A], cancrosis B [CBCD-B], and Mexican lime canker [CBCD-C]). The utilization of l-fucose, d-galactose, and alaninamide can be used as markers to differentiate strains associated with these groups. A single strain associated with bacteriosis of Mexican lime in Mexico (CBCD-D) was closely similar to CBCD-B strains.

Verniere, C.; Pruvost, O.; Civerolo, E. L.; Gambin, O.; Jacquemoud-Collet, J. P.; Luisetti, J.

1993-01-01

219

Membrane topology of conserved components of the type III secretion system from the plant pathogen Xanthomonas campestris pv. vesicatoria.  

PubMed

Type III secretion (T3S) systems play key roles in the assembly of flagella and the translocation of bacterial effector proteins into eukaryotic host cells. Eleven proteins which are conserved among gram-negative plant and animal pathogenic bacteria have been proposed to build up the basal structure of the T3S system, which spans both inner and outer bacterial membranes. We studied six conserved proteins, termed Hrc, predicted to reside in the inner membrane of the plant pathogen Xanthomonas campestris pv. vesicatoria. The membrane topology of HrcD, HrcR, HrcS, HrcT, HrcU and HrcV was studied by translational fusions to a dual alkaline phosphatase-beta-galactosidase reporter protein. Two proteins, HrcU and HrcV, were found to have the same membrane topology as the Yersinia homologues YscU and YscV. For HrcR, the membrane topology differed from the model for the homologue from Yersinia, YscR. For our data on three other protein families, exemplified by HrcD, HrcS and HrcT, we derived the first topology models. Our results provide what is believed to be the first complete model of the inner membrane topology of any bacterial T3S system and will aid in elucidating the architecture of T3S systems by ultrastructural analysis. PMID:20378646

Berger, Carolin; Robin, Guillaume P; Bonas, Ulla; Koebnik, Ralf

2010-04-08

220

Molecular identification of the turf grass rapid blight pathogen.  

PubMed

Rapid blight is a newly described disease on turf grasses, primarily found on golf courses using suboptimal water for irrigation purposes. On the basis of shared morphological characteristics, it has been proposed that the rapid blight pathogen belongs to a genus of stramenopiles, Labyrinthula, which had been known to cause disease of marine plants only. We have collected 10 isolates from four species of turf grass in five states and sequenced portions of the SSU (18S) rDNA gene from each to provide a definitive taxonomic placement for rapid blight pathogens. We also included sequences from Labyrinthuloides yorkensis, Schizochytrium aggregatum, Aplanochytrium sp., Thraustochytrium striatum, Achlya bisexualis and several nonturf-grass isolates of Labyrinthula. We found that rapid blight isolates indeed are placed firmly within the genus Labyrinthula and that they lack detectable genetic diversity in the 18S rDNA region. We propose that the rapid blight pathogens share a recent common ancestor and might have originated from a single, infected population. PMID:16389967

Craven, K D; Peterson, P D; Windham, D E; Mitchell, T K; Martin, S B

221

The Arabidopsis flagellin receptor FLS2 mediates the perception of Xanthomonas Ax21 secreted peptides  

PubMed Central

Detection of microbes by plants relies in part on an array of pattern-recognition receptors that recognize conserved microbial signatures, so-called “microbe-associated molecular patterns.” The Arabidopsis thaliana receptor-like kinase FLS2 is the pattern-recognition receptor for bacterial flagellin. Similarly to FLS2, the rice transmembrane protein XA21 is the receptor for the sulfated form of the Xanthomonas oryzae pv. oryzae secreted protein Ax21. Here we show that Ax21-derived peptides activate Arabidopsis immunity, triggering responses similar to those elicited by flagellin, including an oxidative burst, induction of defense-response genes, and enhanced resistance to bacterial pathogens. To identify Arabidopsis Xa21 functional homologs, we used a reverse genetics approach to screen T-DNA insertion mutants corresponding to all 47 of the Arabidopsis genes encoding non-RD kinases belonging to the interleukin-1 receptor-associated kinase (IRAK) family. Surprisingly, among all of these mutant lines, only fls2 mutants exhibited a significant loss of response to Ax21-derived peptides. Ax21 peptides also failed to activate defense-related responses in an fls2-24 mutant that does not bind Flg22. Moreover, a Flg22?2 variant of Flg22 that binds to FLS2 but does not activate FLS2-mediated signaling suppressed Ax21-derived peptide signaling, indicating mutually exclusive perception of Flg22 or Ax21 peptides by FLS2. The data indicate that FLS2 functions beyond flagellin perception to detect other microbe-associated molecular patterns.

Danna, Cristian H.; Millet, Yves A.; Koller, Teresa; Han, Sang-Wook; Bent, Andrew F.; Ronald, Pamela C.; Ausubel, Frederick M.

2011-01-01

222

Identification of Genes Required for Nonhost Resistance to Xanthomonas oryzae pv. oryzae Reveals Novel Signaling Components  

PubMed Central

Background Nonhost resistance is a generalized, durable, broad-spectrum resistance exhibited by plant species to a wide variety of microbial pathogens. Although nonhost resistance is an attractive breeding strategy, the molecular basis of this form of resistance remains unclear for many plant-microbe pathosystems, including interactions with the bacterial pathogen of rice, Xanthomonas oryzae pv. oryzae (Xoo). Methods and Findings Virus-induced gene silencing (VIGS) and an assay to detect the hypersensitive response (HR) were used to screen for genes required for nonhost resistance to Xoo in N. benthamiana. When infiltrated with Xoo strain YN-1, N. benthamiana plants exhibited a strong necrosis within 24 h and produced a large amount of H2O2 in the infiltrated area. Expression of HR- and defense-related genes was induced, whereas bacterial numbers dramatically decreased during necrosis. VIGS of 45 ACE (Avr/Cf-elicited) genes revealed identified seven genes required for nonhost resistance to Xoo in N. benthamiana. The seven genes encoded a calreticulin protein (ACE35), an ERF transcriptional factor (ACE43), a novel Solanaceous protein (ACE80), a hydrolase (ACE117), a peroxidase (ACE175) and two proteins with unknown function (ACE95 and ACE112). The results indicate that oxidative burst and calcium-dependent signaling pathways play an important role in nonhost resistance to Xoo. VIGS analysis further revealed that ACE35, ACE80, ACE95 and ACE175, but not the other three ACE genes, interfered with the Cf-4/Avr4-dependent HR. Conclusions/Significance N. benthamiana plants inoculated with Xoo respond by rapidly eliciting an HR and nonhost resistance. The oxidative burst and other signaling pathways are pivotal in Xoo-N. benthamiana nonhost resistance, and genes involved in this response partially overlap with those involved in Cf/Avr4-dependent HR. The seven genes required for N. benthamiana-mediated resistance to Xoo provide a basis for further dissecting the molecular mechanism of nonhost resistance.

Li, Wen; Xu, You-Ping; Zhang, Zhi-Xin; Cao, Wen-Yuan; Li, Fei; Zhou, Xueping; Chen, Gong-You; Cai, Xin-Zhong

2012-01-01

223

Populations of Xanthomonas citri pv. mangiferaeindicae from Asymptomatic Mango Leaves Are Primarily Endophytic  

Microsoft Academic Search

Epiphytic survival of several Xanthomonas pathovars has been reported, but most studies failed to determine whether such populations were resident epiphytes, resulting\\u000a from latent infections, or casual epiphytes. This study aimed at understanding the nature of Xanthomonas citri pv. mangiferaeindicae populations associated with asymptomatic leaves. When spray-inoculated on mango leaves cv. Maison Rouge, the pathogen multiplied\\u000a markedly in association with

Olivier Pruvost; Caroline Savelon; Claudine Boyer; Frédéric Chiroleu; Lionel Gagnevin; Marie-Agnès Jacques

2009-01-01

224

Characterization of an extracellular poly(3-hydroxy-5-phenylvalerate) depolymerase from Xanthomonas sp. JS02  

Microsoft Academic Search

A bacterium, JS02, capable of degrading an aromatic medium-chain-length polyhydroxyalkanoate (PHAMCL), poly(3-hydroxy-5-phenylvalerate) (PHPV), was isolated from wastewater-treatment sludge (Ju et?al. 1998), and was identified\\u000a as a Xanthomonas species. An extracellular PHPV depolymerase was purified from the concentrated culture broth of Xanthomonas sp. JS02 by using a chromatography series on Sephadex G-75, QAE-Sephadex A-50 and hydroxyapatite. The molecular mass of the

H. Kim; H.-S. Ju; J. Kim

2000-01-01

225

Phylogenetic structure of Xanthomonas determined by comparison of gyrB sequences.  

PubMed

Previously, we have produced a phylogeny of species type strains from the plant-pathogenic genus Xanthomonas based on gyrB sequences. To evaluate this locus further for species and infraspecies identification, we sequenced an additional 203 strains comprising all the pathovar reference strains (which have defined plant hosts), 67 poorly characterized pathovars, currently classified as Xanthomonas campestris, and 59 unidentified xanthomonads. The well-characterized pathovars grouped either in clades containing their respective species type strain or in clades containing species related to Xanthomonas axonopodis. The Xanthomonas euvesicatoria, Xanthomonas perforans and Xanthomonas alfalfae species complex, Xanthomonas fuscans and Xanthomonas citri were discriminated as X. axonopodis-related clades and comprised a large proportion of unidentified strains as well as 80 pathovars representing all the X. axonopodis pathovars and many poorly characterized pathovars, greatly increasing the plant host ranges of the constituent species. Most xanthomonads from these three large clades were isolated from a taxonomically diverse range of plant hosts, including many weed species, from field systems in India, suggesting that these lineages became established and diversified in agricultural areas in this region. The majority of these xanthomonads had minimal sequence diversity, consistent with rapid and highly extensive pathovar diversification that has occurred in relatively recent times. Low-intensity farming practices may have provided conditions conducive to pathovar development, and evidence for pathovar diversification within other regional angiosperm floras is discussed. The gyrB locus was sufficiently discriminating to identify diversity within many species. Seven branches or clades were sufficiently distinct to be considered as potential novel species. This study has provided a comprehensive xanthomonad classification framework and has firmly established gyrB sequencing as a rapid and efficient identification tool. PMID:19196764

Parkinson, Neil; Cowie, Claire; Heeney, John; Stead, David

2009-02-01

226

Assessment of the Genetic Diversity among Strains of Xanthomonas cynarae by Randomly Amplified Polymorphic DNA Analysis and Development of Specific Characterized Amplified Regions for the Rapid Identification of X. cynarae  

PubMed Central

The randomly amplified polymorphic DNA (RAPD) method was used to investigate the genetic diversity in Xanthomonas cynarae, which causes bacterial bract spot disease of artichoke. This RAPD analysis was also intended to identify molecular markers characteristic of this species, in order to develop PCR-based markers which can be used to detect this pathogenic bacterium in artichoke fields. Among the 340 RAPD primers tested, 40 were selected on their ability to produce reproducible and reliable fingerprints in our genetic background. These 40 primers produced almost similar patterns for the 37 X. cynarae strains studied, different from the fingerprints obtained for other Xanthomonas species and other xanthomonad-like bacteria isolated from artichoke leaves. Therefore, X. cynarae strains form a homogeneous genetic group. However, a little DNA polymorphism within this species was observed and the collection of X. cynarae isolates was divided into two groups (one containing three strains, the second one including all other strains). Out of seven RAPD markers characteristic of X. cynarae that were cloned, four did not hybridize to the genomic DNA of strains belonging to other Xanthomonas species. These four RAPD markers were converted into PCR markers (specific characterized amplified regions [SCARs]); they were sequenced, and a PCR primer pair was designed for each of them. Three derived SCARs are good candidates to develop PCR-based tests to detect X. cynarae in artichoke fields.

Trebaol, Gaelle; Manceau, Charles; Tirilly, Yves; Boury, Stephane

2001-01-01

227

Evaluation of kasugamycin for fire blight management, effect on nontarget bacteria, and assessment of kasugamycin resistance potential in Erwinia amylovora.  

PubMed

The emergence and spread of streptomycin-resistant strains of Erwinia amylovora in Michigan has necessitated the evaluation of new compounds effective for fire blight control. The aminoglycoside antibiotic kasugamycin (Ks) targets the bacterial ribosome and is particularly active against E. amylovora. The efficacy of Ks formulated as Kasumin 2L for control of fire blight was evaluated in six experiments conducted over four field seasons in our experimental orchards in East Lansing, MI. Blossom blight control was statistically equivalent to the industry standard streptomycin in all experiments. E. amylovora populations remained constant on apple flower stigmas pretreated with Kasumin and were ?100-fold lower than on stigmas treated with water. Kasumin applied to apple trees in the field also resulted in a 100-fold reduced total culturable bacterial population compared with trees treated with water. We performed a prospective analysis of the potential for kasugamycin resistance (Ks(R)) development in E. amylovora which focused on spontaneous resistance development and acquisition of a transferrable Ks(R) gene. In replicated lab experiments, the development of spontaneous resistance in E. amylovora to Ks at 250 or 500 ppm was not observed when cells were directly plated on medium containing high concentrations of the antibiotic. However, exposure to increasing concentrations of Ks in media (initial concentration 25 ?g ml(-1)) resulted in the selection of Ks resistance (at 150 ?g ml(-1)) in the E. amylovora strains Ea110, Ea273, and Ea1189. Analysis of mutants indicated that they harbored mutations in the kasugamycin target ksgA gene and that all mutants were impacted in relative fitness observable through a reduced growth rate in vitro and decreased virulence in immature pear fruit. The possible occurrence of a reservoir of Ks(R) genes in orchard environments was also examined. Culturable gram-negative bacteria were surveyed from six experimental apple orchards that had received at least one Kasumin application. In total, 401 Ks(R) isolates (42 different species) were recovered from apple flowers and leaves and orchard soil samples. Although we have not established the presence of a transferrable Ks(R) gene in orchard bacteria, the frequency, number of species, and presence of Ks(R) enterobacterial species in orchard samples suggests the possible role of nontarget bacteria in the future transfer of a Ks(R) gene to E. amylovora. Our data confirm the importance of kasugamycin as an alternate antibiotic for fire blight management and lay the groundwork for the development and incorporation of resistance management strategies. PMID:20923369

McGhee, Gayle C; Sundin, George W

2011-02-01

228

Xanthomonas campestris atcc 31601 and process for use  

SciTech Connect

A degenerative-resistant strain of Xanthomonas campestris has been developed and a process for using this strain to effectively overcome the problems of continuous xanthan production. This strain of X. campestris, designated X. campestris XCP-19 ATCC 31601, is capable of continuously producing xanthan at high specific productivities, i.e., 0.24 to 0.32 gm xanthan/gm cells/hr, for several hundred hours without culture degeneration from inexpensive aqueous nutrient media such as, for example, a minimal medium consisting primarily of inorganic salts, glucose, and NH4Cl. The medium may or may not also contain a yeast extract or yeast autolysate as a supplemental nitrogen source. Any medium having assimilable sources of carbon, nitrogen, and inorganic substances will serve satisfactorily for use with this new organism. 14 claims.

Weisrock, W.P.; McCarthy, E.F.

1983-11-29

229

Prospects for advanced late blight resistance breeding in potato  

Technology Transfer Automated Retrieval System (TEKTRAN)

The potato late blight pathogen, Phytophthora infestans, is able to rapidly evolve to overcome resistance genes. The pathogen accomplishes this by secreting an arsenal of proteins, termed effectors, that function to modify host cells. Although hundreds of candidate effectors have been identified in ...

230

Management of gummy stem blight of cantaloupe in south Texas  

Technology Transfer Automated Retrieval System (TEKTRAN)

In the Lower Rio Grande Valley of Texas (LRGV), Didymella bryoniae (Auersw.) Rehm commonly causes lesions in the crown and foliage of cantaloupe (Cucumis melo L.) but only occasionally on fruit. In Spring-1997, a severe gummy stem blight (GSB) epidemic occurred resulting in numerous corky-brown les...

231

Resistance to ascochyta blights of cool season food legumes.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Ascochyta blight is the most important disease problem of the cool season food legumes (peas, lentils, chickpeas, and faba beans) and is found in nearly all production regions around the world. Despite of the same common disease name, the pathogen species differ for each of the crops. These disease...

232

Brassica cover cropping for management of sheath blight of rice  

Technology Transfer Automated Retrieval System (TEKTRAN)

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...

233

FIELD EVALUATION OF CHEMICALS IN CONTROLLING CHICKPEA ASCOCHYTA BLIGHT, 2002  

Technology Transfer Automated Retrieval System (TEKTRAN)

The effectiveness of five chemicals (four fungicides and one laboratory chemical) in controlling Ascochyta blight of chickpea was evaluated at two locations. The five chemicals and their applied full rates were Headline (10.4 fl oz/A), Bravo Weather Stik (1.4 pt/A), Quadris SC (9.2 fl oz/A), Tilt (...

234

SALTS APPLICATION FOR SUPPRESSING POTATO EARLY BLIGHT DISEASE  

Microsoft Academic Search

The suppressive effect of sodium and calcium salts applied individually or combined with the yeast Saccharomyces cerevisiae against Alternaria solani the causal agent of early blight disease of potato was evaluated under laboratory, greenhouse and field condi- tions. In vitro test a complete inhibition in fungal growth was observed at concentration of 30 mg\\/ml of both sodium bicarbonate and calcium

Nehal S. El-Mougy; Mokhtar M. Abdel-Kader

2009-01-01

235

FIRST REPORT OF CITRUS BLIGHT IN COSTA RICA  

Technology Transfer Automated Retrieval System (TEKTRAN)

Citrus blight (CB), causing a chronic decline of citrus, has been an important disease in Florida for over 100 years. CB was first reported in Brazil in the 1980s and is now responsible for the removal of nearly 10% of the trees from production annually. No causal agent has been identified, but CB h...

236

Evaluation of Commercial Watermelon Rootstocks for Tolerance to Phytophthora Blight  

Technology Transfer Automated Retrieval System (TEKTRAN)

Phytophthora blight and fruit rot caused by Phytophthora capsici is becoming an important and emerging disease of watermelons (Citrullus lanatus). The disease mainly occurs in low lying areas of the fields where water logged conditions may be present. In recent years, the practice of grafting seed...

237

SUSCEPTIBILITY OF SOUTHERN HIGHBUSH BLUEBERRY CULTIVARS TO BOTRYOSPHAERIA STEM BLIGHT  

Technology Transfer Automated Retrieval System (TEKTRAN)

Stem blight, caused by the fungus Botryosphaeria dothidea, is a destructive disease of rabbiteye (Vaccinium ashei) and highbush (V. corymbosum) blueberries in the southeastern United States. The susceptibility of 23 southern highbush, seven rabbiteye, and two highbush blueberry cultivars was compar...

238

Plant Disease Lesson: Late blight of potato and tomato  

NSDL National Science Digital Library

This plant disease lesson on Late blight of potato and tomato (caused by Phytophthora infestans) includes information on symptoms and signs, pathogen biology, disease cycle and epidemiology, disease management, and the significance of the disease. Selected references are listed and a glossary is also available for use with this resource.

Gail L. Schumann (University of Massachusetts;); Cleora J. D'Arcy (University of Illinois;)

2000-07-24

239

Transcriptional response in apple to fire blight disease  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fire blight, caused by the bacterium Erwinia amylovora, is a destructive disease of apple, pear, and other plants in the subfamily Maloideae of the Rosaceae. The goal of this study was to use a global analysis of gene expression to characterize the temporal response of apple to infection by E. amyl...

240

Quince (Cydonia oblonga) emerges from the ashes of fire blight  

Technology Transfer Automated Retrieval System (TEKTRAN)

The two-decade history of fire blight in Bulgaria revealed quince as one of the most frequently attacked hosts and its production on a large scale has almost been entirely eliminated. Nevertheless, this species will play an important epidemiological role as a permanent source of inoculum for other p...

241

Field Susceptibility of Quince Hybrids to Fire Blight in Bulgaria  

Technology Transfer Automated Retrieval System (TEKTRAN)

Spread of fire blight in Bulgaria during the last 20 years has nearly eliminated commercial production of pear and quince. Damage has increased in both nurseries and orchards, yet susceptible cultivars continue to be planted. Quince is the host most frequently attacked by Erwinia amylovora in Bulgar...

242

Plant Disease Lesson: Fire blight of apple and pear  

NSDL National Science Digital Library

This plant disease lesson on Fire blight of apple and pear (caused by Erwinia amylovora) includes information on symptoms and signs, pathogen biology, disease cycle and epidemiology, disease management, and the significance of the disease. Selected references are listed and a glossary is also available for use with this resource.

Kenneth B. Johnson, (Oregon State University;)

2000-07-26

243

Plant Disease Lesson: Fusarium head blight (FHB) or scab  

NSDL National Science Digital Library

This plant disease lesson on Fusarium head blight (FHB) or scab (caused by the fungus Fusarium graminearum (anamorph) Gibberella zeae (teleomorph)) includes information on symptoms and signs, pathogen biology, disease cycle and epidemiology, disease management, and the significance of the disease. Selected references are listed and a glossary is also available for use with this resource.

David G. Schmale III (Cornell University;); Gary C. Bergstrom (Cornell University;)

2003-06-12

244

Nanotechnology in Plant Disease Management: DNA-Directed Silver Nanoparticles on Graphene Oxide as an Antibacterial against Xanthomonas perforans.  

PubMed

Bacterial spot caused by Xanthomonas perforans is a major disease of tomatoes, leading to reduction in production by 10-50%. While copper (Cu)-based bactericides have been used for disease management, most of the X. perforans strains isolated from tomatoes in Florida and other locations worldwide are Cu-resistant. We have developed DNA-directed silver (Ag) nanoparticles (NPs) grown on graphene oxide (GO). These Ag@dsDNA@GO composites effectively decrease X. perforans cell viability in culture and on plants. At the very low concentration of 16 ppm of Ag@dsDNA@GO, composites show excellent antibacterial capability in culture with significant advantages in improved stability, enhanced antibacterial activity, and stronger adsorption properties. Application of Ag@dsDNA@GO at 100 ppm on tomato transplants in a greenhouse experiment significantly reduced the severity of bacterial spot disease compared to untreated plants, giving results similar to those of the current grower standard treatment, with no phytotoxicity. PMID:24016217

Ocsoy, Ismail; Paret, Mathews L; Ocsoy, Muserref Arslan; Kunwar, Sanju; Chen, Tao; You, Mingxu; Tan, Weihong

2013-09-17

245

An Adenosine Kinase Exists in Xanthomonas campestris Pathovar campestris and Is Involved in Extracellular Polysaccharide Production, Cell Motility, and Virulence?  

PubMed Central

Adenosine kinase (ADK) is a purine salvage enzyme and a typical housekeeping enzyme in eukaryotes which catalyzes the phosphorylation of adenosine to form AMP. Since prokaryotes synthesize purines de novo and no endogenous ADK activity is detectable in Escherichia coli, ADK has long been considered to be rare in bacteria. To date, only two prokaryotes, both of which are gram-positive bacteria, have been reported to contain ADK. Here we report that the gram-negative bacterium Xanthomonas campestris pathovar campestris, the causal agent of black rot of crucifers, possesses a gene (designated adkXcc) encoding an ADK (named ADKXcc), and we demonstrate genetically that the ADKXcc is involved in extracellular polysaccharide (EPS) production, cell motility, and pathogenicity of X. campestris pv. campestris. adkXcc was overexpressed as a His6-tagged protein in E. coli, and the purified His6-tagged protein exhibited ADK activity. Mutation of adkXcc did not affect bacterial growth in rich and minimal media but led to an accumulation of intracellular adenosine and diminutions of intracellular ADK activity and ATP level, as well as EPS. The adkXcc mutant displayed significant reductions in bacterial growth and virulence in the host plant.

Lu, Guang-Tao; Tang, Yong-Qin; Li, Cai-Yue; Li, Rui-Fang; An, Shi-Qi; Feng, Jia-Xun; He, Yong-Qiang; Jiang, Bo-Le; Tang, Dong-Jie; Tang, Ji-Liang

2009-01-01

246

Hpa2 Required by HrpF To Translocate Xanthomonas oryzae Transcriptional Activator-Like Effectors into Rice for Pathogenicity?†  

PubMed Central

Xanthomonas oryzae pv. oryzicola, the causative agent of bacterial leaf streak, injects a plethora of effectors through the type III secretion system (T3SS) into rice cells to cause disease. The T3SS, encoded by the hrp genes, is essential for the pathogen to elicit the hypersensitive response (HR) in nonhost tobacco and for pathogenicity in host rice. Whether or not a putative lytic transglycosylase, Hpa2, interacts with a translocon protein, HrpF, to facilitate bacterial pathogenicity remains unknown. Here we demonstrated that both the hpa2 and hrpF genes are required for the pathogenicity of X. oryzae pv. oryzicola strain RS105 in rice but not for HR induction in tobacco. The expression of hpa2 was positively regulated by HrpG and HrpD6 but not by HrpX. In vivo secretion and subcellular localization analyses confirmed that Hpa2 secretion is dependent on HpaB (a T3SS exit protein) and that Hpa2 binds to the host cell membrane. Protein-protein assays demonstrated that Hpa2 interacts with HrpF. In planta translocation of AvrXa10 indicated that the mutation in hpa2 and hrpF inhibits the injection of the HpaB-dependent transcriptional activator-like (TAL) effector into rice. These findings suggest that Hpa2 and HrpF form a complex to translocate T3S effectors into plant cells for pathogenesis in host rice.

Li, Yu-Rong; Che, Yi-Zhou; Zou, Hua-Song; Cui, Yi-Ping; Guo, Wei; Zou, Li-Fang; Biddle, Eulandria M.; Yang, Ching-Hong; Chen, Gong-You

2011-01-01

247

An adenosine kinase exists in Xanthomonas campestris pathovar campestris and is involved in extracellular polysaccharide production, cell motility, and virulence.  

PubMed

Adenosine kinase (ADK) is a purine salvage enzyme and a typical housekeeping enzyme in eukaryotes which catalyzes the phosphorylation of adenosine to form AMP. Since prokaryotes synthesize purines de novo and no endogenous ADK activity is detectable in Escherichia coli, ADK has long been considered to be rare in bacteria. To date, only two prokaryotes, both of which are gram-positive bacteria, have been reported to contain ADK. Here we report that the gram-negative bacterium Xanthomonas campestris pathovar campestris, the causal agent of black rot of crucifers, possesses a gene (designated adk(Xcc)) encoding an ADK (named ADK(Xcc)), and we demonstrate genetically that the ADK(Xcc) is involved in extracellular polysaccharide (EPS) production, cell motility, and pathogenicity of X. campestris pv. campestris. adk(Xcc) was overexpressed as a His(6)-tagged protein in E. coli, and the purified His(6)-tagged protein exhibited ADK activity. Mutation of adk(Xcc) did not affect bacterial growth in rich and minimal media but led to an accumulation of intracellular adenosine and diminutions of intracellular ADK activity and ATP level, as well as EPS. The adk(Xcc) mutant displayed significant reductions in bacterial growth and virulence in the host plant. PMID:19329636

Lu, Guang-Tao; Tang, Yong-Qin; Li, Cai-Yue; Li, Rui-Fang; An, Shi-Qi; Feng, Jia-Xun; He, Yong-Qiang; Jiang, Bo-Le; Tang, Dong-Jie; Tang, Ji-Liang

2009-03-27

248

Genetic and Proteomic Analyses of a Xanthomonas campestris pv. campestris purC Mutant Deficient in Purine Biosynthesis and Virulence.  

PubMed

Bacterial proliferation in hosts requires activation of a number of housekeeping pathways, including purine de novo biosynthesis. Although inactivation of purine biosynthesis genes can attenuate virulence, it is unclear which biochemical or virulence factors are associated with the purine biosynthesis pathway in vivo. We report that inactivation of purC, a gene encoding phosphoribosylaminoimidazole-succinocarboxamide synthase, caused complete loss of virulence in Xanthomonas campestris pv. campestris, the causal agent of black rot disease of cruciferous plants. The purC mutant was a purine auxotroph; it could not grow on minimal medium, whereas addition of purine derivatives, such as hypoxanthine or adenine plus guanine, restored growth of the mutant. The purC mutation also significantly enhanced the production of an unknown purine synthesis associated pigment and extracellular polysaccharides by the bacterium. In addition, comparative proteomic analyses of bacteria grown on rich and minimal media revealed that the purC mutation affected the expression levels of diverse proteins involved in purine and pyrimidine synthesis, carbon and energy metabolisms, iron uptake, proteolysis, protein secretion, and signal transduction. These results provided clues to understanding the contributions of purine synthesis to bacterial virulence and interactions with host immune systems. PMID:24053949

Yuan, Zhihui; Wang, Li; Sun, Shutao; Wu, Yao; Qian, Wei

2013-06-02

249

Identification and characterization of a novel gene, hshB, in Xanthomonas oryzae pv. oryzicola co-regulated by quorum sensing and clp.  

PubMed

Virulence factors of Xanthomonas oryzae pv. oryzicola, the causal agent of bacterial leaf streak in rice, are regulated by a diffusible signal factor (DSF)-dependent quorum-sensing (QS) system. In this study, a novel pathogenicity-related gene, Xoryp_010100018570 (named hshB), of X. oryzae pv. oryzicola was characterized. hshB encodes a hydrolase with a putative signal peptide, which is a homolog of imidazolonepropionase. Bioinformatic analysis showed that hshB is relatively conserved in the genus Xanthomonas but the homologous gene of hshB was not found in X. oryzae pv. oryzae. Reverse-transcription polymerase chain reaction (PCR) analysis showed that hshB and its upstream gene, Xoryp_010100018565 (named hshA), are co-transcribed in X. oryzae pv. oryzicola. Subsequent experimental results indicated that mutation of hshB remarkably impaired the virulence, extracellular protease activity, extracellular polysaccharide production, growth in minimal medium, and resistance to oxidative stress and bismerthiazol of X. oryzae pv. oryzicola. Mutation of clp, encoding a global regulator, resulted in similar phenotypes. Real-time PCR assays showed that hshB transcription is positively regulated by clp and DSF, and induced by poor nutrition. Our study not only found a novel gene hshB regulated by DSF-dependent QS system and clp but also showed that hshB was required for virulence of X. oryzae pv. oryzicola. PMID:22106829

Zhao, Yancun; Qian, Guoliang; Fan, Jiaqin; Yin, Fangqun; Zhou, Yijin; Liu, Chunhui; Shen, Qin; Hu, Baishi; Liu, Fengquan

2012-03-01

250

Aconitase B is required for optimal growth of Xanthomonas campestris pv. vesicatoria in pepper plants.  

PubMed

The aerobic plant pathogenic bacterium Xanthomonas campestris pv. vesicatoria (Xcv) colonizes the intercellular spaces of pepper and tomato. One enzyme that might contribute to the successful proliferation of Xcv in the host is the iron-sulfur protein aconitase, which catalyzes the conversion of citrate to isocitrate in the tricarboxylic acid (TCA) cycle and might also sense reactive oxygen species (ROS) and changes in cellular iron levels. Xcv contains three putative aconitases, two of which, acnA and acnB, are encoded by a single chromosomal locus. The focus of this study is aconitase B (AcnB). acnB is co-transcribed with two genes, XCV1925 and XCV1926, encoding putative nucleic acid-binding proteins. In vitro growth of acnB mutants was like wild type, whereas in planta growth and symptom formation in pepper plants were impaired. While acnA, XCV1925 or XCV1926 mutants showed a wild-type phenotype with respect to bacterial growth and in planta symptom formation, proliferation of the acnB mutant in susceptible pepper plants was significantly impaired. Furthermore, the deletion of acnB led to reduced HR induction in resistant pepper plants and an increased susceptibility to the superoxide-generating compound menadione. As AcnB complemented the growth deficiency of an Escherichia coli aconitase mutant, it is likely to be an active aconitase. We therefore propose that optimal growth and survival of Xcv in pepper plants depends on AcnB, which might be required for the utilization of citrate as carbon source and could also help protect the bacterium against oxidative stress. PMID:22493725

Kirchberg, Janine; Büttner, Daniela; Thiemer, Barbara; Sawers, R Gary

2012-04-06

251

Proteome of the phytopathogen Xanthomonas citri subsp. citri: a global expression profile  

PubMed Central

Background Citrus canker is a disease caused by Xantomonas citri subsp.citri (Xac), and has emerged as one of the major threats to the worldwide citrus crop because it affects all commercial citrus varieties, decreases the production and quality of the fruits and can spread rapidly in citrus growing areas. In this work, the first proteome of Xac was analyzed using two methodologies, two-dimensional liquid chromatography (2D LC) and tandem mass spectrometry (MS/MS). Results In order to gain insight into the metabolism of Xac, cells were grown on two different media (NB - Nutrient Broth and TSE - Tryptone Sucrose broth enriched with glutamic acid), and proteins were proteolyzed with trypsin and examined by 2D LC-MS/MS. Approximately 39% of all predicted proteins by annotation of Xac were identified with their component peptides unambiguously assigned to tandem mass spectra. The proteins, about 1,100, were distributed in all annotated functional categories. Conclusions This is the first proteomic reference map for the most aggressive strain of Xanthomonas pathogen of all orange varieties. The compilation of metabolic pathways involved with bacterial growth showed that Xac expresses a complete central and intermediary metabolism, replication, transcription and translation machineries and regulation factors, distinct membrane transporters (ABC, MFS and pumps) and receptors (MCP, TonB dependent and metabolites acquisition), two-component systems (sensor and regulatory components) and response regulators. These data corroborate the growth curve in vitro and are the first reports indicating that many of these genome annotated genes are translated into operative in Xac. This proteomic analysis also provided information regarding the influence of culture medium on growth and protein expression of Xac.

2010-01-01

252

Aconitase B Is Required for Optimal Growth of Xanthomonas campestris pv. vesicatoria in Pepper Plants  

PubMed Central

The aerobic plant pathogenic bacterium Xanthomonas campestris pv. vesicatoria (Xcv) colonizes the intercellular spaces of pepper and tomato. One enzyme that might contribute to the successful proliferation of Xcv in the host is the iron-sulfur protein aconitase, which catalyzes the conversion of citrate to isocitrate in the tricarboxylic acid (TCA) cycle and might also sense reactive oxygen species (ROS) and changes in cellular iron levels. Xcv contains three putative aconitases, two of which, acnA and acnB, are encoded by a single chromosomal locus. The focus of this study is aconitase B (AcnB). acnB is co-transcribed with two genes, XCV1925 and XCV1926, encoding putative nucleic acid-binding proteins. In vitro growth of acnB mutants was like wild type, whereas in planta growth and symptom formation in pepper plants were impaired. While acnA, XCV1925 or XCV1926 mutants showed a wild-type phenotype with respect to bacterial growth and in planta symptom formation, proliferation of the acnB mutant in susceptible pepper plants was significantly impaired. Furthermore, the deletion of acnB led to reduced HR induction in resistant pepper plants and an increased susceptibility to the superoxide-generating compound menadione. As AcnB complemented the growth deficiency of an Escherichia coli aconitase mutant, it is likely to be an active aconitase. We therefore propose that optimal growth and survival of Xcv in pepper plants depends on AcnB, which might be required for the utilization of citrate as carbon source and could also help protect the bacterium against oxidative stress.

Kirchberg, Janine; Buttner, Daniela; Thiemer, Barbara; Sawers, R. Gary

2012-01-01

253

Relative importance of bacteriocin-like genes in antagonism of Xanthomonas perforans tomato race 3 to Xanthomonas euvesicatoria tomato race 1 strains.  

PubMed

In a previous study, tomato race 3 (T3) strains of Xanthomonas perforans became predominant in fields containing both X. euvesicatoria and X. perforans races T1 and T3, respectively. This apparent ability to take over fields led to the discovery that there are three bacteriocin-like compounds associated with T3 strains. T3 strain 91-118 produces at least three different bacteriocin-like compounds (BCN-A, BCN-B, and BCN-C) antagonistic toward T1 strains. We determined the relative importance of the bacteriocin-like compounds by constructing the following mutant forms of a wild-type (WT) T3 strain to evaluate the antagonism to WT T1 strains: Mut-A (BCN-A-), Mut-B (BCN-B-), Mut-C (BCN-C-), Mut-AB, Mut-BC, and Mut-ABC. Although all mutant and WT T3 strains reduced the T1 populations in in planta growth room experiments, Mut-B and WT T3 were significantly more effective. Mutants expressing BCN-B and either BCN-A or BCN-C reduced T1 populations less than mutants expressing only BCN-A or BCN-C. The triple-knockout mutant Mut-ABC also had a significant competitive advantage over the T1 strain. In pairwise-inoculation field experiments where plants were coinoculated with an individual mutant or WT T3 strain and the T1 strain, the mutant strains and the WT T3 strain were reisolated from more than 70% of the lesions. WT T3 and Mut-B were the most frequently reisolated strains. In field experiments where plants were group inoculated with Mut-A, Mut-B, Mut-C, Mut-ABC, and WT T1 and T3 strains, Mut-B populations dominated all three seasons. In greenhouse and field experiments, the WT and mutant T3 strains had a selective advantage over T1 strains. Bacterial strains expressing both BCN-A and BCN-C appeared to have a competitive advantage over all other mutant and WT strains. Furthermore, BCN-B appeared to be a negative factor, with mutant T3 strains lacking BCN-B having a selective advantage in the field. PMID:16000765

Hert, A P; Roberts, P D; Momol, M T; Minsavage, G V; Tudor-Nelson, S M; Jones, J B

2005-07-01

254

Recognition of the Bacterial Avirulence Protein AvrBs3 Occurs inside the Host Plant Cell  

Microsoft Academic Search

The molecular mechanism by which bacterial avirulence genes mediate recognition by resistant host plants has been enigmatic for more than a decade. In this paper we provide evidence that the Xanthomonas campestris pv. vesicatoria avirulence protein AvrBs3 is recognized inside the plant cell. Transient expression of avrBs3 in pepper leaves, using Agrobacterium tumefaciens for gene delivery, results in hypersensitive cell

Guido Van den Ackerveken; Eric Marois; Ulla Bonas

1996-01-01

255

Identification of QTL associated with resistance to bacterial spot race T4 in tomato  

Microsoft Academic Search

Bacterial spot of tomato (Solanum lycopersicum L.), caused by several Xanthomonas sp., is a serious but difficult disease to control by chemical means. Development of resistance has been hindered by emergence\\u000a of races virulent to tomato, by the quantitative inheritance of resistance, and by a low correlation between seedling assays\\u000a and resistance in the field. Resistance to multiple races, including

Samuel F. HuttonJay; Jay W. Scott; Wencai Yang; Sung-Chur Sim; David M. Francis; Jeffrey B. Jones

2010-01-01

256

Potato yield losses due to early blight in Minnesota fields, 1981 and 1982  

Microsoft Academic Search

In both 1981 and 1982, 51 potato fields were surveyed every 7–10 days for early blight severity and fungicide use. Early blight\\u000a severity data from each field were used as input to a regression model to estimate yield loss in that field. The model for\\u000a early maturing potato cultivars was Percent Yield Loss=0.8183+0.6441* (% blight increment between days 56 and

P. S. Teng; H. L. Bissonnette

1985-01-01

257

Tomato early blight ( Alternaria solani ): the pathogen, genetics, and breeding for resistance  

Microsoft Academic Search

Alternaria solani causes diseases on foliage (early blight), basal stems of seedlings (collar rot), stems of adult plants (stem lesions), and\\u000a fruits (fruit rot) of tomato. Early blight is the most destructive of these diseases and hence receives considerable attention\\u000a in breeding. For over 60 years, breeding for early blight resistance has been practiced, but the development of cultivars\\u000a with

Reni Chaerani; Roeland E. Voorrips

2006-01-01

258

Xanthomonas campestris diffusible factor is 3-hydroxybenzoic acid and is associated with xanthomonadin biosynthesis, cell viability, antioxidant activity, and systemic invasion.  

PubMed

Xanthomonas campestris pv. campestris produces a membrane-bound yellow pigment called xanthomonadin. A diffusible factor (DF) has been reported to regulate xanthomonadin biosynthesis. In this study, DF was purified from bacterial culture supernatants using a combination of solvent extraction, flash chromatography, and high-performance liquid chromatography. Mass spectrometry and nuclear magnetic resonance analyses resolved the DF chemical structure as 3-hydroxybenzoic acid (3-HBA), which was further confirmed by synthetic 3-HBA. Significantly, bioassay and in silico analysis suggest that DF production is widely conserved in a range of bacterial species. Analysis of DF derivatives established the hydroxyl group and its position as the key structural features for the role of DF in xanthomonadin biosynthesis. In addition, we showed that DF is also associated with bacterial survival, H2O2 resistance, and systemic invasion. Furthermore, evidence was also presented that DF and diffusible signaling factor have overlapping functions in modulation of bacterial survival, H2O2 resistance, and virulence. Utilization of different mechanisms to modulate similar virulence traits may provide X. campestris pv. campestris with plasticity in response to various environmental cues. PMID:21539432

He, Ya-Wen; Wu, Ji'en; Zhou, Lian; Yang, Fan; He, Yong-Qiang; Jiang, Bo-Le; Bai, Linquan; Xu, Yuquan; Deng, Zixin; Tang, Ji-Liang; Zhang, Lian-Hui

2011-08-01

259

Modifications of Xanthomonas axonopodis pv. citri Lipopolysaccharide Affect the Basal Response and the Virulence Process during Citrus Canker  

PubMed Central

Xanthomonas axonopodis pv. citri (Xac) is the phytopathogen responsible for citrus canker, one of the most devastating citrus diseases in the world. A broad range of pathogens is recognized by plants through so-called pathogen-associated molecular patterns (PAMPs), which are highly conserved fragments of pathogenic molecules. In plant pathogenic bacteria, lipopolisaccharyde (LPS) is considered a virulence factor and it is being recognized as a PAMP. The study of the participation of Xac LPS in citrus canker establishment could help to understand the molecular bases of this disease. In the present work we investigated the role of Xac LPS in bacterial virulence and in basal defense during the interaction with host and non host plants. We analyzed physiological features of Xac mutants in LPS biosynthesis genes (wzt and rfb303) and the effect of these mutations on the interaction with orange and tobacco plants. Xac mutants showed an increased sensitivity to external stresses and differences in bacterial motilities, in vivo and in vitro adhesion and biofilm formation. Changes in the expression levels of the LPS biosynthesis genes were observed in a medium that mimics the plant environment. Xacwzt exhibited reduced virulence in host plants compared to Xac wild-type and Xacrfb303. However, both mutant strains produced a lower increase in the expression levels of host plant defense-related genes respect to the parental strain. In addition, Xac LPS mutants were not able to generate HR during the incompatible interaction with tobacco plants. Our findings indicate that the structural modifications of Xac LPS impinge on other physiological attributes and lead to a reduction in bacterial virulence. On the other hand, Xac LPS has a role in the activation of basal defense in host and non host plants.

Petrocelli, Silvana; Tondo, Maria Laura; Daurelio, Lucas D.; Orellano, Elena G.

2012-01-01

260

Effects of sulfur dioxide on expansion of lesions caused by Corynebacterium nebraskense in maize and by Xanthomonas phaseoli var. sojensis in soybean  

SciTech Connect

In order to assess the effects of air pollution on plant disease development, the authors investigated the effects of SO/sub 2/ on lesion development by two bacterial pathogens. Maize or soybean plants were exposed to sulfur dioxide (SO/sub 2/) at 524 ..mu..g m/sup -3/ or 262 ..mu..g m/sup -3/ before, after or before and after inoculation with Corynebacterium nebraskense or Xanthomonas phaseoli var. sojensis, respectively. Lesion development was inhibited in both cases, regardless of when the exposures occurred. The time of exposure, however, altered the subsequent effect on lesion size. Dry weight and sulfur content of host tissue were not altered by the joint effects of the pollutant and the pathogens.

Laurence, J.A.; Aluisio, A.L.

1981-01-01

261

Fire blight: applied genomic insights of the pathogen and host.  

PubMed

The enterobacterial phytopathogen Erwinia amylovora causes fire blight, an invasive disease that threatens a wide range of commercial and ornamental Rosaceae host plants. The response elicited by E. amylovora in its host during disease development is similar to the hypersensitive reaction that typically leads to resistance in an incompatible host-pathogen interaction, yet no gene-for-gene resistance has been described for this host-pathogen system. Comparative genomic analysis has found an unprecedented degree of genetic uniformity among strains of E. amylovora, suggesting that the pathogen has undergone a recent genetic bottleneck. The genome of apple, an important host of E. amylovora, has been sequenced, creating new opportunities for the study of interactions between host and pathogen during fire blight development and for the identification of resistance genes. This review includes recent advances in the genomics of both host and pathogen. PMID:22702352

Malnoy, Mickael; Martens, Stefan; Norelli, John L; Barny, Marie-Anne; Sundin, George W; Smits, Theo H M; Duffy, Brion

2012-06-11

262

Epidemiology of Northern leaf blight on sweet corn  

Microsoft Academic Search

The epidemiology of northern leaf blight of corn, caused byExserohilum turcicum (Pass.) Leonard and Suggs, is reviewed. The minimal dew period required for infection is temperature-dependent. At 25°C,\\u000a 1 h of dew is sufficient to cause infection and at this temperature the minimal dew period for sporulation is 14 h. Under\\u000a natural conditions when one dew night is not long

Y. Levy; J. K. Pataky

1992-01-01

263

Influence of silicon on sheath blight of rice in Brazil  

Microsoft Academic Search

The effect of silicon (Si) on sheath blight (Rhizoctonia solani Kühn) of rice was studied under greenhouse conditions. The predominant commercial rice cultivars ‘BR-IRGA 409’, ‘Metica-1’, ‘EPAGRI-109’, ‘Rio Formoso’, ‘Javaé’, and ‘CICA-8’, were grown in pots containing low-Si soil amended with 0, 0.48, 0.96, 1.44 or 1.92g Si pot?1. Plants were inoculated at the maximum tillering stage. For all cultivars,

F. Á. Rodrigues; F. X. R. Vale; G. H. Korndörfer; A. S. Prabhu; L. E. Datnoff; A. M. A. Oliveira; L. Zambolim

2003-01-01

264

A Xanthomonas uridine 5'-monophosphate transferase inhibits plant immune kinases.  

PubMed

Plant innate immunity is activated on the detection of pathogen-associated molecular patterns (PAMPs) at the cell surface, or of pathogen effector proteins inside the plant cell. Together, PAMP-triggered immunity and effector-triggered immunity constitute powerful defences against various phytopathogens. Pathogenic bacteria inject a variety of effector proteins into the host cell to assist infection or propagation. A number of effector proteins have been shown to inhibit plant immunity, but the biochemical basis remains unknown for the vast majority of these effectors. Here we show that the Xanthomonas campestris pathovar campestris type III effector AvrAC enhances virulence and inhibits plant immunity by specifically targeting Arabidopsis BIK1 and RIPK, two receptor-like cytoplasmic kinases known to mediate immune signalling. AvrAC is a uridylyl transferase that adds uridine 5'-monophosphate to and conceals conserved phosphorylation sites in the activation loop of BIK1 and RIPK, reducing their kinase activity and consequently inhibiting downstream signalling. PMID:22504181

Feng, Feng; Yang, Fan; Rong, Wei; Wu, Xiaogang; Zhang, Jie; Chen, She; He, Chaozu; Zhou, Jian-Min

2012-04-15

265

Genetic Diversity among Xanthomonas campestris Strains Pathogenic for Small Grains  

PubMed Central

A collection of 51 Xanthomonas campestris strains from throughout the world was studied to detect and assess genetic diversity among pathogens of small grains. Isolates from barley, bread wheat, bromegrass, canary grass, cassava, maize, orchard grass, rice, rough-stalked meadow grass, rye, timothy, and triticale were analyzed by pathogenicity tests on bread wheat cv. Alondra and barley cv. Corona, indirect immunofluorescence, and restriction fragment length polymorphism (RFLP). Three probes were used for the RFLP analysis. They were an acetylaminofluorene-labelled 16S+23S rRNA probe from Escherichia coli and two (sup32)P-labelled restriction fragments from either plasmidic (pBSF2) or chromosomal (pBS8) DNA of X. campestris pv. manihotis. Strains clustered in 9 and 20 groups with the rRNA probe and the pBSF2 DNA probe, respectively. Strains of X. campestris pv. graminis, X. campestris pv. phleipratensis, and X. campestris pv. poae are shown to be related but are also distinguishable by RFLP patterns, serology, and pathogenicity on bread wheat. Strains pathogenic only for barley and not for wheat grouped together. Another group is temporarily designated deviant X. campestris pv. undulosa. These South American isolates from bread wheat did not react by indirect immunofluorescence and produced atypical lesions in pathogenicity tests. The results stress the need to perform pathogenicity tests before strains are named at the pathovar level. The importance of the different probes used for epidemiological studies or phylogenetic studies of closely related strains is underlined.

Bragard, C.; Verdier, V.; Maraite, H.

1995-01-01

266

Differential expression of pathogenicity- and virulence-related genes of Xanthomonas axonopodis pv. citri under copper stress  

PubMed Central

In this study, we used real-time quantitative PCR (RT-qPCR) to evaluate the expression of 32 genes of Xanthomonas axonopodis pv. citri related to pathogenicity and virulence that are also involved in copper detoxification. Nearly all of the genes were up-regulated, including copA and copB. Two genes homologous to members of the type II secretion system (xcsH and xcsC) and two involved in the degradation of plant cell wall components (pglA and pel) were the most expressed in response to an elevated copper concentration. The type II secretion system (xcs operon) and a few homologues of proteins putatively secreted by this system showed enhanced expression when the bacteria were exposed to a high concentration of copper sulfate. The enhanced expression of the genes of secretion II system during copper stress suggests that this pathway may have an important role in the adaptative response of X. axonopodis pv. citri to toxic compounds. These findings highlight the potential role of these genes in attenuating the toxicity of certain metals and could represent an important means of bacterial resistance against chemicals used to control diseases.

2010-01-01

267

Use of oligonucleotide probes to identify members of two-component regulatory systems in Xanthomonas campestris pathovar campestris.  

PubMed

Two-component regulatory systems comprising a sensor and a regulator protein, both with highly conserved amino acid domains, and commonly genetically linked, have been described in a range of bacterial species and are involved in sensing environmental stimuli. We used two oligonucleotide probes matching the postulated coding regions for domains of sensor and regulator proteins respectively in Xanthomonas campestris pathovar campestris (Xcc) to identify possible two-component regulatory systems in Xcc. Two different fragments of Xcc DNA with homology to both of these probes were cloned. The DNA sequence of part of one of these fragments encompassed a potential open reading frame (ORF), the predicted amino acid sequence of which had extensive homology with regulator proteins of two-component regulatory systems. Analysis of the predicted amino acid sequence for the 3' end of an adjacent ORF revealed a very high level of homology with the C-terminal end of sensor proteins. Strains of Xcc with Tn5-induced mutations in the regulator gene were affected in extracellular polysaccharide production, and also in resistance to salt and chloramphenicol. No effects of mutation in the second clone were observed. PMID:2233675

Osbourn, A E; Clarke, B R; Stevens, B J; Daniels, M J

1990-06-01

268

Construction of a Tn5-tagged mutant library of Xanthomonas oryzae pv. oryzicola as an invaluable resource for functional genomics.  

PubMed

To genome-widely mine pathogenesis-related genes of Xanthomonas oryzae pv. oryzicola (Xoc), which is the casual agent of bacterial leaf streak resulting in significant yield loss and poor quality in rice, a Tn5 transposon-mediated mutation library was generated. Twenty-five thousand transformants were produced by using Tn5 transposome, appropriately corresponding to 5 × ORF coverage of the genome, and inoculated into rice and tobacco, individually and respectively, for screening candidate virulence genes. Southern blot and thermal asymmetric interlaced polymerase chain reaction analysis of Tn5 insertion sites of randomly selected mutants suggested a random mode of transposition and a saturation library. Characterization of extracellular polysaccharides, extracellular protease activity, and pigment production of individual mutants in the growth media revealed that 11 mutants enhanced in growth, 12 reduced extracellular polysaccharide production, 12 lost extracellular protease activity completely or partially, and 21 were pigment deficient. In planta pathogenicity assays revealed 253 mutants reduced virulence in rice, but kept triggering hypersensitive response in tobacco; 49 lost the ability to elicit HR in tobacco and pathogenicity in rice; and 3 still induced hypersensitive response in tobacco, but lost pathogenicity in rice. The achieved mutant library of Xoc is of high-quality and nearly saturated and candidate virulence mutants provided a strong basis for functional genomics of Xoc. PMID:21046389

Zou, Hua-Song; Yuan, Liang; Guo, Wei; Li, Yu-Rong; Che, Yi-Zhou; Zou, Li-Fang; Chen, Gong-You

2010-11-04

269

Identification of a host 14-3-3 Protein that Interacts with Xanthomonas effector AvrRxv  

PubMed Central

AvrRxv is a member of a family of pathogen effectors present in pathogens of both plant and mammalian species. Xanthomonas campestris pv. vesicatoria strains carrying AvrRxv induce a hypersensitive response (HR) in the tomato cultivar Hawaii 7998. Using a yeast two-hybrid screen, we identified a 14-3-3 protein from tomato that interacts with AvrRxv called AvrRxv Interactor 1 (ARI1). The interaction was confirmed in vitro with affinity chromatography. Using mutagenesis, we identified a 14-3-3-binding domain in AvrRxv and demonstrated that a mutant in that domain showed concomitant loss of interaction with ARI1 and HR-inducing activity in tomato. These results demonstrate that the AvrRxv bacterial effector recruits 14-3-3 proteins for its function within host cells. AvrRxv homologues YopP and YopJ from Yersinia do not have AvrRxv-specific HR-inducing activity when delivered into tomato host cells by Agrobacterium. Although YopP itself cannot induce HR, its C-terminal domain containing the catalytic residues can replace that of AvrRxv in an AvrRxv-YopP chimera for HR-inducing activity. Phylogenetic analysis indicates that the sequences encoding the C-termini of family members are evolving independently from those encoding the N-termini. Our results support a model in which there are three functional domains in proteins of the family, translocation, interaction, and catalytic.

Whalen, Maureen; Richter, Todd; Zakhareyvich, Kseniya; Yoshikawa, Masayasu; Al-Azzeh, Dana; Adefioye, Adeshola; Spicer, Greg; Mendoza, Laura L.; Morales, Christine Q.; Klassen, Vicki; Perez-Baron, Gina; Toebe, Carole S.; Tzovolous, Ageliki; Gerstman, Emily; Evans, Erika; Thompson, Cheryl; Lopez, Mary; Ronald, Pamela C.

2009-01-01

270

Identification and Characterization of RB Orthologous Genes from the Late Blight Resistant Wild Potato Species Solanum verrucosum  

Technology Transfer Automated Retrieval System (TEKTRAN)

Late blight is one of the most devastating plant pathogens of potato. A major late blight resistance gene, called RB, was previously identified in the wild potato species Solanum bulbocastanum. Another wild potato species, S. verrucosum also contains resistance to late blight. We have now identif...

271

A Statistical Comparison of the Blossom Blight Forecasts of MARYBLYT and Cougarblight with Receiver Operating Characteristic Curve Analysis  

Technology Transfer Automated Retrieval System (TEKTRAN)

Blossom blight forecasting is an important aspect of fire blight, caused by Erwinia amylovora, management for both apple and pear. A comparison of the forecast accuracy of two common fire blight forecasters, MARYBLYT and Cougarblight, was performed with receiver operating characteristic (ROC) curve ...

272

Molecular Tools to Study Epidemiology and Toxicology of Fusarium Head Blight of Cereals  

Microsoft Academic Search

Fusarium head blight (FHB) of cereals is a disease complex. Fusarium graminearum is the major pathogen worldwide, while F. culmorum, F. avenaceum and F. poae are also associated with this disease. In addition to the true Fusarium species, Microdochium nivale may also cause head blight and is particularly prevalent where cooler, wetter conditions prevail. Other species such as F. sporotrichioides,

Paul Nicholson; E. Chandler; R. C. Draeger; N. E. Gosman; D. R. Simpson; M. Thomsett; A. H. Wilson

2003-01-01

273

PATHOTYPE-SPECIFIC GENETIC FACTORS IN CHICKPEA (CICER ARIETINUM L.) FOR QUANTITATIVE RESISTANCE TO ASCOCHYTA BLIGHT  

Technology Transfer Automated Retrieval System (TEKTRAN)

Ascochyta blight in chickpea (Cicer arietinum L.) is a devastating fungal disease caused by the necrotrophic pathogen, Ascochyta rabiei (Pass.) Lab. The objectives of our study were to elucidate the genetic mechanism of pathotype-dependent blight resistance in chickpea and to identify genomic regio...

274

PGPR-induced defense responses in the tea plant against blister blight disease  

Microsoft Academic Search

Plant growth-promoting rhizobacteria (PGPR) bioformulations (Pseudomonas and Bacillus) were tested for their efficacy against blister blight (Exobasidium vexans) disease in tea (Camellia sinensis) under field conditions for two seasons. Among the bioformulations tested, foliar application of Pseudomonas fluorescens Pf1 at 7-d intervals consistently reduced the disease incidence of blister blight for two seasons, almost comparable with that of chemical fungicide.

D. Saravanakumar; Charles Vijayakumar; N. Kumar; R. Samiyappan

2007-01-01

275

GENETIC CHARACTERIZATION OF BINUCLEATE RHIZOCTONIA SPECIES CAUSING WEB BLIGHT ON AZALEA IN MISSISSIPPI AND ALABAMA  

Technology Transfer Automated Retrieval System (TEKTRAN)

Web blight on containerized azalea is an annual problem for commercial nurseries during the summer months in the southern US. Losses to web blight are associated with the cost of fungicides, delayed marketing of diseased plants, and plant death. Three hundred and nine isolates of Rhizoctonia recover...

276

Development and characterization of RiceCAP QTL mapping population for sheath blight resistance  

Technology Transfer Automated Retrieval System (TEKTRAN)

RiceCAP is a USDA CSREES funded project that has as one of its main objectives developing genetic markers associated with sheath blight resistance. Sheath blight, caused by Rhizoctonia solani, is an important disease of rice in the southern US. Tolerance to the disease is quantitatively inherited an...

277

Occurrence of Late Blight caused by Phytophthora infestans on Potato and Tomato in Alaska  

Technology Transfer Automated Retrieval System (TEKTRAN)

Potato late blight, a disease caused by the plant pathogen Phytophthora infestans, is a recent, sporadic problem for commercial growers in Alaska. Since the 1930’s potato has been the main vegetable crop produced in Alaska, however late blight outbreaks have occurred only recently. The 1995 outbreak...

278

Evaluation of Commercially Available PGPR for Control of Rice Sheath Blight Caused by Rhizoctonia solani  

Microsoft Academic Search

Sheath blight disease of rice caused by Rhizoctonia solani is a major production constraint in all rice producing areas of the world. The annual losses due to sheath blight are estimated to be 25 % under optimum conditions of disease development. Disease management is currently focused on extensive use of fungicides which has created concerns about environmental pollution, pathogen resistance

K. Vijay Krishna Kumar; S. Krishnam Raju; M. S. Reddy; J. W. Kloepper; K. S. Lawrence; D. E. Groth; M. E. Miller; H. Sudini; Binghai Du

2009-01-01

279

Utilization of alien genes to enhance Fusarium head blight resistance in wheat – A review  

Microsoft Academic Search

Fusarium head blight (FHB) is a destructive disease of wheat worldwide. Sources of resistance to FHB are limited in wheat. Search for novel sources of effective resistance to this disease has been an urgent need in wheat breeding. Fusarium head blight resistance has been identified in relatives of wheat. Alien chromatin carrying FHB resistance genes has been incorporated into wheat

X. Cai; P. D. Chen; S. S. Xu; R. E. Oliver; X. Chen

2005-01-01

280

INTERRELATIONSHIP OF TEMPERATURE, FLOWER DEVELOPMENT, AND BIOLOGICAL CONTROL OF FIRE BLIGHT  

Technology Transfer Automated Retrieval System (TEKTRAN)

BlightBan (a.i., Pseudomonas fluorescens strain A506) has been available in recent years and other biological agents (e.g., Pantoea agglomerans strains C9-1 and E325) are being developed for fire blight control. Advances will partly depend on an understanding of interrelationships involving environ...

281

In vitro identification of cultivar responses to rice sheath blight pathogen Rhizoctonia solani  

Technology Transfer Automated Retrieval System (TEKTRAN)

The goal of this project is to identify critical genes for the control of sheath blight disease. To this end, an in vitro method to examine interactions of rice with the rice sheath blight pathogen Rhizocotnia solani was developed. The initial analysis of R. solani isolates from the Arkansas rice ...

282

MOLECULAR AND PATHOLOGICAL CHARACTERIZATION OF THE RICE SHEATH BLIGHT PATHOGEN RHIZOCTONIA SOLANI IN ARKANSAS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Rice sheath blight, caused by the fungal pathogen Rhizoctonia solani (AG1-IA), is an economically important disease in Arkansas. To identify the sheath blight resistance gene(s) an extensive molecular and pathological characterization of R., solani was initiated. A wide range of pathogen isolates ...

283

NOTICE OF RELEASE OF NEW PINTO BEAN (PHASEOLUS VULGARIS L.) GERMPLASM LINER ABCP-8, ABCP-15, AND ABCP-17  

Technology Transfer Automated Retrieval System (TEKTRAN)

Pinto bean germplasm lines ABCP-8, ABCP-15, and ABCP-17 were developed by the Nebraska Agricultural Experimental Station in collaboration with USDA-ARS. These lines were bred specifically for enhanced resistance to common bacterial blight caused by Xanthomonas campestris pv. phaseoli (Smith) Dye. Th...

284

Xanthan production by Xanthomonas campestris using whey permeate medium.  

PubMed

Xanthan gum is a polysaccharide that is widely used as stabilizer and thickener with many industrial applications in food industry. Our aim was to estimate the ability of Xanthomonas campestris ATCC 13951 for the production of xanthan gum by using whey as a growth medium, a by-product of dairy industry. X. campestris ATCC 13951 has been studied in batch cultures using a complex medium for the determination of the optimal concentration of glucose, galactose and lactose. In addition, whey was used under various treatment procedures (de-proteinated, partially hydrolyzed by ?-lactamase and partially hydrolyzed and de-proteinated) as culture medium, to study the production of xanthan in a 2 l bioreactor with constant stirring and aeration. A production of 28 g/l was obtained when partially hydrolysed ?-lactamase was used, which proved to be one of the highest xanthan gum production reported so far. At the same time, an effort has been made for the control and selection of the most appropriate procedure for the preservation of the strain and its use as inoculant in batch cultures, without loss of its viability and its capability of xanthan gum production. The pre-treatment of whey (whey permeate medium hydrolyzed, WPH) was very important for the production of xanthan by the strain X. campestris ATCC 13951 during batch culture conditions in a 2 l bioreactor. Preservation methods such as lyophilization, cryopreservation at various glycerol solution and temperatures have been examined. The results indicated that the best preservation method for the producing strain X. campestris ATCC 13951 was the lyophilization. Taking into account that whey permeate is a low cost by-product of the dairy industry, the production of xanthan achieved under the studied conditions was considered very promising for industrial application. PMID:22806202

Savvides, A L; Katsifas, E A; Hatzinikolaou, D G; Karagouni, A D

2012-05-31

285

Controlled release of Pantoea agglomerans E325 for biocontrol of fire blight disease of apple.  

PubMed

Microencapsulation and controlled release of the biocontrol agent Pantoea agglomerans strain E325 (E325), an antagonist to the bacterial plant pathogen Erwinia amylovora that causes fire blight, a devastating disease of apple and pear, have been investigated. Uniform core-shell alginate microcapsules (AMCs), 60-300 ?m in diameter, were fabricated to encapsulate E325 within the core, along with nutrients, to preserve viability and promote proliferation. Controlled release of E325 was achieved by separately adjusting alginate concentrations in the shell and core solutions, and by modifying the AMC size. Viability of E325 was monitored via fluorescent staining, revealing either lack of or minimal stress during or after encapsulation. Proliferation of E325 within AMCs, followed by their subsequent release, and colonization activities within confines of apple flowers were studied under different encapsulation conditions using rfp-labeled E325 to obtain highly promising results. This study provided a 'proof of concept' of the successful use of a microencapsulated biocontrol agent, E325, against E. amylovora, and could serve as a model for further studies on the development of effective plant disease management strategies. PMID:22516094

Kim, In-Yong; Pusey, Paul Lawrence; Zhao, Youfu; Korban, Schuyler S; Choi, Hyungsoo; Kim, Kyekyoon Kevin

2012-04-10

286

Purification and Characterization of OleA from Xanthomonas campestris and Demonstration of a Non-decarboxylative Claisen Condensation Reaction*  

PubMed Central

OleA catalyzes the condensation of fatty acyl groups in the first step of bacterial long-chain olefin biosynthesis, but the mechanism of the condensation reaction is controversial. In this study, OleA from Xanthomonas campestris was expressed in Escherichia coli and purified to homogeneity. The purified protein was shown to be active with fatty acyl-CoA substrates that ranged from C8 to C16 in length. With limiting myristoyl-CoA (C14), 1 mol of the free coenzyme A was released/mol of myristoyl-CoA consumed. Using [14C]myristoyl-CoA, the other products were identified as myristic acid, 2-myristoylmyristic acid, and 14-heptacosanone. 2-Myristoylmyristic acid was indicated to be the physiologically relevant product of OleA in several ways. First, 2-myristoylmyristic acid was the major condensed product in short incubations, but over time, it decreased with the concomitant increase of 14-heptacosanone. Second, synthetic 2-myristoylmyristic acid showed similar decarboxylation kinetics in the absence of OleA. Third, 2-myristoylmyristic acid was shown to be reactive with purified OleC and OleD to generate the olefin 14-heptacosene, a product seen in previous in vivo studies. The decarboxylation product, 14-heptacosanone, did not react with OleC and OleD to produce any demonstrable product. Substantial hydrolysis of fatty acyl-CoA substrates to the corresponding fatty acids was observed, but it is currently unclear if this occurs in vivo. In total, these data are consistent with OleA catalyzing a non-decarboxylative Claisen condensation reaction in the first step of the olefin biosynthetic pathway previously found to be present in at least 70 different bacterial strains.

Frias, Janice A.; Richman, Jack E.; Erickson, Jasmine S.; Wackett, Lawrence P.

2011-01-01

287

Bioinformatic identification of cassava miRNAs differentially expressed in response to infection by Xanthomonas axonopodis pv. manihotis  

PubMed Central

Background microRNAs (miRNAs) are short RNA molecules that control gene expression by silencing complementary mRNA. They play a crucial role in stress response in plants, including biotic stress. Some miRNAs are known to respond to bacterial infection in Arabidopsis thaliana but it is currently unknown whether these responses are conserved in other plants and whether novel species-specific miRNAs could have a role in defense. Results This work addresses the role of miRNAs in the Manihot esculenta (cassava)-Xanthomonas axonopodis pv. manihotis (Xam) interaction. Next-generation sequencing was used for analyzing small RNA libraries from cassava tissue infected and non-infected with Xam. A full repertoire of cassava miRNAs was characterized, which included 56 conserved families and 12 novel cassava-specific families. Endogenous targets were predicted in the cassava genome for many miRNA families. Some miRNA families' expression was increased in response to bacterial infection, including miRNAs known to mediate defense by targeting auxin-responding factors as well as some cassava-specific miRNAs. Some bacteria-repressed miRNAs included families involved in copper regulation as well as families targeting disease resistance genes. Putative transcription factor binding sites (TFBS) were identified in the MIRNA genes promoter region and compared to promoter regions in miRNA target genes and protein coding genes, revealing differences between MIRNA gene transcriptional regulation and other genes. Conclusions Taken together these results suggest that miRNAs in cassava play a role in defense against Xam, and that the mechanism is similar to what's known in Arabidopsis and involves some of the same families.

2012-01-01

288

Bacterial Fertilizers.  

National Technical Information Service (NTIS)

The term bacterial (microbial) fertilizers refers to preparations containing primarily active strains of the microorganisms mainly bacteria in sufficient numbers. This report covers various aspects of bacterial fertilizers: Nitrogen Preparation and Usage;...

W. V. B. Sundra Rao

1981-01-01

289

Domain Structure of HrpE, the Hrp Pilus Subunit of Xanthomonas campestris pv. vesicatoria  

Microsoft Academic Search

The plant-pathogenic bacterium Xanthomonas campestris pv. vesicatoria possesses a type III secretion (TTS) system necessary for pathogenicity in susceptible hosts and induction of the hypersensitive response in resistant plants. This specialized protein transport system is encoded by a 23-kb hrp (hypersensitive response and pathogenicity) gene cluster. X. campestris pv. vesicatoria produces filamentous structures, Hrp pili, at the cell surface under

Ernst Weber; Ralf Koebnik

2005-01-01

290

40 CFR 180.1261 - Xanthomonas campestris pv. vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages.  

Code of Federal Regulations, 2011 CFR

40 Ç Protection of Environment Ç 24 Ç 2011-07-01 Ç 2011-07-01 Ç false Ç Xanthomonas campestris pv. vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages. Ç 180.1261 Ç Section 180.1261 Ç Protection of Environment Ç ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) Ç PESTICIDE PROGRAMS...

2011-07-01

291

40 CFR 180.1261 - Xanthomonas campestris pv. vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages.  

Code of Federal Regulations, 2012 CFR

40 Ç Protection of Environment Ç 25 Ç 2012-07-01 Ç 2012-07-01 Ç false Ç Xanthomonas campestris pv. vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages. Ç 180.1261 Ç Section 180.1261 Ç Protection of Environment Ç ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) Ç PESTICIDE PROGRAMS...

2012-07-01

292

Characterization of xanthans from selected Xanthomonas strains cultivated under constant dissolved oxygen  

Microsoft Academic Search

Seventeen wild-type Xanthomonas isolates were screened in terms of broth viscosity in shake-flasks. As culture conditions affect polymer characteristics, a fair comparison among isolates required their cultivation in a fermenter under controlled dissolved oxygen tension. Three isolates and a reference strain were studied. The mean molecular weights and molecular weight distributions of their xanthans were determined. Products showed different pyruvate

A. Sa´nchez; M. E. Rami´rez; L. G. Torres; E. Galindo

1997-01-01

293

In vitro evaluation of sugarcane resistance to gumming disease and of Xanthomonas campestris pv. vasculorum aggressiveness  

Microsoft Academic Search

Sugarcane plantlets were sectioned halfway between the base and the youngest ligule and then inoculated by soaking the wound in a suspension of Xanthomonas campestris pv. vasculorum. The infection caused rapid necrosis of the inoculated leaves, chlorosis of uninoculated leaves, or death of the inoculated plantlet. New tillers sometimes showed chlorosis or white streaks. The effects of the inoculum concentration,

Jean-Pierre Peros; Hughes Lombard

1992-01-01

294

Systematic analysis of xanthomonads (Xanthomonas spp.) associated with pepper and tomato lesions  

Microsoft Academic Search

The taxonomy and evolutionary relationships among members of the genus Xanthomonas associated with tomato and pepper have been a matter of considerable controversy since their original description in 1921. These bacteria, which are a major affliction of tomato and pepper crops in warm and humid regions, were originally described as a single species, but subsequent research has shown the existence

J. B. Jones; H. Bouzar; R. E. Stall; E. C. Almira; P. D. Roberts; B. W. Bowen; J. Sudberry; P. M. Strickler; J. Chun

2000-01-01

295

Non-Host Defense Response in a Novel Arabidopsis-Xanthomonas citri subsp. citri Pathosystem  

Microsoft Academic Search

Citrus canker, caused by Xanthomonas citri subsp. citri (Xcc), is one of the most destructive diseases of citrus. Progress of breeding citrus canker-resistant varieties is modest due to limited resistant germplasm resources and lack of candidate genes for genetic manipulation. The objective of this study is to establish a novel heterologous pathosystem between Xcc and the well-established model plant Arabidopsis

Chuanfu An; Zhonglin Mou

2012-01-01

296

GENETIC DIVERSITY IN POPULATIONS OF XANTHOMONAS CAMPESTRIS PV. CAMPESTRIS IN CRUCIFEROUS WEEDS IN CENTRAL COASTAL CALIFORNIA  

Technology Transfer Automated Retrieval System (TEKTRAN)

Xanthomonas campestris pv. campestris (Xcc) infects a large number of cruciferous plants, including weeds. California has one of the largest and most diverse populations of wild cruciferous plants in the world. Although considerable information is available on the genetic diversity of Xcc in commerc...

297

Involvement of Phaseolotoxin in Halo Blight of Beans  

PubMed Central

Phaseolotoxin ([N?-phosphosulfamyl]ornithylalanylhomoarginine) is produced by Pseudomonas phaseolicola (Burkh.) Dows. in liquid culture. When phaseolotoxin was applied to leaves of bean (Phaseolus vulgaris L.) at 0.1 to 1 nmoles/g fresh weight of leaf by a prick-assay procedure, the characteristic “halo” symptom of bean halo blight disease developed after 24 to 48 hours. At higher concentrations (10-100 nmoles/g fresh weight) the systemic symptoms, which are commonly a feature of diseased plants, also developed after 24 to 48 hours. When applied to bean leaves, phaseolotoxin was rapidly broken down by the sequential removal of homoarginine and alanine. N?-Phosphosulfamylornithine was the major product formed, although phosphosulfamate and unreacted phaseolotoxin were also present. When P. phaseolicola infected bean plants, very little phaseolotoxin was detected within the plant, but the amount of N?-phosphosulfamylornithine formed was sufficient to account for the observed chlorosis, the ornithine accumulation, and the systemic symptoms. N?-Phosphosulfamylornithine therefore seemed to be the main functional phytotoxin of bean halo blight disease. When 35S-phaseolotoxin was applied to primary leaves, 35S (assumed to be a mixture of phaseolotoxin, N?-phosphosulfamylornithine, and phosphosulfamate) was actively loaded into the fine veins of the leaf and moved through the plant in the vascular system at a speed greater than 3 cm/hour, particularly toward the apical and lateral buds and the root tips. Certain factors which affect pholem transport (arsenate, cold) affected toxin movement and the expression of systemic symptoms. Autoradiography suggested that the 35S was transported in the phloem. A model for the involvement of phaseolotoxin in halo blight disease is presented. Images

Mitchell, Robin E.; Bieleski, Roderick L.

1977-01-01

298

Comparison of two culture media for determination of the copper resistance of Xanthomonas strains and their usefulness for prediction of control with copper bactericides  

Microsoft Academic Search

Two bacteriological culture media were compared for determination of copper resistance among strains of Xanthomonas euvesicatoria and Xanthomonas perforans from pepper and tomato and Xanthomonas campestris pv. vitians from lettuce. Of 94 strains tested, 73 grew on glucose-nutrient agar (GNA) amended with 200?gml?1 of copper sulfate. None of the 94 strains grew on modified casitone-yeast extract (CYE) agar amended with

Ken Pernezny; Russell Nagata; Nikol Havranek; Jairo Sanchez

2008-01-01

299

Bacterial vaginosis  

Microsoft Academic Search

Bacterial vaginosis, the most prevalent cause of vaginal discharge in the United States, is characterized microbiologically\\u000a by a shift in the vagina away from a lactobacillus-predominant flora and toward a predominantly anaerobic milieu. The cause\\u000a of bacterial vaginosis is unknown, but the epidemiology of the syndrome suggests that it is sexually associated. Bacterial\\u000a vaginosis has been associated with various complications,

Jane R. Schwebke

2000-01-01

300

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

PubMed

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. PMID:19522564

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

2009-07-01

301

The Periplasmic HrpB1 Protein from Xanthomonas spp. Binds to Peptidoglycan and to Components of the Type III Secretion System.  

PubMed

The plant-pathogenic bacterium Xanthomonas campestris pv. vesicatoria employs a type III secretion (T3S) system to translocate bacterial effector proteins into eukaryotic host cells. The membrane-spanning secretion apparatus consists of 11 core components and several associated proteins with yet unknown functions. In this study, we analyzed the role of HrpB1, which was previously shown to be essential for T3S and the formation of the extracellular T3S pilus. We provide experimental evidence that HrpB1 localizes to the bacterial periplasm and binds to peptidoglycan, which is in agreement with its predicted structural similarity to the putative peptidoglycan-binding domain of the lytic transglycosylase Slt70 from Escherichia coli. Interaction studies revealed that HrpB1 forms protein complexes and binds to T3S system components, including the inner membrane protein HrcD, the secretin HrcC, the pilus protein HrpE, and the putative inner rod protein HrpB2. The analysis of deletion and point mutant derivatives of HrpB1 led to the identification of amino acid residues that contribute to the interaction of HrpB1 with itself and HrcD and/or to protein function. The finding that HrpB1 and HrpB2 colocalize to the periplasm and both interact with HrcD suggests that they are part of a periplasmic substructure of the T3S system. PMID:23934485

Hausner, Jens; Hartmann, Nadine; Lorenz, Christian; Büttner, Daniela

2013-08-09

302

A novel antimicrobial protein for plant protection consisting of a Xanthomonas oryzae harpin and active domains of cecropin A and melittin.  

PubMed

Discoveries about antimicrobial peptides and plant defence activators have made possible the de novo and rational design of novel peptides for use in crop protection. Here we report a novel chimeric protein, Hcm1, which was made by linking the active domains of cecropin A and melittin to the hypersensitive response (HR)-elicitor Hpa1 of Xanthomonas oryzae pv. oryzicola, the causal agent of rice bacterial leaf streak. The resulting chimeric protein maintained not only the HR-inducing property of the harpin, but also the antimicrobial activity of the cecropin A-melittin hybrid. Hcm1 was purified from engineered Escherichia coli and evaluated in terms of the minimal inhibitory concentration (MIC) and the 50% effective dose (ED(50)) against important plant pathogenic bacteria and fungi. Importantly, the protein acted as a potential pesticide by inducing disease resistance for viral, bacterial and fungal pathogens. This designed drug can be considered as a lead compound for use in plant protection, either for the development of new broad-spectrum pesticides or for expression in transgenic plants. PMID:21895994

Che, Yi-Zhou; Li, Yu-Rong; Zou, Hua-Song; Zou, Li-Fang; Zhang, Bing; Chen, Gong-You

2011-09-06

303

Morphological, Pathogenic, and Molecular Characterization of Alternaria Isolates Associated with Alternaria Late Blight of Pistachio  

Microsoft Academic Search

ABSTRACT Pryor, B. M., and Michailides, T. J. 2002. Morphological, pathogenic, and molecular characterization of ,Alternaria isolates associated with Alternaria late blight of pistachio. Phytopathology 92:406-416. Alternaria isolates ,were ,obtained from ,various pistachio tissues

Barry M. Pryor; Themis J. Michailides

2002-01-01

304

Identification of a host 14-3-3 Protein that Interacts with Xanthomonas effector AvrRxv.  

PubMed

AvrRxv is a member of a family of pathogen effectors present in pathogens of both plant and mammalian species. Xanthomonas campestris pv. vesicatoria strains carrying AvrRxv induce a hypersensitive response (HR) in the tomato cultivar Hawaii 7998. Using a yeast two-hybrid screen, we identified a 14-3-3 protein from tomato that interacts with AvrRxv called AvrRxv Interactor 1 (ARI1). The interaction was confirmed in vitro with affinity chromatography. Using mutagenesis, we identified a 14-3-3-binding domain in AvrRxv and demonstrated that a mutant in that domain showed concomitant loss of interaction with ARI1 and HR-inducing activity in tomato. These results demonstrate that the AvrRxv bacterial effector recruits 14-3-3 proteins for its function within host cells. AvrRxv homologues YopP and YopJ from Yersinia do not have AvrRxv-specific HR-inducing activity when delivered into tomato host cells by Agrobacterium. Although YopP itself cannot induce HR, its C-terminal domain containing the catalytic residues can replace that of AvrRxv in an AvrRxv-YopP chimera for HR-inducing activity. Phylogenetic analysis indicates that the sequences encoding the C-termini of family members are evolving independently from those encoding the N-termini. Our results support a model in which there are three functional domains in proteins of the family, translocation, interaction, and catalytic. PMID:21796232

Whalen, Maureen; Richter, Todd; Zakhareyvich, Kseniya; Yoshikawa, Masayasu; Al-Azzeh, Dana; Adefioye, Adeshola; Spicer, Greg; Mendoza, Laura L; Morales, Christine Q; Klassen, Vicki; Perez-Baron, Gina; Toebe, Carole S; Tzovolous, Ageliki; Gerstman, Emily; Evans, Erika; Thompson, Cheryl; Lopez, Mary; Ronald, Pamela C

2008-01-01

305

Bacterial vaginosis  

Microsoft Academic Search

Bacterial vaginosis is the most common cause of vaginitis, affecting over 3 million women in the United States annually. Depopulation of lactobacilli from the normal vaginal flora and overgrowth of Gardnerella vaginalis and other anaerobic species are the presumed etiology. To date, no scientific evidence shows that bacterial vaginosis is a sexually transmitted disease. Malodorous vaginal discharge is the most

Jeff Wang

2000-01-01

306

Disease Severity and Yield of Sweet Corn Hybrids with Resistance to Northern Leaf Blight  

Microsoft Academic Search

Pataky, J. K., Raid, R. N., du Toit, L. J., and Schueneman, T. J. 1998. Disease severity and yield of sweet corn hybrids with resistance to northern leaf blight. Plant Dis. 82:57-63. Reactions of supersweet (sh2) sweet corn to northern leaf blight (NLB) and associated yields were evaluated in Belle Glade, Florida and Urbana, Illinois in yield-loss trials, hybrid evalua-

J. K. Pataky; R. N. Raid; L. J. du Toit; T. J. Schueneman

1998-01-01

307

A method for estimating the decrease in marketable tubers caused by potato late blight  

Microsoft Academic Search

A regression analysis was used to develop a method to estimate the decrease in marketable tubers caused by late blight of\\u000a potato (Phytophthora infestans), based on estimates of percentage loss in total tuber yield computed from a published method. The economic loss due to late\\u000a blight in table stocks is the relative percentage marketable yield loss, calculated from the expression:

W. C. James; C. S. Shih; W. A. Hodgson; L. C. Callbeck

1973-01-01

308

Estimating potato yield responses from chemical control of early blight in Minnesota  

Microsoft Academic Search

The effect of early blight on tuber yield of two potato (Solanum tuberosum L.) cultivars (Russet Burbank and Norland) was evaluated using number and timing of applications of three chemicals to generate\\u000a different disease epidemics in 1981 and 1982. Under the non-irrigated farming conditions in Minnesota, there were no significant\\u000a differences among captafol, triphenyltin hydroxide and maneb-Zn in blight control

P. S. Teng; H. L. Bissonnette

1985-01-01

309

Developing equations to estimate potato yield loss caused by early blight in Minnesota  

Microsoft Academic Search

Regression analyses were performed on field data from 1981 and 1982 to determine models for estimating yield loss caused by\\u000a early blight in potato cvs. Norland and Russet Burbank. Percent yield loss (total tubers and US# 1 tubers) caused by early\\u000a blight could not be satisfactorily explained by any regression model using only a single disease assessment as the input

P. S. Teng; H. L. Bissonnette

1985-01-01

310

Occurrence of Soybean Sleeping Blight Caused by Septogloeum sojae in Korea  

PubMed Central

Sleeping blight was observed on soybean plants grown in Yanggu, Suwon and Geumsan from 2005 to 2011. Symptoms developed on stems and pods of affected soybean plants. Five fungal isolates were obtained from the diseased plants and identified as Septogloeum sojae based on their morphological, cultural and molecular characteristics. Pathogenicity of the fungus was confirmed on soybean plants by artificial inoculation. This is the first report of S. sojae causing sleeping blight in soybean plants in Korea.

Choi, Hyo Won; Lee, Young Kee; Lee, Sang Yeob; Shim, Hong Sik

2012-01-01

311

Societal Costs of Late Blight in Potato and Prospects of Durable Resistance Through Cisgenic Modification  

Microsoft Academic Search

In the European Union almost 6 Mha of potatoes are grown representing a value of close to €6,000,000,000. Late blight caused\\u000a by Phytophthora infestans causes annual losses (costs of control and damage) estimated at more than €1,000,000,000. Chemical control is under pressure\\u000a as late blight becomes increasingly aggressive and there is societal resistance against the use of environmentally unfriendly\\u000a chemicals. Breeding

A. J. Haverkort; P. M. Boonekamp; R. C. B. Hutten; E. Jacobsen; L. A. P. Lotz; G. J. T. Kessel; R. G. F. Visser; E. A. G. van der Vossen

2008-01-01

312

Assessment of early blight ( Alternaria solani ) resistance in tomato using a droplet inoculation method  

Microsoft Academic Search

A droplet inoculation method was used for evaluation of tomato resistance to early blight, a destructive foliar disease of\\u000a tomato caused by Alternaria solani (Ellis and Martin) Sorauer. In this test method, leaflets are inoculated with small droplets of a spore suspension in either\\u000a water or a 0.1% agar solution. Early blight resistance was evaluated based on lesion size. The

Reni Chaerani; Remmelt Groenwold; Piet Stam; Roeland E. Voorrips

2007-01-01

313

Head Blight Gradients Caused by Gibberella zeae from Area Sources of Inoculum in Wheat Field Plots  

Microsoft Academic Search

Fernando, W. G. D., Paulitz, T. C., Seaman, W. L., Dutilleul, P., and Miller, J. D. 1997. Head blight gradients caused by Gibberella zeae from area sources of inoculum in wheat field plots. Phytopathology 87:414-421. The spread of Fusarium head blight of wheat from a small area inocu- lum source was examined in wheat plots (100, 625, or 2,500 m

W. G. D. Fernando; T. C. Paulitz; W. L. Seaman; P. Dutilleul; J. D. Miller

1997-01-01

314

Commercial Potential of Microbial Inoculants for Sheath Blight Management and Yield Enhancement of Rice  

Microsoft Academic Search

\\u000a Sheath blight of rice is an economically significant disease worldwide. Use of plant growth-promoting rhizobacteria (PGPR),\\u000a one type of microbial inoculants, for sheath blight management and yield enhancement of rice is gaining popularity in modern\\u000a agriculture due to increasing concerns with the use of chemical fungicides. Among different microbial inoculants, PGPR are\\u000a used for their growth-promoting activities and managing sheath

K. Vijay Krishna Kumar; M. S. Reddy; J. W. Kloepper; K. S. Lawrence; X. G. Zhou; D. E. Groth; S. Zhang; R. Sudhakara Rao; Qi Wang; M. R. B. Raju; S. Krishnam Raju; W. G. Dilantha Fernando; H. Sudini; B. Du; M. E. Miller

315

Reduction of Fusarium head blight and deoxynivalenol in wheat with early fungicide applications of prothioconazole.  

PubMed

Numerous studies have identified the benefit of fungicides applied at flowering (Zadoks Growth Stage (GS) 59-69) in the reduction of Fusarium head blight and the reduction of deoxynivalenol (DON) in harvested wheat grain. Two experiments were performed to identify the ability of prothioconazole (Proline) at three timings to reduce Fusarium head blight and resulting DON in harvested grain of wheat. Prothioconazole (150 g ha(-1)) was applied to plots of wheat at GS31, GS39, and GS65 in a full-factorial design. Plots were inoculated with Fusarium-infected oat grain at GS30 and mist-irrigated at GS65 to encourage head blight development. Plots were assessed for head blight symptoms at GS77 and harvested grain was analysed for yield, specific weight, thousand grain weight, and DON. Factorial analysis of variance (ANOVA) identified prothioconazole applications at each timing that resulted in significant reductions in Fusarium head blight and DON. The control achieved with combinations of spray timings was additive with no significant interactions. The control of Fusarium head blight at GS31, GS39, and GS65 was 50, 58 and 83%, respectively. The reduction in Fusarium head blight achieved by all three timings combined was 97% compared to the fully untreated control plots. The reduction of DON after application of prothioconazole at GS31, GS39, and GS65 was 27%, 49%, and 57%, respectively. The application of prothioconazole at all three timings achieved 83% reduction of DON compared with the fully untreated control plots. These experiments have determined, for the first time, significant additional head blight disease control and mycotoxin reduction with applications of a fungicide before flowering. PMID:20349372

Edwards, S G; Godley, N P

2010-05-01

316

Influence of temperature regimes on resistance gene-mediated response to rice bacterial blight  

Technology Transfer Automated Retrieval System (TEKTRAN)

Increasing temperatures could reduce yield growth rate of rice by 10% in several rice production areas. Similarly, higher temperatures are predicted to accelerate the breakdown of plant disease resistance through higher disease pressure or altered resistance (R) gene effectiveness in many host-path...

317

Molecular characterization of the avrXa7 locus from Xanthomonas oryzae pv. oryzae field isolates  

Microsoft Academic Search

The effector gene avrXa7 from Xanthomonas oryzae pv. oryzae has avirulence function in rice with the Xa7 resistance gene and confers pathogenic fitness (aggressiveness). Field strains of X. oryzae pv. oryzae displayed a diversity of phenotypes on rice ranging from complete to partial loss of these functions. To understand the molecular basis for variation in avrXa7 function, we sequenced the

Grisel Ponciano; Kimberly Webb; Jianfa Bai; Casiana Vera Cruz; Jan E. Leach

2004-01-01

318

Growth requirements for production of stable cells of the bioherbicidal bacterium Xanthomonas campestris  

Microsoft Academic Search

Xanthomonas campestris   MB245, a specific pathogen of the weedy grass Poa annua (annual bluegrass), is being developed as a bioherbicide to control this pest in turf. Nutritional and environmental factors\\u000a were evaluated based on their ability to support rapid submerged culture growth and high cell yield. Temperature optima for\\u000a the growth of X. campestris cells in submerged culture were between

M A Jackson; J S Frymier; B J Wilkinson; P Zorner; S Evans

1998-01-01

319

Production of Hesperetin Glycosides by Xanthomonas campestris and Cyclodextrin Glucanotransferase and Their Anti-allergic Activities  

PubMed Central

The production of hesperetin glycosides was investigated using glycosylation with Xanthomonas campestris and cyclodextrin glucanotransferase (CGTase). X. campestris glucosylated hesperetin to its 3'-, 5-, and 7-O-glucosides, and CGTase converted hesperetin glucosides into the corresponding maltosides. The resulting 7-O-glucoside and 7-O-maltoside of hesperetin showed inhibitory effects on IgE antibody production and on O2- generation from rat neutrophils.

Shimoda, Kei; Hamada, Hiroki

2010-01-01

320

Expression Profiling of Virulence and Pathogenicity Genes of Xanthomonas axonopodis pv. citri  

PubMed Central

DNA macroarrays of 279 genes of Xanthomonas axonopodis pv. citri potentially associated with pathogenicity and virulence were used to compare the transcriptional alterations of this bacterium in response to two synthetic media. Data analysis indicated that 31 genes were up-regulated by synthetic medium XVM2, while only 7 genes were repressed. The results suggest that XVM2 could be used as an in vitro system to identify candidate genes involved in pathogenesis of X. axonopodis pv. citri.

Astua-Monge, Gustavo; Freitas-Astua, Juliana; Bacocina, Gisele; Roncoletta, Juliana; Carvalho, Sergio A.; Machado, Marcos A.

2005-01-01

321

Specific protein phosphorylation induced in Xanthomonas campestris pv. oryzae by bacteriophage Xp12  

Microsoft Academic Search

We have investigated the endogenous phosphorylation patterns of phosphorylated proteins of Xanthomonas campestris pv. oryzae induced by its bacteriophages. For bacteriophage Xp12-infected cells, at least three phosphoproteins with apparent molecular weights of 28, 28.5 and 45kDa were detected by in vitro labeling with [?-32P]-ATP. These Xp12-specific phosphoproteins only occurred with Xp12 infection, and were not shown in uninfected or Xp10-infected

Ching-Ming Cheng; Jenn Tu; Chen-Chung Yang; Tsong-Teh Kuo

1994-01-01

322

Constitutive Expression of a Chromosomal Class A (BJM Group 2)  Lactamase in Xanthomonas campestris  

Microsoft Academic Search

Sequencing of the upstream region of the -lactamase gene from Xanthomonas campestris pv. campestris 11 (blaXCC-1) revealed the cognate ampR1 gene (289 amino acids, 31 kDa). It runs divergently from blaXCC-1 with a 100-bp intergenic region (IG) containing partially overlapped promoters with structural features typical of the bla-ampR IG. The deduced AmpR1 protein shows significant identity in amino acid sequence

Shu-Fen Weng; Juey-Wen Lin; Chih-Hung Chen; Yih-Yuan Chen; Yi-Hsuan Tseng; Yi-Hsiung Tseng

2004-01-01

323

Optimization of xanthan gum production by Xanthomonas campestris grown in molasses  

Microsoft Academic Search

Xanthan gum production by Xanthomonas campestris ATCC 1395 using sugar beet molasses as carbon source was studied. The pre-treatment of sugar beet molasses and the supplementation of the medium were investigated in order to improve xanthan gum production. Addition of K2HPO4 to the medium had a significant positive effect on both xanthan gum and biomass production. The medium was subsequently

Stavros Kalogiannis; Gesthimani Iakovidou; Maria Liakopoulou-Kyriakides; Dimitrios A Kyriakidis; George N Skaracis

2003-01-01

324

An Oxidoreductase Is Involved in Cercosporin Degradation by the Bacterium Xanthomonas campestris pv. zinniae  

Microsoft Academic Search

The polyketide toxin cercosporin plays a key role in pathogenesis by fungal species of the genus Cercospora. The bacterium Xanthomonas campestris pv. zinniae is able to rapidly degrade this toxin. Growth of X. campestris pv. zinniae strains in cercosporin-containing medium leads to the breakdown of cercosporin and to the formation of xanosporic acid, a nontoxic breakdown product. Five non-cercosporin-degrading mutants

Tanya V. Taylor; Thomas K. Mitchell; Margaret E. Daub

2006-01-01

325

Diversity of effector genes in plant pathogenic bacteria of genus Xanthomonas  

Microsoft Academic Search

Gram-negative plant pathogenic bacteria are secreting into plant cell a special type of pathogeni city-related proteins called\\u000a effectors. They are capable of suppressing plant innate immunity or stimulating synthesis and export of metabolites desired\\u000a by the pathogen. We identified a number of effector-coding genes typical of xanthomonads analyzing 8 completely sequenced\\u000a genomes of genus Xanthomonas. Using representative collection provided by

M. V. Mokryakova; I. A. Abdeeva; E. S. Piruzyan; N. W. Schaad; A. N. Ignatov

2010-01-01

326

Metabolic Versatility and Antibacterial Metabolite Biosynthesis Are Distinguishing Genomic Features of the Fire Blight Antagonist Pantoea vagans C9-1  

PubMed Central

Background Pantoea vagans is a commercialized biological control agent used against the pome fruit bacterial disease fire blight, caused by Erwinia amylovora. Compared to other biocontrol agents, relatively little is currently known regarding Pantoea genetics. Better understanding of antagonist mechanisms of action and ecological fitness is critical to improving efficacy. Principal Findings Genome analysis indicated two major factors contribute to biocontrol activity: competition for limiting substrates and antibacterial metabolite production. Pathways for utilization of a broad diversity of sugars and acquisition of iron were identified. Metabolism of sorbitol by P. vagans C9-1 may be a major metabolic feature in biocontrol of fire blight. Biosynthetic genes for the antibacterial peptide pantocin A were found on a chromosomal 28-kb genomic island, and for dapdiamide E on the plasmid pPag2. There was no evidence of potential virulence factors that could enable an animal or phytopathogenic lifestyle and no indication of any genetic-based biosafety risk in the antagonist. Conclusions Identifying key determinants contributing to disease suppression allows the development of procedures to follow their expression in planta and the genome sequence contributes to rationale risk assessment regarding the use of the biocontrol strain in agricultural systems.

Smits, Theo H. M.; Rezzonico, Fabio; Kamber, Tim; Blom, Jochen; Goesmann, Alexander; Ishimaru, Carol A.; Frey, Jurg E.; Stockwell, Virginia O.; Duffy, Brion

2011-01-01

327

Phylogenetic analysis of Xanthomonas based on partial rpoB gene sequences and species differentiation by PCR-RFLP.  

PubMed

The rpoB gene was evaluated as an alternative molecular marker for the differentiation of Xanthomonas species and in order to understand better the phylogenetic relationships within the genus. PCR-RFLP experiments using HaeIII allowed differentiation of Xanthomonas species, particularly those that affect the same plant host such as Xanthomonas albilineans and X. sacchari, pathogenic to sugar cane, Xanthomonas cucurbitae and X. melonis, which cause disease in melon, and Xanthomonas gardneri, X. vesicatoria and X. euvesicatoria/X. perforans, pathogenic to tomato. Phylogenetic relationships within the genus Xanthomonas were also examined by comparing partial rpoB gene sequences (612 nt) and the Xanthomonas species were separated into two main groups. Group I, well supported by bootstrap values of 99?%, comprised X. euvesicatoria, X. perforans, X. alfalfae, X. citri, X. dyei, X. axonopodis, X. oryzae, X. hortorum, X. bromi, X. vasicola, X. cynarae, X. gardneri, X. campestris, X. fragariae, X. arboricola, X. cassavae, X. cucurbitae, X. pisi, X. vesicatoria, X. codiaei and X. melonis. Group II, again well supported by bootstrap values of 99 %, comprised X. albilineans, X. sacchari, X. theicola, X. translucens and X. hyacinthi. The rpoB gene sequence similarity observed among the species in this study ranged from 87.8 to 99.7 %. The results of PCR-RFLP of the rpoB gene indicated that this technique can be used for diagnosis and identification of most Xanthomonas strains, including closely related species within the genus. However, species that showed identical profiles could be differentiated clearly only by sequence analysis. The results obtained in our phylogenetic analysis suggested that the rpoB gene can be used as an alternative molecular marker for genetic relatedness in the genus Xanthomonas. The results of PCR-RFLP of the rpoB gene indicate that this technique can be used for diagnosis and identification of closely related species within the genus, representing a rapid and inexpensive tool that can be easily standardized between laboratories. PMID:21984675

Ferreira-Tonin, Mariana; Rodrigues-Neto, Júlio; Harakava, Ricardo; Destéfano, Suzete Aparecida Lanza

2011-10-07

328

Bacterial meningitis  

Microsoft Academic Search

Opinion statement  Initial empiric therapy for community-acquired bacterial meningitis should be based on the possibility that penicillin-resistant\\u000a pneumococci may be the etiologic organisms and, hence, should include a combination of third-generation cephalosporin (cefotaxime\\u000a or ceftriaxone) and vancomycin. Ampicillin should be included if the patient has predisposing factors that are associated\\u000a with a risk for infection with Listeria monocytogenes. Bacterial isolates from

Karen L. Roos

1999-01-01

329

Bacterial Cystitis  

Microsoft Academic Search

Urinary tract infection is one of the most common health problems affecting patients of all ages. It is the most common nosocomial\\u000a bacterial infection in the elderly. Women are especially prone to urinary tract infections (UTIs). Although prostatitis syndrome\\u000a accounts for 25% of male office visits for genitourinary tract infections, only 5% are attributed to a bacterial cause. Acute\\u000a cystitis

Joseph B. Abdelmalak; Jeannette M. Potts

330

Fructose-Bisphophate Aldolase Exhibits Functional Roles between Carbon Metabolism and the hrp System in Rice Pathogen Xanthomonas oryzae pv. oryzicola  

PubMed Central

Fructose-bisphophate aldolase (FbaB), is an enzyme in glycolysis and gluconeogenesis in living organisms. The mutagenesis in a unique fbaB gene of Xanthomonas oryzae pv. oryzicola, the causal agent of rice bacterial leaf streak, led the pathogen not only unable to use pyruvate and malate for growth and delayed its growth when fructose was used as the sole carbon source, but also reduced extracellular polysaccharide (EPS) production and impaired bacterial virulence and growth in rice. Intriguingly, the fbaB promoter contains an imperfect PIP-box (plant-inducible promoter) (TTCGT-N9-TTCGT). The expression of fbaB was negatively regulated by a key hrp regulatory HrpG and HrpX cascade. Base substitution in the PIP-box altered the regulation of fbaB with the cascade. Furthermore, the expression of fbaB in X. oryzae pv. oryzicola RS105 strain was inducible in planta rather than in a nutrient-rich medium. Except other hrp-hrc-hpa genes, the expression of hrpG and hrpX was repressed and the transcripts of hrcC, hrpE and hpa3 were enhanced when fbaB was deleted. The mutation in hrcC, hrpE or hpa3 reduced the ability of the pathogen to acquire pyruvate and malate. In addition, bacterial virulence and growth in planta and EPS production in R?fbaB mutant were completely restored to the wild-type level by the presence of fbaB in trans. This is the first report to demonstrate that carbohydrates, assimilated by X. oryzae pv. oryzicola, play critical roles in coordinating hrp gene expression through a yet unknown regulator.

Li, Yu-rong; Cui, Yi-ping; Ji, Zhi-yuan; Cai, Lu-lu; Zou, Hua-song; Hutchins, William C.; Yang, Ching-hong; Chen, Gong-you

2012-01-01

331

Sgt1, but not Rar1, is essential for the RB-mediated broad-spectrum resistance to potato late blight  

Microsoft Academic Search

BACKGROUND: Late blight is the most serious potato disease world-wide. The most effective and environmentally sound way for controlling late blight is to incorporate natural resistance into potato cultivars. Several late blight resistance genes have been cloned recently. However, there is almost no information available about the resistance pathways mediated by any of those genes. RESULTS: We previously cloned a

Pudota B Bhaskar; John A Raasch; Lara C Kramer; Pavel Neumann; Susan M Wielgus; Sandra Austin-Phillips; Jiming Jiang

2008-01-01

332

Bacterial rheotaxis  

PubMed Central

The motility of organisms is often directed in response to environmental stimuli. Rheotaxis is the directed movement resulting from fluid velocity gradients, long studied in fish, aquatic invertebrates, and spermatozoa. Using carefully controlled microfluidic flows, we show that rheotaxis also occurs in bacteria. Excellent quantitative agreement between experiments with Bacillus subtilis and a mathematical model reveals that bacterial rheotaxis is a purely physical phenomenon, in contrast to fish rheotaxis but in the same way as sperm rheotaxis. This previously unrecognized bacterial taxis results from a subtle interplay between velocity gradients and the helical shape of flagella, which together generate a torque that alters a bacterium's swimming direction. Because this torque is independent of the presence of a nearby surface, bacterial rheotaxis is not limited to the immediate neighborhood of liquid–solid interfaces, but also takes place in the bulk fluid. We predict that rheotaxis occurs in a wide range of bacterial habitats, from the natural environment to the human body, and can interfere with chemotaxis, suggesting that the fitness benefit conferred by bacterial motility may be sharply reduced in some hydrodynamic conditions.

Marcos; Fu, Henry C.; Powers, Thomas R.; Stocker, Roman

2012-01-01

333

GIS-based climatic regionalization of potato late blight in mountain areas of Southwest Sichuan  

NASA Astrophysics Data System (ADS)

Through the geographic insemination test in installments on five phases of potato late blight in four areas of Mianning and Zhaojue with the altitude of 1,600m, 1,800m, 2,100m and 2,500m respectively, this paper researches the meteorological causes, leading factors and climatic indexes for potato late blight in mountain areas of southwest Sichuan in detail. Based on that, short-term section climatic inspection data of mountain areas, observation data from meteorological post and latest data from automatic weather station are extensively collected, organized and processed by extension, based on which the Spatial Distribution Model of climatic indexes for potato late blight in mountain areas of southwest Sichuan is established in association with the routine surface observation data, y=f(h,?,l,?). With the geographic information data of 1:250000 and GIS technology, southwest Sichuan is divided into climatic liable region of potato blight, climatic secondary liable region and climatic non-liable region by factor setting and optimization method. Providing scientific basis for selection, distribution and prevention decision making for late blight resistant species of potato in southwest Sichuan, it has important value for production and application.

Luo, Qing; Peng, Guozhao; Ruan, Jun; Cao, Yanqiu; Fang, Peng; Li, Dazhong; Armuzhong, .; Huang, Doumin; Hu, Qiaojuan; Chen, Yuanzhi

2008-10-01

334

Studies on Plant Pathogenic Bacterium Causal Agent of Soybean Bacterial Spots ( Pseudomonas syringae pv. glycinea (Coerper) Young et al.)  

Microsoft Academic Search

Bacterial blight is a disease of soybean appearing regularly with high intensity in Serbia. Isolation of pathogen was done\\u000a using beef extract (MPA) and the medium enriched with sucrose (NSA) from infected soybean leaves of several varieties grown\\u000a in Vojvodina province, during 2005.\\u000a \\u000a Only the representative isolates were chosen for analyses. Pathogenicity of the isolates including the reference strain (National

M. Ignjatov; J. Balaž; M. Miloševic ´; M. Vidic ´; T. Popovic ´

335

Quantitative Trait Loci in Sweet Corn Associated with Partial Resistance to Stewart's Wilt, Northern Corn Leaf Blight, and Common Rust  

Microsoft Academic Search

Brown, A. F., Juvik, J. A., and Pataky, J. K. 2001. Quan titative trait loci in sweet corn associated with partial resistance to Stewart's wilt, northern corn leaf blight, and common rust. Phytopathology 91:293-300. Partial resistance to Stewart's wilt ( Erwina stewartii, syn. Pantoea stewartii), northern corn leaf blight (NCLB) ( Exserohilum turcicum), and common rust (Puccinia sorghi) was observed

A. F. Brown; J. A. Juvik; J. K. Pataky

2001-01-01

336

Complete genome sequence of the fire blight pathogen Erwinia pyrifoliae DSM 12163T and comparative genomic insights into plant pathogenicity  

Microsoft Academic Search

BACKGROUND: Erwinia pyrifoliae is a newly described necrotrophic pathogen, which causes fire blight on Asian (Nashi) pear and is geographically restricted to Eastern Asia. Relatively little is known about its genetics compared to the closely related main fire blight pathogen E. amylovora. RESULTS: The genome of the type strain of E. pyrifoliae strain DSM 12163T, was sequenced using both 454

Theo HM Smits; Sebastian Jaenicke; Fabio Rezzonico; Tim Kamber; Alexander Goesmann; Jürg E Frey; Brion Duffy

2010-01-01

337

Evaluation of plant growth-promoting rhizobacteria for control of Phytophthora blight on squash under greenhouse conditions  

Microsoft Academic Search

Phytophthora blight caused by Phytophthora capsici is a serious threat to vegetable production worldwide. Currently, no single method provides adequate control of P. capsici. Greenhouse studies were conducted to evaluate the potential of the use of bacilli plant growth-promoting rhizobacteria (PGPR) for control of Phytophthora blight on squash. PGPR strains were applied as a soil drench 1 and 2weeks after

Shouan Zhang; Thomas L. White; Miriam C. Martinez; John A. McInroy; Joseph W. Kloepper; Waldemar Klassen

2010-01-01

338

DYNAMICS OF DEVELOPMENT OF LATE BLIGHT (PHYTOPHTHORA INFESTANS) IN POTATO, AND COMPARATIVE RESISTANCE OF CULTIVARS IN THE HIGHLAND TROPICS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Field studies were conducted to determine the resistance of potato varieties to potato late blight at two locations in Kenya during the 2000, 2001 and 2002 cropping seasons. The varieties consisted of population A with R-genes and major resistance to foliar potato late blight, and population B with ...

339

Efficacy of Bumble Bee Disseminated Biological Control Agents for Control of Botrytis Blossom Blight of Rabbiteye Blueberry  

Microsoft Academic Search

Botrytis blossom blight caused by Botrytis cinerea may cause severe crop loss in rabbiteye blueberry, necessitating applications of expensive fungicides. Commercial bumble bees, Bombus impatiens, were tested as vectors of the fungicidal biological control agents, Prestop® (Gliocladium catenulatum) and Mycostop® (Streptomyces griseoviridis), against blueberry blossom blight. A single bumble bee hive and four flowering blueberry plants were confined within each

Barbara J. Smith; Blair J. Sampson; Monika Walter

2012-01-01

340

Molecular comparison of pathogenic bacteria from pear trees in Japan and the fire blight pathogen Erwinia amylovora  

Microsoft Academic Search

Several strains of the genus Erwinia, which were isolated in Japan from pear trees with necrotic symptoms that resembled fire blight, and tentatively identified as Erwinia amylovora, were reinvestigated for their relationship to the fire blight pathogen. These isolates produced ooze on slices of immature pears and were mucoid on MM2Cu agar plates, but did not synthesize levan and did

Won-Sik Kim; Maja Hildebrand; Susanne Jock; Klaus Geider

341

High-resolution transcriptional analysis of the regulatory influence of cell-to-cell signalling reveals novel genes that contribute to Xanthomonas phytopathogenesis  

PubMed Central

The bacterium Xanthomonas campestris is an economically important pathogen of many crop species and a model for the study of bacterial phytopathogenesis. In X. campestris, a regulatory system mediated by the signal molecule DSF controls virulence to plants. The synthesis and recognition of the DSF signal depends upon different Rpf proteins. DSF signal generation requires RpfF whereas signal perception and transduction depends upon a system comprising the sensor RpfC and regulator RpfG. Here we have addressed the action and role of Rpf/DSF signalling in phytopathogenesis by high-resolution transcriptional analysis coupled to functional genomics. We detected transcripts for many genes that were unidentified by previous computational analysis of the genome sequence. Novel transcribed regions included intergenic transcripts predicted as coding or non-coding as well as those that were antisense to coding sequences. In total, mutation of rpfF, rpfG and rpfC led to alteration in transcript levels (more than fourfold) of approximately 480 genes. The regulatory influence of RpfF and RpfC demonstrated considerable overlap. Contrary to expectation, the regulatory influence of RpfC and RpfG had limited overlap, indicating complexities of the Rpf signalling system. Importantly, functional analysis revealed over 160 new virulence factors within the group of Rpf-regulated genes.

An, Shi-Qi; Febrer, Melanie; McCarthy, Yvonne; Tang, Dong-Jie; Clissold, Leah; Kaithakottil, Gemy; Swarbreck, David; Tang, Ji-Liang; Rogers, Jane; Dow, J Maxwell; Ryan, Robert P

2013-01-01

342

The cyclic nucleotide monophosphate domain of Xanthomonas campestris global regulator Clp defines a new class of cyclic di-GMP effectors.  

PubMed

The widely conserved second messenger cyclic diguanosine monophosphate (c-di-GMP) plays a key role in quorum-sensing (QS)-dependent production of virulence factors in Xanthomonas campestris pv. campestris. The detection of QS diffusible signal factor (DSF) by the sensor RpfC leads to the activation of response regulator RpfG, which activates virulence gene expression by degrading c-di-GMP. Here, we show that a global regulator in the X. campestris pv. campestris QS regulatory pathway, Clp, is a c-di-GMP effector. c-di-GMP specifically binds to Clp with high affinity and induces allosteric conformational changes that abolish the interaction between Clp and its target gene promoter. Clp is similar to the cyclic AMP (cAMP) binding proteins Crp and Vfr and contains a conserved cyclic nucleotide monophosphate (cNMP) binding domain. Using site-directed mutagenesis, we found that the cNMP binding domain of Clp contains a glutamic acid residue (E99) that is essential for c-di-GMP binding. Substituting the residue with serine (E99S) resulted in decreased sensitivity to changes in the intracellular c-di-GMP level and attenuated bacterial virulence. These data establish the direct role of Clp in the response to fluctuating c-di-GMP levels and depict a novel mechanism by which QS links the second messenger with the X. campestris pv. campestris virulence regulon. PMID:20008070

Tao, Fei; He, Ya-Wen; Wu, Dong-Hui; Swarup, Sanjay; Zhang, Lian-Hui

2009-12-11

343

Haplotype diversity at fusarium head blight resistance QTLs in wheat.  

PubMed

Fusarium head blight (FHB) reduces grain yield and quality in common and durum wheat. Host FHB resistance is an effective control measure that is achieved by stacking multiple resistance genes into a wheat line. Therefore, breeders would benefit from knowing which resistance sources carry different resistance genes. A diverse collection of FHB-resistant and -susceptible wheat lines was characterized with microsatellite markers linked to FHB resistance quantitative trait loci (QTLs) on chromosomes 2DL, 3BS (distal to the centromere), 3BSc (proximal to the centromere), 4B, 5AS and 6BS identified in wheat lines Maringa, Sumai 3 and Wuhan 1. Putative Sumai 3 QTLs were commonly observed in advanced breeding lines, whereas putative Maringa and Wuhan 1 QTLs were relatively rare. Marker data suggested the 3BS, 3BSc and 5AS QTLs in the Brazilian cv. Maringa were derived from Asian germplasm and not from Frontana or other Brazilian lines. Haplotype diversity was reduced near the 5AS QTL, which might impact the deployment of this QTL. Finally, Brazilian germplasm was not closely related to other resistance sources and might be useful for pyramiding with Asian wheat-derived FHB resistance. PMID:15057418

McCartney, C A; Somers, D J; Fedak, G; Cao, W

2004-04-01

344

Xanthomonas biopolymer for use in displacement of oil from partially depleted reservoirs  

SciTech Connect

A mutant strain of the genus xanthomonas produces a pyruvatefree biopolymer. This biopolymer and the deacetylated form of this new biopolymer provide mobility control solutions which are especially useful for enhanced oil recovery where high brine applications are involved. The mobility control solutions of the present invention may be made from whole or filtered fermentation broth containing the pyrvuate-free biopolymer or its deacetylated form. Alternatively, the biopolymer or its deacetylated form may be recovered from the broth and the recovered product used to form the desired mobility control solutions.

Wernau, W.C.

1982-10-05

345

Xanthomonas bipolymer for use in displacement of oil from partially depleted reservoirs  

SciTech Connect

A mutant strain of the genus xanthomonas produces a pyruvatefree biopolymer. This biopolymer and the deacetylated form of this new biopolymer provide mobility control solutions which are especially useful for enhanced oil recovery where high brine applications are involved. The mobility control solutions of the present invention may be made from whole or filtered fermentation broth containing the pyruvate-free biopolymer or its deacetylated form. Alternatively, the biopolymer or its deacetylated form may be recovered from the broth and the recovered product used to form the desired mobility control solutions.

Wernau, W.C.

1981-10-20

346

Bacterial vaginosis  

Microsoft Academic Search

Bacterial vaginosis is a common cause of abnormal discharge in women of child-bearing age. It is present in 10–20% women in the UK, and may recur or regress spontaneously. It is not regarded as an STI because it can occur in virgin women, but it is more common in sexually active women. Other associations include smoking, partner change, having a

Phillip Hay

2005-01-01

347

Bacterial Biofertilizers  

Microsoft Academic Search

Many bacteria and fungi can enhance plant growth. The present review is limited to plant growth promoting rhizobacteria (PGPR). However, it includes endophytic bacteria that show plant growth enhancing activity as well. Also the best studied bacterial mechanisms of plant growth promotion are discussed, with a special emphasis on biological nitrogen fixation and synthesis of phytohormones, including less understood mechanisms

LUIS E. FUENTES-RAMIREZ; Jesus Caballero-Mellado

348

Xanthomonas campestris Overcomes Arabidopsis Stomatal Innate Immunity through a DSF Cell-to-Cell Signal-Regulated Virulence Factor1[OA  

PubMed Central

Pathogen-induced stomatal closure is part of the plant innate immune response. Phytopathogens using stomata as a way of entry into the leaf must avoid the stomatal response of the host. In this article, we describe a factor secreted by the bacterial phytopathogen Xanthomonas campestris pv campestris (Xcc) capable of interfering with stomatal closure induced by bacteria or abscisic acid (ABA). We found that living Xcc, as well as ethyl acetate extracts from Xcc culture supernatants, are capable of reverting stomatal closure induced by bacteria, lipopolysaccharide, or ABA. Xcc ethyl acetate extracts also complemented the infectivity of Pseudomonas syringae pv tomato (Pst) mutants deficient in the production of the coronatine toxin, which is required to overcome stomatal defense. By contrast, the rpfF and rpfC mutant strains of Xcc, which are unable to respectively synthesize or perceive a diffusible molecule involved in bacterial cell-to-cell signaling, were incapable of reverting stomatal closure, indicating that suppression of stomatal response by Xcc requires an intact rpf/diffusible signal factor system. In addition, we found that guard cell-specific Arabidopsis (Arabidopsis thaliana) Mitogen-Activated Protein Kinase3 (MPK3) antisense mutants were unresponsive to bacteria or lipopolysaccharide in promotion of stomatal closure, and also more sensitive to Pst coronatine-deficient mutants, showing that MPK3 is required for stomatal immune response. Additionally, we found that, unlike in wild-type Arabidopsis, ABA-induced stomatal closure in MPK3 antisense mutants is not affected by Xcc or by extracts from Xcc culture supernatants, suggesting that the Xcc factor might target some signaling component in the same pathway as MPK3.

Gudesblat, Gustavo E.; Torres, Pablo S.; Vojnov, Adrian A.

2009-01-01

349

Regulation of Cell Wall-Bound Invertase in Pepper Leaves by Xanthomonas campestris pv. vesicatoria Type Three Effectors  

PubMed Central

Xanthomonas campestris pv. vesicatoria (Xcv) possess a type 3 secretion system (T3SS) to deliver effector proteins into its Solanaceous host plants. These proteins are involved in suppression of plant defense and in reprogramming of plant metabolism to favour bacterial propagation. There is increasing evidence that hexoses contribute to defense responses. They act as substrates for metabolic processes and as metabolic semaphores to regulate gene expression. Especially an increase in the apoplastic hexose-to-sucrose ratio has been suggested to strengthen plant defense. This shift is brought about by the activity of cell wall-bound invertase (cw-Inv). We examined the possibility that Xcv may employ type 3 effector (T3E) proteins to suppress cw-Inv activity during infection. Indeed, pepper leaves infected with a T3SS-deficient Xcv strain showed a higher level of cw-Inv mRNA and enzyme activity relative to Xcv wild type infected leaves. Higher cw-Inv activity was paralleled by an increase in hexoses and mRNA abundance for the pathogenesis-related gene PRQ. These results suggest that Xcv suppresses cw-Inv activity in a T3SS-dependent manner, most likely to prevent sugar-mediated defense signals. To identify Xcv T3Es that regulate cw-Inv activity, a screen was performed with eighteen Xcv strains, each deficient in an individual T3E. Seven Xcv T3E deletion strains caused a significant change in cw-Inv activity compared to Xcv wild type. Among them, Xcv lacking the xopB gene (Xcv ?xopB) caused the most prominent increase in cw-Inv activity. Deletion of xopB increased the mRNA abundance of PRQ in Xcv ?xopB-infected pepper leaves, but not of Pti5 and Acre31, two PAMP-triggered immunity markers. Inducible expression of XopB in transgenic tobacco inhibited Xcv-mediated induction of cw-Inv activity observed in wild type plants and resulted in severe developmental phenotypes. Together, these data suggest that XopB interferes with cw-Inv activity in planta to suppress sugar-enhanced defense responses during Xcv infection.

Sonnewald, Sophia; Priller, Johannes P. R.; Schuster, Julia; Glickmann, Eric; Hajirezaei, Mohammed-Reza; Siebig, Stefan; Mudgett, Mary Beth; Sonnewald, Uwe

2012-01-01

350

Spectroscopic properties of rubber oxygenase RoxA from Xanthomonas sp., a new type of dihaem dioxygenase.  

PubMed

Natural rubber [poly-(cis-1,4-isoprene)] is cleaved to 12-oxo-4,8-dimethyltrideca-4,8-diene-1-al (ODTD) by rubber oxygenase A (RoxA) isolated from Xanthomonas sp. RoxA has two c-type haem centres that show two distinct alpha-bands at 549 and 553 nm in the dithionite-reduced state. A well-resolved midpoint potential (E(0)') of -65 mV was determined for one haem by spectrophotometric titrations in the absence of dioxygen with dithionite and ferricyanide as reductant and oxidant, respectively. The midpoint potential of the second haem was not resolvable (E(0)' about -130 to -160 mV). One of the two haems was reduced by NADH (549 nm alpha-band), similar to bacterial dihaem peroxidases. Evidence for an electron transfer between the two haems was provided by slow reduction of the second haem (553 nm alpha-band) upon incubation of the partially reduced enzyme at room temperature. Addition of imidazole or related compounds to RoxA led to UV/vis spectral features similar to those observed for partially reduced RoxA. Notably, reduction of RoxA with dithionite or NADH, or binding of compounds such as imidazole, resulted in a reversible inactivation of the enzyme, unlike dihaem peroxidases. In line with this result, RoxA did not show any peroxidase activity. EPR spectra of RoxA as isolated showed two low-spin Fe(III) haem centres, with apparent g-values of 3.39, 3.09, 2.23, 1.92 and 1.50. A weak signal in the g=6 region resulting from a high-spin Fe(III) haem was also observed with a preparation-dependent intensity that disappeared in the presence of imidazole. Attempts to provide spectroscopic evidence for binding of the natural substrate (polyisoprene latex) to RoxA failed. However, experimental data are presented that RoxA is able to subtract redox equivalents from its substrate or from model compounds. In conclusion, RoxA is a novel type of dihaem dioxygenase with features clearly different from classical cytochrome c peroxidases. PMID:20413555

Schmitt, Georg; Seiffert, Grazyna; Kroneck, Peter M H; Braaz, Reinhard; Jendrossek, Dieter

2010-04-22

351

Colonization of cauliflower blossom (Brassica oleracea) by Xanthomonas campestris pv. campestris, via flies (Calliphora vomitoria) can result in seed infestation  

Microsoft Academic Search

Inoculation of cauliflower blossom with Xanthomonas campestris pv. campestris (Xcc), by brush or pollination with blue bottle flies (Calliphora vomitoria) as a vector, can result in seed infestation. Two years of poly-tunnel experiments with fly inoculation of cauliflower has shown that in approximately 30% of seed batches of a breeding line, high densities of Xcc (>10 000 CFU\\/g) were found

Wolf van der J. M; Zouwen van der P. S

2010-01-01

352

USE OF THE GREEN FLUORESCENT PROTEIN (GFP) TO STUDY SURVIVAL OF XANTHOMONAS AXONOPODIS ON CITRUS PLANT SURFACES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Although much research has been conducted on survival of Xanthomonas axonopodis pv. citri (Xac) as an epiphyte some important issues remain unresolved. Xac can survive on non-symptomatic leaves for short periods (hours) as an epiphyte depending on the relative humidity conditions the leaves are subj...

353

Genome-Wide Mutagenesis of Xanthomonas axonopodis pv. citri Reveals Novel Genetic Determinants and Regulation Mechanisms of Biofilm Formation  

Microsoft Academic Search

Xanthomonas axonopodis pv. citri (Xac) causes citrus canker disease, a major threat to citrus production worldwide. Accumulating evidence suggests that the formation of biofilms on citrus leaves plays an important role in the epiphytic survival of this pathogen prior to the development of canker disease. However, the process of Xac biofilm formation is poorly understood. Here, we report a genome-scale

Jinyun Li; Nian Wang

2011-01-01

354

Amino ester hydrolase from Xanthomonas campestris pv. campestris, ATCC 33913 for enzymatic synthesis of ampicillin  

PubMed Central

?-Amino ester hydrolases (AEH) are a small class of proteins, which are highly specific for hydrolysis or synthesis of ?-amino containing amides and esters including ?-lactam antibiotics such as ampicillin, amoxicillin, and cephalexin. A BLAST search revealed the sequence of a putative glutaryl 7-aminocephalosporanic acid (GL-7-ACA) acylase 93% identical to a known AEH from Xanthomonas citri. The gene, termed gaa, was cloned from the genomic DNA of Xanthomonas campestris pv. campestris sp. strain ATCC 33913 and the corresponding protein was expressed into Escherichia coli. The purified protein was able to perform both hydrolysis and synthesis of a variety of ?-amino ?-lactam antibiotics including (R)-ampicillin and cephalexin, with optimal ampicillin hydrolytic activity at 25 °C and pH 6.8, with kinetic parameters of kcat of 72.5 s?1 and KM of 1.1 mM. The synthesis parameters ?, ?o, and ? for ampicillin, determined here first for this class of proteins, are ? = 0.25, ?o = 42.8 M?1, and ? = 0.23, and demonstrate the excellent synthetic potential of these enzymes. An extensive study of site-directed mutations around the binding pocket of X. campestris pv. campestris AEH strongly suggests that mutation of almost any first-shell amino acid residues around the active site leads to inactive enzyme, including Y82, Y175, D207, D208, W209, Y222, and E309, in addition to those residues forming the catalytic triad, S174, H340, and D307.

Blum, Janna K.; Bommarius, Andreas S.

2010-01-01

355

In Vivo and in Vitro Effects of Secondary Metabolites against Xanthomonas campestris pv. campestris.  

PubMed

Brassica rapa is a crucifer that is grown worldwide, mainly as a vegetable. The quality of B. rapa crops is highly affected by the disease caused by the bacteria Xanthomonas campestris pv. campestris (Xcc). Glucosinolates and phenolic compounds can confer resistance to Brassica crops against pests and diseases, but few works have been done to evaluate their role in Xcc resistance. The objectives of this work were: (1) to evaluate the in vivo and in vitro antibacterial effect of gluconapin, its isothiocyanate and the methanolic extracts of B. rapa against the type 4 of Xcc, and (2) to test if there is induced resistance mediated by glucosinolates or phenolic compounds in two varieties of B. rapa. Gluconapin and its ITC varieties had an antibacterial effect on the development of Xanthomonas and this effect was strongly dependent on the concentration applied. Methanolic extracts from B. rapa, containing glucosinolates and phenolic compounds, inhibited the growth of these bacteria. Concentration of gluconapin is higher in resistant plants than in the susceptible ones and there is an induction of gluconapin, some flavonoids and sinapic acid 48 to 72 h after inoculation. Gluconapin plays a role in the constitutive resistance to Xcc, while gluconapin, some flavonoids and hydroxycinnamic acids are induced by a Xcc infection but it is not clear if this induction confers resistance to this disease. PMID:24029746

Velasco, Pablo; Lema, Margarita; Francisco, Marta; Soengas, Pilar; Cartea, María Elena

2013-09-11

356

Bacterial Rheotaxis  

NASA Astrophysics Data System (ADS)

Rheotaxis is the directed movement of an organism resulting from fluid velocity gradients, long studied in fish, aquatic invertebrates and spermatozoa. Here we show that rheotaxis also occurs in bacteria. Using controlled microfluidic shear flows, we demonstrate and quantify rheotaxis in Bacillus subtilis. A mathematical model of a bacterium swimming in a shear flow is in good agreement with observations and reveals that bacterial rheotaxis results from a subtle interplay between velocity gradients and the helical shape of flagella, which together generate a torque that reorients the cell, altering its swimming direction. The magnitude of the observed rheotactic velocity is comparable to typical chemotactic velocities, suggesting that rheotaxis can interfere with bacterial processes based on directed motility, such as foraging and infection.

Marcos, Marcos; Fu, Henry; Powers, Thomas; Stocker, Roman

2011-11-01

357

RICE BLAST AND SHEATH BLIGHT EVALUATION RESULTS FOR NEWLY INTRODUCED RICE GERMPLASM  

Technology Transfer Automated Retrieval System (TEKTRAN)

Newly introduced rice germplasm and selected reference cultivars were evaluated in artificially inoculated greenhouse tests with individual blast races at Stuttgart, AR and field nurseries established with inoculation of blast race-mixture, and with inoculation of sheath blight isolates during the 2...

358

Evaluation of genomic prediction methods for fusarium head blight resistance in wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fusarium head blight (FHB) resistance is quantitative and difficult to evaluate. Genomic selection (GS) could accelerate FHB resistance breeding. We used US cooperative FHB wheat nursery data to evaluate GS models for several FHB resistance traits including deoxynivalenol (DON) levels. For all trait...

359

Involvement of a phytotoxic peptide in the development of the Northern leaf blight of corn  

Microsoft Academic Search

Non pathogenic isolates ofExserohilum turcicum successfully infect corn plants in the presence of syntheticE. turcicum toxin during inoculation. The toxin significantly increased the number of appressoria and the ramification of germinating conidia both on host leaves and on artificial media. These findings indicate that this toxin plays an important role in infection of Northern leaf blight.

Bilha Bashan; Rachel Abadi; Yehouda Levy

1996-01-01

360

RAPD MARKERS LINKED TO EASTERN FILBERT BLIGHT RESISTANCE IN CORYLUS AVELLANA  

Technology Transfer Automated Retrieval System (TEKTRAN)

A total of 1420 decamer primers were screened for RAPD markers linked to a dominant allele in hazelnut (Corylus avellana), that confers resistance to eastern filbert blight caused by Anisogramma anomala. Twenty RAPD markers linked in coupling and five additional markers linked in repulsion were fou...

361

A real-time PCR assay for early detection of eastern filbert blight  

Technology Transfer Automated Retrieval System (TEKTRAN)

Eastern filbert blight (EFB) is a devastating disease of European hazelnut, Corylus avellana, which causes economic losses in Oregon where 99% of the U.S. crop is produced. The causal fungus, Anisogramma anomala, is native to eastern North America, where it is found associated with the American haz...

362

Reaction of peanut genotypes to Southern blight in small field plots  

Technology Transfer Automated Retrieval System (TEKTRAN)

Southern blight of peanut (Arachis hypogaea L.) is a serious disease caused by the fungus Sclerotium rolfsii. The disease negatively impacts peanut production in all growing areas of the United States. Eleven peanut genotypes (PI 501983, 501996, 502046, 502071, 502093, 502154, Grif 13826, Okrun, S...

363

SELECTED GENES FROM THE FUSARIUM HEAD BLIGHT RESISTANT CULTIVAR FUNDULEA 201R  

Technology Transfer Automated Retrieval System (TEKTRAN)

The development of wheat varieties with resistance to Fusarium head blight (FHB) is slowly occurring through breeding techniques. The varieties so far developed provide improved resistance to the spread of infection within the spike (Type II resistance). Immunity to FHB (Type I) has not yet been r...

364

THE SOUTHEASTERN U.S. FUSARIUM HEAD BLIGHT EPIDEMIC OF 2003  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fusarium head blight (FHB) caused unprecedented losses to southeastern U.S. wheat producers and millers in 2003. The epidemic was documented afterward through interviews with 120 researchers, extension agents, millers, and growers. Sixty-seven counties in five states were individually assigned an ...

365

Current status and future prospects in biological control of rice sheath blight in Mekong Delta  

Microsoft Academic Search

This research paper addresses the beneficial bacteria covering the aspects of biological control and plant growth promotion in terms of sheath blight (ShB) disease control. Six strains of beneficial bacteria (NF1, NF3, NF 52, NF 49, CT 6- 37, and W 23) were selected from 300 strains isolated from seeds and other components of the rice ecosystem in Mekong Delta.

Lai Van E; Nguyen Thi; Phong Lan; Pham Van Du; T. W. Mew

366

SUPPRESSION OF FUSARIUM ROOT ROT AND SOUTHERN BLIGHT ON PEANUT BY SOIL SOLARIZATION  

Microsoft Academic Search

Both southern blight ( Sclerotium rolfsii ) and Fusarium root rot ( Fusarium solani ) are the important soil-borne diseases found in peanut ( Arachis hypogaea ) in the Bogor area, including the Seed Technology Experimental Station of Bogor Agricultural University (IPB). Solar heating by means of clear polyethylene sheets to control these two soil-borne diseases was performed in naturally

Tati Budiarti

2009-01-01

367

BREEDING FOR DURABLE RESISTANCE TO LATE BLIGHT: THE MISSING MEXICAN LINK  

Technology Transfer Automated Retrieval System (TEKTRAN)

Late blight, a foliar and tuber disease caused by the water mold Phytophthora infestans, is a highly variable pathogen of potato. Potatoes may be resistant to one form, but completely susceptible to another form that will appear at a later time. For this reason it is necessary to check the durabil...

368

ADVANCES IN DEVELOPING BIOLOGICAL CONTROL PRODUCTS ACTIVE AGAINST FUSARIUM HEAD BLIGHT OF WHEAT  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fresh and frozen concentrates of Cryptococcus nodaensis OH 182.9 (NRRL Y-30216, patent culture collection) cells have reduced Fusarium head blight (FHB) in multiple greenhouse and field trials. Development of a dried commercial product of OH 182.9 would have potential advantages of ease of handling...

369

STRATEGIES FOR OBTAINING FIRE BLIGHT RESISTANCE IN APPLE BY RDNA TECHNOLOGY  

Technology Transfer Automated Retrieval System (TEKTRAN)

The fire blight disease of apple (Malus X domestica), caused by the bacterium Erwinia amylovora, is difficult to manage on most cultivars because of their susceptibility and the paucity of effective control materials. Because of apple's heterozygosity, self-incompatibility, and long generation time...

370

Potato agriculture, late blight science, and the molecularization of plant pathology.  

PubMed

By the mid-1980s nucleic-acid based methods were penetrating the farthest reaches of biological science, triggering rivalries among practitioners, altering relationships among subfields, and transforming the research front. This article delivers a "bottom up" analysis of that transformation at work in one important area of biological science, plant pathology, by tracing the "molecularization" of efforts to understand and control one notorious plant disease -- the late blight of potatoes. It mobilizes the research literature of late blight science as a tool through which to trace the changing typography of the research front from 1983 to 2003. During these years molecularization intensified the traditional fragmentation of the late blight research community, even as it dramatically integrated study of the causal organism into broader areas of biology. In these decades the pathogen responsible for late blight, the oomycete "Phytophthora infestans," was discovered to be undergoing massive, frightening, and still largely unexplained genetic diversification -- a circumstance that lends the episode examined here an urgency that reinforces its historiographical significance as a case-study in the molecularization of the biological sciences. PMID:20073121

Turner, R Steven

2008-01-01

371

Fusarium head blight resistance in wheat using the in vitro androgenic approach  

Microsoft Academic Search

Wheat ( Triticum aestivum L.) belongs to the three most important food crops in the world. In certain years, the crop can suffer considerable damage as a result of Fusarium Head Blight (FHB), especially as no chemical control is effective against this disease. This disease is mainly caused by the fungi Fusarium culmorum and F. graminearum but in the cooler

M. B. M. Bruins

1998-01-01

372

Ranking cultivated blueberry for Mummy Berry Blight and Fruit Infection Incidence  

Technology Transfer Automated Retrieval System (TEKTRAN)

Mummy berry is an important disease of cultivated blueberry. The disease has two distinct phases; a blighting phase initiated by ascospores and a fruit infection stage initiated by conidia. In this study we investigated the resistance of more than 100 blueberry cultivar to both phases of the disease...

373

Evaluation of Fungicides for Control of Phytophthora Blight of Watermelon in North Carolina and South Carolina  

Technology Transfer Automated Retrieval System (TEKTRAN)

Phytophthora blight, caused by Phytophthora capsici, is an important disease of cucurbits in the eastern U.S. Fungicides, crop rotation, and water management are recommended to control the disease. Watermelon (Citrullus lanatus) poses a particularly difficult challenge to disease control because o...

374

Effect of Plant Spacing on Microclimate and Rhizoctonia Web Blight Development in Container Grown Azalea  

Technology Transfer Automated Retrieval System (TEKTRAN)

Rhizoctonia web blight is a reoccurring problem in compact varieties of container-grown azalea (Rhododendron sp.) in the Gulf Coast States. During the summers of 2002 and 2003, disease severity was measured weekly in the inoculated center plant of plots consisting of 49 ‘Gumpo’ azalea plants. Plant ...

375

Evaluation of the USDA Rice Core Collection for sheath blight disease using micro-chamber  

Technology Transfer Automated Retrieval System (TEKTRAN)

The USDA rice core collection, including 1,794 accessions from 114 countries, was developed using a stratified random sampling method to represent the entire NSGC collection including over 18,000 accessions. Sheath blight (Rhizoctonia solani) is one of the most important and widely distributed disea...

376

GENE SILENCING INDICATES A ROLE FOR POTATO ENDOGLUCANASE INHIBITOR PROTEIN IN GERMPLASM RESISTANCE TO LATE BLIGHT  

Technology Transfer Automated Retrieval System (TEKTRAN)

Durable resistance to late blight is believed to be dependent on genes other than R genes. Reduced rates of lesion expansion, as found in the germplasm B 0767-2, can provide durable resistance by limiting tissue damage and reducing pathogen populations. We have tested the role of the proteinaceous x...

377

Effect of Trichothecenes Produced by Fusarium graminearum during Fusarium Head Blight Development in Six Cereal Species  

Microsoft Academic Search

Fusarium head blight (FHB) is a complex cereal disease associated with trichothecene production; these mycotoxins are factors of aggressiveness in wheat. Six species (bread and durum wheat, triticale, rye, barley and oats) were submitted to point inoculations with two isogenic strains of Fusarium graminearum; a wild strain (Tri5 +) produced trichothecenes and the mutated strain (Tri5 -) did not. The

François Langevin; François Eudes; André Comeau

2004-01-01

378

DEFENDER: A HIGH-YIELDING, PROCESSING POTATO CULTIVAR WITH FOLIAR AND TUBER RESISTANCE TO LATE BLIGHT  

Technology Transfer Automated Retrieval System (TEKTRAN)

The potato cultivar ‘Defender’ is high-yielding, white-skinned, and notable for having foliar and tuber resistance to late blight infection caused by Phytophthora infestans (Mont.) de Bary. It was released in 2004 by the USDA-ARS and the Agricultural Experiment Stations of Idaho, Oregon, and Washin...

379

QTL ANALYSIS OF LATE BLIGHT RESISTANCE IN A DIPLOID POTATO FAMILY OF SOLANUM PHUREJA S.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Field resistance to Phytophthora infestans (Mont.) de Bary, the causal agent of late blight in potatoes, has been characterized in a potato segregating family of 230 full-sib progenies derived from a cross between two hybrid Solanum phureja S. stenotomum clones. The distribution of area under th...

380

Fire blight risk assessment during bloom in an experimental orchard using BIS (Billing's Integrated System)  

Microsoft Academic Search

The value of BIS for blossom blight risk assessment was studied from data collected in an experimental orchard in south-west France. Trees observed included mature commercial pear and apple trees and some young trees in experimental plots. There was a weather station in the orchard and beehives were present. Field records included flowering times of the pear and apple cultivars

Pascal Lecomte; Jean-Pierre Paulin; Eve Billing

1998-01-01

381

Greenhouse Detached-leaf and Field Testing Methods to Determine Cucumber Resistance to Gummy Stem Blight  

Microsoft Academic Search

Abstract. The effects of leaf age, guttation, stomata and hydathode characteristics, and wounding on the symptom development of gummy stem blight [Didymella bryoniae (Auersw.) Rehm] of cucumber (Cucumis sativus L.) were studied to develop a useful germplasm screening method. Older cucumber leaves were more susceptible than younger leaves in field, greenhouse, and detached-leaf tests. Compared to seedlings with true leaves,

Paul C. St. Amand; Todd C. Wehner

382

Induced resistance against Alternaria brassicae blight of mustard through plant extracts  

Microsoft Academic Search

An experiment was conducted to study the effect of plant extracts on soluble sugar, soluble phenol and defence-related enzymes response against Alternaria blight in mustard crop. The efficacy of six selected plant extracts (5 and 10%) used as foliar sprays at 60 and 70 days after sowing and mustard leaves was used for investigation. The results indicate that soluble phenol

Singh Surendra; S. L. Godara; S. Gangopadhayay; K. S. Jadon

2012-01-01

383

FIRST REPORT OF PHYTOPHTHORA RAMORUM BLIGHT ON PIERIS, RHODODENDRON, VIBURNUM, AND CAMELLIA IN OREGON NURSERIES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Phytophthora ramorum, the cause of the Sudden Oak Death syndrome in California and Oregon and shoot blight and leaf spot of many landscape plant species in Europe, was detected in wholesale and retail nurseries in Oregon for the first time. The pathogen was isolated and identified by means of cultu...

384

Evaluation of Commercial Watermelon Rootstocks for Tolerance to Phytophthora Blight and Watermelon Vine Decline  

Technology Transfer Automated Retrieval System (TEKTRAN)

Phytophthora blight and fruit rot caused by Phytophthora capsici, and watermelon vine decline (WVD) caused by Squash vein yellowing virus (SqVYV), are two important and emerging diseases of watermelons (Citrullus lanatus). Recently, the practice of grafting seedless watermelons (triploids) onto roo...

385

Control of sheath blight disease in rice by thermostable secondary metabolites of Trichothecium roseum MML003  

Microsoft Academic Search

The aim of the study is to investigate the biocontrol mechanisms of Trichothecium roseum MML003 against the rice sheath blight (ShB) pathogen, Rhizoctonia solani as the former exhibited strong antagonistic activity against the latter. It has been found that T. roseum MML003 did not show any hyperparasitic interaction against R. solani. Further, it did not produce siderophores and hydrogen cyanide.

M. Jayaprakashvel; M. Selvakumar; K. Srinivasan; S. Ramesh; N. Mathivanan

2010-01-01

386

Relationship between the incidences of ear and spikelet infection of Fusarium ear blight in wheat  

Microsoft Academic Search

There is a urgent need to develop a rational strategy for managing Fusarium ear blight in order to reduce current reliance on routine fungicide applications, based on an objective assessment of disease risks. One of important components for such a management strategy is a fast, easy, accurate and reliable method for disease assessment. The relationship between incidence of Fusarium ear

X.-m. Xu; D. W. Parry; S. G. Edwards; B. M. Cooke; F. M. Doohan; A. Maanen; J. M. Brennan; S. Monaghan; A. Moretti; G. Tocco; G. Mule; L. Hornok; G. Giczey; J. Tatnell; P. Nicholson; A. Ritieni

2004-01-01

387

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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),...

388

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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...

389

Chemical and Biological Treatments for Control of Gummy Stem Blight of Greenhouse Cucumbers  

Microsoft Academic Search

Experiments were conducted to determine the effects of chemical and biological treatments on gummy stem blight of cucumber caused by Didymella bryoniae in vitro and under greenhouse conditions. Eleven strains of Bacillus subtilis, strain AGB10 of B. cereus, and strain B8Fr of Enterobacter agglomerans produced antagonistic zone against D. bryoniae in vitro. Of four experiments conducted, the chemical treatments ‘Nova’,1

R. S. Utkhede; C. A. Koch

2002-01-01

390

Predicting wheat head blight incidence using models based on meteorological factors in Pergamino, Argentina  

Microsoft Academic Search

A computer program using the language and statistical procedures available from SAS (Statistical Analysis System) was written in order to identify the most highly correlated meteorological factors with the incidence of wheat head blight (caused byFusarium graminearum Schwabe) at Pergamino, in the humid pampeana region. Applying linear regression techniques, different models from simple up to a maximum of three independent

R. C. Moschini; C. Fortugno

1996-01-01

391

Antifungal compounds from Melia azedarach leaves for management of Ascochyta rabiei, the cause of chickpea blight  

Microsoft Academic Search

The antifungal activity of Melia azedarach L. leaves was investigated against Ascochyta rabiei (Pass.) Lab., the cause of destructive blight disease of chickpea (Cicer arietinum L.). Bioassay guided fractionation revealed that the chloroform fraction of the methanolic extract of M. azedarach leaves was highly effective against A. rabiei. Six compounds, namely ?-sitosterol (1), ?-amyrin (2), ursolic acid (3), benzoic acid

Khajista Jabeen; Arshad Javaid; Ejaz Ahmad; Makshoof Athar

2011-01-01

392

Riparian vegetation in the southern Appalachian mountains (USA) following chestnut blight  

Microsoft Academic Search

American chestnut is often listed as an important component of mesic midslopes and xeric ridges in pre-blight southern Appalachian forests, but its former importance in riparian forests has generally been considered minor. To document its importance in riparian forests, 589 American chestnut stumps were located on four sites (two previously logged, two unlogged) in the Blue Ridge physiographic province of

D. B Vandermast; D. H Van Lear

2002-01-01

393

EFFECT OF TRANSPLANTING TIME ON INCIDENCE OF ALTERNATARIA LEAF BLIGHT IN SOLANUM KHASIANUM CLARK  

PubMed Central

Solanum khasi Clark is a shrub which yields solasodine, a steroidal alkaloid. Transplating of seedlings of S. khasianum during November was found to be favourable for development of Alternaria leaf blight followed by transplanting in December, January and February. This paper presents the findings of the investigation.

Sharma, Rabin K.; Baruah, Pavan; Ghosh, Anil C.

1997-01-01

394

Effect of transplanting time on incidence of alternataria leaf blight in solanum khasianum clark.  

PubMed

Solanum khasi Clark is a shrub which yields solasodine, a steroidal alkaloid. Transplating of seedlings of S. khasianum during November was found to be favourable for development of Alternaria leaf blight followed by transplanting in December, January and February. This paper presents the findings of the investigation. PMID:22556822

Sharma, R K; Baruah, P; Ghosh, A C

1997-07-01

395

Plant Spacing Effects on Microclimate and Rhizoctonia Web Blight Development in Container-grown Azalea  

Microsoft Academic Search

Rhizoctonia web blight, caused by Rhizoctonia solani and binucleate Rhizoctonia spp., is an annual problem in compact cultivars of container-grown azalea (Rhododendron spp.) in the Gulf Coast states. Increasing the space between plants is commonly recom- mended for suppression of the disease, but experimental evidence for the effectiveness of this cultural practice in container-grown azalea is lacking. During the summers

Warren E. Copes

2005-01-01

396

Experimental Induction of Foetal Malformation with ``Blighted'' Potato: a Preliminary Report  

Microsoft Academic Search

SEVERAL reports have linked anencephaly and spina bifida with a dietary factor related to the consumption of potatoes. Recently Renwick1 has examined epidemiological data on anencephaly and spina bifida and postulates a link between the incidence of these neural dysplasias and the consumption of winter-stored ``blighted'' potatoes. He cites Leck and Record (unpublished results), who suggested that potatoes might become

D. E. Poswillo; Dinah Sopher; Sandra Mitchell

1972-01-01

397

Development of co-cultivated mixtures of antagonists active against Fusarium head blight of wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

Multistrain mixtures of biocontrol agents can foster greater and more consistent reductions of plant disease. Several different mixtures of Agricultural Research Service/Ohio State University-discovered antagonists reduced Fusarium head blight (FHB) in field studies. Microbial mixtures commonly ar...

398

A Test of Taxonomic Predictivity: Resistance to Early Blight in Wild Relatives of Cultivated Potato  

Technology Transfer Automated Retrieval System (TEKTRAN)

Early blight (caused by the foliar fungus Alternaria solani) is a widespread disease that appears annually in potato crops worldwide. This is our second study of a disease resistance in wild potatoes to test the assumed ability of taxonomy to predict the presence of traits in a group for which the t...

399

INDUCED RESISTANCE AGAINST FUSARIUM HEAD BLIGHT OF WHEAT BY AUTOCLAVED FUNGAL BIOMASS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fusarium head blight (FHB) is a devastating disease throughout the wheat growing regions of the world. We studied the influence of autoclaved fungal biomass (AFB) for inducing resistance against FHB. In greenhouse trials, AFB were sprayed on the plants before or at flowering. After 7-10 days, hea...

400

RESISTANCE OF APPLE ROOTSTOCKS TO FIRE BLIGHT CAUSED BY ERWINIA AMYLOVORA  

Technology Transfer Automated Retrieval System (TEKTRAN)

Ungrafted rootstocks were screened for susceptibility to fire blight (Erwinia amylovora). Dormant rootstock liners from commercial layer (stool) beds were planted in midwinter in a greenhouse. New growth from each liner was reduced to one shoot. Vigorously growing shoots were inoculated with a co...

401

QTL analysis of late blight resistance in a diploid potato family of Solanum phureja × S. stenotomum  

Microsoft Academic Search

Field resistance to Phytophthora infestans (Mont.) de Bary, the causal agent of late blight in potatoes, has been characterized in a potato segregating family of 230 full-sib progenies derived from a cross between two hybrid Solanum phureja × S. stenotomum clones. The distribution of area under the disease progress curve values, measured in different years and locations, was consistent with

S. Costanzo; I. Simko; B. J. Christ; K. G. Haynes

2005-01-01

402

Characterization of Fusarium head blight (FHB) resistance and deoxynivalenol accumulation in hulled and hulless winter barley  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fusarium head blight (FHB), caused by Fusarium graminearum, is one of the most serious diseases impacting the U.S. barley (Hordeum vulgare L.) industry. The mycotoxin deoxynivalenol (DON) produced by the pathogen renders grain unmarketable if concentrations exceed threshold values set for end-use m...

403

Evaluation of Fungicides for Control of Rapid Blight of Poa trivialis in fall 2006  

Microsoft Academic Search

Rapid blight is a new disease of cool season turf grasses caused by Labyrinthula terrestris, an organism in a group referred to as the marine slime molds. A trial was conducted in fall 2006-winter 2007 to repeat an evaluation of efficacy of different rates and intervals of Insignia fungicide and elemental sulfur, both of which gave acceptable control in trials

M. W. Olsen; G. Towers; J. Gilbert

404

Genetic and genomic dissection of resistance genes to the rice sheath blight pathogen  

Technology Transfer Automated Retrieval System (TEKTRAN)

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...

405

FIRST REPORT OF BLIGHT ON IPOMOEA PURPUREA CAUSED BY PHYTOPHTHORA IPOMOEAE  

Technology Transfer Automated Retrieval System (TEKTRAN)

Several wild species of Ipomoea grow in the central highlands of Mexico. During the summer of 1999, in Metepec, Mexico, blighted leaves and petioles of Ipomoea purpurea were collected from diseased plants and placed in a moist chamber to induce sporulation. Sporangia that formed on the lesions were ...

406

Head blight of wheat in South Africa is associated with numerous Fusarium species and chemotypes  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fusarium head blight (FHB) of wheat is caused by numerous Fusarium species, including trichothecene-producers. In South Africa, FHB is mostly associated with irrigated wheat rotated with maize. Twenty symptomatic wheat heads were collected from four cultivars each in irrigated fields during 2008 and...

407

Fine mapping of the Ph-3 gene conferring resistance to late blight (Phytophthora infestans) in tomato.  

PubMed

Late blight, caused by the oomycete pathogen Phytophthora infestans (Mont.) de Bary, is a devastating disease for tomato and potato crops. In the past decades, many late blight resistance (R) genes have been characterized in potato. In contrast, less work has been conducted on tomato. The Ph-3 gene from Solanum pimpinellifolium was introgressed into cultivated tomatoes and conferred broad-spectrum resistance to P. infestans. It was previously assigned to the long arm of chromosome 9. In this study, a high-resolution genetic map covering the Ph-3 locus was constructed using an F2 population of a cross between Solanum lycopersicum CLN2037B (containing Ph-3) and S. lycopersicum LA4084. Ph-3 was mapped in a 0.5 cM interval between two markers, Indel_3 and P55. Eight putative genes were found in the corresponding 74 kb region of the tomato Heinz1706 reference genome. Four of these genes are resistance gene analogs (RGAs) with a typical nucleotide-binding adaptor shared by APAF-1, R proteins, and CED-4 domain. Each RGA showed high homology to the late blight R gene Rpi-vnt1.1 from Solanum venturii. Transient gene silencing indicated that a member of this RGA family is required for Ph-3-mediated resistance to late blight in tomato. Furthermore, this RGA family was also found in the potato genome, but the number of the RGAs was higher than in tomato. PMID:23921955

Zhang, Chunzhi; Liu, Lei; Zheng, Zheng; Sun, Yuyan; Zhou, Longxi; Yang, Yuhong; Cheng, Feng; Zhang, Zhonghua; Wang, Xiaowu; Huang, Sanwen; Xie, Bingyan; Du, Yongchen; Bai, Yuling; Li, Junming

2013-08-07

408

IDENTIFICATION OF A FUSARIUM HEAD BLIGHT RESISTANCE QTL ON CHROMOSOME 6B IN TETRAPLOID WHEAT.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fusarium head blight (FHB) is one of the most devastating diseases of bread wheat (Triticum aestivum L., 2n=6x=42) and durum wheat (T. turgidum L., 2n=4x=28). Resistant sources of hexaploid bread wheat have been identified and are currently being employed in breeding programs, but development of re...

409

Identification of a novel Fusarium head blight resistance QTL on chromosome 7A in tetraploid wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fusarium head blight (FHB) caused by Fusarium graminearum is one of the most destructive diseases of durum (Triticum turgidum ssp. durum) and common wheat (T. aestivum). Promising sources of FHB resistance have been identified among common (hexaploid) wheats, but the same is not true for durum (tetr...

410

Saturation and comparative mapping of a major Fusarium head blight resistance QTL in tetraploid wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fusarium head blight (FHB) is a devastating disease of cultivated wheat worldwide. Partial resistance to FHB has been identified in common wheat (Triticum aestivum L.). However, sources of effective FHB resistance have not been found in durum wheat (T. turgidum L. var. durum). A major FHB resista...

411

Molecular mapping of Fusarium head blight resistance in the winter wheat population Dream\\/Lynx  

Microsoft Academic Search

Fusarium head blight (FHB), mainly caused by Fusarium graminearum and F. culmorum, can significantly reduce the grain quality of wheat (Triticum aestivum L.) due to mycotoxin contamination. The objective of this study was to identify quantitative trait loci (QTLs) for FHB resistance in a winter wheat population developed by crossing the resistant German cultivar Dream with the susceptible British cultivar

M. Schmolke; G. Zimmermann; H. Buerstmayr; G. Schweizer; T. Miedaner; V. Korzun; E. Ebmeyer; L. Hartl

2005-01-01

412

EFFECT OF THE IRON CHELATE FEEDDHA ON CONTROL OF FIRE BLIGHT BY PSEUDOMONAS FLUORESCENS A506  

Technology Transfer Automated Retrieval System (TEKTRAN)

The biocontrol agent Pseudomonas fluorescens A506 produces an antibiotic toxic to Erwinia amylovora on media amended with iron. We tested the influence of the iron chelate FeEDDHA on growth of A506 on flowers and on fire blight suppression in orchard trials from 2000 to 2004. Pear and apple trees...

413

DIFFERENTIAL SUSCEPTIBILITY TO FIRE BLIGHT IN COMMERCIAL AND EXPERIMENTAL APPLE ROOTSTOCK CULTIVARS  

Technology Transfer Automated Retrieval System (TEKTRAN)

The Geneva rootstock breeding program has developed several new rootstocks that exhibit disease resistance to Erwinia amylovora. Utilization of disease resistant apple rootstocks increases the survivability of young trees infected by fire blight. The goal of this experiment was to further investigat...

414

Effect of surface seeding on foliar blight severity and wheat performance  

Microsoft Academic Search

Spot blotch, caused by Cochliobolus sativus, is a serious disease constraint to wheat (Triticum aestivum L.) yields under rice–wheat systems in the lowlands of South Asia. The surface seeding of wheat, which is becoming popular as a resource conserving technology on resource-poor farms, might provide a more conducive environment for early foliar blight development. During 2002 and 2003 wheat growing

B. N. Mahto; E. Duveiller; R. C. Sharma

2006-01-01

415

Fire blight incidence on Malus sieversii grown in New York and Minnesota  

Technology Transfer Automated Retrieval System (TEKTRAN)

Malus sieversii, a wild apple species native to Central Asia, has been recognized as the major progenitor of the domestic apple. This investigation summarizes the natural infection by Erwinia amylovora (fire blight) on 2590 M. sieversii seedlings grown as own-rooted trees. At a USDA orchard in Gen...

416

Community Analysis of Biofilters Using Fluorescence In Situ Hybridization Including a New Probe for the Xanthomonas Branch of the Class Proteobacteria  

Microsoft Academic Search

Domain-, class-, and subclass-specific rRNA-targeted probes were applied to investigate the microbial communities of three industrial and three laboratory-scale biofilters. The set of probes also included a new probe (named XAN818) specific for the Xanthomonas branch of the class Proteobacteria; this probe is described in this study. The members of the Xanthomonas branch do not hybridize with previously developed rRNA-

UDO FRIEDRICH; MICHELE M. NAISMITH; KARLHEINZ ALTENDORF

1999-01-01

417

Bacterial Growth  

NSDL National Science Digital Library

Dr. Brett Finlay shows how bacteria can grow rapidly to incredible numbers, and also explains what limits this explosive growth. This resource would be great preparation material for a classroom discussion or video presentation for both the students and the teacher. This visual helps further broaden the knowledge of students in both the upper high school and college undergraduate on bacterial growth. The lecture is featured on the DVD 2000 and Beyond: Confronting the Microbe Menace, available free from HHMI. The video is 54 seconds long and available on WMV (10MB) and MOV (8MB). All Infection Disease videos can be found at http://www.hhmi.org/biointeractive/disease/video.html .

Howard Hughes Medical Institute (;)

2007-03-27

418

Efficiacy of bumble bee disseminated biological control agents for control of Botrytis Blossom blight of Rabbiteye Blueberry  

Technology Transfer Automated Retrieval System (TEKTRAN)

Botrytis blossom blight caused by Botrytis cinerea may cause severe crop loss in rabbiteye blueberry, necessitating applications of expensive fungicides. Commercial bumble bees, Bombus impatiens, were tested as vectors of the fungicidal biological control agents (BCAs), Prestop® Gliocladium catenula...

419

Gluconacetobacter diazotrophicus Elicits a Sugarcane Defense Response Against a Pathogenic Bacteria Xanthomonas albilineans  

PubMed Central

A new role for the plant growth-promoting nitrogen-fixing endophytic bacteria Gluconacetobacter diazotrophicus has been identified and characterized while it is involved in the sugarcane-Xanthomonas albilineans pathogenic interactions. Living G.diazotrophicus possess and/or produce elicitor molecules which activate the sugarcane defense response resulting in the plant resistance to X. albilineans, in this particular case controlling the pathogen transmission to emerging agamic shoots. A total of 47 differentially expressed transcript derived fragments (TDFs) were identified by cDNA-AFLP. Transcripts showed significant homologies to genes of the ethylene signaling pathway (26%), proteins regulates by auxins (9%), ?-1,3 Glucanase proteins (6%) and ubiquitin genes (4%), all major signaling mechanisms. Results point toward a form of induction of systemic resistance in sugarcane-G. diazotrophicus interactions which protect the plant against X. albilineans attack.

Vinagre, Fabiano; Estevez, Yandi; Bernal, Aydiloide; Perez, Juana; Cavalcanti, Janaina; Santana, Ignacio; Hemerly, Adriana S

2006-01-01

420

Inoculation with Xanthomonas oryzae pv. oryzae induces thylakoid membrane association of Rubisco activase in Oryza meyeriana.  

PubMed

Oryza meyeriana is a wild species of rice with high resistance to Xanthomonas oryzae pv. oryzae (Xoo), but the resistance mechanism is poorly understood. Protein gel blot analysis and immuno-gold electron microscopy showed that Xoo infection induced an association of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activase (RCA) with the thylakoid membrane in O. meyeriana, which led to considerable decline in the initial activity and the activation state of Rubisco. In susceptible cultivated rice, RCA remained in the chloroplast stroma. RCA may play a role in resistance to Xoo in O. meyeriana that differs from its well-known role in activating Rubisco, perhaps by protecting the thylakoid membrane against damage from Xoo. PMID:21501886

Yang, Yong; Yu, Chu-Lang; Wang, Xu-Ming; Yan, Cheng-Qi; Cheng, Ye; Chen, Jian-Ping

2011-04-17

421

Extracellular proteases from Xanthomonas campestris pv. campestris, the black rot pathogen.  

PubMed Central

Two proteases (PRT1 and PRT2) were fractionated from culture supernatants of wild-type Xanthomonas campestris pv. campestris by cation-exchange chromatography on SP-5PW. Inhibitor experiments showed that PRT 1 was a serine protease which required calcium ions for activity or stability or both and that PRT 2 was a zinc-requiring metalloprotease. PRT 1 and PRT 2 showed different patterns of degradation of beta-casein. The two proteases comprised almost all of the extracellular proteolytic activity of the wild type. A protease-deficient mutant which lacked both PRT 1 and PRT 2 showed considerable loss of virulence in pathogenicity tests when bacteria were introduced into mature turnip leaves through cut vein endings. This suggests that PRT 1 and PRT 2 have a role in black rot pathogenesis. Images

Dow, J M; Clarke, B R; Milligan, D E; Tang, J L; Daniels, M J

1990-01-01

422

[Study on PVA-alginate co-immobilization of Xanthomonas ampelina TS206].  

PubMed

Ice nucleation activity and anti-leaking capability are both important technical parameters in INA (Ice nucleation active bactetia) bacteria immobilization which can be adopted on freezing concentrate. Both PVA and alginate are good medium for immobilization. They can be used on co-immobilization of ice nucleation-active bacteria (Xanthomonas ampelinaTS206). The results showed that quantity of embedding affects ice nucleation activity greatly. The order of importance to comprehensive scores of technical standard should be concentration of Sodium alginate > Boric acid > PVA > CaCl2. The optimized concentration are PVA 8%, sodium alginate 1%, CaCl2 1.1% and boric acid 5%. A conclusion can be draw that ice nucleation activity increases with the number of beads and shows little pertinency with the time of immobilization, whereas anti-leaking capability can be influenced faintly by the number of beads and the time of immobilization. PMID:16276925

Chen, Qingsen; Liu, Jian

2003-08-01

423

Nutritional Studies on Xanthan Production by Xanthomonas campestris NRRL B1459  

PubMed Central

The nutritional requirements of Xanthomonas campestris NRRL B1459 for optimal xanthan production were studied in a chemically defined medium. Of the carbon sources tested, a 4% sucrose or glucose medium yielded the highest xanthan titers. The further addition of certain organic acids, such as succinate, pyruvate, and ?-ketoglutarate, stimulated xanthan production; excess concentrations of these organic acids inhibited xanthan formation. Certain amino acids (e.g., glutamate) and nitrate salts were superior to ammonium salts for xanthan production. Concentrations of these nitrogen sources higher than the optimal levels inhibited xanthan production while stimulating growth. Xanthan production was also sensitive to high concentrations of inorganic phosphate. High xanthan potencies, up to 30 g/kg of broth, were achieved in these shake-flask studies, in which completely defined media were used.

Souw, Peter; Demain, Arnold L.

1979-01-01

424

Discovery and characterization of the major late blight resistance complex in potato: genomic structure, functional diversity, and implications  

Microsoft Academic Search

Potato is the most important non-cereal crop in the world. Late blight, caused by the oomycete pathogen Phytophthora infestans, is the most devastating disease of potato. In the mid-191h century, P. infestans attacked the European potato fields and this resulted in a widespread famine in Ireland. Late blight remains the No.l constraint to potato production and causes a yearly multi-billion

S. Huang

2005-01-01

425

Biosynthesis of the Antimetabolite 6-Thioguanine in Erwinia amylovora Plays a Key Role in Fire Blight Pathogenesis.  

PubMed

Sulfur for fire: The molecular basis for the biosynthesis of the antimetabolite 6-thioguanine (6TG) was unveiled in Erwinia amylovora, the causative agent of fire blight. Bioinformatics, heterologous pathway reconstitution in E.?coli, and mutational analyses indicate that the protein YcfA mediates guanine thionation in analogy to 2-thiouridylase. Assays in?planta and in cell cultures reveal for the first time a crucial role of 6TG in fire blight pathogenesis. PMID:24038828

Coyne, Sébastien; Chizzali, Cornelia; Khalil, Mohammed N A; Litomska, Agnieszka; Richter, Klaus; Beerhues, Ludger; Hertweck, Christian

2013-08-22

426

A simple yeast-based strategy to identify host cellular processes targeted by bacterial effector proteins.  

PubMed

Bacterial effector proteins, which are delivered into the host cell via the type III secretion system, play a key role in the pathogenicity of gram-negative bacteria by modulating various host cellular processes to the benefit of the pathogen. To identify cellular processes targeted by bacterial effectors, we developed a simple strategy that uses an array of yeast deletion strains fitted into a single 96-well plate. The array is unique in that it was optimized computationally such that despite the small number of deletion strains, it covers the majority of genes in the yeast synthetic lethal interaction network. The deletion strains in the array are screened for hypersensitivity to the expression of a bacterial effector of interest. The hypersensitive deletion strains are then analyzed for their synthetic lethal interactions to identify potential targets of the bacterial effector. We describe the identification, using this approach, of a cellular process targeted by the Xanthomonas campestris type III effector XopE2. Interestingly, we discover that XopE2 affects the yeast cell wall and the endoplasmic reticulum stress response. More generally, the use of a single 96-well plate makes the screening process accessible to any laboratory and facilitates the analysis of a large number of bacterial effectors in a short period of time. It therefore provides a promising platform for studying the functions and cellular targets of bacterial effectors and other virulence proteins. PMID:22110728

Bosis, Eran; Salomon, Dor; Sessa, Guido

2011-11-15

427

Within-Species Flagellin Polymorphism in Xanthomonas campestris pv campestris and Its Impact on Elicitation of Arabidopsis FLAGELLIN SENSING2-Dependent Defenses[W  

PubMed Central

Bacterial flagellins have been portrayed as a relatively invariant pathogen-associated molecular pattern. We have found within-species, within-pathovar variation for defense-eliciting activity of flagellins among Xanthomonas campestris pv campestris (Xcc) strains. Arabidopsis thaliana FLAGELLIN SENSING2 (FLS2), a transmembrane leucine-rich repeat kinase, confers flagellin responsiveness. The flg22 region was the only Xcc flagellin region responsible for detectable elicitation of Arabidopsis defense responses. A Val-43/Asp polymorphism determined the eliciting/noneliciting nature of Xcc flagellins (structural gene fliC). Arabidopsis detected flagellins carrying Asp-43 or Asn-43 but not Val-43 or Ala-43, and it responded minimally for Glu-43. Wild-type Xcc strains carrying nonrecognized flagellin were more virulent than those carrying a recognized flagellin when infiltrated into Arabidopsis leaf mesophyll, but this correlation was misleading. Isogenic Xcc fliC gene replacement strains expressing eliciting or noneliciting flagellins grew similarly, both in leaf mesophyll and in hydathode/vascular colonization assays. The plant FLS2 genotype also had no detectable effect on disease outcome when previously untreated plants were infected by Xcc. However, resistance against Xcc was enhanced if FLS2-dependent responses were elicited 1 d before Xcc infection. Prior immunization was not required for FLS2-dependent restriction of Pseudomonas syringae pv tomato. We conclude that plant immune systems do not uniformly detect all flagellins of a particular pathogen species and that Xcc can evade Arabidopsis FLS2-mediated defenses unless the FLS2 system has been activated by previous infections.

Sun, Wenxian; Dunning, F. Mark; Pfund, Christine; Weingarten, Rebecca; Bent, Andrew F.

2006-01-01

428

Genetic characterization of the HrpL regulon of the fire blight pathogen Erwinia amylovora reveals novel virulence factors.  

PubMed

The bacterial pathogen Erwinia amylovora is the causal agent of fire blight, an economically significant disease of apple and pear. Disease initiation by E. amylovora requires the translocation of effector proteins into host cells via the hypersensitive response and pathogenicity (hrp) type III secretion system (T3SS). The alternative sigma factor HrpL positively regulates the transcription of structural and translocated components of the T3SS via hrp promoter elements. To characterize genome-wide HrpL-dependent gene expression in E. amylovora Ea1189, wild-type and Ea1189?hrpL strains were cultured in hrp-inducing minimal medium, and total RNA was compared using a custom microarray designed to represent the annotated genes of E. amylovora ATCC 49946. The results revealed 24 genes differentially regulated in Ea1189?hrpL relative to Ea1189 with fold-change expression ratios greater than 1.5; of these, 19 genes exhibited decreased transcript abundance and five genes showed increased transcript abundance relative to Ea1189. To expand our understanding of the HrpL regulon and to elucidate direct versus indirect HrpL-mediated effects on gene expression, the genome of E. amylovora ATCC 49946 was examined in silico using a hidden Markov model assembled from known Erwinia spp. hrp promoters. This technique identified 15 putative type III novel hrp promoters, seven of which were validated with quantitative polymerase chain reaction based on expression analyses. It was found that HrpL-regulated genes encode all known components of the hrp T3SS, as well as five putative type III effectors. Eight genes displayed apparent indirect HrpL regulation, suggesting that the HrpL regulon is connected to downstream signalling networks. The construction of deletion mutants of three novel HrpL-regulated genes resulted in the identification of additional virulence factors as well as mutants displaying abnormal motility and biofilm phenotypes. PMID:21831138

McNally, R Ryan; Toth, Ian K; Cock, Peter J A; Pritchard, Leighton; Hedley, Pete E; Morris, Jenny A; Zhao, Youfu; Sundin, George W

2011-08-10

429

Bacterial Diseases of Minor Importance  

Technology Transfer Automated Retrieval System (TEKTRAN)

Several bacteria are reported to attack hop infrequently, including a Corynebacterium spp. and Xanthomonas campestris pv. cannabis. Reports of Pseudomonas cannabina as a pathogen of hop can be found in the popular press, although the limited information on this organism in the scientific literature...

430

Identification of two novel hrp-associated genes in the hrp gene cluster of Xanthomonas oryzae pv. oryzae.  

PubMed

We have cloned a hrp gene cluster from Xanthomonas oryzae pv. oryzae. Bacteria with mutations in the hrp region have reduced growth in rice leaves and lose the ability to elicit a hypersensitive response (HR) on the appropriate resistant cultivars of rice and the nonhost plant tomato. A 12,165-bp portion of nucleotide sequence from the presumed left end and extending through the hrpB operon was determined. The region was most similar to hrp genes from Xanthomonas campestris pv. vesicatoria and Ralstonia solanacearum. Two new hrp-associated loci, named hpa1 and hpa2, were located beyond the hrpA operon. The hpa1 gene encoded a 13-kDa glycine-rich protein with a composition similar to those of harpins and PopA. The product of hpa2 was similar to lysozyme-like proteins. Perfect PIP boxes were present in the hrpB and hpa1 operons, while a variant PIP box was located upstream of hpa2. A strain with a deletion encompassing hpa1 and hpa2 had reduced pathogenicity and elicited a weak HR on nonhost and resistant host plants. Experiments using single mutations in hpa1 and hpa2 indicated that the loss of hpa1 was the principal cause of the reduced pathogenicity of the deletion strain. A 1,519-bp insertion element was located immediately downstream of hpa2. Hybridization with hpa2 indicated that the gene was present in all of the strains of Xanthomonas examined. Hybridization experiments with hpa1 and IS1114 indicated that these sequences were detectable in all strains of X. oryzae pv. oryzae and some other Xanthomonas species. PMID:10714988

Zhu, W; MaGbanua, M M; White, F F

2000-04-01

431

The RpfCG two-component system negatively regulates the colonization of sugar cane stalks by Xanthomonas albilineans.  

PubMed

The genome of Xanthomonas albilineans, the causal agent of sugar cane leaf scald, carries a gene cluster encoding a predicted quorum sensing system that is highly related to the diffusible signalling factor (DSF) systems of the plant pathogens Xylella fastidiosa and Xanthomonas campestris. In these latter pathogens, a cluster of regulation of pathogenicity factors (rpf) genes encodes the DSF system and is involved in control of various cellular processes. Mutation of Xanthomonas albilineans rpfF, encoding a predicted DSF synthase, in Florida strain XaFL07-1 resulted in a small reduction of disease severity (DS). Single-knockout mutations of rpfC and rpfG (encoding a predicted DSF sensor and regulator, respectively) had no effect on DS or swimming motility of the pathogen. However, capacity of the pathogen to cause disease was slightly reduced and swimming motility was severely affected when rpfG and rpfC were both deleted. Similar results were obtained when the entire rpfGCF region was deleted. Surprisingly, when the pathogen was mutated in rpfG or rpfC (single or double mutations) it was able to colonize sugar cane spatially more efficiently than the wild-type. Mutation in rpfF alone did not affect the degree of spatial invasion. We conclude that the DSF signal contributes to symptom expression but not to invasion of sugar cane stalks by Xanthomonas albilineans strain XaFL07-1, which is mainly controlled by the RpfCG two-component system. PMID:23538716

Rott, Philippe; Fleites, Laura A; Mensi, Imène; Sheppard, Lauren; Daugrois, Jean-Heinrich; Dow, J Maxwell; Gabriel, Dean W

2013-03-28

432

Analysis of outer membrane vesicle associated proteins isolated from the plant pathogenic bacterium Xanthomonas campestris pv. campestris  

Microsoft Academic Search

BACKGROUND: Outer membrane vesicles (OMVs) are released from the outer membrane of many Gram-negative bacteria. These extracellular compartments are known to transport compounds involved in cell-cell signalling as well as virulence associated proteins, e.g. the cytolysine from enterotoxic E. coli. RESULTS: We have demonstrated that Xanthomonas campestris pv. campestris (Xcc) releases OMVs into the culture supernatant during growth. A proteome

Vishaldeep K Sidhu; Frank-Jörg Vorhölter; Karsten Niehaus; Steven A Watt

2008-01-01

433

Isolation of an insertion sequence (IS1051) from Xanthomonas campestris pv. dieffenbachiae with potential use for strain identification and characterization.  

PubMed Central

A new insertion sequence was isolated from Xanthomonas campestris pv. dieffenbachiae. Sequence analysis showed that this element is 1,158 bp long and has 15-bp inverted repeat ends containing two mismatches. Comparison of this sequence with sequences in data bases revealed significant homology with Escherichia coli IS5. IS1051, which detected multiple restriction fragment length polymorphisms, was used as a probe to characterize strains from the pathovar dieffenbachiae. Images

Berthier, Y; Thierry, D; Lemattre, M; Guesdon, J L

1994-01-01

434

Chemical modulation of physiological adaptation and cross-protective responses against oxidative stress in soil bacterium and phytopathogen, Xanthomonas  

Microsoft Academic Search

Soil bacteria need to adapt quickly to changes in the environmental conditions. Physiological adaptation plays an important\\u000a role in microbial survival, especially under stressful conditions. Here the abilities of chemicals and pesticides to modulate\\u000a physiological adaptive and cross-protective responses, that make the bacteria more resistant to oxidative stress, are examined\\u000a in the soil bacterium and phytopathogen, Xanthomonas. The genetic basis

Skorn Mongkolsuk; James M. Dubbs; Paiboon Vattanaviboon

2005-01-01

435

Hsp70 and Hsp90 expression in citrus and pepper plants in response to Xanthomonas axonopodis pv. citri  

Microsoft Academic Search

Hsp70 and Hsp90 expression in response to high and low temperatures was studied in orange, the host plant of Xanthomonas axonopodis pv. citri and in a non-host resistant plant, pepper. As expected in both plants, the expression of these chaperones was induced at\\u000a high temperatures while at cold temperatures the response was chaperone and plant-dependent. Expression of Hsp70 and Hsp90

Betiana S. Garavaglia; Cecilia G. Garofalo; Elena G. Orellano; Jorgelina Ottado

2009-01-01

436

Interactive Effects of pH and Temperature on Cell Growth and Polymer Production by Xanthomonas campestris  

Microsoft Academic Search

An experimental statistical design was used to determine pH and temperature optima for growth and polymer production by Xanthomonas campestris. A pH between 6·0-7·5 and a temperature between 25–27°C were optimal for growth. While for xanthan production and broth consistency index, the pH and temperature optimal ranges were between 7·0-8·0 and 25–30°C, respectively. At these optimal ranges a cell concentration

M. Eugénia Esgalhado; J. Carlos Roseiro; M. T. Amaral Collaço

1995-01-01

437

A “defeated” rice resistance gene acts as a QTL against a virulent strain of Xanthomonas oryzae pv. oryzae  

Microsoft Academic Search

The genetic components responsible for qualitative and quantitative resistance of rice plants to three strains (CR4, CXO8,\\u000a and CR6) of Xanthomonas oryzae pv. oryzae (Xoo) were investigated using a set of 315 recombinant inbred lines (RILs) from the cross Lemont (japonica) × Teqing (indica) and a complete linkage map with 182 well distributed RFLP markers. We mapped a major gene

Z.-K. Li; L. J. Luo; H. W. Mei; A. H. Paterson; X. H. Zhao; D. B. Zhong; Y. P. Wang; X. Q. Yu; L. Zhu; R. Tabien; J. W. Stansel; C. S. Ying

1999-01-01

438

Cloning of genes involved in negative regulation of production of extracellular enzymes and polysaccharide of Xanthomonas campestris pathovar campestris  

Microsoft Academic Search

A recombinant plasmid pIJ3079 contains DNA sequences from Xanthomonas campestris pv campestris involved in coordinate negative regulation of production of the extracellular enzymes protease, endoglucanase, amylase and polygalacturonate lyase, and extracellular polysaccharide (EPS). Wild-type bacteria harbouring pIJ3079 and therefore carrying extra copies of the gene(s) therein showed reduced enzyme and EPS production and reduced aggresiveness to plants. Localised Tn5 mutagenesis

Ji-Liang Tang; Clare L. Gough; Michael J. Daniels

1990-01-01

439

Effects of yeast extract and glucose on xanthan production and cell growth in batch culture of Xanthomonas campestris  

Microsoft Academic Search

Although available kinetic data provide a useful insight into the effects of medium composition on xanthan production by\\u000a Xanthomonas campestris, they cannot account for the synergetic effects of carbon (glucose) and nitrogen (yeast extract) substrates on cell growth\\u000a and xanthan production. In this work, we studied the effects of the glucose\\/yeast-extract ratio (G\\/YE) in the medium on cell\\u000a growth and

Yang-Ming Lo; Shang-Tian Yang; David B. Min

1997-01-01

440

Crystal Structures and Mutagenesis of Sucrose Hydrolase from Xanthomonas axonopodis pv. glycines: Insight into the Exclusively Hydrolytic Amylosucrase Fold  

Microsoft Academic Search

Neisseria polysaccharea amylosucrase (NpAS), a transglucosidase of glycoside hydrolase family 13, is a hydrolase and glucosyltransferase that catalyzes the synthesis of amylose-like polymer from a sucrose substrate. Recently, an NpAS homolog from Xanthomonas axonopodis pv. glycines was identified as a member of the newly defined carbohydrate utilization locus that regulates the utilization of plant sucrose in phytopathogenic bacteria. Interestingly, this

Myung-Il Kim; Hong-Suk Kim; Jin Jung; Sangkee Rhee

2008-01-01

441

Effect of Cultural Practices, Soil Phosphorus, Potassium, and pH on the Incidence of Fusarium Head Blight and Deoxynivalenol Levels in Wheat  

PubMed Central

In a survey conducted in 1984 in Essex, Lambton, and Middlesex Counties of Ontario, Canada, greater incidences of head blight and greater concentrations of deoxynivalenol in grain were observed in fields of winter wheat planted after corn than in those planted after soybeans, barley, and mixed grains. Neither head blight nor deoxynivalenol level were correlated significantly with soil P, K, or pH. Head blight was reduced in wheat planted after corn where the residues from a preceding corn crop were plowed down or where seed was treated with Vitaflo 280. However, head blight and deoxynivalenol levels were not affected significantly by the level of N application, cultivar, other diseases or herbicides.

Teich, A. H.; Hamilton, J. R.

1985-01-01

442

Characterization of mutants of the chestnut blight fungus ( Cryphonectria parasitica ) with unusual hypovirus symptoms  

Microsoft Academic Search

The type virus of the family Hypoviridae,\\u000a Cryphonectria hypovirus 1 strain EP713 (CHV1-EP713), infects Cryphonectria parasitica, the filamentous causal fungus of chestnut blight, and reduces its virulence. This pathosystem serves as a model to study\\u000a fungus-mycovirus interactions. We previously developed a genetic screening protocol for host factors associated with symptom\\u000a induction by CHV1-EP713 and its mutants. In the procedure the

Masatoshi Izumimoto; Nobuhiro Suzuki

2008-01-01

443

Passalora blight of anise ( Pimpinella anisum ) and its control in Turkey  

Microsoft Academic Search

Passalora blight of anise, caused byPassalora malkoffii (Bubák) U. Braun, is an important disease of anise in Turkey. The disease affects all the aboveground parts of plants including\\u000a flower clusters. Infected seeds have dark, linear stromata. Detection of the pathogen on seeds was studied by the blotter\\u000a method, agar method, washing test and sowing infected seeds in disease-free soils. The

K. ERzurum; F. Demirci; A. Karakaya; E. Çak?r; G. Tuncer; S. Maden

2005-01-01

444

A method for estimating the loss in tuber yield caused by late blight of potato  

Microsoft Academic Search

A method was developed for estimating tuber yield losses caused by late blight of potato (Phytophthora infestans) (Mont.) de Bary. The method is based on yield and disease data collected for the varieties Green Mountain and Katahdin grown\\u000a in eastern Canada during the period 1953–1970. The percentage yield loss can be calculated for any disease progress curve.\\u000a The estimated loss

W. C. James; C. S. Shih; L. C. Callbeck; W. A. Hodgson

1971-01-01

445

Characterization and distribution of mating type genes in the Dothistroma needle blight pathogens  

Microsoft Academic Search

Dothistroma septosporum and D. pini are the two causal agents of Dothistroma needle blight of Pinus spp. in natural forests and plantations. Degenerate primers amplified portions of mating type genes (MAT1-1-1 and MAT1-2) and chromosome walking was applied to obtain the full-length genes in both species. The mating-type-specific primers designed in this study could distinguish between the morphologically similar D.

Marizeth Groenewald; Irene Barnes; Rosie E. Bradshaw; Anna V. Brown; Angie Dale; Johannes Z. Groenewald; Kathy J. Lewis; Brenda D. Wingfield; Michael J. Wingfield; Pedro W. Crous

2007-01-01

446

Antifungal activity of Syzygium cumini against Ascochyta rabiei–the cause of chickpea blight  

Microsoft Academic Search

Aqueous, ethanol and n-hexane extracts from leaves, fruit, root-bark and stem-bark of Syzygium cumini (L.) Skeels were tested for their antifungal activity against Ascochyta rabiei (Pass.) Lab., the cause of blight disease of the chickpea (Cicer arietinum L.). Different concentrations, namely 1, 2, …, 5% of both aqueous and the two organic solvent extracts were used in this study. Aqueous

Khajista Jabeen; Arshad Javaid

2010-01-01

447

Efficacy of Trichoderma harzianum (Rifaii) on inhibition of ascochyta blight disease of chickpea  

Microsoft Academic Search

Trichoderma harzianum is a widely distributed soil fungus that antagonies numerous fungal phytopathogens. In this study, interactions between theT. harzianum isolates andAscochyta rabiei in experiments on agar growth medium were studied. All testedT. harzianum isolates produced metabolite that inhibited growth ofA. rabiei the agent of ascochyta blight disease of chickpea in culture. Isolates ofT. harzianum produced chitinase and ?-1,3-glucanase when

Çi?dem KüÇük; Merih KivanÇ; Engin Kinaci; Gülcan Kinaci

2007-01-01

448

Efficacy of Trichoderma chitinases against Rhizoctonia solani , the rice sheath blight pathogen  

Microsoft Academic Search

Thirty-five strains ofTrichoderma viride andT. harzianum were screened for their antagonistic ability against the rice sheath blight pathogen,Rhizoctonia solani. The strains that inhibited\\/overgrew the phytopathogenic fungus were considered effective. Light microscopic studies showed\\u000a the antagonism of the hyphae of effectiveTrichoderma strains towards their host hyphae. Chitinase activity ofTrichoderma culture filtrates was enhanced, when colloidal chitin was used as the sole

J. Krishnamurthy; R. Samiyappan; P. Vidhyasekaran; S. Nakkeeran; E. Rajeswari; J. A. J. Raja; P. Balasubramanian

1999-01-01

449

Crop Production Factors Associated with Fusarium Head Blight in Spring Wheat in Eastern Saskatchewan  

Microsoft Academic Search

RedSpring(CWRS)wheatclass,FDKgreaterthan0.25% by weight will cause downgrading to CWRS #2, over Fusariumhead blight(FHB) hasbeen increasingin westernregions 1% to CWRS #3, and over 2% to CWRS #4 (Canadian of the Canadian Prairies. The objective of this 4-yr study was to iden- tify crop production factors (CPF), associated with FHB development Grain Commission, 2003). These low tolerance levels rep- in spring wheat (Triticum

M. R. Fernandez; F. Selles; D. Gehl; R. M. DePauw; R. P. Zentner

2005-01-01

450

QTL identification for early blight resistance ( Alternaria solani ) in a Solanum lycopersicum  ×  S. arcanum cross  

Microsoft Academic Search

Alternaria solani (Ellis and Martin) Sorauer, the causal agent of early blight (EB) disease, infects aerial parts of tomato at both seedling\\u000a and adult plant stages. Resistant cultivars would facilitate a sustainable EB management. EB resistance is a quantitatively\\u000a expressed character, a fact that has hampered effective breeding. In order to identify and estimate the effect of genes conditioning\\u000a resistance

R. Chaerani; M. J. M. Smulders; C. G. van der Linden; B. Vosman; P. Stam; R. E. Voorrips

2007-01-01

451

Quantitative trait loci associated with resistance to Fusarium head blight and kernel discoloration in barley  

Microsoft Academic Search

Resistance to Fusarium head blight (FHB), deoxynivalenol (DON) accumulation, and kernel discoloration (KD) in barley are difficult\\u000a traits to introgress into elite varieties because current screening methods are laborious and disease levels are strongly\\u000a influenced by environment. To improve breeding strategies directed toward enhancing these traits, we identified genomic regions\\u000a containing quantitative trait loci (QTLs) associated with resistance to FHB,

R. C. de la Pena; K. P. Smith; F. Capettini; G. J. Muehlbauer; M. Gallo-Meagher; R. Dill-Macky; D. A. Somers; D. C. Rasmusson

1999-01-01

452

Brachypodium distachyon : a new pathosystem to study Fusarium head blight and other Fusarium diseases of wheat  

Microsoft Academic Search

Background  \\u000a Fusarium species cause Fusarium head blight (FHB) and other important diseases of cereals. The causal agents produce trichothecene\\u000a mycotoxins such as deoxynivalenol (DON). The dicotyledonous model species Arabidopsis thaliana has been used to study Fusarium-host interactions but it is not ideal for model-to-crop translation. Brachypodium distachyon (Bd) has been proposed as a new monocotyledonous model species for functional genomic

Antoine Peraldi; Giovanni Beccari; Andrew Steed; Paul Nicholson

2011-01-01

453

Potato cultivars from the Mexican National Program: Sources and durability of resistance against late blight  

Microsoft Academic Search

The Mexican National Potato Program has produced several cultivars with\\u000a high levels of field resistance. We evaluated the durability of\\u000a resistance to potato late blight of a selection of 12 such cultivars\\u000a using data from 1960 to the present. Data were extracted from the field\\u000a notebooks located in the archives of the Mexican National Potato Program\\u000a in the John S.

NJ Grunwald; Mateo A. Cadena Hinojosa; Oswaldo Rubio Covarrubias; AR Pena; John S. Niederhauser; William E. Fry

2002-01-01

454

DNA markers for Fusarium head blight resistance QTLs in two wheat populations  

Microsoft Academic Search

Genetic resistance to Fusarium head blight (FHB), caused by Fusarium graminearum, is necessary to reduce the wheat grain yield and quality losses caused by this disease. Development of resistant cultivars\\u000a has been slowed by poorly adapted and incomplete resistance sources and confounding environmental effects that make screening\\u000a of germplasm difficult. DNA markers for FHB resistance QTLs have been identified and

J. A. Anderson; R. W. Stack; S. Liu; B. L. Waldron; A. D. Fjeld; C. Coyne; B. Moreno-Sevilla; J. Mitchell Fetch; Q. J. Song; P. B. Cregan; R. C. Frohberg

2001-01-01

455

Androgenic response of barley accessions and F1s with Fusarium head blight resistance  

Microsoft Academic Search

Most Fusarium head blight (FHB) resistant barley (Hordeum vulgare L.) accessions perform relatively poorly from an agronomic point of view. Due to the polygenic inheritance of FHB resistance,\\u000a introgression of this complex trait into well-adapted elite germplasm will likely require multiple cycles of hybridization\\u000a and selection to combine resistance and agronomic performance. The use of anther culture to produce doubled

Suzanne Marchand; Gaudéric Fonquerne; Isabelle Clermont; Liette Laroche; Tung Thanh Huynh; François J. Belzile

2008-01-01

456

Bacterial concrete  

NASA Astrophysics Data System (ADS)

Cracks in concrete are inevitable and are one of the inherent weaknesses of concrete. Water and other salts seep through these cracks, corrosion initiates, and thus reduces the life of concrete. So there was a need to develop an inherent biomaterial, a self-repairing material which can remediate the cracks and fissures in concrete. Bacterial concrete is a material, which can successfully remediate cracks in concrete. This technique is highly desirable because the mineral precipitation induced as a result of microbial activities is pollution free and natural. As the cell wall of bacteria is anionic, metal accumulation (calcite) on the surface of the wall is substantial, thus the entire cell becomes crystalline and they eventually plug the pores and cracks in concrete. This paper discusses the plugging of artificially cracked cement mortar using Bacillus Pasteurii and Sporosarcina bacteria combined with sand as a filling material in artificially made cuts in cement mortar which was cured in urea and CaCl2 medium. The effect on the compressive strength and stiffness of the cement mortar cubes due to the mixing of bacteria is also discussed in this paper. It was found that use of bacteria improves the stiffness and compressive strength of concrete. Scanning electron microscope (SEM) is used to document the role of bacteria in microbiologically induced mineral precipitation. Rod like impressions were found on the face of calcite crystals indicating the presence of bacteria in those places. Energy- dispersive X-ray (EDX) spectra of the microbial precipitation on the surface of the crack indicated the abundance of calcium and the precipitation was inferred to be calcite (CaCO3).

Ramakrishnan, Venkataswamy; Ramesh, K. P.; Bang, S. S.

2001-04-01

457

Bacterial tyrosinases.  

PubMed

Tyrosinases are nearly ubiquitously distributed in all domains of life. They are essential for pigmentation and are important factors in wound healing and primary immune response. Their active site is characterized by a pair of antiferromagnetically coupled copper ions, CuA and CuB, which are coordinated by six histidine residues. Such a "type 3 copper centre" is the common feature of tyrosinases, catecholoxidases and haemocycanins. It is also one of several other copper types found in the multi-copper oxidases (ascorbate oxidase, laccase). The copper pair of tyrosinases binds one molecule of atmospheric oxygen to catalyse two different kinds of enzymatic reactions: (1) the ortho-hydroxylation of monophenols (cresolase activity) and (2) the oxidation of o-diphenols to o-diquinones (catecholase activity). The best-known function is the formation of melanins from L-tyrosine via L-dihydroxyphenylalanine (L-dopa). The complicated hydroxylation mechanism at the active centre is still not completely understood, because nothing is known about their tertiary structure. One main reason for this deficit is that hitherto tyrosinases from eukaryotic sources could not be isolated in sufficient quantities and purities for detailed structural studies. This is not the case for prokaryotic tyrosinases from different Streptomyces species, having been intensively characterized genetically and spectroscopically for decades. The Streptomyces tyrosinases are non-modified monomeric proteins with a low molecular mass of ca. 30kDa. They are secreted to the surrounding medium, where they are involved in extracellular melanin production. In the species Streptomyces, the tyrosinase gene is part of the melC operon. Next to the tyrosinase gene (melC2), this operon contains an additional ORF called melC1, which is essential for the correct expression of the enzyme. This review summarizes the present knowledge of bacterial tyrosinases, which are promising models in order to get more insights in structure, enzymatic reactions and functions of "type 3 copper" proteins in general. PMID:16423650

Claus, Harald; Decker, Heinz

2005-09-06

458

Characteristics of Hypovirulent Strains of Chestnut Blight Fungus, Cryphonectria parasitica, Isolated in Korea  

PubMed Central

Chestnut blight disease caused by Cryphonectria parasitica is widely distributed throughout chestnut tree plantations in Korea. We surveyed 65 sites located at 9 provinces in South Korea, and isolated 248 virulent and 3 hypovirulent strains of chestnut blight fungus. Hypovirulent strains had dsRNA virus in the cytoplasm, which is one of the typical characteristics of hypovirulent strains. In addition, they showed more characteristics of hypovirulent strains, i.e., suppressed conidiation, reduced pigmentation in colony color, and reduced phenol oxidase activity as well as reduced pathogenicity. Hypovirulent strains, KCPH-22, KCPH-135 and KCPH-136, had a genomic dsRNA band with the molecular weight of 12.7 kb, which is the L-dsRNA of CHV1. They also had a 2.7 kb defective dsRNA band. Single conidia isolated from hypovirulent strains were cultured and various phenotypes and absence of dsRNA bands were obtained from single conidial cultures, which means that hypovirulence transmission is unstable in asexual reproduction and variations in viral heredity by asexual reproduction. Biocontrol trial using hypovirulent strains was also carried out in the chestnut tree plantations, and canker expansion in the treated trees was stopped and healed by callus formation at the margin of the canker. These results show the potentials in successful biocontrol of chestnut blight if the vegetatively compatible hypovirulent strains could be directly used around the canker formed by compatible virulent strains.

Lee, Sang Hyun; Moon, Byung Ju

2006-01-01

459

Enhanced resistance to early blight in transgenic tomato lines expressing heterologous plant defense genes.  

PubMed

Genes coding for an iris ribosomal-inactivating protein (I-RIP), a maize beta-glucanase (M-GLU), and a Mirabilis jalapa antimicrobial peptide (Mj-AMP1) were separately introduced into tomato (Lycopersicon esculentum cv. Sweet Chelsea) cotyledons via Agrobacterium tumefaciens-mediated transformation. Transgenic lines carrying each of the transgenes were confirmed for integration into the tomato genome using Southern blot hybridization. Transcription of I-RIP, M-GLU, and Mj-AMP1 genes in various transgenic lines was determined using Northern blot analysis. Plants of selected transgenic lines were inoculated with a 2-3x10(4) conidial spores/ml suspension of the fungal pathogen Alternaria solani, the causal agent of tomato early blight. Compared to control (non-transformed) plants, two transgenic lines carrying either a M-GLU or Mj-AMP1 showed enhanced resistance to early blight disease. None of the four lines carrying the I-RIP transgene showed increased resistance to early blight. PMID:16047198

Schaefer, Scott C; Gasic, Ksenija; Cammue, Bruno; Broekaert, Willem; van Damme, Els J M; Peumans, Willy J; Korban, Schuyler S

2005-07-27

460

Future Prospects for Ascochyta Blight Resistance Breeding in Cool Season Food Legumes  

PubMed Central

Legume cultivation is strongly hampered by the occurrence of ascochyta blights. Strategies of control have been developed but only marginal successes achieved. Breeding for disease resistance is regarded the most cost efficient method of control. Significant genetic variation for disease resistance exists in most legume crops with numerous germplasm lines maintained, providing an excellent resource for plant breeders. Fast and reliable screening methods have been adjusted to fulfill breeding program needs. However, the complex inheritance controlled quantitatively by multiple genes, has been difficult to manipulate. Successful application of biotechnology to ascochyta blight resistance breeding in legume crops will facilitate a good biological knowledge both of the crops–pathogen interaction and of the mechanisms underlying resistance. The current focus in applied breeding is leveraging biotechnological tools to develop more and better markers to speed up the delivery of improved cultivars to the farmer. To date, however, progress in marker development and delivery of useful markers has been slow in most legumes. The limited saturation of the genomic regions bearing putative QTLs in legume crops makes difficult to identify the most tightly linked markers and to determine the accurate position of QTLs. The application of next generation sequencing technologies will contribute to the development of new markers and the identification of candidate genes for ascochyta blight resistance.

Rubiales, D.; Fondevilla, S.

2012-01-01

461

Bacterial start site prediction  

Microsoft Academic Search

With the growing number of completely sequenced bacterial genes, accurate gene prediction in bacterial genomes remains an important problem. Although the existing tools predict genes in bacterial genomes with high overall accuracy, their ability to pinpoint the translation start site remains unsatisfactory. In this paper, we present a novel approach to bacterial start site prediction that takes into account multiple

Sridhar S. Hannenhalli; William S. Hayes; Artemis G. Hatzigeorgiou; James W. Fickett

1999-01-01

462

Small RNA sX13: A Multifaceted Regulator of Virulence in the Plant Pathogen Xanthomonas  

PubMed Central

Small noncoding RNAs (sRNAs) are ubiquitous posttranscriptional regulators of gene expression. Using the model plant-pathogenic bacterium Xanthomonas campestris pv. vesicatoria (Xcv), we investigated the highly expressed and conserved sRNA sX13 in detail. Deletion of sX13 impinged on Xcv virulence and the expression of genes encoding components and substrates of the Hrp type III secretion (T3S) system. qRT-PCR analyses revealed that sX13 promotes mRNA accumulation of HrpX, a key regulator of the T3S system, whereas the mRNA level of the master regulator HrpG was unaffected. Complementation studies suggest that sX13 acts upstream of HrpG. Microarray analyses identified 63 sX13-regulated genes, which are involved in signal transduction, motility, transcriptional and posttranscriptional regulation and virulence. Structure analyses of in vitro transcribed sX13 revealed a structure with three stable stems and three apical C-rich loops. A computational search for putative regulatory motifs revealed that sX13-repressed mRNAs predominantly harbor G-rich motifs in proximity of translation start sites. Mutation of sX13 loops differentially affected Xcv virulence and the mRNA abundance of putative targets. Using a GFP-based reporter system, we demonstrated that sX13-mediated repression of protein synthesis requires both the C-rich motifs in sX13 and G-rich motifs in potential target mRNAs. Although the RNA-binding protein Hfq was dispensable for sX13 activity, the hfq mRNA and Hfq::GFP abundance were negatively regulated by sX13. In addition, we found that G-rich motifs in sX13-repressed mRNAs can serve as translational enhancers and are located at the ribosome-binding site in 5% of all protein-coding Xcv genes. Our study revealed that sX13 represents a novel class of virulence regulators and provides insights into sRNA-mediated modulation of adaptive processes in the plant pathogen Xanthomonas.

Schmidtke, Cornelius; Abendroth, Ulrike; Brock, Juliane; Serrania, Javier; Becker, Anke; Bonas, Ulla

2013-01-01

463

Comparative Aspects of Some Bacterial Dehydrogenases and Transhydrogenases1  

PubMed Central

Ragland, T. E. (Brandeis University, Waltham, Mass.), T. Kawasaki, and J. M. Lowenstein. Comparative aspects of some bacterial dehydrogenases and transhydrogenases. J. Bacteriol. 91:236–244. 1966.—Twenty-eight diverse bacterial species were surveyed for the activities and coenzyme specificities of four enzymes: isocitrate dehydrogenase (ICDH), glucose-6-phosphate dehydrogenase (G-6-PDH), 6-phosphogluconate dehydrogenase (6-PGDH), and reduced nicotinamide adenine dinucleotide phosphate-nicotinamide adenine dinucleotide (NAD) transhydrogenase (TH). Most of the species that exhibited a nicotinamide adenine dinucleotide phosphate (NADP)-linked ICDH also showed significant TH activity, but there were several which did not. Only one of the organisms tested, Xanthomonas pruni, had an ICDH active with both NAD and NADP; it was devoid of TH activity. Acetobacter suboxydans, which lacks ICDH altogether, also had no TH. Some of the species examined had G-6-PDH or 6-PGDH (or both) of dual coenzyme specificity, but there was no apparent relation between these findings and the presence or absence of TH. The TH reaction was assayed by use of analogues of NAD as acceptors. The bacteria could be divided into two groups on the basis of TH specificity, one group reacting at a much faster rate with the 3-acetylpyridine analogue of NAD than with the thionicotinamide analogue, whereas the converse was true for the other group. A few organisms showed no marked specificity for either analogue. This division of specificity can be related to the currently accepted taxonomic classification of the organisms, although a few apparent anomalies were found.

Ragland, T. E.; Kawasaki, T.; Lowenstein, J. M.

1966-01-01

464

Role of temperature and free moisture in onion flower blight. [Botrytis squamosa; Botrytis cinerea; and Botrytis allii  

SciTech Connect

The cardinal temperatures at which onion umbels were blighted (after inoculation when two-thirds of the florets were open) with Botrytis squamosa, B. cinerea, and B. allii (isolated from blighted onion florets) were near 9, 21, and 27 C for B. squamosa, near 12, 21, and 30 C for B. cinerea, and near 9, 24, and 30 C for B. allii. The cardinal temperatures for mycelial growth (potato-dextrose agar) of B. squamosa, B. cinerea, and B. allii were near 5, 22, and 30 C for each fungus. The cardinal temperatures for conidial germination (on purified water agar) were near 6, 15, and 30 C for B. squamosa; 3, 18, and 33 C for B. cinerea; and 6, 24, and 33 C for B. allii. When the duration of free moisture on umbels after inoculation with the three pathogens was increased from 0 to 96 hr. the percentages of unopened florets, open florets, and immature seed capsules blighted at 21 C were increased significantly. Free moisture durations of 12-24, 6-12, and 6-12 hr were necessary for blighting of unopen florets, open florets, and immature seed capsules, respectively, by each pathogen at 21 C. A positive correlation between the amount of July rainfall and the natural incidence of onion flower blight was observed in Orange County, New York, from 1976 to 1981. 10 references, 2 figures, 1 table.

Ramsey, G.R.; Lorbeer, J.W.

1986-06-01

465

Effects of latent infection, temperature, precipitation, and irrigation on panicle and shoot blight of pistachio in california.  

PubMed

ABSTRACT Panicle and shoot blight, caused by a Fusicoccum sp., is an economically important disease of pistachio in California. Between 1999 and 2001, the disease severity was monitored throughout the growing season in 10 pistachio orchards, irrigated with drip, microsprinklers, low-angled (12 degrees ) sprinklers, or flood. The effect of temperature, precipitation pattern, irrigation system, and incidence of Fusicoccum sp. latent infection on panicle and shoot blight severity was quantified with a generalized linear model for repeated measures. The number of continuous rainy days in April and May and the cumulative daily mean temperatures from June to early September had a significant positive effect on panicle and shoot blight of pistachio leaves and fruit. Drip irrigation significantly decreased disease risk. Other factors, such as the number of discontinuous rainy days in April and May, the cumulative deviation from the 30-year average temperature during the dry days of April and May, the incidence of latent infection (only on leaves), and irrigation with microsprinklers or lowangled (12 degrees ) sprinklers were weak explanatory variables of panicle and shoot blight severity. Knowledge of panicle and shoot blight risk may contribute significantly to decisions regarding the appropriate application of fungicides, especially in years or fields of low risk. PMID:18944415

Mila, A L; Driever, G F; Morgan, D P; Michailides, T J

2005-08-01

466

Non-Host Defense Response in a Novel Arabidopsis-Xanthomonas citri subsp. citri Pathosystem  

PubMed Central

Citrus canker, caused by Xanthomonas citri subsp. citri (Xcc), is one of the most destructive diseases of citrus. Progress of breeding citrus canker-resistant varieties is modest due to limited resistant germplasm resources and lack of candidate genes for genetic manipulation. The objective of this study is to establish a novel heterologous pathosystem between Xcc and the well-established model plant Arabidopsis thaliana for defense mechanism dissection and resistance gene identification. Our results indicate that Xcc bacteria neither grow nor decline in Arabidopsis, but induce multiple defense responses including callose deposition, reactive oxygen species and salicylic aicd (SA) production, and defense gene expression, indicating that Xcc activates non-host resistance in Arabidopsis. Moreover, Xcc-induced defense gene expression is suppressed or attenuated in several well-characterized SA signaling mutants including eds1, pad4, eds5, sid2, and npr1. Interestingly, resistance to Xcc is compromised only in eds1, pad4, and eds5, but not in sid2 and npr1. However, combining sid2 and npr1 in the sid2npr1 double mutant compromises resistance to Xcc, suggesting genetic interactions likely exist between SID2 and NPR1 in the non-host resistance against Xcc in Arabidopsis. These results demonstrate that the SA signaling pathway plays a critical role in regulating non-host defense against Xcc in Arabidopsis and suggest that the SA signaling pathway genes may hold great potential for breeding citrus canker-resistant varieties through modern gene transfer technology.

An, Chuanfu; Mou, Zhonglin

2012-01-01

467

Location and cloning of the ketal pyruvate transferase gene of Xanthomonas campestris.  

PubMed Central

Genes required for xanthan polysaccharide synthesis (xps) are clustered in a DNA region of 13.5 kb in the chromosome of Xanthomonas campestris. Plasmid pCHC3 containing a 12.4-kb insert of xps genes has been suggested to include a gene involved in the pyruvylation of xanthan gum (N.E. Harding, J.M. Cleary, D.K. Cabañas, I. G. Rosen, and K. S. Kang, J. Bacteriol. 169:2854-2861, 1987). An essential step toward understanding the biosynthesis of xanthan gum and to enable genetic manipulation of xanthan structure is the determination of the biochemical function encoded by the xps genes. On the basis of biochemical characterization of an X. campestris mutant which produces pyruvate-free xanthan gum, complementation studies, and heterologous expression, we have identified the gene coding for the ketal pyruvate transferase (kpt) enzyme. This gene was located on a 1.4-kb BamHI fragment of pCHC3 and cloned in the broad-host-range cloning vector pRK404. An X. campestris kpt mutant was constructed by mini-Mu(Tetr) mutagenesis of the cloned gene and then by recombination of the mutation into the chromosome of the wild-type strain.

Marzocca, M P; Harding, N E; Petroni, E A; Cleary, J M; Ielpi, L

1991-01-01

468

Xanthomonas campestris pv. campestris gum Mutants: Effects on Xanthan Biosynthesis and Plant Virulence  

PubMed Central

Xanthan is an industrially important exopolysaccharide produced by the phytopathogenic, gram-negative bacterium Xanthomonas campestris pv. campestris. It is composed of polymerized pentasaccharide repeating units which are assembled by the sequential addition of glucose-1-phosphate, glucose, mannose, glucuronic acid, and mannose on a polyprenol phosphate carrier (L. Ielpi, R. O. Couso, and M. A. Dankert, J. Bacteriol. 175:2490–2500, 1993). A cluster of 12 genes in a region designated xpsI or gum has been suggested to encode proteins involved in the synthesis and polymerization of the lipid intermediate. However, no experimental evidence supporting this suggestion has been published. In this work, from the biochemical analysis of a defined set of X. campestris gum mutants, we report experimental data for assigning functions to the products of the gum genes. We also show that the first step in the assembly of the lipid-linked intermediate is severely affected by the combination of certain gum and non-gum mutations. In addition, we provide evidence that the C-terminal domain of the gumD gene product is sufficient for its glucosyl-1-phosphate transferase activity. Finally, we found that alterations in the later stages of xanthan biosynthesis reduce the aggressiveness of X. campestris against the plant.

Katzen, Federico; Ferreiro, Diego U.; Oddo, Cristian G.; Ielmini, M. Veronica; Becker, Anke; Puhler, Alfred; Ielpi, Luis

1998-01-01

469

Functional analysis of genes for benzoate metabolism in the albicidin biosynthetic region of Xanthomonas albilineans.  

PubMed

Albicidins are potent DNA-gyrase-inhibiting antibiotics and phytotoxins synthesised by Xanthomonas albilineans. Functions have been deduced for some clustered biosynthetic genes, including a PKS-NRPS megasynthase, methyltransferases and regulatory genes, and resistance genes including a transporter and a gyrase-binding protein. More puzzling is the presence in this cluster of apparent aromatic metabolism genes. Here, we describe functional analysis of several such genes and propose a model for their role. An apparent benzoate CoA ligase (xabE) proved essential for albicidin production and pathogenicity. A neighbouring operon includes genes for p-aminobenzoate (PABA) metabolism. A PABA synthase fusion (pabAB) restored prototrophy in pabA and pabB mutants of Escherichia coli, proving functionality. Inactivation of pabAB increased susceptibility to sulphanilamide but did not block albicidin production. X. albilineans contains a remote pabB gene which evidently supplies enough PABA for albicidin biosynthesis in culture. Additional capacity from pabAB may be advantageous in more demanding environments such as infected plants. Downstream from pabAB are a known resistance gene (albG) and ubiC which encodes a p-hydroxybenzoate (PHBA) synthase. PHBA protects X. albilineans from inhibition by PABA. Therefore, coordinated expression may protect X. albilineans against toxicity of both the PABA intermediate and the albicidin product, under conditions that induce high-level antibiotic biosynthesis. PMID:20437231

Hashimi, Saeed M; Birch, Robert G

2010-05-02

470

A multifunctional polyketide-peptide synthetase essential for albicidin biosynthesis in Xanthomonas albilineans.  

PubMed

Albicidins, a family of potent antibiotics and phytotoxins produced by the sugarcane leaf scald pathogen <