Mining natural variation for maize improvement: Selection on phenotypes and genes

USDA-ARS?s Scientific Manuscript database

Maize is highly genetically and phenotypically diverse. Tropical maize and teosinte are important genetic resources that harbor unique alleles not found in temperate maize hybrids. To access these resources, breeders must be able to extract favorable unique alleles from tropical maize and teosinte f...

Metabolic pathway resources at MaizeGDB

USDA-ARS?s Scientific Manuscript database

Two maize metabolic networks are available at MaizeGDB: MaizeCyc (http://maizecyc.maizegdb.org, also at Gramene) and CornCyc (http://corncyc.maizegdb.org, also at the Plant Metabolic Network). MaizeCyc was developed by Gramene, and CornCyc by the Plant Metabolic Network, both in collaboration with M...

Viruses in maize and Johnsongrass in southern Ohio

USDA-ARS?s Scientific Manuscript database

Two major maize viruses in the United States, Maize dwarf mosaic virus and Maize chlorotic dwarf virus, were first described in Southern Ohio and surrounding regions in the 1960s when they were major problems in maize (Zea mays L.) production. Planting resistant varieties and changing cultural prac...

MaizeGDB: Curation and outreach go hand-in-hand

USDA-ARS?s Scientific Manuscript database

This is a brief synopsis of the formal and informal interactions among MaizeGDB (www.maizegdb.org) and maize researchers; and among MaizeGDB and other stakeholders, especially the MaizeGDB Working Group and farmers growing this important crop. Particular note is made of the efficacy in distribution ...

MaizeGDB: enabling access to basic, translational, and applied research information

USDA-ARS?s Scientific Manuscript database

MaizeGDB is the Maize Genetics and Genomics Database (available online at http://www.maizegdb.org). The MaizeGDB project is not simply an online database and website but rather an information service to maize researchers that supports customized data access and analysis needs to individual research...

Breeder survey, tools, and resources to visualize diversity and pedigree relationships at MaizeGDB

USDA-ARS?s Scientific Manuscript database

In collaboration with maize researchers, the MaizeGDB Team prepared a survey to identify breeder needs for visualizing pedigrees, diversity data, and haplotypes, and distributed it to the maize community on behalf of the Maize Genetics Executive Committee (Summer 2015). We received 48 responses from...

Potential subchronic food safety of the stacked trait transgenic maize GH5112E-117C in Sprague-Dawley rats.

PubMed

Han, Shiwen; Zou, Shiying; He, Xiaoyun; Huang, Kunlun; Mei, Xiaohong

2016-08-01

The food safety of stacked trait genetically modified (GM) maize GH5112E-117C containing insect-resistance gene Cry1Ah and glyphosate-resistant gene G2-aroA was evaluated in comparison to non-GM Hi-II maize fed to Sprague-Dawley rats during a 90-day subchronic feeding study. Three different dietary concentrations (12.5, 25 and 50 %, w/w) of the GM maize were used or its corresponding non-GM maize. No biologically significant differences in the animals' clinical signs, body weights, food consumption, hematology, clinical chemistry, organ weights and histopathology were found between the stacked trait GM maize groups, and the non-GM maize groups. The results of the 90-day subchronic feeding study demonstrated that the stacked trait GM maize GH5112E-117C is as safe as the conventional non-GM maize Hi-II.

Maize-Pathogen Interactions: An Ongoing Combat from a Proteomics Perspective.

PubMed

Pechanova, Olga; Pechan, Tibor

2015-11-30

Maize (Zea mays L.) is a host to numerous pathogenic species that impose serious diseases to its ear and foliage, negatively affecting the yield and the quality of the maize crop. A considerable amount of research has been carried out to elucidate mechanisms of maize-pathogen interactions with a major goal to identify defense-associated proteins. In this review, we summarize interactions of maize with its agriculturally important pathogens that were assessed at the proteome level. Employing differential analyses, such as the comparison of pathogen-resistant and susceptible maize varieties, as well as changes in maize proteomes after pathogen challenge, numerous proteins were identified as possible candidates in maize resistance. We describe findings of various research groups that used mainly mass spectrometry-based, high through-put proteomic tools to investigate maize interactions with fungal pathogens Aspergillus flavus, Fusarium spp., and Curvularia lunata, and viral agents Rice Black-streaked Dwarf Virus and Sugarcane Mosaic Virus.

Maize-Pathogen Interactions: An Ongoing Combat from a Proteomics Perspective

PubMed Central

Pechanova, Olga; Pechan, Tibor

2015-01-01

Maize (Zea mays L.) is a host to numerous pathogenic species that impose serious diseases to its ear and foliage, negatively affecting the yield and the quality of the maize crop. A considerable amount of research has been carried out to elucidate mechanisms of maize-pathogen interactions with a major goal to identify defense-associated proteins. In this review, we summarize interactions of maize with its agriculturally important pathogens that were assessed at the proteome level. Employing differential analyses, such as the comparison of pathogen-resistant and susceptible maize varieties, as well as changes in maize proteomes after pathogen challenge, numerous proteins were identified as possible candidates in maize resistance. We describe findings of various research groups that used mainly mass spectrometry-based, high through-put proteomic tools to investigate maize interactions with fungal pathogens Aspergillus flavus, Fusarium spp., and Curvularia lunata, and viral agents Rice Black-streaked Dwarf Virus and Sugarcane Mosaic Virus. PMID:26633370

Identification of Genetic Differentiation between Waxy and Common Maize by SNP Genotyping

PubMed Central

Hao, Derong; Zhang, Zhenliang; Cheng, Yujing; Chen, Guoqing; Lu, Huhua; Mao, Yuxiang; Shi, Mingliang; Huang, Xiaolan; Zhou, Guangfei; Xue, Lin

2015-01-01

Waxy maize (Zea mays L. var. ceratina) is an important vegetable and economic crop that is thought to have originated from cultivated flint maize and most recently underwent divergence from common maize. In this study, a total of 110 waxy and 110 common maize inbred lines were genotyped with 3072 SNPs to evaluate the genetic diversity, population structure, and linkage disequilibrium decay as well as identify putative loci that are under positive selection. The results revealed abundant genetic diversity in the studied panel and that genetic diversity was much higher in common than in waxy maize germplasms. Principal coordinate analysis and neighbor-joining cluster analysis consistently classified the 220 accessions into two major groups and a mixed group with mixed ancestry. Subpopulation structure in both waxy and common maize sets were associated with the germplasm origin and corresponding heterotic groups. The LD decay distance (1500–2000 kb) in waxy maize was lower than that in common maize. Fourteen candidate loci were identified as under positive selection between waxy and common maize at the 99% confidence level. The information from this study can assist waxy maize breeders by enhancing parental line selection and breeding program design. PMID:26566240

Ontogeny of the Maize Shoot Apical Meristem[W][OA

PubMed Central

Takacs, Elizabeth M.; Li, Jie; Du, Chuanlong; Ponnala, Lalit; Janick-Buckner, Diane; Yu, Jianming; Muehlbauer, Gary J.; Schnable, Patrick S.; Timmermans, Marja C.P.; Sun, Qi; Nettleton, Dan; Scanlon, Michael J.

2012-01-01

The maize (Zea mays) shoot apical meristem (SAM) arises early in embryogenesis and functions during stem cell maintenance and organogenesis to generate all the aboveground organs of the plant. Despite its integral role in maize shoot development, little is known about the molecular mechanisms of SAM initiation. Laser microdissection of apical domains from developing maize embryos and seedlings was combined with RNA sequencing for transcriptomic analyses of SAM ontogeny. Molecular markers of key events during maize embryogenesis are described, and comprehensive transcriptional data from six stages in maize shoot development are generated. Transcriptomic profiling before and after SAM initiation indicates that organogenesis precedes stem cell maintenance in maize; analyses of the first three lateral organs elaborated from maize embryos provides insight into their homology and to the identity of the single maize cotyledon. Compared with the newly initiated SAM, the mature SAM is enriched for transcripts that function in transcriptional regulation, hormonal signaling, and transport. Comparisons of shoot meristems initiating juvenile leaves, adult leaves, and husk leaves illustrate differences in phase-specific (juvenile versus adult) and meristem-specific (SAM versus lateral meristem) transcript accumulation during maize shoot development. This study provides insight into the molecular genetics of SAM initiation and function in maize. PMID:22911570

Host Status of Five Weed Species and Their Effects on Pratylenchus zeae Infestation of Maize.

PubMed

Jordaan, E M; De Waele, D

1988-10-01

The host suitability of five of the most common weed species occurring in maize (Zea mays L.) fields in South Africa to Pratylenchus zeae was tested. Based on the number of nematodes per root unit, mealie crotalaria (Crotalaria sphaerocarpa) was a good host; goose grass (Eleusine indica), common pigweed (Amaranthus hybridus), and thorn apple (Datura stramonium) were moderate hosts; and khaki weed (Tagetes minuta) was a poor host. Only the root residues of khaki weed suppressed the P. zeae infestation of subsequently grown maize. When goose grass, khaki weed, and mealie crotalaria were grown in association with maize in soil infested with P. zeae, goose grass and khaki weed severely suppressed maize root development; this resulted in a low number of nematodes per maize root system and a high number of nematodes per maize root unit. Mealie crotalaria did not restrict maize root growth and did not affect nematode densities per maize root system or maize root unit. Special attention should be given to the control of mealie crotalaria, which is a good host for P. zeae, and goose grass, which, in addition to its ability to compete with maize, is also a suitable host for P. zeae.

Host Status of Five Weed Species and Their Effects on Pratylenchus zeae Infestation of Maize

PubMed Central

Jordaan, Elizabeth M.; De Waele, D.

1988-01-01

The host suitability of five of the most common weed species occurring in maize (Zea mays L.) fields in South Africa to Pratylenchus zeae was tested. Based on the number of nematodes per root unit, mealie crotalaria (Crotalaria sphaerocarpa) was a good host; goose grass (Eleusine indica), common pigweed (Amaranthus hybridus), and thorn apple (Datura stramonium) were moderate hosts; and khaki weed (Tagetes minuta) was a poor host. Only the root residues of khaki weed suppressed the P. zeae infestation of subsequently grown maize. When goose grass, khaki weed, and mealie crotalaria were grown in association with maize in soil infested with P. zeae, goose grass and khaki weed severely suppressed maize root development; this resulted in a low number of nematodes per maize root system and a high number of nematodes per maize root unit. Mealie crotalaria did not restrict maize root growth and did not affect nematode densities per maize root system or maize root unit. Special attention should be given to the control of mealie crotalaria, which is a good host for P. zeae, and goose grass, which, in addition to its ability to compete with maize, is also a suitable host for P. zeae. PMID:19290263

Genetic Diversity and Molecular Evolution of Chinese Waxy Maize Germplasm

PubMed Central

Zheng, Hongjian; Wang, Hui; Yang, Hua; Wu, Jinhong; Shi, Biao; Cai, Run; Xu, Yunbi; Wu, Aizhong; Luo, Lijun

2013-01-01

Waxy maize (Zea mays L. var. certaina Kulesh), with many excellent characters in terms of starch composition and economic value, has grown in China for a long history and its production has increased dramatically in recent decades. However, the evolution and origin of waxy maize still remains unclear. We studied the genetic diversity of Chinese waxy maize including typical landraces and inbred lines by SSR analysis and the results showed a wide genetic diversity in the Chinese waxy maize germplasm. We analyzed the origin and evolution of waxy maize by sequencing 108 samples, and downloading 52 sequences from GenBank for the waxy locus in a number of accessions from genus Zea. A sharp reduction of nucleotide diversity and significant neutrality tests (Tajima’s D and Fu and Li’s F*) were observed at the waxy locus in Chinese waxy maize but not in nonglutinous maize. Phylogenetic analysis indicated that Chinese waxy maize originated from the cultivated flint maize and most of the modern waxy maize inbred lines showed a distinct independent origin and evolution process compared with the germplasm from Southwest China. The results indicated that an agronomic trait can be quickly improved to meet production demand by selection. PMID:23818949

The Importance of Maize Management on Dung Beetle Communities in Atlantic Forest Fragments

PubMed Central

Campos, Renata Calixto; Hernández, Malva Isabel Medina

2015-01-01

Dung beetle community structures changes due to the effects of destruction, fragmentation, isolation and decrease in tropical forest area, and therefore are considered ecological indicators. In order to assess the influence of type of maize cultivated and associated maize management on dung beetle communities in Atlantic Forest fragments surrounded by conventional and transgenic maize were evaluated 40 Atlantic Forest fragments of different sizes, 20 surrounded by GM maize and 20 surrounded by conventional maize, in February 2013 and 2014 in Southern Brazil. After applying a sampling protocol in each fragment (10 pitfall traps baited with human feces or carrion exposed for 48 h), a total of 3454 individuals from 44 species were captured: 1142 individuals from 38 species in GM maize surrounded fragments, and 2312 from 42 species in conventional maize surrounded fragments. Differences in dung beetle communities were found between GM and conventional maize communities. As expected for fragmented areas, the covariance analysis showed a greater species richness in larger fragments under both conditions; however species richness was greater in fragments surrounded by conventional maize. Dung beetle structure in the forest fragments was explained by environmental variables, fragment area, spatial distance and also type of maize (transgenic or conventional) associated with maize management techniques. In Southern Brazil’s scenario, the use of GM maize combined with associated agricultural management may be accelerating the loss of diversity in Atlantic Forest areas, and consequently, important ecosystem services provided by dung beetles may be lost. PMID:26694874

The Importance of Maize Management on Dung Beetle Communities in Atlantic Forest Fragments.

PubMed

Campos, Renata Calixto; Hernández, Malva Isabel Medina

2015-01-01

Dung beetle community structures changes due to the effects of destruction, fragmentation, isolation and decrease in tropical forest area, and therefore are considered ecological indicators. In order to assess the influence of type of maize cultivated and associated maize management on dung beetle communities in Atlantic Forest fragments surrounded by conventional and transgenic maize were evaluated 40 Atlantic Forest fragments of different sizes, 20 surrounded by GM maize and 20 surrounded by conventional maize, in February 2013 and 2014 in Southern Brazil. After applying a sampling protocol in each fragment (10 pitfall traps baited with human feces or carrion exposed for 48 h), a total of 3454 individuals from 44 species were captured: 1142 individuals from 38 species in GM maize surrounded fragments, and 2312 from 42 species in conventional maize surrounded fragments. Differences in dung beetle communities were found between GM and conventional maize communities. As expected for fragmented areas, the covariance analysis showed a greater species richness in larger fragments under both conditions; however species richness was greater in fragments surrounded by conventional maize. Dung beetle structure in the forest fragments was explained by environmental variables, fragment area, spatial distance and also type of maize (transgenic or conventional) associated with maize management techniques. In Southern Brazil's scenario, the use of GM maize combined with associated agricultural management may be accelerating the loss of diversity in Atlantic Forest areas, and consequently, important ecosystem services provided by dung beetles may be lost.

Surveying the Maize community for their diversity and pedigree visualization needs to prioritize tool development and curation

PubMed Central

Braun, Bremen L.; Schott, David A.; Portwood, II, John L.; Schaeffer, Mary L.; Harper, Lisa C.; Gardiner, Jack M.; Cannon, Ethalinda K.; Andorf, Carson M.

2017-01-01

Abstract The Maize Genetics and Genomics Database (MaizeGDB) team prepared a survey to identify breeders’ needs for visualizing pedigrees, diversity data and haplotypes in order to prioritize tool development and curation efforts at MaizeGDB. The survey was distributed to the maize research community on behalf of the Maize Genetics Executive Committee in Summer 2015. The survey garnered 48 responses from maize researchers, of which more than half were self-identified as breeders. The survey showed that the maize researchers considered their top priorities for visualization as: (i) displaying single nucleotide polymorphisms in a given region for a given list of lines, (ii) showing haplotypes for a given list of lines and (iii) presenting pedigree relationships visually. The survey also asked which populations would be most useful to display. The following two populations were on top of the list: (i) 3000 publicly available maize inbred lines used in Romay et al. (Comprehensive genotyping of the USA national maize inbred seed bank. Genome Biol, 2013;14:R55) and (ii) maize lines with expired Plant Variety Protection Act (ex-PVP) certificates. Driven by this strong stakeholder input, MaizeGDB staff are currently working in four areas to improve its interface and web-based tools: (i) presenting immediate progenies of currently available stocks at the MaizeGDB Stock pages, (ii) displaying the most recent ex-PVP lines described in the Germplasm Resources Information Network (GRIN) on the MaizeGDB Stock pages, (iii) developing network views of pedigree relationships and (iv) visualizing genotypes from SNP-based diversity datasets. These survey results can help other biological databases to direct their efforts according to user preferences as they serve similar types of data sets for their communities. Database URL: https://www.maizegdb.org PMID:28605768

Diversification, phylogeny and evolution of auxin response factor (ARF) family: insights gained from analyzing maize ARF genes.

PubMed

Wang, Yijun; Deng, Dexiang; Shi, Yating; Miao, Nan; Bian, Yunlong; Yin, Zhitong

2012-03-01

Auxin response factors (ARFs), member of the plant-specific B3 DNA binding superfamily, target specifically to auxin response elements (AuxREs) in promoters of primary auxin-responsive genes and heterodimerize with Aux/IAA proteins in auxin signaling transduction cascade. In previous research, we have isolated and characterized maize Aux/IAA genes in whole-genome scale. Here, we report the comprehensive analysis of ARF genes in maize. A total of 36 ARF genes were identified and validated from the B73 maize genome through an iterative strategy. Thirty-six maize ARF genes are distributed in all maize chromosomes except chromosome 7. Maize ARF genes expansion is mainly due to recent segmental duplications. Maize ARF proteins share one B3 DNA binding domain which consists of seven-stranded β sheets and two short α helixes. Twelve maize ARFs with glutamine-rich middle regions could be as activators in modulating expression of auxin-responsive genes. Eleven maize ARF proteins are lack of homo- and heterodimerization domains. Putative cis-elements involved in phytohormones and light signaling responses, biotic and abiotic stress adaption locate in promoters of maize ARF genes. Expression patterns vary greatly between clades and sister pairs of maize ARF genes. The B3 DNA binding and auxin response factor domains of maize ARF proteins are primarily subjected to negative selection during selective sweep. The mixed selective forces drive the diversification and evolution of genomic regions outside of B3 and ARF domains. Additionally, the dicot-specific proliferation of ARF genes was detected. Comparative genomics analysis indicated that maize, sorghum and rice duplicate chromosomal blocks containing ARF homologs are highly syntenic. This study provides insights into the distribution, phylogeny and evolution of ARF gene family.

MaizeGDB: Global support for maize research through open access information [abstract

USDA-ARS?s Scientific Manuscript database

MaizeGDB is the open-access global repository for maize genetic and genomic information – from single genes that determine nutritional quality to whole genome-scale data for complex traits including yield and drought tolerance. The data and tools at MaizeGDB enable researchers from Ethiopia to Ghan...

Surveying the maize community for their diversity and pedigree visualization needs to prioritize tool development and curation

USDA-ARS?s Scientific Manuscript database

The Maize Genetics and Genomics Database (MaizeGDB) team prepared a survey to identify breeders’ needs for visualizing pedigrees, diversity data, and haplotypes in order to prioritize tool development and curation efforts at MaizeGDB. The survey was distributed to the maize research community on beh...

Maize lethal necrosis (MLN), an emerging threat to maize-based food security in sub-Saharan Africa

USDA-ARS?s Scientific Manuscript database

In sub-Saharan Africa, maize is a staple food and key determinant of food security for smallholder farming communities. Pest and disease outbreaks are key constraints to maize productivity. In September 2011, a serious disease outbreak, later diagnosed as maize lethal necrosis (MLN), was reported on...

A selfish gene governing pollen-pistil compatibility confers reproductive isolation between maize relatives.

PubMed

Kermicle, Jerry L

2006-01-01

Some populations of maize's closest relatives, the annual teosintes of Mexico, are unreceptive to maize pollen. When present in the pistil (silk and ovary) a number of maize genes discriminate against or exclude pollen not carrying the same allele. An analogous gene Tcb1-s was found in some teosinte populations but not in sympatric or parapatric maize. It was polymorphic among populations of teosinte growing wild, but regularly present in populations growing in intimate association with maize as a weed. Introduction of Tcb1-s into maize substantially to fully restored compatibility with Tcb1-s carrying teosintes. Although Tcb1-s pollen can fertilize tcb1 tcb1 maize, it is at a competitive disadvantage relative to tcb1 pollen. Hence, the influence of Tcb1-s on crossability is bidirectional. In the absence of maize, Tcb1-s can increase in teosinte populations without improving their fitness. In the presence of maize, Tcb1-s appears to have been co-opted to provide reproductive isolation for adaptation to a cultivated habitat.

Occurrence of maize detritus and a transgenic insecticidal protein (Cry1Ab) within the stream network of an agricultural landscape

PubMed Central

Tank, Jennifer L.; Rosi-Marshall, Emma J.; Royer, Todd V.; Whiles, Matt R.; Griffiths, Natalie A.; Frauendorf, Therese C.; Treering, David J.

2010-01-01

Widespread planting of maize throughout the agricultural Midwest may result in detritus entering adjacent stream ecosystems, and 63% of the 2009 US maize crop was genetically modified to express insecticidal Cry proteins derived from Bacillus thuringiensis. Six months after harvest, we conducted a synoptic survey of 217 stream sites in Indiana to determine the extent of maize detritus and presence of Cry1Ab protein in the stream network. We found that 86% of stream sites contained maize leaves, cobs, husks, and/or stalks in the active stream channel. We also detected Cry1Ab protein in stream-channel maize at 13% of sites and in the water column at 23% of sites. We found that 82% of stream sites were adjacent to maize fields, and Geographical Information Systems analyses indicated that 100% of sites containing Cry1Ab-positive detritus in the active stream channel had maize planted within 500 m during the previous crop year. Maize detritus likely enters streams throughout the Corn Belt; using US Department of Agriculture land cover data, we estimate that 91% of the 256,446 km of streams/rivers in Iowa, Illinois, and Indiana are located within 500 m of a maize field. Maize detritus is common in low-gradient stream channels in northwestern Indiana, and Cry1Ab proteins persist in maize leaves and can be measured in the water column even 6 mo after harvest. Hence, maize detritus, and associated Cry1Ab proteins, are widely distributed and persistent in the headwater streams of a Corn Belt landscape. PMID:20876106

Occurrence of maize detritus and a transgenic insecticidal protein (Cry1Ab) within the stream network of an agricultural landscape.

PubMed

Tank, Jennifer L; Rosi-Marshall, Emma J; Royer, Todd V; Whiles, Matt R; Griffiths, Natalie A; Frauendorf, Therese C; Treering, David J

2010-10-12

Widespread planting of maize throughout the agricultural Midwest may result in detritus entering adjacent stream ecosystems, and 63% of the 2009 US maize crop was genetically modified to express insecticidal Cry proteins derived from Bacillus thuringiensis. Six months after harvest, we conducted a synoptic survey of 217 stream sites in Indiana to determine the extent of maize detritus and presence of Cry1Ab protein in the stream network. We found that 86% of stream sites contained maize leaves, cobs, husks, and/or stalks in the active stream channel. We also detected Cry1Ab protein in stream-channel maize at 13% of sites and in the water column at 23% of sites. We found that 82% of stream sites were adjacent to maize fields, and Geographical Information Systems analyses indicated that 100% of sites containing Cry1Ab-positive detritus in the active stream channel had maize planted within 500 m during the previous crop year. Maize detritus likely enters streams throughout the Corn Belt; using US Department of Agriculture land cover data, we estimate that 91% of the 256,446 km of streams/rivers in Iowa, Illinois, and Indiana are located within 500 m of a maize field. Maize detritus is common in low-gradient stream channels in northwestern Indiana, and Cry1Ab proteins persist in maize leaves and can be measured in the water column even 6 mo after harvest. Hence, maize detritus, and associated Cry1Ab proteins, are widely distributed and persistent in the headwater streams of a Corn Belt landscape.

A multiplex PCR method of detecting recombinant DNAs from five lines of genetically modified maize.

PubMed

Matsuoka, T; Kuribara, H; Akiyama, H; Miura, H; Goda, Y; Kusakabe, Y; Isshiki, K; Toyoda, M; Hino, A

2001-02-01

Seven lines of genetically modified (GM) maize have been authorized in Japan as foods and feeds imported from the USA. We improved a multiplex PCR method described in the previous report in order to distinguish the five lines of GM maize. Genomic DNA was extracted from GM maize with a silica spin column kit, which could reduce experimental time and improve safety in the laboratory and potentially in the environment. We sequenced recombinant DNA (r-DNA) introduced into GM maize, and re-designed new primer pairs to increase the specificity of PCR to distinguish five lines of GM maize by multiplex PCR. A primer pair for the maize intrinsic zein gene (Ze1) was also designed to confirm the presence of amplifiable maize DNA. The lengths of PCR products using these six primer pairs were different. The Ze1 and the r-DNAs from the five lines of GM maize were qualitatively detected in one tube. The specific PCR bands were distinguishable from each other on the basis of the expected length. The r-DNA could be detected from maize samples containing 0.5% of each of the five lines of GM maize. The sensitivity would be acceptable to secure the verification of non-GMO materials and to monitor the reliability of the labeling system.

Sequence Resources at MaizeGDB with Emphasis on POPcorn: A Project Portal for Corn

USDA-ARS?s Scientific Manuscript database

MaizeGDB is the maize research community’s centralized, long-term repository for genetic and genomic information about the crop plant and model organism Zea mays ssp. mays. The MaizeGDB team endeavors to meet the needs of the maize research community based on feedback and guidance. Recent work has f...

19 CFR 10.57 - Certified seed potatoes, and seed corn or maize.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 19 Customs Duties 1 2010-04-01 2010-04-01 false Certified seed potatoes, and seed corn or maize... Provisions Potatoes, Corn, Or Maize § 10.57 Certified seed potatoes, and seed corn or maize. Claim for classification as seed potatoes under subheading 0701.10.00, as seed corn (maize) under subheading 1005.10...

Diverse chromosomal locations of quantitative trait loci for tolerance to maize chlorotic mottle in five maize populations

USDA-ARS?s Scientific Manuscript database

The recent rapid emergence of maize lethal necrosis (MLN), caused by coinfection of maize with maize chlorotic mottle virus (MCMV) and a second virus usually from the family Potyviridae, is causing extensive losses for farmers in East Africa, Southeast Asia and South America. Although the genetic ba...

19 CFR 10.57 - Certified seed potatoes, and seed corn or maize.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 19 Customs Duties 1 2011-04-01 2011-04-01 false Certified seed potatoes, and seed corn or maize... Provisions Potatoes, Corn, Or Maize § 10.57 Certified seed potatoes, and seed corn or maize. Claim for classification as seed potatoes under subheading 0701.10.00, as seed corn (maize) under subheading 1005.10...

19 CFR 10.57 - Certified seed potatoes, and seed corn or maize.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 19 Customs Duties 1 2014-04-01 2014-04-01 false Certified seed potatoes, and seed corn or maize... Provisions Potatoes, Corn, Or Maize § 10.57 Certified seed potatoes, and seed corn or maize. Claim for classification as seed potatoes under subheading 0701.10.00, as seed corn (maize) under subheading 1005.10...

19 CFR 10.57 - Certified seed potatoes, and seed corn or maize.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 19 Customs Duties 1 2013-04-01 2013-04-01 false Certified seed potatoes, and seed corn or maize... Provisions Potatoes, Corn, Or Maize § 10.57 Certified seed potatoes, and seed corn or maize. Claim for classification as seed potatoes under subheading 0701.10.00, as seed corn (maize) under subheading 1005.10...

19 CFR 10.57 - Certified seed potatoes, and seed corn or maize.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 19 Customs Duties 1 2012-04-01 2012-04-01 false Certified seed potatoes, and seed corn or maize... Provisions Potatoes, Corn, Or Maize § 10.57 Certified seed potatoes, and seed corn or maize. Claim for classification as seed potatoes under subheading 0701.10.00, as seed corn (maize) under subheading 1005.10...

Global Maize Trade and Food Security: Implications from a Social Network Model

PubMed Central

Wu, Felicia; Guclu, Hasan

2013-01-01

In this study, we developed a social network model of the global trade of maize: one of the most important food, feed, and industrial crops worldwide, and critical to food security. We used this model to analyze patterns of maize trade among nations, and to determine where vulnerabilities in food security might arise if maize availability were decreased due to factors such as diversion to non-food uses, climatic factors, or plant diseases. Using data on imports and exports from the United Nations Commodity Trade Statistics Database for each year from 2000 to 2009 inclusive, we summarized statistics on volumes of maize trade between pairs of nations for 217 nations. There is evidence of market segregation among clusters of nations; with three prominent clusters representing Europe, Brazil and Argentina, and the United States. The United States is by far the largest exporter of maize worldwide, while Japan and the Republic of Korea are the largest maize importers. In particular, the star-shaped cluster of the network that represents US maize trade to other nations indicates the potential for food security risks because of the lack of trade these other nations conduct with other maize exporters. If a scenario arose in which US maize could not be exported in as large quantities, maize supplies in many nations could be jeopardized. We discuss this in the context of recent maize ethanol production and its attendant impacts on food prices elsewhere worldwide. PMID:23656551

Global maize trade and food security: implications from a social network model.

PubMed

Wu, Felicia; Guclu, Hasan

2013-12-01

In this study, we developed a social network model of the global trade of maize: one of the most important food, feed, and industrial crops worldwide, and critical to food security. We used this model to analyze patterns of maize trade among nations, and to determine where vulnerabilities in food security might arise if maize availability was decreased due to factors such as diversion to nonfood uses, climatic factors, or plant diseases. Using data on imports and exports from the U.N. Commodity Trade Statistics Database for each year from 2000 to 2009 inclusive, we summarized statistics on volumes of maize trade between pairs of nations for 217 nations. There is evidence of market segregation among clusters of nations; with three prominent clusters representing Europe, Brazil and Argentina, and the United States. The United States is by far the largest exporter of maize worldwide, whereas Japan and the Republic of Korea are the largest maize importers. In particular, the star-shaped cluster of the network that represents U.S. maize trade to other nations indicates the potential for food security risks because of the lack of trade these other nations conduct with other maize exporters. If a scenario arose in which U.S. maize could not be exported in as large quantities, maize supplies in many nations could be jeopardized. We discuss this in the context of recent maize ethanol production and its attendant impacts on food prices elsewhere worldwide. © 2013 Society for Risk Analysis.

Maize variety and method of production

DOEpatents

Pauly, Markus; Hake, Sarah; Kraemer, Florian J

2014-05-27

The disclosure relates to a maize plant, seed, variety, and hybrid. More specifically, the disclosure relates to a maize plant containing a Cal-1 allele, whose expression results in increased cell wall-derived glucan content in the maize plant. The disclosure also relates to crossing inbreds, varieties, and hybrids containing the Cal-1 allele to produce novel types and varieties of maize plants.

Analysis of recombination QTLs, segregation distortion, and epistasis for fitness in maize multiple populations using ultra-high-density markers

USDA-ARS?s Scientific Manuscript database

Understanding the maize genomic features would be useful for the study of genetic diversity and evolution and for maize breeding. Here, we used two maize nested association mapping (NAM) populations separately derived in China (CN-NAM) and the US (US-NAM) to explore the maize genomic features. The t...

Kernel Composition, Starch Structure, and Enzyme Digestibility of Opaque-2 Maize and Quality Protein Maize

USDA-ARS?s Scientific Manuscript database

Objectives of this study were to understand how opaque-2 (o2) mutation and quality protein maize (QPM) affect maize kernel composition and starch structure, property, and enzyme digestibility. Kernels of o2 maize contained less protein (9.6−12.5%) than those of the wild-type (WT) counterparts (12...

How are arbuscular mycorrhizal associations related to maize growth performance during short-term cover crop rotation?

PubMed

Higo, Masao; Takahashi, Yuichi; Gunji, Kento; Isobe, Katsunori

2018-03-01

Better cover crop management options aiming to maximize the benefits of arbuscular mycorrhizal fungi (AMF) to subsequent crops are largely unknown. We investigated the impact of cover crop management methods on maize growth performance and assemblages of AMF colonizing maize roots in a field trial. The cover crop treatments comprised Italian ryegrass, wheat, brown mustard and fallow in rotation with maize. The diversity of AMF communities among cover crops used for maize management was significantly influenced by the cover crop and time course. Cover crops did not affect grain yield and aboveground biomass of subsequent maize but affected early growth. A structural equation model indicated that the root colonization, AMF diversity and maize phosphorus uptake had direct strong positive effects on yield performance. AMF variables and maize performance were related directly or indirectly to maize grain yield, whereas root colonization had a positive effect on maize performance. AMF may be an essential factor that determines the success of cover crop rotational systems. Encouraging AMF associations can potentially benefit cover cropping systems. Therefore, it is imperative to consider AMF associations and crop phenology when making management decisions. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Monitoring of Bt11 and Bt176 genetically modified maize in food sold commercially in Brazil from 2005 to 2007.

PubMed

Dinon, Andréia Z; Bosco, Kenia T; Arisi, Ana Carolina M

2010-07-01

The first genetically modified (GM) maize lines were approved for trading in Brazil after December 2007 and they were T25, MON810, Bt11, NK603 and GA21. The polymerase chain reaction (PCR) method was employed to monitor the presence of Bt11 and nested PCR was used to detect the presence of Bt176 in 81 maize-derived products (maize flour, corn meal, maize flour flakes and polenta) that were sold in Brazilian market from 2005 to 2007, before the release of GM maize in Brazil. The PCR detection limit for Bt11 was 10 g kg(-1) and for nested PCR of Bt176 it was 1 g kg(-1). All Brazilian samples analyzed showed no positive signal for these GM maize events. Bt11 and Bt176 GM maize lines were not detected by specific PCR in 81 maize-derived food samples sold in Brazil from 2005 to 2007, before the commercial release of GM maize in Brazil. These Brazilian food industries were in compliance with the rules stipulated by the current legislation with respect to consumer requirements about GMO labeling.

Occupational Rhinoconjunctivitis due to Maize in a Snack Processor: A Cross-Reactivity Study Between Lipid Transfer Proteins From Different Cereals and Peach.

PubMed

Guillen, Daiana; Barranco, Pilar; Palacín, Arantxa; Quirce, Santiago

2014-09-01

We report the case of a snack processor who developed occupational rhinoconjunctivitis due to maize brand exposure during the extrusion process, and who experienced abdominal pain upon drinking beer. The allergens implicated and the cross-reactivity between non-specific lipid transfer proteins (LTPs) from different cereals and peach were investigated. Skin prick tests and specific IgE to cereal flours, pulmonary functions tests and specific conjunctival and inhalation challenges to maize extract were performed. In vitro studies included IgE immunoblotting and ELISA inhibition assays. Skin prick tests with maize flour, maize brand and wheat flour extracts were positive, whereas serum specific IgE was positive only to maize flour. Specific inhalation challenge (SIC) to maize flour did not elicit an asthmatic reaction; however, conjunctival challenge test with the same extract was positive. Patient's serum recognized IgE-binding bands in the maize and beer extracts corresponding to LTPs. In the ELISA inhibition assays, a significant degree of allergenic cross-reactivity was found between maize and beer LTPs, whereas no cross-reactivity was observed between maize LTP and wheat and peach LTPs.

Pollen-Mediated Gene Flow in Maize: Implications for Isolation Requirements and Coexistence in Mexico, the Center of Origin of Maize.

PubMed

Baltazar, Baltazar M; Castro Espinoza, Luciano; Espinoza Banda, Armando; de la Fuente Martínez, Juan Manuel; Garzón Tiznado, José Antonio; González García, Juvencio; Gutiérrez, Marco Antonio; Guzmán Rodríguez, José Luis; Heredia Díaz, Oscar; Horak, Michael J; Madueño Martínez, Jesús Ignacio; Schapaugh, Adam W; Stojšin, Duška; Uribe Montes, Hugo Raúl; Zavala García, Francisco

2015-01-01

Mexico, the center of origin of maize (Zea mays L.), has taken actions to preserve the identity and diversity of maize landraces and wild relatives. Historically, spatial isolation has been used in seed production to maintain seed purity. Spatial isolation can also be a key component for a strategy to minimize pollen-mediated gene flow in Mexico between transgenic maize and sexually compatible plants of maize conventional hybrids, landraces, and wild relatives. The objective of this research was to generate field maize-to-maize outcrossing data to help guide coexistence discussions in Mexico. In this study, outcrossing rates were determined and modeled from eight locations in six northern states, which represent the most economically important areas for the cultivation of hybrid maize in Mexico. At each site, pollen source plots were planted with a yellow-kernel maize hybrid and surrounded by plots with a white-kernel conventional maize hybrid (pollen recipient) of the same maturity. Outcrossing rates were then quantified by assessing the number of yellow kernels harvested from white-kernel hybrid plots. The highest outcrossing values were observed near the pollen source (12.9% at 1 m distance). The outcrossing levels declined sharply to 4.6, 2.7, 1.4, 1.0, 0.9, 0.5, and 0.5% as the distance from the pollen source increased to 2, 4, 8, 12, 16, 20, and 25 m, respectively. At distances beyond 20 m outcrossing values at all locations were below 1%. These trends are consistent with studies conducted in other world regions. The results suggest that coexistence measures that have been implemented in other geographies, such as spatial isolation, would be successful in Mexico to minimize transgenic maize pollen flow to conventional maize hybrids, landraces and wild relatives.

Pollen-Mediated Gene Flow in Maize: Implications for Isolation Requirements and Coexistence in Mexico, the Center of Origin of Maize

PubMed Central

Gutiérrez, Marco Antonio; Guzmán Rodríguez, José Luis; Horak, Michael J.; Madueño Martínez, Jesús Ignacio; Schapaugh, Adam W.; Stojšin, Duška; Uribe Montes, Hugo Raúl

2015-01-01

Mexico, the center of origin of maize (Zea mays L.), has taken actions to preserve the identity and diversity of maize landraces and wild relatives. Historically, spatial isolation has been used in seed production to maintain seed purity. Spatial isolation can also be a key component for a strategy to minimize pollen-mediated gene flow in Mexico between transgenic maize and sexually compatible plants of maize conventional hybrids, landraces, and wild relatives. The objective of this research was to generate field maize-to-maize outcrossing data to help guide coexistence discussions in Mexico. In this study, outcrossing rates were determined and modeled from eight locations in six northern states, which represent the most economically important areas for the cultivation of hybrid maize in Mexico. At each site, pollen source plots were planted with a yellow-kernel maize hybrid and surrounded by plots with a white-kernel conventional maize hybrid (pollen recipient) of the same maturity. Outcrossing rates were then quantified by assessing the number of yellow kernels harvested from white-kernel hybrid plots. The highest outcrossing values were observed near the pollen source (12.9% at 1 m distance). The outcrossing levels declined sharply to 4.6, 2.7, 1.4, 1.0, 0.9, 0.5, and 0.5% as the distance from the pollen source increased to 2, 4, 8, 12, 16, 20, and 25 m, respectively. At distances beyond 20 m outcrossing values at all locations were below 1%. These trends are consistent with studies conducted in other world regions. The results suggest that coexistence measures that have been implemented in other geographies, such as spatial isolation, would be successful in Mexico to minimize transgenic maize pollen flow to conventional maize hybrids, landraces and wild relatives. PMID:26162097

Significant accumulation of C(4)-specific pyruvate, orthophosphate dikinase in a C(3) plant, rice.

PubMed

Fukayama, H; Tsuchida, H; Agarie, S; Nomura, M; Onodera, H; Ono, K; Lee, B H; Hirose, S; Toki, S; Ku, M S; Makino, A; Matsuoka, M; Miyao, M

2001-11-01

The C(4)-Pdk gene encoding the C(4) enzyme pyruvate, orthophosphate dikinase (PPDK) of maize (Zea mays cv Golden Cross Bantam) was introduced into the C(3) plant, rice (Oryza sativa cv Kitaake). When the intact maize C(4)-Pdk gene, containing its own promoter and terminator sequences and exon/intron structure, was introduced, the PPDK activity in the leaves of some transgenic lines was greatly increased, in one line reaching 40-fold over that of wild-type plants. In a homozygous line, the PPDK protein accounted for 35% of total leaf-soluble protein or 16% of total leaf nitrogen. In contrast, introduction of a chimeric gene containing the full-length cDNA of the maize PPDK fused to the maize C(4)-Pdk promoter or the rice Cab promoter only increased PPDK activity and protein level slightly. These observations suggest that the intron(s) or the terminator sequence of the maize gene, or a combination of both, is necessary for high-level expression. In maize and transgenic rice plants carrying the intact maize gene, the level of transcript in the leaves per copy of the maize C(4)-Pdk gene was comparable, and the maize gene was expressed in a similar organ-specific manner. These results suggest that the maize C(4)-Pdk gene behaves in a quantitatively and qualitatively similar way in maize and transgenic rice plants. The activity of the maize PPDK protein expressed in rice leaves was light/dark regulated as it is in maize. This is the first reported evidence for the presence of an endogenous PPDK regulatory protein in a C(3) plant.

[Nitrogen status diagnosis and yield prediction of spring maize after green manure incorporation by using a digital camera].

PubMed

Bai, Jin-Shun; Cao, Wei-Dong; Xiong, Jing; Zeng, Nao-Hua; Shimizu, Katshyoshi; Rui, Yu-Kui

2013-12-01

In order to explore the feasibility of using the image processing technology to diagnose the nitrogen status and to predict the maize yield, a field experiment with different nitrogen rates with green manure incorporation was conducted. Maize canopy digital images over a range of growth stages were captured by digital camera. Maize nitrogen status and the relationships between image color indices derived by digital camera for maize at different growth stages and maize nitrogen status indicators were analyzed. These digital camera sourced image color indices at different growth stages for maize were also regressed with maize grain yield at maturity. The results showed that the plant nitrogen status for maize was improved by green manure application. The leaf chlorophyll content (SPAD value), aboveground biomass and nitrogen uptake for green manure treatments at different maize growth stages were all higher than that for chemical fertilization treatments. The correlations between spectral indices with plant nitrogen indicators for maize affected by green manure application were weaker than that affected by chemical fertilization. And the correlation coefficients for green manure application were ranged with the maize growth stages changes. The best spectral indices for diagnosis of plant nitrogen status after green manure incorporation were normalized blue value (B/(R+G+B)) at 12-leaf (V12) stage and normalized red value (R/(R+G+B)) at grain-filling (R4) stage individually. The coefficients of determination based on linear regression were 0. 45 and 0. 46 for B/(R+G+B) at V12 stage and R/(R+G+B) at R4 stage respectively, acting as a predictor of maize yield response to nitrogen affected by green manure incorporation. Our findings suggested that digital image technique could be a potential tool for in-season prediction of the nitrogen status and grain yield for maize after green manure incorporation when the suitable growth stages and spectral indices for diagnosis were selected.

Comparative diversity of arthropods on Bt maize and non-Bt maize in two different cropping systems in South Africa.

PubMed

Truter, J; Van Hamburg, H; Van Den Berg, J

2014-02-01

The biodiversity of an agroecosystem is not only important for its intrinsic value but also because it influences ecological functions that are vital for crop production in sustainable agricultural systems and the surrounding environment. A concern about genetically modified (GM) crops is the potential negative impact that such crops could have on diversity and abundance of nontarget organisms, and subsequently on ecosystem functions. Therefore, it is essential to assess the potential environmental risk of the release of a GM crop and to study its effect on species assemblages within that ecosystem. Assessment of the impact of Bt maize on the environment is hampered by the lack of basic checklists of species present in maize agroecosystems. The aims of the study were to compile a checklist of arthropods that occur on maize in South Africa and to compare the diversity and abundance of arthropods and functional groups on Bt maize and non-Bt maize. Collections of arthropods were carried out during two growing seasons on Bt maize and non-Bt maize plants at two localities. Three maize fields were sampled per locality during each season. Twenty plants, each of Bt maize and non-Bt maize, were randomly selected from the fields at each site. The arthropods collected during this study were classified to morphospecies level and grouped into the following functional groups: detritivores, herbivores, predators, and parasitoids. Based on feeding strategy, herbivores and predators were further divided into sucking herbivores or predators (piercing-sucking mouthparts) and chewing herbivores or predators (chewing mouthparts). A total of 8,771 arthropod individuals, comprising 288 morphospecies and presenting 20 orders, were collected. Results from this short-term study indicated that abundance and diversity of arthropods in maize and the different functional guilds were not significantly affected by Bt maize, either in terms of diversity or abundance.

[Effects of reduced N application rate on yield and nutrient uptake and utilization in maize-soybean relay strip intercropping system].

PubMed

Yong, Tai-Wen; Liu, Xiao-Ming; Wen-Yu, Liu; Su, Ben-Ying; Song, Chun; Yang, Feng; Wang, Xiao-Chun; Yang, Wen-Yu

2014-02-01

A field experiment with three N application rates (0, 180, 240 N kg x hm(-2), representing zero, reduced and conventional N application, respectively) and three planting patterns (maize monoculture, soybean monoculture and maize-soybean relay strip intercropping) was conducted to reveal the effects of cropping patterns and N application rates on yield, nutrient uptake and nitrogen use efficiency of maize and soybean. The results showed that the grain yield, N, P and K uptake and harvest index of the intercropped maize reduced slightly compared with the monoculture maize, however these indices of the intercropped soybean increased significantly compared with the monoculture. With the increase in nitrogen fertilizer application, the excellence of relay strip intercropping was weakened in the maize-soybean intercropping system. The grain yield, economic coefficient, N, P and K uptake, harvest index, N agronomy efficiency and N uptake efficiency of maize and soybean increased significantly at the reduced nitrogen rate (180 N kg x hm(-2)), but the rate of soil N contribution declined, compared with the conventional rate of N application by local farmers (240 N kg x hm(-2)). In the reduced nitrogen rate treatment, total soil N and P contents of the maize strip reduced, whereas the total soil N, P and K contents of soybean strip and the total K content of maize strip increased compared with the zero N application treatment. With the reduced N application, the annual total grain yield, N, P and K uptake of above-ground biomass in the maize-soybean relay strip intercropping system were higher than in the monoculture, and the land equivalent ratio (LER) was 2.28. N uptake efficiency of maize in the relay strip intercropping system was 20.2% higher than in the maize monoculture, and the index of soybean was 30.5% lower than in the monoculture. The rate of soil N contribution in the relay strip intercropping system was 20.0% and 8.8% lower than in the maize and soybean monoculture, respectively. The reduced N application in the maize-soybean relay strip intercropping system was helpful to promote annual grain yield and improve N utilization efficiency.

Life-History Traits of Spodoptera frugiperda Populations Exposed to Low-Dose Bt Maize

PubMed Central

Sousa, Fernanda F.; Mendes, Simone M.; Santos-Amaya, Oscar F.; Araújo, Octávio G.; Oliveira, Eugenio E.

2016-01-01

Exposure to Bacillus thuringiensis (Bt) toxins in low- and moderate-dose transgenic crops may induce sublethal effects and increase the rate of Bt resistance evolution, potentially compromising control efficacy against target pests. We tested this hypothesis using the fall armyworm Spodoptera frugiperda, a major polyphagous lepidopteran pest relatively tolerant to Bt notorious for evolving field-relevant resistance to single-gene Bt maize. Late-instar larvae were collected from Bt Cry1Ab and non-Bt maize fields in five locations in Brazil, and their offspring was compared for survival, development, and population growth in rearing environment without and with Cry1Ab throughout larval development. Larval survival on Cry1Ab maize leaves varied from 20 to 80% among the populations. Larvae reared on Cry1Ab maize had seven-day delay in development time in relation to control larvae, and such delay was shorter in offspring of armyworms from Cry1Ab maize. Population growth rates were 50–70% lower for insects continuously exposed to Cry1Ab maize relative to controls, showing the population-level effect of Cry1Ab, which varied among the populations and prior exposure to Cry1Ab maize in the field. In three out of five populations, armyworms derived from Bt maize reared on Cry1Ab maize showed higher larval weight, faster larval development and better reproductive performance than the armyworms derived from non-Bt maize, and one of these populations showed better performance on both Cry1Ab and control diets, indicating no fitness cost of the resistance trait. Altogether, these results indicate that offspring of armyworms that developed on field-grown, single-gene Bt Cry1Ab maize had reduced performance on Cry1Ab maize foliage in two populations studied, but in other three populations, these offspring had better overall performance on the Bt maize foliage than that of the armyworms from non-Bt maize fields, possibly because of Cry1Ab resistance alleles in these populations. Implications of these findings for resistance management of S. frugiperda in Bt crops are discussed. PMID:27243977

Life-History Traits of Spodoptera frugiperda Populations Exposed to Low-Dose Bt Maize.

PubMed

Sousa, Fernanda F; Mendes, Simone M; Santos-Amaya, Oscar F; Araújo, Octávio G; Oliveira, Eugenio E; Pereira, Eliseu J G

2016-01-01

Exposure to Bacillus thuringiensis (Bt) toxins in low- and moderate-dose transgenic crops may induce sublethal effects and increase the rate of Bt resistance evolution, potentially compromising control efficacy against target pests. We tested this hypothesis using the fall armyworm Spodoptera frugiperda, a major polyphagous lepidopteran pest relatively tolerant to Bt notorious for evolving field-relevant resistance to single-gene Bt maize. Late-instar larvae were collected from Bt Cry1Ab and non-Bt maize fields in five locations in Brazil, and their offspring was compared for survival, development, and population growth in rearing environment without and with Cry1Ab throughout larval development. Larval survival on Cry1Ab maize leaves varied from 20 to 80% among the populations. Larvae reared on Cry1Ab maize had seven-day delay in development time in relation to control larvae, and such delay was shorter in offspring of armyworms from Cry1Ab maize. Population growth rates were 50-70% lower for insects continuously exposed to Cry1Ab maize relative to controls, showing the population-level effect of Cry1Ab, which varied among the populations and prior exposure to Cry1Ab maize in the field. In three out of five populations, armyworms derived from Bt maize reared on Cry1Ab maize showed higher larval weight, faster larval development and better reproductive performance than the armyworms derived from non-Bt maize, and one of these populations showed better performance on both Cry1Ab and control diets, indicating no fitness cost of the resistance trait. Altogether, these results indicate that offspring of armyworms that developed on field-grown, single-gene Bt Cry1Ab maize had reduced performance on Cry1Ab maize foliage in two populations studied, but in other three populations, these offspring had better overall performance on the Bt maize foliage than that of the armyworms from non-Bt maize fields, possibly because of Cry1Ab resistance alleles in these populations. Implications of these findings for resistance management of S. frugiperda in Bt crops are discussed.

Row Ratios of Intercropping Maize and Soybean Can Affect Agronomic Efficiency of the System and Subsequent Wheat

PubMed Central

Zhang, Yitao; Liu, Jian; Zhang, Jizong; Liu, Hongbin; Liu, Shen; Zhai, Limei; Wang, Hongyuan; Lei, Qiuliang; Ren, Tianzhi; Yin, Changbin

2015-01-01

Intercropping is regarded as an important agricultural practice to improve crop production and environmental quality in the regions with intensive agricultural production, e.g., northern China. To optimize agronomic advantage of maize (Zea mays L.) and soybean (Glycine max L.) intercropping system compared to monoculture of maize, two sequential experiments were conducted. Experiment 1 was to screening the optimal cropping system in summer that had the highest yields and economic benefits, and Experiment 2 was to identify the optimum row ratio of the intercrops selected from Experiment 1. Results of Experiment 1 showed that maize intercropping with soybean (maize || soybean) was the optimal cropping system in summer. Compared to conventional monoculture of maize, maize || soybean had significant advantage in yield, economy, land utilization ratio and reducing soil nitrate nitrogen (N) accumulation, as well as better residual effect on the subsequent wheat (Triticum aestivum L.) crop. Experiment 2 showed that intercropping systems reduced use of N fertilizer per unit land area and increased relative biomass of intercropped maize, due to promoted photosynthetic efficiency of border rows and N utilization during symbiotic period. Intercropping advantage began to emerge at tasseling stage after N topdressing for maize. Among all treatments with different row ratios, alternating four maize rows with six soybean rows (4M:6S) had the largest land equivalent ratio (1.30), total N accumulation in crops (258 kg ha-1), and economic benefit (3,408 USD ha-1). Compared to maize monoculture, 4M:6S had significantly lower nitrate-N accumulation in soil both after harvest of maize and after harvest of the subsequent wheat, but it did not decrease yield of wheat. The most important advantage of 4M:6S was to increase biomass of intercropped maize and soybean, which further led to the increase of total N accumulation by crops as well as economic benefit. In conclusion, alternating four maize rows with six soybean rows was the optimum row ratio in maize || soybean system, though this needs to be further confirmed by pluri-annual trials. PMID:26061566

Aflatoxin Regulations in a Network of Global Maize Trade

PubMed Central

Wu, Felicia; Guclu, Hasan

2012-01-01

Worldwide, food supplies often contain unavoidable contaminants, many of which adversely affect health and hence are subject to regulations of maximum tolerable levels in food. These regulations differ from nation to nation, and may affect patterns of food trade. We soughtto determine whether there is an association between nations' food safety regulations and global food trade patterns, with implications for public health and policymaking. We developed a network model of maize trade around the world. From maize import/export data for 217 nations from 2000–2009, we calculated basic statistics on volumes of trade; then examined how regulations of aflatoxin, a common contaminant of maize, are similar or different between pairs of nations engaging in significant amounts of maize trade. Globally, market segregation appears to occur among clusters of nations. The United States is at the center of one cluster; European countries make up another cluster with hardly any maize trade with the US; and Argentina, Brazil, and China export maize all over the world. Pairs of nations trading large amounts of maize have very similar aflatoxin regulations: nations with strict standards tend to trade maize with each other, while nations with more relaxed standards tend to trade maize with each other. Rarely among the top pairs of maize-trading nations do total aflatoxin standards (standards based on the sum of the levels of aflatoxins B1, B2, G1, and G2) differ by more than 5 µg/kg. These results suggest that, globally, separate maize trading communities emerge; and nations tend to trade with other nations that have very similar food safety standards. PMID:23049773

Early competition shapes maize whole-plant development in mixed stands

PubMed Central

Evers, Jochem B.

2014-01-01

Mixed cropping is practised widely in developing countries and is gaining increasing interest for sustainable agriculture in developed countries. Plants in intercrops grow differently from plants in single crops, due to interspecific plant interactions, but adaptive plant morphological responses to competition in mixed stands have not been studied in detail. Here the maize (Zea mays) response to mixed cultivation with wheat (Triticum aestivum) is described. Evidence is provided that early responses of maize to the modified light environment in mixed stands propagate throughout maize development, resulting in different phenotypes compared with pure stands. Photosynthetically active radiation (PAR), red:far-red ratio (R:FR), leaf development, and final organ sizes of maize grown in three cultivation systems were compared: pure maize, an intercrop with a small distance (25cm) between maize and wheat plants, and an intercop with a large distance (44cm) between the maize and the wheat. Compared with maize in pure stands, maize in the mixed stands had lower leaf and collar appearance rates, increased blade and sheath lengths at low ranks and smaller sizes at high ranks, increased blade elongation duration, and decreased R:FR and PAR at the plant base during early development. Effects were strongest in the treatment with a short distance between wheat and maize strips. The data suggest a feedback between leaf initiation and leaf emergence at the plant level and coordination between blade and sheath growth at the phytomer level. A conceptual model, based on coordination rules, is proposed to explain the development of the maize plant in pure and mixed stands. PMID:24307719

Maize databases

USDA-ARS?s Scientific Manuscript database

This chapter is a succinct overview of maize data held in the species-specific database MaizeGDB (the Maize Genomics and Genetics Database), and selected multi-species data repositories, such as Gramene/Ensembl Plants, Phytozome, UniProt and the National Center for Biotechnology Information (NCBI), ...

Maize flour fortification in Africa: markets, feasibility, coverage, and costs.

PubMed

Fiedler, John L; Afidra, Ronald; Mugambi, Gladys; Tehinse, John; Kabaghe, Gladys; Zulu, Rodah; Lividini, Keith; Smitz, Marc-Francois; Jallier, Vincent; Guyondet, Christophe; Bermudez, Odilia

2014-04-01

The economic feasibility of maize flour and maize meal fortification in Kenya, Uganda, and Zambia is assessed using information about the maize milling industry, households' purchases and consumption levels of maize flour, and the incremental cost and estimated price impacts of fortification. Premix costs comprise the overwhelming share of incremental fortification costs and vary by 50% in Kenya and by more than 100% across the three countries. The estimated incremental cost of maize flour fortification per metric ton varies from $3.19 in Zambia to $4.41 in Uganda. Assuming all incremental costs are passed onto the consumer, fortification in Zambia would result in at most a 0.9% increase in the price of maize flour, and would increase annual outlays of the average maize flour-consuming household by 0.2%. The increases for Kenyans and Ugandans would be even less. Although the coverage of maize flour fortification is not likely to be as high as some advocates have predicted, fortification is economically feasible, and would reduce deficiencies of multiple micronutrients, which are significant public health problems in each of these countries. © 2013 New York Academy of Sciences.

Contributions of Zea mays subspecies mexicana haplotypes to modern maize.

PubMed

Yang, Ning; Xu, Xi-Wen; Wang, Rui-Ru; Peng, Wen-Lei; Cai, Lichun; Song, Jia-Ming; Li, Wenqiang; Luo, Xin; Niu, Luyao; Wang, Yuebin; Jin, Min; Chen, Lu; Luo, Jingyun; Deng, Min; Wang, Long; Pan, Qingchun; Liu, Feng; Jackson, David; Yang, Xiaohong; Chen, Ling-Ling; Yan, Jianbing

2017-11-30

Maize was domesticated from lowland teosinte (Zea mays ssp. parviglumis), but the contribution of highland teosinte (Zea mays ssp. mexicana, hereafter mexicana) to modern maize is not clear. Here, two genomes for Mo17 (a modern maize inbred) and mexicana are assembled using a meta-assembly strategy after sequencing of 10 lines derived from a maize-teosinte cross. Comparative analyses reveal a high level of diversity between Mo17, B73, and mexicana, including three Mb-size structural rearrangements. The maize spontaneous mutation rate is estimated to be 2.17 × 10 -8 ~3.87 × 10 -8 per site per generation with a nonrandom distribution across the genome. A higher deleterious mutation rate is observed in the pericentromeric regions, and might be caused by differences in recombination frequency. Over 10% of the maize genome shows evidence of introgression from the mexicana genome, suggesting that mexicana contributed to maize adaptation and improvement. Our data offer a rich resource for constructing the pan-genome of Zea mays and genetic improvement of modern maize varieties.

78 FR 21603 - Change in Bank Control Notices; Acquisitions of Shares of a Bank or Bank Holding Company

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-11

..., LP, Mexicio City, Mexico and Rogelio Barrenechea Banzalez, Mexico City, Mexico; Constructora Maiz Mier, S.A. de C.V, Jose Sebastian Maiz Garcia, Carlos Francisco Maiz Garcia and Ricardo Javier Maiz...

MaizeCyc: Metabolic networks in maize

USDA-ARS?s Scientific Manuscript database

MaizeCyc is a catalog of known and predicted metabolic and transport pathways that enables plant researchers to graphically represent the metabolome of maize (Zea mays), thereby supporting integrated systems-biology analysis. Supported analyses include molecular and genetic/phenotypic profiling (e.g...

Field trials to evaluate the effects of transgenic cry1le maize on the community characteristics of arthropod natural enemies

USDA-ARS?s Scientific Manuscript database

Possible non-target effects of transgenic cry1Ie gene maize exerts on natural enemy community biodiversity in the field is unresolved. In the present study, a 2-yr study of transgenic cry1Ie gene maize (Event IE09S034, Bt maize) and its near isoline (Zong 31, non-Bt maize) on natural enemy community...

Screening and Selection of Maize to Enhance Associative Bacterial Nitrogen Fixation 1

PubMed Central

Ela, Stephen W.; Anderson, Mary Ann; Brill, Winston J.

1982-01-01

The ability of maize (corn, Zea mays L.) to support bacterial nitrogen fixation in or on maize roots has been increased, through screening and selection. Isotopic N fixed from 15N2 was found on the roots. The nitrogen-fixing association was found in germplasm from tropical maize, but this activity can be transferred to maize currently used in midwestern United States agriculture. PMID:16662718

Alfalfa (Medicago sativa L.)/maize (Zea mays L.) intercropping provides a feasible way to improve yield and economic incomes in farming and pastoral areas of northeast China.

PubMed

Sun, Baoru; Peng, Yi; Yang, Hongyu; Li, Zhijian; Gao, Yingzhi; Wang, Chao; Yan, Yuli; Liu, Yanmei

2014-01-01

Given the growing challenges to food and eco-environmental security as well as sustainable development of animal husbandry in the farming and pastoral areas of northeast China, it is crucial to identify advantageous intercropping modes and some constraints limiting its popularization. In order to assess the performance of various intercropping modes of maize and alfalfa, a field experiment was conducted in a completely randomized block design with five treatments: maize monoculture in even rows, maize monoculture in alternating wide and narrow rows, alfalfa monoculture, maize intercropped with one row of alfalfa in wide rows and maize intercropped with two rows of alfalfa in wide rows. Results demonstrate that maize monoculture in alternating wide and narrow rows performed best for light transmission, grain yield and output value, compared to in even rows. When intercropped, maize intercropped with one row of alfalfa in wide rows was identified as the optimal strategy and the largely complementary ecological niches of alfalfa and maize were shown to account for the intercropping advantages, optimizing resource utilization and improving yield and economic incomes. These findings suggest that alfalfa/maize intercropping has obvious advantages over monoculture and is applicable to the farming and pastoral areas of northeast China.

Determination of carotenoids in yellow maize, the effects of saponification and food preparations.

PubMed

Muzhingi, Tawanda; Yeum, Kyung-Jin; Russell, Robert M; Johnson, Elizabeth J; Qin, Jian; Tang, Guangwen

2008-05-01

Maize is an important staple food consumed by millions of people in many countries. Yellow maize naturally contains carotenoids which not only provide provitamin A carotenoids but also xanthophylls, which are known to be important for eye health. This study was aimed at 1) evaluating the effect of saponification during extraction of yellow maize carotenoids, 2) determining the major carotenoids in 36 genotypes of yellow maize by high-performance liquid chromatography with a C30 column, and 3) determining the effect of cooking on the carotenoid content of yellow maize. The major carotenoids in yellow maize were identified as all-trans lutein, cis-isomers of lutein, all-trans zeaxanthin, alpha- and beta-cryptoxanthin, all-trans beta-carotene, 9-cis beta-carotene, and 13-cis beta-carotene. Our results indicated that carotenoid extraction without saponification showed a significantly higher yield than that obtained using saponification. Results of the current study indicate that yellow maize is a good source of provitamin A carotenoids and xanthophylls. Cooking by boiling yellow maize at 100 degrees C for 30 minutes increased the carotenoid concentration, while baking at 450 degrees F for 25 minutes decreased the carotenoid concentrations by almost 70% as compared to the uncooked yellow maize flour.

Alfalfa (Medicago sativa L.)/Maize (Zea mays L.) Intercropping Provides a Feasible Way to Improve Yield and Economic Incomes in Farming and Pastoral Areas of Northeast China

PubMed Central

Sun, Baoru; Peng, Yi; Yang, Hongyu; Li, Zhijian; Gao, Yingzhi; Wang, Chao; Yan, Yuli; Liu, Yanmei

2014-01-01

Given the growing challenges to food and eco-environmental security as well as sustainable development of animal husbandry in the farming and pastoral areas of northeast China, it is crucial to identify advantageous intercropping modes and some constraints limiting its popularization. In order to assess the performance of various intercropping modes of maize and alfalfa, a field experiment was conducted in a completely randomized block design with five treatments: maize monoculture in even rows, maize monoculture in alternating wide and narrow rows, alfalfa monoculture, maize intercropped with one row of alfalfa in wide rows and maize intercropped with two rows of alfalfa in wide rows. Results demonstrate that maize monoculture in alternating wide and narrow rows performed best for light transmission, grain yield and output value, compared to in even rows. When intercropped, maize intercropped with one row of alfalfa in wide rows was identified as the optimal strategy and the largely complementary ecological niches of alfalfa and maize were shown to account for the intercropping advantages, optimizing resource utilization and improving yield and economic incomes. These findings suggest that alfalfa/maize intercropping has obvious advantages over monoculture and is applicable to the farming and pastoral areas of northeast China. PMID:25329376

Prevalence of genetically modified rice, maize, and soy in Saudi food products.

PubMed

Elsanhoty, Rafaat M; Al-Turki, A I; Ramadan, Mohamed Fawzy

2013-10-01

Qualitative and quantitative DNA-based methods were applied to detect genetically modified foods in samples from markets in the Kingdom of Saudi Arabia. Two hundred samples were collected from Al-Qassim, Riyadh, and Mahdina in 2009 and 2010. GMOScreen 35S and NOS test kits for the detection of genetically modified organism varieties in samples were used. The positive results obtained from GMOScreen 35S and NOS were identified using specific primer pairs. The results indicated that all rice samples gave negative results for the presence of 35S and NOS terminator. About 26 % of samples containing soybean were positive for 35S and NOS terminator and 44 % of samples containing maize were positive for the presence of 35S and/or NOS terminator. The results showed that 20.4 % of samples was positive for maize line Bt176, 8.8 % was positive for maize line Bt11, 8.8 % was positive for maize line T25, 5.9 % was positive for maize line MON 810, and 5.9 % was positive for StarLink maize. Twelve samples were shown to contain <3 % of genetically modified (GM) soy and 6 samples >10 % of GM soy. Four samples containing GM maize were shown to contain >5 % of GM maize MON 810. Four samples containing GM maize were shown to contain >1 % of StarLink maize. Establishing strong regulations and certified laboratories to monitor GM foods or crops in Saudi market is recommended.

A laboratory assessment of the potential effect of Cry1Ab/Cry2Aj-containing Bt maize pollen on Folsomia candida by toxicological and biochemical analyses.

PubMed

Zhang, Bing; Yang, Yan; Zhou, Xiang; Shen, Ping; Peng, Yufa; Li, Yunhe

2017-03-01

The common soil arthropod Folsomia candida can survive well when fed only maize pollen and thus may be exposed to insecticidal proteins by ingesting insect-resistant genetically engineered maize pollen containing Bacillus thuringiensis (Bt) proteins when being released into the soil. Laboratory experiments were conducted to assess the potential effects of Cry1Ab/Cry2Aj-producing transgenic Bt maize (Shuangkang 12-5) pollen on F. candida fitness. Survival, development, and the reproduction were not significantly reduced when F. candida fed on Bt maize pollen rather than on non-Bt maize pollen, but these parameters were significantly reduced when F. candida fed on non-Bt maize pollen containing the protease inhibitor E-64 at 75 μg/g pollen. The intrinsic rate of increase (r m ) was not significantly reduced when F. candida fed on Bt maize pollen but was significantly reduced when F. candida fed on non-Bt maize pollen containing E-64. The activities of antioxidant-related enzymes in F. candida were not significantly affected when F. candida fed on Bt maize pollen but were significantly increased when F. candida fed on non-Bt pollen containing E-64. The results demonstrate that consumption of Bt maize pollen containing Cry1Ab/Cry2Aj has no lethal or sublethal effects on F. candida. Copyright © 2017 Elsevier Ltd. All rights reserved.

Resistance of Tripsacorn-introgressed maize lines to Sitophilus zeamais

USDA-ARS?s Scientific Manuscript database

The maize weevil, Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae), is one of the major pests of maize worldwide. We tested one Tripsacorn-introgressed inbred maize line and 42 hybrid combinations between eleven public inbred lines and 16 different Tripsacorn-introgressed inbreds for resis...

MaizeGDB: The Maize Genetics and Genomics Database.

USDA-ARS?s Scientific Manuscript database

MaizeGDB is the community database for biological information about the crop plant Zea mays. Genomic, genetic, sequence, gene product, functional characterization, literature reference, and person/organization contact information are among the datatypes stored at MaizeGDB. At the project’s website...

Genetic Mapping of the Leaf Number above the Primary Ear and Its Relationship with Plant Height and Flowering Time in Maize.

PubMed

Cui, Min; Jia, Bo; Liu, Huanhuan; Kan, Xin; Zhang, Yu; Zhou, Ronghua; Li, Zhipeng; Yang, Liang; Deng, Dexiang; Yin, Zhitong

2017-01-01

The leaf number above the primary ear (LA) is a major contributing factor to plant architecture in maize. The yield of leafy maize, which has extra LA compared to normal maize, is higher than normal maize in some regions. One major concern is that increasing LA may be accompanied by increased plant height and/or flowering time. Using an F 2:3 population comprising 192 families derived from a leafy maize line and a normal maize line, an association population comprising 437 inbred maize lines, and a pair of near-isogenic maize lines, we mapped the quantitative trait loci (QTL) associated with LA and assessed its genetic relationship with flowering time and plant height. Ten QTL with an additive and dominant effect, 18 pairs of interacting QTL in the F 2:3 population and seventeen significant SNPs in the association population were detected for LA. Two major QTL, qLA3-4 and qLA7-1 , were repeatedly detected and explained a large proportion of the phenotypic variation. The qLA3-4 was centered on lfy1 , which is a dominant gene underlying extra leaves above the ear in leafy maize. Four LA QTL were found to overlap with flowering time and/or plant height, which suggested that these QTL might have a pleiotropic effect. The pleiotropy of the lfy1 locus on LA, flowering time and plant height were validated by near-isogenic line analysis. These results enhance our understanding of the genetic architecture affecting maize LA and the development of maize hybrids with increased LA.

Exploring karyotype diversity of Argentinian Guaraní maize landraces: Relationship among South American maize

PubMed Central

Poggio, Lidia

2018-01-01

In Argentina there are two different centers of maize diversity, the Northeastern (NEA) and the Northwestern (NWA) regions of the country. In NEA, morphological studies identified 15 landraces cultivated by the Guaraní communities in Misiones Province. In the present study we analyzed the karyotype diversity of 20 populations of Guaraní maize landraces through classical and molecular cytogenetic analyses. Our results demonstrate significant intra and inter-populational variation in the percentage, number, size, chromosome position and frequencies of the heterochromatic blocks, which are called knobs. Knob sequence analysis (180-bp and TR-1) did not show significant differences among Guaraní populations. B chromosomes were not detected, and abnormal 10 (AB10) chromosomes were found with low frequency (0.1≥f ≤0.40) in six populations. Our results allowed karyotypic characterization of each analyzed population, defining for the first time the chromosomal constitution of maize germplasm from NEA. The multivariate analysis (PCoA and UPGMA) of karyotype parameters allowed the distinction between two populations groups: the Popcorn and the Floury maize populations. These results are in agreement with previously published microsatellite and morphological/phenological studies. Finally, we compared our karyotype results with those previously reported for NWA and Central Region of South America maize. Our data suggest that there are important differences between maize from NEA and NWA at the karyotype level, supporting the hypothesis that there are two pathways of input of South America maize. Our results also confirm the existence of two centers of diversification of Argentinian native maize, NWA and NEA. This work contributes new knowledge about maize diversity, which is relevant for future plans to improve commercial maize, and for conservation of agrobiodiversity. PMID:29879173

Exploring karyotype diversity of Argentinian Guaraní maize landraces: Relationship among South American maize.

PubMed

Realini, María Florencia; Poggio, Lidia; Cámara Hernández, Julián; González, Graciela Esther

2018-01-01

In Argentina there are two different centers of maize diversity, the Northeastern (NEA) and the Northwestern (NWA) regions of the country. In NEA, morphological studies identified 15 landraces cultivated by the Guaraní communities in Misiones Province. In the present study we analyzed the karyotype diversity of 20 populations of Guaraní maize landraces through classical and molecular cytogenetic analyses. Our results demonstrate significant intra and inter-populational variation in the percentage, number, size, chromosome position and frequencies of the heterochromatic blocks, which are called knobs. Knob sequence analysis (180-bp and TR-1) did not show significant differences among Guaraní populations. B chromosomes were not detected, and abnormal 10 (AB10) chromosomes were found with low frequency (0.1≥f ≤0.40) in six populations. Our results allowed karyotypic characterization of each analyzed population, defining for the first time the chromosomal constitution of maize germplasm from NEA. The multivariate analysis (PCoA and UPGMA) of karyotype parameters allowed the distinction between two populations groups: the Popcorn and the Floury maize populations. These results are in agreement with previously published microsatellite and morphological/phenological studies. Finally, we compared our karyotype results with those previously reported for NWA and Central Region of South America maize. Our data suggest that there are important differences between maize from NEA and NWA at the karyotype level, supporting the hypothesis that there are two pathways of input of South America maize. Our results also confirm the existence of two centers of diversification of Argentinian native maize, NWA and NEA. This work contributes new knowledge about maize diversity, which is relevant for future plans to improve commercial maize, and for conservation of agrobiodiversity.

Lack of Detectable Allergenicity in Genetically Modified Maize Containing “Cry” Proteins as Compared to Native Maize Based on In Silico & In Vitro Analysis

PubMed Central

Mathur, Chandni; Kathuria, Pooran C.; Dahiya, Pushpa; Singh, Anand B.

2015-01-01

Background Genetically modified, (GM) crops with potential allergens must be evaluated for safety and endogenous IgE binding pattern compared to native variety, prior to market release. Objective To compare endogenous IgE binding proteins of three GM maize seeds containing Cry 1Ab,1Ac,1C transgenic proteins with non GM maize. Methods An integrated approach of in silico & in vitro methods was employed. Cry proteins were tested for presence of allergen sequence by FASTA in allergen databases. Biochemical assays for maize extracts were performed. Specific IgE (sIgE) and Immunoblot using food sensitized patients sera (n = 39) to non GM and GM maize antigens was performed. Results In silico approaches, confirmed for non sequence similarity of stated transgenic proteins in allergen databases. An insignificant (p> 0.05) variation in protein content between GM and non GM maize was observed. Simulated Gastric Fluid (SGF) revealed reduced number of stable protein fractions in GM then non GM maize which might be due to shift of constituent protein expression. Specific IgE values from patients showed insignificant difference in non GM and GM maize extracts. Five maize sensitized cases, recognized same 7 protein fractions of 88-28 kD as IgE bindng in both GM and non-GM maize, signifying absence of variation. Four of the reported IgE binding proteins were also found to be stable by SGF. Conclusion Cry proteins did not indicate any significant similarity of >35% in allergen databases. Immunoassays also did not identify appreciable differences in endogenous IgE binding in GM and non GM maize. PMID:25706412

Bacterial Diversity and Mycotoxin Reduction During Maize Fermentation (Steeping) for Ogi Production

PubMed Central

Okeke, Chiamaka A.; Ezekiel, Chibundu N.; Nwangburuka, Cyril C.; Sulyok, Michael; Ezeamagu, Cajethan O.; Adeleke, Rasheed A.; Dike, Stanley K.; Krska, Rudolf

2015-01-01

Bacterial diversity and community structure of two maize varieties (white and yellow) during fermentation/steeping for ogi production, and the influence of spontaneous fermentation on mycotoxin reduction in the gruel were studied. A total of 142 bacterial isolates obtained at 24–96 h intervals were preliminarily identified by conventional microbiological methods while 60 selected isolates were clustered into 39 OTUs consisting of 15 species, 10 genera, and 3 phyla by 16S rRNA sequence analysis. Lactic acid bacteria constituted about 63% of all isolated bacteria and the genus Pediococcus dominated (white maize = 84.8%; yellow maize = 74.4%). Pediococcus acidilactici and Lactobacillus paraplantarum were found at all steeping intervals of white and yellow maize, respectively, while P. claussenii was present only at the climax stage of steeping white maize. In both maize varieties, P. pentosaceus was found at 24–72 h. Mycotoxin concentrations (μg/kg) in the unsteeped grains were: white maize (aflatoxin B1 = 0.60; citrinin = 85.8; cyclopiazonic acid = 23.5; fumonisins (B1/B2/B3) = 68.4–483; zearalenone = 3.3) and yellow maize (aflatoxins (B1/B2/M1) = 22.7–513; citrinin = 16,800; cyclopiazonic acid = 247; fumonisins (B1/B2/B3) = 252–1,586; zearalenone = 205). Mycotoxins in both maize varieties were significantly (p < 0.05) reduced across steeping periods. This study reports for the first time: (a) the association of L. paraplantarum, P. acidilactici, and P. claussenii with ogi production from maize, (b) citrinin occurrence in Nigerian maize and ogi, and (c) aflatoxin M1, citrinin and cyclopiazonic acid degradation/loss due to fermentation in traditional cereal-based fermented food. PMID:26697001

The Asian corn borer Ostrinia furnacalis feeding increases the direct and indirect defense of mid-whorl stage commercial maize in the field.

PubMed

Guo, Jingfei; Qi, Jinfeng; He, Kanglai; Wu, Jianqiang; Bai, Shuxiong; Zhang, Tiantao; Zhao, Jiuran; Wang, Zhenying

2018-05-13

The Asian corn borer (Ostrinia furnacalis Guenée) is a destructive pest of maize (Zea mays L.). Despite large-scale commercial maize production, little is known about the defensive responses of field-grown commercial maize to O. furnacalis herbivory, and how these responses result in direct and indirect defense against this pest. To elucidate the maize transcriptome response to O. furnacalis feeding, leaves of maize hybrid Jingke968 were infested with O. furnacalis for 0, 2, 4, 12 and 24 h. O. furnacalis feeding elicited stronger and more rapid changes in the defense-related gene expression (i.e. after 2 h), and more differentially expressed genes (DEGs) were up-regulated than down-regulated at all times post induction (i.e. 2, 4, 12 and 24 h) in the O. furnacalis pre-infested maize plants. KEGG pathway analysis indicated that the DEGs in the O. furnacalis pre-infested maize are involved in benzoxazinoids, phytohormones, volatiles, and other metabolic pathways related to maize resistance to herbivores. In addition, the maize leaves previously infested by O. furnacalis for 24 h showed an obvious inhibition of the subsequent O. furnacalis performance, and maize volatiles induced by O. furnacalis feeding for 24 and 48 h attracted the parasitic wasp, Macrocentrus cingulum Brischke. The increased direct and indirect defenses induced by O. furnacalis feeding were correlated with O. furnacalis-induced phytohormones, benzoxazinoids, and volatiles. Together, our findings provide new insights into how commercial maize orchestrates its transcriptome and metabolome to directly and indirectly defend against O. furnacalis at the mid-whorl stage in the field. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Study Progress on Tissue Culture of Maize Mature Embryo

NASA Astrophysics Data System (ADS)

Wang, Hongzhen; Cheng, Jun; Cheng, Yanping; Zhou, Xioafu

It has been paid more and more attention on maize tissue culture as it is a basic work in maize genetic transformation, especially huge breakthrough has been made in maize tissue culture utilizing mature embryos as explants in the recent years. This paper reviewed the study progress on maize tissue culture and plant regeneration utilizing mature embryos as explants from callus induction, subculture, plant regeneration and browning reduction and so on.

Characterization and competitive ability of non-aflatoxigenic Aspergillus flavus isolated from the maize agro-ecosystem in Argentina as potential aflatoxin biocontrol agents.

PubMed

Alaniz Zanon, María Silvina; Clemente, María Paz; Chulze, Sofía Noemí

2018-07-20

Aspergillus flavus is an opportunistic pathogen and may produce aflatoxins in maize, one of the most important crops in Argentina. A promising strategy to reduce aflatoxin accumulation is the biological control based on competitive exclusion. In order to select potential biocontrol agents among isolates from the maize growing region in Argentina, a total of 512 A. flavus strains were isolated from maize kernels and soil samples. Thirty-six per cent of the isolates from maize kernels did not produce detectable levels of aflatoxins, while 73% of the isolates from soil were characterized as non-aflatoxin producers. Forty percent and 49% of the isolates from maize kernels and soil samples, respectively, were not producers of cyclopiazonic acid (CPA). Sclerotia morphology was evaluated using Czapek Dox media. Eighty-six per cent of the isolates from maize kernels and 85% of the isolates from soil samples were L sclerotia morphotype (average diameter > 400 μm). The remaining isolates did not produce sclerotia. All isolates had MAT 1-1 idiomorph. The competitive ability of 9 non aflatoxigenic strains, 4 CPA(+) and 5 CPA(-), was evaluated in co-inoculations of maize kernels with an aflatoxigenic strain. All evaluated strains significantly (p < 0.05) reduced aflatoxin contamination in maize kernels. The aflatoxin B 1 (AFB 1 ) reduction ranged from 6 to 60%. The strain A. flavus ARG5/30 isolated from maize kernels would be a good candidate as a potential biocontrol agent to be used in maize, since it was characterized as neither aflatoxin nor CPA producer, morphotype L, MAT 1-1 idiomorph, and reduced AFB 1 content in maize kernels by 59%. This study showed the competitive ability of potential aflatoxin biocontrol agents to be evaluated under field trials in a maize agro-ecosystem in Argentina. Copyright © 2018 Elsevier B.V. All rights reserved.

Dynamics of maize carbon contribution to soil organic carbon in association with soil type and fertility level.

PubMed

Pei, Jiubo; Li, Hui; Li, Shuangyi; An, Tingting; Farmer, John; Fu, Shifeng; Wang, Jingkuan

2015-01-01

Soil type and fertility level influence straw carbon dynamics in the agroecosystems. However, there is a limited understanding of the dynamic processes of straw-derived and soil-derived carbon and the influence of the addition of straw carbon on soil-derived organic carbon in different soils associated with different fertility levels. In this study, we applied the in-situ carborundum tube method and 13C-labeled maize straw (with and without maize straw) at two cropland (Phaeozem and Luvisol soils) experimental sites in northeast China to quantify the dynamics of maize-derived and soil-derived carbon in soils associated with high and low fertility, and to examine how the addition of maize carbon influences soil-derived organic carbon and the interactions of soil type and fertility level with maize-derived and soil-derived carbon. We found that, on average, the contributions of maize-derived carbon to total organic carbon in maize-soil systems during the experimental period were differentiated among low fertility Luvisol (from 62.82% to 42.90), high fertility Luvisol (from 53.15% to 30.00%), low fertility Phaeozem (from 58.69% to 36.29%) and high fertility Phaeozem (from 41.06% to 16.60%). Furthermore, the addition of maize carbon significantly decreased the remaining soil-derived organic carbon in low and high fertility Luvisols and low fertility Phaeozem before two months. However, the increasing differences in soil-derived organic carbon between both soils with and without maize straw after two months suggested that maize-derived carbon was incorporated into soil-derived organic carbon, thereby potentially offsetting the loss of soil-derived organic carbon. These results suggested that Phaeozem and high fertility level soils would fix more maize carbon over time and thus were more beneficial for protecting soil-derived organic carbon from maize carbon decomposition.

Dynamics of Maize Carbon Contribution to Soil Organic Carbon in Association with Soil Type and Fertility Level

PubMed Central

Pei, Jiubo; Li, Hui; Li, Shuangyi; An, Tingting; Farmer, John; Fu, Shifeng; Wang, Jingkuan

2015-01-01

Soil type and fertility level influence straw carbon dynamics in the agroecosystems. However, there is a limited understanding of the dynamic processes of straw-derived and soil-derived carbon and the influence of the addition of straw carbon on soil-derived organic carbon in different soils associated with different fertility levels. In this study, we applied the in-situ carborundum tube method and 13C-labeled maize straw (with and without maize straw) at two cropland (Phaeozem and Luvisol soils) experimental sites in northeast China to quantify the dynamics of maize-derived and soil-derived carbon in soils associated with high and low fertility, and to examine how the addition of maize carbon influences soil-derived organic carbon and the interactions of soil type and fertility level with maize-derived and soil-derived carbon. We found that, on average, the contributions of maize-derived carbon to total organic carbon in maize-soil systems during the experimental period were differentiated among low fertility Luvisol (from 62.82% to 42.90), high fertility Luvisol (from 53.15% to 30.00%), low fertility Phaeozem (from 58.69% to 36.29%) and high fertility Phaeozem (from 41.06% to 16.60%). Furthermore, the addition of maize carbon significantly decreased the remaining soil-derived organic carbon in low and high fertility Luvisols and low fertility Phaeozem before two months. However, the increasing differences in soil-derived organic carbon between both soils with and without maize straw after two months suggested that maize-derived carbon was incorporated into soil-derived organic carbon, thereby potentially offsetting the loss of soil-derived organic carbon. These results suggested that Phaeozem and high fertility level soils would fix more maize carbon over time and thus were more beneficial for protecting soil-derived organic carbon from maize carbon decomposition. PMID:25774529

Quantitative disease resistance: dissection and adoption in maize

USDA-ARS?s Scientific Manuscript database

Maize is the world’s most widely cultivated crop, providing food, feed, and biofuel. Maize production is constantly threatened by the presence of devastating pathogens worldwide. Characterization of the genetic components underlying disease resistance is a major research area in maize which is highl...

MaizeGDB: New tools and resource

USDA-ARS?s Scientific Manuscript database

MaizeGDB, the USDA-ARS genetics and genomics database, is a highly curated, community-oriented informatics service to researchers focused on the crop plant and model organism Zea mays. MaizeGDB facilitates maize research by curating, integrating, and maintaining a database that serves as the central...

The Effect of Pollination on Cd Phytoextraction From Soil by Maize (Zea mays L.).

PubMed

Xu, Wending; Lu, Guining; Wang, Rui; Guo, Chuling; Liao, Changjun; Yi, Xiaoyun; Dang, Zhi

2015-01-01

A pot experiment was conducted to investigate the effects of pollination on cadmium (Cd) phytoextraction from soil by mature maize plants. The results showed that the unpollinated maize plants accumulated 50% more Cd than that of the pollinated plants, even though the dry weight of the former plants was 15% less than that of the latter plants. The Cd accumulation in root and leaf of the unpollinated maize plant was 0.47 and 0.89 times higher than that of the pollinated plant, respectively. The Cd concentration in the cob was significantly decreased because of pollination. Preventing pollination is a promising approach for enhancing the effectiveness of phytoextraction in Cd-contaminated soils by maize. This study suggested that in low Cd-contaminated soil pollination should be encouraged because accumulation of Cd in maize grains is very little and maize seeds can bring farmers economic benefits, while in high Cd-contaminated soil, inhibition of pollination can be applied to enhance phytoextraction of Cd from soil by maize plant.

Preparation of acetylated waxy, normal, and high-amylose maize starches with intermediate degrees of substitution in aqueous solution and their properties.

PubMed

Luo, Zhi-Gang; Shi, Yong-Cheng

2012-09-19

Acetylated waxy, normal, and high-amylose maize starches with intermediate degrees of substitution (DS) were prepared in aqueous solution with 20% (w/w) sodium hydroxide as a catalyst. The level of DS was in the order high-amylose maize starch > waxy maize starch > normal maize starch. Settling volume indicated that during the early reaction, normal maize starch swelled to a lesser extent compared with waxy and high-amylose maize starches. The settling volume of all three starches increased initially but decreased after long reaction time. Aggregation of granules was observed as DS increased. The A-type X-ray diffraction pattern of acetylated normal and waxy maize starches weakened as DS increased, whereas the diffraction peaks disappeared in acetylated high-amylose starch when DS was 0.95. Low DS promoted the swelling of the starches in water, but at high DS, the starches became more hydrophobic and the peak viscosity of acetylated starches decreased.

Response of Main Maize Varieties to Water Stress and Comprehensive Evaluation in Hebei Province

NASA Astrophysics Data System (ADS)

Yue, Haiwang; Chen, Shuping; Bu, Junzhou; Wei, Jianwei; Peng, Haicheng; Li, Yuan; Li, Chunjie; Xie, Junliang

2018-01-01

Drought is a serious threat to maize production in Hebei province. Planting drought resistant maize varieties is an effective measure to solve drought in arid and less rain areas. Drought resistance in maize is controlled by many genes, and multiple indexes should be used for comprehensive evaluation (Campos H et al.2004). In the arid rain shed, using 34 maize varieties to promote crop production compared to the drought resistance test. The experiment was conducted with two treatments of drought stress (irrigation only at seedling stage) and normal irrigation, and 12 agronomic traits related to drought resistance of maize were determined. The results showed that drought had significant effects on maize yield and main agronomic characters. Under drought stress, plant height, ear length, bare tip, ear row number, row grains, 1000-kernel weight, ASI index can be used as identification index of drought resistance of maize in different period. The results indicated that the variety with strong drought resistance is Zhongdi175, the worst drought resistance is Woyu964.

Corn and culture in central andean prehistory.

PubMed

Johannessen, S; Hastorf, C A

1989-05-12

The prehistoric development and spread of domesticated maize varieties in the highlands of Peru, unlike the drier coastal deserts, is little known because ancient maize remains in this area survive mainly as fragments, kernels, and cob parts. An analysis of fragmented charred maize from prehistoric households (A.D.450 to 1500) in the Mantaro Valley reveals a developmental sequence of maize varieties for Highland Peru. The evidence indicates an adoption of large-kernelled maize varieties beginning in the Late Intermediate (A.D. 1000). This is centuries later than a similar change in maize, associated with the Wari expansion, that occurred in coastal areas, and indicates minimal Wari impact in the Mantaro Valley.

Advances in Maize Transformation Technologies and Development of Transgenic Maize

PubMed Central

Yadava, Pranjal; Abhishek, Alok; Singh, Reeva; Singh, Ishwar; Kaul, Tanushri; Pattanayak, Arunava; Agrawal, Pawan K.

2017-01-01

Maize is the principal grain crop of the world. It is also the crop where genetic engineering has been employed to a great extent to improve its various traits. The ability to transform maize is a crucial step for application of gene technology in maize improvement. There have been constant improvements in the maize transformation technologies over past several years. The choice of genotype and the explant material to initiate transformation and the different types of media to be used in various stages of tissue culture can have significant impact on the outcomes of the transformation efforts. Various methods of gene transfer, like the particle bombardment, protoplast transformation, Agrobacterium-mediated, in planta transformation, etc., have been tried and improved over years. Similarly, various selection systems for retrieval of the transformants have been attempted. The commercial success of maize transformation and transgenic development is unmatched by any other crop so far. Maize transformation with newer gene editing technologies is opening up a fresh dimension in transformation protocols and work-flows. This review captures the various past and recent facets in improvement in maize transformation technologies and attempts to present a comprehensive updated picture of the current state of the art in this area. PMID:28111576

Advances in Maize Transformation Technologies and Development of Transgenic Maize.

PubMed

Yadava, Pranjal; Abhishek, Alok; Singh, Reeva; Singh, Ishwar; Kaul, Tanushri; Pattanayak, Arunava; Agrawal, Pawan K

2016-01-01

Maize is the principal grain crop of the world. It is also the crop where genetic engineering has been employed to a great extent to improve its various traits. The ability to transform maize is a crucial step for application of gene technology in maize improvement. There have been constant improvements in the maize transformation technologies over past several years. The choice of genotype and the explant material to initiate transformation and the different types of media to be used in various stages of tissue culture can have significant impact on the outcomes of the transformation efforts. Various methods of gene transfer, like the particle bombardment, protoplast transformation, Agrobacterium -mediated, in planta transformation, etc., have been tried and improved over years. Similarly, various selection systems for retrieval of the transformants have been attempted. The commercial success of maize transformation and transgenic development is unmatched by any other crop so far. Maize transformation with newer gene editing technologies is opening up a fresh dimension in transformation protocols and work-flows. This review captures the various past and recent facets in improvement in maize transformation technologies and attempts to present a comprehensive updated picture of the current state of the art in this area.

Maize diversity and ethnolinguistic diversity in Chiapas, Mexico

PubMed Central

Perales, Hugo R.; Benz, Bruce F.; Brush, Stephen B.

2005-01-01

The objective of this study is to investigate whether ethnolinguistic diversity influences crop diversity. Factors suggest a correlation between biological diversity of crops and cultural diversity. Although this correlation has been noted, little systematic research has focused on the role of culture in shaping crop diversity. This paper reports on research in the Maya highlands (altitude > 1,800 m) of central Chiapas in southern Mexico that examined the distribution of maize (Zea mays) types among communities of two groups, the Tzeltal and Tzotzil. The findings suggest that maize populations are distinct according to ethnolinguistic group. However, a study of isozymes indicates no clear separation of the region's maize into two distinct populations based on ethnolin-guistic origin. A reciprocal garden experiment shows that there is adaptation of maize to its environment but that Tzeltal maize sometimes out-yields Tzotzil maize in Tzotzil environments. Because of the proximity of the two groups and selection for yield, we would expect that the superior maize would dominate both groups' maize populations, but we find that such domination is not the case. The role of ethnolinguistic identity in shaping social networks and information exchange is discussed in relation to landrace differentiation. PMID:15640353

Maize diversity and ethnolinguistic diversity in Chiapas, Mexico.

PubMed

Perales, Hugo R; Benz, Bruce F; Brush, Stephen B

2005-01-18

The objective of this study is to investigate whether ethnolinguistic diversity influences crop diversity. Factors suggest a correlation between biological diversity of crops and cultural diversity. Although this correlation has been noted, little systematic research has focused on the role of culture in shaping crop diversity. This paper reports on research in the Maya highlands (altitude >1,800 m) of central Chiapas in southern Mexico that examined the distribution of maize (Zea mays) types among communities of two groups, the Tzeltal and Tzotzil. The findings suggest that maize populations are distinct according to ethnolinguistic group. However, a study of isozymes indicates no clear separation of the region's maize into two distinct populations based on ethnolinguistic origin. A reciprocal garden experiment shows that there is adaptation of maize to its environment but that Tzeltal maize sometimes out-yields Tzotzil maize in Tzotzil environments. Because of the proximity of the two groups and selection for yield, we would expect that the superior maize would dominate both groups' maize populations, but we find that such domination is not the case. The role of ethnolinguistic identity in shaping social networks and information exchange is discussed in relation to landrace differentiation.

Microfossil evidence for pre-Columbian maize dispersals in the neotropics from San Andres, Tabasco, Mexico.

PubMed

Pohl, Mary E D; Piperno, Dolores R; Pope, Kevin O; Jones, John G

2007-04-17

The history of maize (Zea mays L.) is one of the most debated topics in New World archaeology. Molecular and genetic studies indicate that maize domestication took place in tropical southwest Mexico. Although archaeological evidence for the evolution of maize from its wild ancestor teosinte has yet to be found in that poorly studied region, other research combining paleoecology and archaeology is documenting the nature and timing of maize domestication and dispersals. Here we report a phytolith analysis of sediments from San Andrés, Tabasco, that confirms the spread of maize cultivation to the tropical Mexican Gulf Coast >7,000 years ago ( approximately 7,300 calendar years before present). We review the different methods used in sampling, identifying, and dating fossil maize remains and compare their strengths and weaknesses. Finally, we examine how San Andrés amplifies the present evidence for widespread maize dispersals into Central and South America. Multiple data sets from many sites indicate that maize was brought under cultivation and domesticated and had spread rapidly out of its domestication cradle in tropical southwest Mexico by the eighth millennium before the present.

Maize Lethal Necrosis (MLN), an Emerging Threat to Maize-Based Food Security in Sub-Saharan Africa.

PubMed

Mahuku, George; Lockhart, Benham E; Wanjala, Bramwel; Jones, Mark W; Kimunye, Janet Njeri; Stewart, Lucy R; Cassone, Bryan J; Sevgan, Subramanian; Nyasani, Johnson O; Kusia, Elizabeth; Kumar, P Lava; Niblett, C L; Kiggundu, Andrew; Asea, Godfrey; Pappu, Hanu R; Wangai, Anne; Prasanna, Boddupalli M; Redinbaugh, Margaret G

2015-07-01

In sub-Saharan Africa, maize is a staple food and key determinant of food security for smallholder farming communities. Pest and disease outbreaks are key constraints to maize productivity. In September 2011, a serious disease outbreak, later diagnosed as maize lethal necrosis (MLN), was reported on maize in Kenya. The disease has since been confirmed in Rwanda and the Democratic Republic of Congo, and similar symptoms have been reported in Tanzania, Uganda, South Sudan, and Ethiopia. In 2012, yield losses of up to 90% resulted in an estimated grain loss of 126,000 metric tons valued at $52 million in Kenya alone. In eastern Africa, MLN was found to result from coinfection of maize with Maize chlorotic mottle virus (MCMV) and Sugarcane mosaic virus (SCMV), although MCMV alone appears to cause significant crop losses. We summarize here the results of collaborative research undertaken to understand the biology and epidemiology of MLN in East Africa and to develop disease management strategies, including identification of MLN-tolerant maize germplasm. We discuss recent progress, identify major issues requiring further research, and discuss the possible next steps for effective management of MLN.

[Predicting the impact of climate change in the next 40 years on the yield of maize in China].

PubMed

Ma, Yu-ping; Sun, Lin-li; E, You-hao; Wu, Wei

2015-01-01

Climate change will significantly affect agricultural production in China. The combination of the integral regression model and the latest climate projection may well assess the impact of future climate change on crop yield. In this paper, the correlation model of maize yield and meteorological factors was firstly established for different provinces in China by using the integral regression method, then the impact of climate change in the next 40 years on China's maize production was evaluated combined the latest climate prediction with the reason be ing analyzed. The results showed that if the current speeds of maize variety improvement and science and technology development were constant, maize yield in China would be mainly in an increasing trend of reduction with time in the next 40 years in a range generally within 5%. Under A2 climate change scenario, the region with the most reduction of maize yield would be the Northeast except during 2021-2030, and the reduction would be generally in the range of 2.3%-4.2%. Maize yield reduction would be also high in the Northwest, Southwest and middle and lower reaches of Yangtze River after 2031. Under B2 scenario, the reduction of 5.3% in the Northeast in 2031-2040 would be the greatest across all regions. Other regions with considerable maize yield reduction would be mainly in the Northwest and the Southwest. Reduction in maize yield in North China would be small, generally within 2%, under any scenarios, and that in South China would be almost unchanged. The reduction of maize yield in most regions would be greater under A2 scenario than under B2 scenario except for the period of 2021-2030. The effect of the ten day precipitation on maize yield in northern China would be almost positive. However, the effect of ten day average temperature on yield of maize in all regions would be generally negative. The main reason of maize yield reduction was temperature increase in most provinces but precipitation decrease in a few provinces. Assessments of the future change of maize yield in China based on the different methods were not consistent. Further evaluation needs to consider the change of maize variety and scientific and technological progress, and to enhance the reliability of evaluation models.

Genetic mechanisms of Maize dwarf mosaic virus resistance in maize

USDA-ARS?s Scientific Manuscript database

Maize resistance to viruses has been well-characterized at the genetic level, and loci responsible for resistance to potyviruses including Maize dwarf mosaic virus (MDMV), Sugarcane mosaic virus (SCMV), Sorghum mosaic virus (SrMV), and Johnsongrass mosaic virus (JGMV), have been mapped in several ge...

MaizeGDB: everything old is new again! [abstract

USDA-ARS?s Scientific Manuscript database

The focus of genetic, genomic, and breeding research evolves over time, making it necessary to continually redefine the paradigm for data access and data analysis tools. Here we report the reinvention of MaizeGDB, the maize genetics and genomics database, to meet maize researchers’ ever changing nee...

Expanding maize genetic resources with predomestication alleles: maize-teosinte introgression populations

USDA-ARS?s Scientific Manuscript database

Teosinte (Zea mays ssp. parviglumis) has greater genetic diversity than maize inbreds and landraces (Z. mays ssp. mays). There are, however, limited genetic resources to efficiently evaluate and tap this diversity. To broaden resources for genetic diversity studies in maize, we developed and evaluat...

Nutritive value of maize silage in relation to dairy cow performance and milk quality.

PubMed

Khan, Nazir A; Yu, Peiqiang; Ali, Mubarak; Cone, John W; Hendriks, Wouter H

2015-01-01

Maize silage has become the major forage component in the ration of dairy cows over the last few decades. This review provides information on the mean content and variability in chemical composition, fatty acid (FA) profile and ensiling quality of maize silages, and discusses the major factors which cause these variations. In addition, the effect of the broad range in chemical composition of maize silages on the total tract digestibility of dietary nutrients, milk production and milk composition of dairy cows is quantified and discussed. Finally, the optimum inclusion level of maize silage in the ration of dairy cows for milk production and composition is reviewed. The data showed that the nutritive value of maize silages is highly variable and that most of this variation is caused by large differences in maturity at harvest. Maize silages ensiled at a very early stage (dry matter (DM) < 250 g kg(-1)) were particularly low in starch content and starch/neutral detergent fibre (NDF) ratio, and resulted in a lower DM intake (DMI), milk yield and milk protein content. The DMI, milk yield and milk protein content increased with advancing maturity, reaching an optimum level for maize silages ensiled at DM contents of 300-350 g kg(-1), and then declined slightly at further maturity beyond 350 g kg(-1). The increases in milk (R(2) = 0.599) and protein (R(2) = 0.605) yields with maturity of maize silages were positively related to the increase in starch/NDF ratio of the maize silages. On average, the inclusion of maize silage in grass silage-based diets improved the forage DMI by 2 kg d(-1), milk yield by 1.9 kg d(-1) and milk protein content by 1.2 g kg(-1). Further comparisons showed that, in terms of milk and milk constituent yields, the optimum grass/maize silage ratio depends on the quality of both the grass and maize silages. Replacement of grass silage with maize silage in the ration, as well as an increasing maturity of the maize silages, altered the milk FA profile of the dairy cows, notably, the concentration of the cis-unsaturated FAs, C18:3n-3 and n-3/n-6 ratio decreased in milk fat. Despite variation in nutritive value, maize silage is rich in metabolizable energy and supports higher DMI and milk yield. Harvesting maize silages at a DM content between 300 and 350 g kg(-1) and feeding in combination with grass silage results in a higher milk yield of dairy cows. © 2014 Society of Chemical Industry.

DNA extraction methods for detecting genetically modified foods: A comparative study.

PubMed

Elsanhoty, Rafaat M; Ramadan, Mohamed Fawzy; Jany, Klaus Dieter

2011-06-15

The work presented in this manuscript was achieved to compare six different methods for extracting DNA from raw maize and its derived products. The methods that gave higher yield and quality of DNA were chosen to detect the genetic modification in the samples collected from the Egyptian market. The different methods used were evaluated for extracting DNA from maize kernels (without treatment), maize flour (mechanical treatment), canned maize (sweet corn), frozen maize (sweet corn), maize starch, extruded maize, popcorn, corn flacks, maize snacks, and bread made from corn flour (mechanical and thermal treatments). The quality and quantity of the DNA extracted from the standards, containing known percentages of GMO material and from the different food products were evaluated. For qualitative detection of the GMO varieties in foods, the GMOScreen 35S/NOS test kit was used, to screen the genetic modification in the samples. The positive samples for the 35S promoter and/or the NOS terminator were identified by the standard methods adopted by EU. All of the used methods extracted yielded good DNA quality. However, we noted that the purest DNA extract were obtained using the DNA extraction kit (Roche) and this generally was the best method for extracting DNA from most of the maize-derived foods. We have noted that the yield of DNA extracted from maize-derived foods was generally lower in the processed products. The results indicated that 17 samples were positive for the presence of 35S promoter, while 34% from the samples were positive for the genetically modified maize line Bt-176. Copyright © 2010 Elsevier Ltd. All rights reserved.

Tracing transgenic maize as affected by breadmaking process and raw material for the production of a traditional maize bread, broa.

PubMed

Fernandes, Telmo J R; Oliveira, M Beatriz P P; Mafra, Isabel

2013-05-01

Broa is a maize bread highly consumed and appreciated, especially in the north and central zones of Portugal. In the manufacturing of broa, maize flour and maize semolina might be used, besides other cereals such as wheat and rye. Considering the needs for genetically modified organism (GMO) traceability in highly processed foods, the aim of this work was to assess DNA degradation, DNA amplification and GMO quantification along breadmaking process of broa. DNA degradation was noticed by its decrease of integrity after dough baking and in all parts of bread sampling. The PCR amplification results of extracted DNA from the three distinct maize breads (broa 1, 2 and 3) showed that sequences for maize invertase gene and for events MON810 and TC1507 were easily detected with strong products. Real-time PCR revealed that quantification of GMO was feasible in the three different breads and that sampling location of baked bread might have a limited influence since the average quantitative results of both events after baking were very close to the actual values in the case of broa 1 (prepared with maize semolina). In the other two maize breads subjected to the same baking treatment, the contents of MON810 maize were considerably underestimated, leading to the conclusion that heat-processing was not the responsible parameter for that distortion, but the size of particle and mechanical processing of raw maize play also a major role in GMO quantification. Copyright © 2012 Elsevier Ltd. All rights reserved.

Maize 27 kDa gamma-zein is a potential allergen for early weaned pigs.

PubMed

Krishnan, Hari B; Kerley, Monty S; Allee, Gary L; Jang, Sungchan; Kim, Won-Seok; Fu, Chunjiang J

2010-06-23

Soybean and maize are extensively used in animal feed, primarily in poultry, swine, and cattle diets. Soybean meal can affect pig performance in the first few weeks following weaning and elicit specific antibodies in weaned piglets. Though maize is a major component of pig feed, it is not known if any of the maize proteins can elicit immunological response in young pigs. In this study, we have identified a prominent 27 kDa protein from maize as an immunodominant protein in young pigs. This protein, like some known allergens, exhibited resistance to pepsin digestion in vitro. Several lines of evidence identify the immunodominant 27 kDa protein as a gamma-zein, a maize seed storage protein. First, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis of different solubility classes of maize seed proteins revealed the presence of an abundant 27 kDa protein in the prolamin (zein) fraction. Antibodies raised against the purified maize 27 kDa gamma-zein also reacted against the same protein recognized by the young pig serum. Additionally, matrix-assisted laser desorption ionization time-of-flight mass spectrometry analysis of the peptides generated by trypsin digestion of the immunodominant 27 kDa protein showed significant homology to the maize 27 kDa gamma-zein. Since eliminating the allergenic protein will have a great impact on the nutritive value of the maize meal and expand its use in the livestock industry, it will be highly desirable to develop maize cultivars completely lacking the 27 kDa allergenic protein.

Johnsongrass mosaic virus contributes to maize lethal necrosis in East Africa

USDA-ARS?s Scientific Manuscript database

Maize lethal necrosis (MLN), a severe virus disease of maize, has emerged in East Africa in recent years with devastating effects on production and food security where maize is a staple subsistence crop. In extensive surveys of MLN-symptomatic plants in East Africa, sequences of Johnsongrass mosaic ...

Genome-Wide Association Mapping of and Aspergillus flavus Aflatoxin Accumulation Resistance in Maize

Treesearch

Marilyn L. Warburton; Juliet D. Tang; Gary L. Windham; Leigh K. Hawkins; Seth C. Murray; Wenwei Xu; Debbie Boykin; Andy Perkins; W. Paul Williams

2015-01-01

Contamination of maize (Zea mays L.) with aflatoxin, produced by the fungus Aspergillus flavus Link, has severe health and economic consequences. Efforts to reduce aflatoxin accumulation in maize have focused on identifying and selecting germplasm with natural host resistance factors, and several maize lines with significantly...

Fast-flowering mini-maize: seed to seed in 60 days

USDA-ARS?s Scientific Manuscript database

Two lines of Zea mays were developed as a short-generation model for maize. The Fast-Flowering Mini-Maize (FFMM) lines A and B are robust inbred lines with a significantly shorter generation time, much smaller stature, and better greenhouse adaptation than traditional maize varieties. Five generatio...

Gene Flow Among Different Teosinte Taxa and Into the Domesticated Maize Gene Pool

USDA-ARS?s Scientific Manuscript database

Maize (Zea mays ssp. mays) was domesticated from one wild species ancestor, the Balsas teosinte (Zea mays ssp. parviglumis) about 9000 years ago. Higher levels of gene diversity are found in teosinte taxa compared to maize following domestication and selection bottlenecks. Diversity in maize can b...

MADS-box genes in maize: Frequent targets of selection during domestication

USDA-ARS?s Scientific Manuscript database

MADS-box genes encode transcription factors that are key regulators of plant inflorescence and flower development. We examined DNA sequence variation in 32 maize MADS-box genes and 32 random loci from the maize genome and investigated their involvement in maize domestication and improvement. Using n...

Comparison of Gene Expressions of Maize Kernel Pathogenesis-Related Proteins in Different Maize Genotypes

USDA-ARS?s Scientific Manuscript database

Aflatoxins are carcinogenic mycotoxins produced by the fungus Aspergillus flavus during infection of various grain crops including maize (Zea mays). Contamination of maize with aflatoxins has been shown to be exasperated by late season drought stress. Previous studies have identified numerous resist...

Monitoring the expression of maize genes in developing kernels under drought stress using oligo-microarray

USDA-ARS?s Scientific Manuscript database

Preharvest A. flavus infection is usually exacerbated when maize plants suffer drought stress in the late grain-fill stage. However, the field observation suggests that drought-tolerant maize lines displayed less aflatoxin contamination under the stress in comparison with the drought-sensitive maize...

Harnessing maize biodiversity

USDA-ARS?s Scientific Manuscript database

Maize is a remarkably diverse species, adapted to a wide range of climatic conditions and farming practices. The latitudinal range of maize is immense, ranging from 54°N in Alberta, Canada, to 45°S in the province of Chubut, Argentina. In terms of altitude, maize is cultivated from sea level to 4000...

Processing maize flour and corn meal food products

PubMed Central

Gwirtz, Jeffrey A; Garcia-Casal, Maria Nieves

2014-01-01

Corn is the cereal with the highest production worldwide and is used for human consumption, livestock feed, and fuel. Various food technologies are currently used for processing industrially produced maize flours and corn meals in different parts of the world to obtain precooked refined maize flour, dehydrated nixtamalized flour, fermented maize flours, and other maize products. These products have different intrinsic vitamin and mineral contents, and their processing follows different pathways from raw grain to the consumer final product, which entail changes in nutrient composition. Dry maize mechanical processing creates whole or fractionated products, separated by anatomical features such as bran, germ, and endosperm. Wet maize processing separates by chemical compound classification such as starch and protein. Various industrial processes, including whole grain, dry milling fractionation, and nixtamalization, are described. Vitamin and mineral losses during processing are identified and the nutritional impacts outlined. Also discussed are the vitamin and mineral contents of corn. PMID:24329576

[Assessment of the impact of GMO of plant origin on rat progeny development in 3 generations].

PubMed

Tyshko, N V; Zhminchenko, V M; Pashorina, V A; Seliaskin, K E; Saprykin, V P; Utembaeva, N T; Tutel'ian, V A

2011-01-01

The publication presents the results of assessment of impact of genetically modified (GM) maize Liberty Link on prenatal and postnatal development of progeny of 3 generations of Wistar rats. A total of 630 adult animals and 2837 pups were used in the experiment. The animals were divided into 5 groups which got the diets with inclusion of maize: the animals of the experimental group got the diet with the GM-maize, animals of the control group - with near isogenic conventional analogue of the GM-maize, animals of the 1st, 2nd and 3rd reference groups - conventional varieties of maize ROSS 144 MV, ROSS 197 MVW, Dokuchayevskaya 250 MV respectively. The maize was included in the diet at maximum possible level not violating the balance of basic nutrients. Analysis of the data obtained during the study did not reveal any impact of GM-maize on rat progeny development.

Detection of maize kernels breakage rate based on K-means clustering

NASA Astrophysics Data System (ADS)

Yang, Liang; Wang, Zhuo; Gao, Lei; Bai, Xiaoping

2017-04-01

In order to optimize the recognition accuracy of maize kernels breakage detection and improve the detection efficiency of maize kernels breakage, this paper using computer vision technology and detecting of the maize kernels breakage based on K-means clustering algorithm. First, the collected RGB images are converted into Lab images, then the original images clarity evaluation are evaluated by the energy function of Sobel 8 gradient. Finally, the detection of maize kernels breakage using different pixel acquisition equipments and different shooting angles. In this paper, the broken maize kernels are identified by the color difference between integrity kernels and broken kernels. The original images clarity evaluation and different shooting angles are taken to verify that the clarity and shooting angles of the images have a direct influence on the feature extraction. The results show that K-means clustering algorithm can distinguish the broken maize kernels effectively.

The W22 genome: a foundation for maize functional genomics and transposon biology

USDA-ARS?s Scientific Manuscript database

The maize W22 inbred has served as a platform for maize genetics since the mid twentieth century. To streamline maize genome analyses, we have sequenced and de novo assembled a W22 reference genome using small-read sequencing technologies. We show that significant structural heterogeneity exists in ...

Maize kernel evolution:From teosinte to maize

USDA-ARS?s Scientific Manuscript database

Maize is the most productive and highest value commodity in the US and around the world: over 1 billion tons were produced each year in 2013 and 2014. Together, maize, rice and wheat comprise over 60% of the world’s caloric intake, with wide regional variability in the importance of each crop. The i...

Evaluation of fall armyworm resistance in maize germplasm lines using visual leaf injury rating and predator survey

USDA-ARS?s Scientific Manuscript database

After examining ear-colonizing pest resistance, 20 maize lines from the USDA-ARS germplasm enhancement of Maize (GEM) Program were evaluated for whorl-feeding fall armyworm (FAW) (Spodoptera frugiperda) resistance using four maize inbred lines as the resistant and susceptible controls. Both FAW inju...

Identification of resistance to Maize rayado fino virus in maize inbred lines

USDA-ARS?s Scientific Manuscript database

Maize rayado fino virus (MRFV) is one of the most important virus diseases of maize in America. Severe yield losses, ranging from 10 to 50% in landraces to nearly 100% in contemporary cultivars, have been reported. Resistance has been reported in populations, but few inbred lines have been identifie...

Population structure of the African Clawed Frog (Xenopus laevis) in maize-growing areas with atrazine application versus non-maize-growing areas in South Africa

USGS Publications Warehouse

Du Preez, L.H.; Solomon, K.R.; Carr, J.A.; Giesy, J.P.; Gross, T.S.; Kendall, R.J.; Smith, E.E.; Van Der Kraak, G. L.; Weldon, C.

2005-01-01

The herbicide atrazine has been suggested to cause gonadal deformities in frogs and could possibly impact on reproduction. Since the early 1960s, atrazine has been used in large amounts in maize production areas of South Africa. These areas overlap with populations of the African Clawed Frog (Xenopus laevis) that has a wide distribution in southern Africa and is found in most water-bodies including those where atrazine residues are detected. The aim of this study was to compare various attributes of individual- and population-level responses of X. laevis from maize-growing and non-maize-growing areas. Xenopus laevis were studied in three reference and five maize-growing sites. Sex ratio, snout-vent length, body-mass and age profiles were found to be similar for populations in maize-growing and non-maize-growing areas. Our mark-recapture data indicated that all sites had robust populations. There were no significant relationships between exposure to atrazine and any of the parameters investigated in populations of X. laevis.

Investigation of the bottleneck leading to the domestication of maize

PubMed Central

Eyre-Walker, Adam; Gaut, Rebecca L.; Hilton, Holly; Feldman, Dawn L.; Gaut, Brandon S.

1998-01-01

Maize (Zea mays ssp. mays) is genetically diverse, yet it is also morphologically distinct from its wild relatives. These two observations are somewhat contradictory: the first observation is consistent with a large historical population size for maize, but the latter observation is consistent with strong, diversity-limiting selection during maize domestication. In this study, we sampled sequence diversity, coupled with simulations of the coalescent process, to study the dynamics of a population bottleneck during the domestication of maize. To do this, we determined the DNA sequence of a 1,400-bp region of the Adh1 locus from 19 individuals representing maize, its presumed progenitor (Z. mays ssp. parviglumis), and a more distant relative (Zea luxurians). The sequence data were used to guide coalescent simulations of population bottlenecks associated with domestication. Our study confirms high genetic diversity in maize—maize contains 75% of the variation found in its progenitor and is more diverse than its wild relative, Z. luxurians—but it also suggests that sequence diversity in maize can be explained by a bottleneck of short duration and very small size. For example, the breadth of genetic diversity in maize is consistent with a founding population of only 20 individuals when the domestication event is 10 generations in length. PMID:9539756

Analysis of Maize versus Ethanol Production in Nebraska, United States and International Agricultural Droughts: Lessons for Global Food Security

NASA Astrophysics Data System (ADS)

Boken, V.; Tenkorang, F.

2012-04-01

Nebraska is one of the eight main corn (maize) belt states of the United States. Maize is the major crop of Nebraska with an average annual production of about 38 million tons (about 12% of U.S. production), which contributes billions of dollars to the state's economy. The yield of maize has increased significantly over the past century - from 1.6 t/ha in 1900 to 10.4 t/ha in 2010. While the majority of maize (about 40%) is currently used for animal feed and ethanol production, only about six percent is exported. It is estimated that about one billion people accounting for about 15% population of the world live in chronic hunger because of low agricultural productivity and drought. Most of these people depend on the U.S. for grains including maize. If a greater quantity of maize is diverted to ethanol production, considerably less quantity of maize would be available for export to developing countries where it could be used for human consumption and to mitigate hunger and improve food security. This paper presents analysis of maize production in Nebraska for the past three decades and examines how its commercialization for ethanol production has affected its exports in the face of drought at an international level.

Impact of genetically engineered maize on agronomic, environmental and toxicological traits: a meta-analysis of 21 years of field data.

PubMed

Pellegrino, Elisa; Bedini, Stefano; Nuti, Marco; Ercoli, Laura

2018-02-15

Despite the extensive cultivation of genetically engineered (GE) maize and considerable number of scientific reports on its agro-environmental impact, the risks and benefits of GE maize are still being debated and concerns about safety remain. This meta-analysis aimed at increasing knowledge on agronomic, environmental and toxicological traits of GE maize by analyzing the peer-reviewed literature (from 1996 to 2016) on yield, grain quality, non-target organisms (NTOs), target organisms (TOs) and soil biomass decomposition. Results provided strong evidence that GE maize performed better than its near isogenic line: grain yield was 5.6 to 24.5% higher with lower concentrations of mycotoxins (-28.8%), fumonisin (-30.6%) and thricotecens (-36.5%). The NTOs analyzed were not affected by GE maize, except for Braconidae, represented by a parasitoid of European corn borer, the target of Lepidoptera active Bt maize. Biogeochemical cycle parameters such as lignin content in stalks and leaves did not vary, whereas biomass decomposition was higher in GE maize. The results support the cultivation of GE maize, mainly due to enhanced grain quality and reduction of human exposure to mycotoxins. Furthermore, the reduction of the parasitoid of the target and the lack of consistent effects on other NTOs are confirmed.

The durable wheat disease resistance gene Lr34 confers common rust and northern corn leaf blight resistance in maize.

PubMed

Sucher, Justine; Boni, Rainer; Yang, Ping; Rogowsky, Peter; Büchner, Heike; Kastner, Christine; Kumlehn, Jochen; Krattinger, Simon G; Keller, Beat

2017-04-01

Maize (corn) is one of the most widely grown cereal crops globally. Fungal diseases of maize cause significant economic damage by reducing maize yields and by increasing input costs for disease management. The most sustainable control of maize diseases is through the release and planting of maize cultivars with durable disease resistance. The wheat gene Lr34 provides durable and partial field resistance against multiple fungal diseases of wheat, including three wheat rust pathogens and wheat powdery mildew. Because of its unique qualities, Lr34 became a cornerstone in many wheat disease resistance programmes. The Lr34 resistance is encoded by a rare variant of an ATP-binding cassette (ABC) transporter that evolved after wheat domestication. An Lr34-like disease resistance phenotype has not been reported in other cereal species, including maize. Here, we transformed the Lr34 resistance gene into the maize hybrid Hi-II. Lr34-expressing maize plants showed increased resistance against the biotrophic fungal disease common rust and the hemi-biotrophic disease northern corn leaf blight. Furthermore, the Lr34-expressing maize plants developed a late leaf tip necrosis phenotype, without negative impact on plant growth. With this and previous reports, it could be shown that Lr34 is effective against various biotrophic and hemi-biotrophic diseases that collectively parasitize all major cereal crop species. © 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

Maize acetylcholinesterase is a positive regulator of heat tolerance in plants.

PubMed

Yamamoto, Kosuke; Sakamoto, Hikaru; Momonoki, Yoshie S

2011-11-01

We previously reported that native tropical zone plants showed high acetylcholinesterase (AChE) activity during heat stress, and that AChE activity in endodermal cells of maize seedlings was increased by heat treatment. However, the physiological role of AChE in heat stressed plants is still unclear. Here we report (1) tissue-specific expression and subcellular localization of maize AChE, (2) elevation of AChE activity and possible post-translational modifications of this enzyme under heat stress, and (3) involvement of AChE in plant heat stress tolerance. Maize AChE was mainly expressed in coleoptile nodes and seeds. Maize AChE fused with green fluorescent protein (GFP) was localized in extracellular spaces of transgenic rice plants. Therefore, in maize coleoptile nodes and seeds AChE mainly functions in the cell wall matrix. After heat treatment, enhanced maize AChE activity was observed by in vitro activity measurement and by in situ cytochemical staining; transcript and protein levels, however, were not changed. Protein gel blot analysis revealed two AChE isoforms (upper and lower); the upper-form gradually disappeared after heat treatment. Thus, maize AChE activity might be enhanced through a post-translational modification response to heat stress. Finally, we found that overexpression of maize AChE in transgenic tobacco plants enhanced heat tolerance relative to that of non-transgenic plants, suggesting AChE plays a positive role in maize heat tolerance. Copyright © 2011 Elsevier GmbH. All rights reserved.

ZCN8 encodes a potential orthologue of Arabidopsis FT florigen that integrates both endogenous and photoperiod flowering signals in maize

PubMed Central

Lazakis, Chloë M.; Coneva, Viktoriya; Colasanti, Joseph

2011-01-01

Higher plants use multiple perceptive measures to coordinate flowering time with environmental and endogenous cues. Physiological studies show that florigen is a mobile factor that transmits floral inductive signals from the leaf to the shoot apex. Arabidopsis FT protein is widely regarded as the archetype florigen found in diverse plant species, particularly in plants that use inductive photoperiods to flower. Recently, a large family of FT homologues in maize, the Zea CENTRORADIALIS (ZCN) genes, was described, suggesting that maize also contains FT-related proteins that act as a florigen. The product of one member of this large family, ZCN8, has several attributes that make it a good candidate as a maize florigen. Mechanisms underlying the floral transition in maize are less well understood than those of other species, partly because flowering in temperate maize is dependent largely on endogenous signals. The maize indeterminate1 (id1) gene is an important regulator of maize autonomous flowering that acts in leaves to mediate the transmission or production of florigenic signals. This study finds that id1 acts upstream of ZCN8 to control its expression, suggesting a possible new link to flowering in day-neutral maize. Moreover, in teosinte, a tropical progenitor of maize that requires short-day photoperiods to induce flowering, ZCN8 is highly up-regulated in leaves under inductive photoperiods. Finally, vascular-specific expression of ZCN8 in Arabidopsis complements the ft-1 mutation, demonstrating that leaf-specific expression of ZCN8 can induce flowering. These results suggest that ZCN8 may encode a florigen that integrates both endogenous and environmental signals in maize. PMID:21730358

Enumerating lepidopteran species associated with maize as a first step in risk assessment in the USA.

PubMed

Losey, John E; Hufbauer, Ruth A; Hartzler, Robert G

2003-01-01

Pest management can have substantial impacts on non-target species both within and outside the units being managed. Assessment of these impacts is hampered by the lack of even the most basic checklist of the species present in most systems. The maize agroecosytem is of particular interest because of the large area covered and the intensity of widely varying forms of pest management. In this study a database of lepidopteran species that occur within the maize agroecosystem in the United States was compiled. The process was initiated by developing a list of plants present in maize using published sources and the first-hand knowledge of "weed" experts. This list of plant species associated with maize was then cross-listed with lepidopteran host feeding records using published sources. Finally, phenological profiles and conservation rankings were added. Although our list is not exhaustive, we found 132 plant species in 33 families associated with maize, and 229 lepidopteran species in 21 families that feed on these plants. The database of plants and lepidopteran species can be a starting point for assessment of risk to non-target Lepidoptera in maize from chemical control, biological control, and the use of transgenic Bt maize. The lepidopteran species associated with maize were found to be significantly less imperiled, as measured by their conservation rankings, than lepidopteran species as a whole in all habitats. This finding suggests that rare or endangered lepidopteran species are unlikely to be impacted by pest management in maize. Based on the likely lack of impact of pest management in maize on individual species, future studies should focus on potential impacts on the ecological services that lepidopteran species provide.

Effects of elevated [CO2] on maize defence against mycotoxigenic Fusarium verticillioides

PubMed Central

Vaughan, Martha M; Huffaker, Alisa; Schmelz, Eric A; Dafoe, Nicole J; Christensen, Shawn; Sims, James; Martins, Vitor F; Swerbilow, Jay; Romero, Maritza; Alborn, Hans T; Allen, Leon HARTWELL; Teal, Peter EA

2014-01-01

Maize is by quantity the most important C4 cereal crop; however, future climate changes are expected to increase maize susceptibility to mycotoxigenic fungal pathogens and reduce productivity. While rising atmospheric [CO2] is a driving force behind the warmer temperatures and drought, which aggravate fungal disease and mycotoxin accumulation, our understanding of how elevated [CO2] will effect maize defences against such pathogens is limited. Here we report that elevated [CO2] increases maize susceptibility to Fusarium verticillioides proliferation, while mycotoxin levels are unaltered. Fumonisin production is not proportional to the increase in F. verticillioides biomass, and the amount of fumonisin produced per unit pathogen is reduced at elevated [CO2]. Following F. verticillioides stalk inoculation, the accumulation of sugars, free fatty acids, lipoxygenase (LOX) transcripts, phytohormones and downstream phytoalexins is dampened in maize grown at elevated [CO2]. The attenuation of maize 13-LOXs and jasmonic acid production correlates with reduced terpenoid phytoalexins and increased susceptibility. Furthermore, the attenuated induction of 9-LOXs, which have been suggested to stimulate mycotoxin biosynthesis, is consistent with reduced fumonisin per unit fungal biomass at elevated [CO2]. Our findings suggest that elevated [CO2] will compromise maize LOX-dependent signalling, which will influence the interactions between maize and mycotoxigenic fungi. Elevated [CO2] increases maize susceptibility to Fusarium verticillioides proliferation but mycotoxin levels are unaltered. The attenuation of maize 13-LOXs and JA production correlates with reduced terpenoid phytoalexins and increased susceptibility. Furthermore, the attenuated induction of 9-LOXs, which have been suggested to stimulate mycotoxin biosynthesis, is consistent with reduced fumonisin per unit fungal biomass at elevated [CO2]. PMID:24689748

Metabolizable energy, nitrogen balance, and ileal digestibility of amino acids in quality protein maize for pigs

PubMed Central

2014-01-01

Background To compare the nutritional value and digestibility of five quality protein maize (QPM) hybrids to that of white and yellow maize, two experiments were carried out in growing pigs. In experiment 1, the energy metabolizability and the nitrogen balance of growing pigs fed one of five QPM hybrid diets were compared against those of pigs fed white or yellow maize. In experiment 2, the apparent and standardized ileal digestibility (AID and SID, respectively) of proteins and amino acids from the five QPM hybrids were compared against those obtained from pigs fed white and yellow maize. In both experiments, the comparisons were conducted using contrasts. Results The dry matter and nitrogen intakes were higher in the pigs fed the QPM hybrids (P < 0.05) than in the pigs fed white or yellow maize. Energy digestibility (P < 0.001) and metabolizability (P < 0.01) were higher in the pigs fed the white and yellow maize diets than in those fed the QPM diets. The AID of lysine was higher (P < 0.01) in the QPM diets than in the white and yellow maize. The AIDs of leucine, isoleucine, valine, phenylalanine, and methionine were lower in the QPM diets than those of maize (white and yellow) (all P < 0.05). Maize (white and yellow) had greater SIDs of leucine, isoleucine, valine, phenylalanine, glutamic acid, serine, alanine, tyrosine, and proline (P < 0.05). Conclusions Based on these results, it was concluded that QPM had a lower metabolizable energy content and a higher amount of digestible lysine than normal maize. PMID:25045520

Genomic-based-breeding tools for tropical maize improvement.

PubMed

Chakradhar, Thammineni; Hindu, Vemuri; Reddy, Palakolanu Sudhakar

2017-12-01

Maize has traditionally been the main staple diet in the Southern Asia and Sub-Saharan Africa and widely grown by millions of resource poor small scale farmers. Approximately, 35.4 million hectares are sown to tropical maize, constituting around 59% of the developing worlds. Tropical maize encounters tremendous challenges besides poor agro-climatic situations with average yields recorded <3 tones/hectare that is far less than the average of developed countries. On the contrary to poor yields, the demand for maize as food, feed, and fuel is continuously increasing in these regions. Heterosis breeding introduced in early 90 s improved maize yields significantly, but genetic gains is still a mirage, particularly for crop growing under marginal environments. Application of molecular markers has accelerated the pace of maize breeding to some extent. The availability of array of sequencing and genotyping technologies offers unrivalled service to improve precision in maize-breeding programs through modern approaches such as genomic selection, genome-wide association studies, bulk segregant analysis-based sequencing approaches, etc. Superior alleles underlying complex traits can easily be identified and introgressed efficiently using these sequence-based approaches. Integration of genomic tools and techniques with advanced genetic resources such as nested association mapping and backcross nested association mapping could certainly address the genetic issues in maize improvement programs in developing countries. Huge diversity in tropical maize and its inherent capacity for doubled haploid technology offers advantage to apply the next generation genomic tools for accelerating production in marginal environments of tropical and subtropical world. Precision in phenotyping is the key for success of any molecular-breeding approach. This article reviews genomic technologies and their application to improve agronomic traits in tropical maize breeding has been reviewed in detail.

Assessment of the potential for gene flow from transgenic maize (Zea mays L.) to eastern gamagrass (Tripsacum dactyloides L.).

PubMed

Lee, Moon-Sub; Anderson, Eric K; Stojšin, Duška; McPherson, Marc A; Baltazar, Baltazar; Horak, Michael J; de la Fuente, Juan Manuel; Wu, Kunsheng; Crowley, James H; Rayburn, A Lane; Lee, D K

2017-08-01

Eastern gamagrass (Tripsacum dactyloides L.) belongs to the same tribe of the Poaceae family as maize (Zea mays L.) and grows naturally in the same region where maize is commercially produced in the USA. Although no evidence exists of gene flow from maize to eastern gamagrass in nature, experimental crosses between the two species were produced using specific techniques. As part of environmental risk assessment, the possibility of transgene flow from maize to eastern gamagrass populations in nature was evaluated with the objectives: (1) to assess the seeds of eastern gamagrass populations naturally growing near commercial maize fields for the presence of a transgenic glyphosate-tolerance gene (cp4 epsps) that would indicate cross-pollination between the two species, and (2) to evaluate the possibility of interspecific hybridization between transgenic maize used as male parent and eastern gamagrass used as female parent. A total of 46,643 seeds from 54 eastern gamagrass populations collected in proximity of maize fields in Illinois, USA were planted in a field in 2014 and 2015. Emerged seedlings were treated with glyphosate herbicide and assessed for survival. An additional 48,000 seeds from the same 54 eastern gamagrass populations were tested for the presence of the cp4 epsps transgene markers using TaqMan ® PCR method. The results from these trials showed that no seedlings survived the herbicide treatment and no seed indicated presence of the herbicide tolerant cp4 epsps transgene, even though these eastern gamagrass populations were exposed to glyphosate-tolerant maize pollen for years. Furthermore, no interspecific hybrid seeds were produced from 135 hand-pollination attempts involving 1529 eastern gamagrass spikelets exposed to maize pollen. Together, these results indicate that there is no evidence of gene flow from maize to eastern gamagrass in natural habitats. The outcome of this study should be taken in consideration when assessing for environmental risks regarding the consequence of gene flow from transgenic maize to its wild relatives.

Economics, energy, and environmental assessment of diversified crop rotations in sub-Himalayas of India.

PubMed

Singh, Raman Jeet; Meena, Roshan Lal; Sharma, N K; Kumar, Suresh; Kumar, Kuldeep; Kumar, Dileep

2016-02-01

Reducing the carbon footprint and increasing energy use efficiency of crop rotations are the two most important sustainability issues of the modern agriculture. Present study was undertaken to assess economics, energy, and environmental parameters of common diversified crop rotations (maize-tomato, and maize-toria-wheat) vis-a-vis traditional crop rotations like maize-wheat, maize + ginger and rice-wheat of the north-western Himalayan region of India. Results revealed that maize-tomato and maize + ginger crop rotations being on par with each other produced significantly higher system productivity in terms of maize equivalent yield (30.2-36.2 t/ha) than other crop rotations (5.04-7.68 t/ha). But interestingly in terms of energy efficiencies, traditional maize-wheat system (energy efficiency 7.9, human energy profitability of 177.8 and energy profitability of 6.9 MJ/ha) was significantly superior over other systems. Maize + ginger rotation showed greater competitive advantage over other rotations because of less consumption of non-renewable energy resources. Similarly, maize-tomato rotation had ability of the production process to exploit natural resources due to 14-38% less use of commercial or purchased energy sources over other crop rotations. Vegetable-based crop rotations (maize + ginger and maize-tomato) maintained significantly the least carbon footprint (0.008 and 0.019 kg CO2 eq./kg grain, respectively) and the highest profitability (154,322 and 274,161 Rs./ha net return, respectively) over other crop rotations. As the greatest inputs of energy and carbon across the five crop rotations were nitrogen fertilizer (15-29% and 17-28%, respectively), diesel (14-24% and 8-19%, respectively) and irrigation (10-27% and 11-44%, respectively), therefore, alternative sources like organic farming, conservation agriculture practices, soil and water conservation measures, rain water harvesting etc. should be encouraged to reduce dependency of direct energy and external carbon inputs particularly in sub-Himalayas of India.

Root inoculation with Pseudomonas putida KT2440 induces transcriptional and metabolic changes and systemic resistance in maize plants.

PubMed

Planchamp, Chantal; Glauser, Gaetan; Mauch-Mani, Brigitte

2014-01-01

Pseudomonas putida KT2440 (KT2440) rhizobacteria colonize a wide range of plants. They have been extensively studied for their capacity to adhere to maize seeds, to tolerate toxic secondary metabolites produced by maize roots and to be attracted by maize roots. However, the response of maize plants to KT2440 colonization has not been investigated yet. Maize roots were inoculated with KT2440 and the local (roots) and systemic (leaves) early plant responses were investigated. The colonization behavior of KT2440 following application to maize seedlings was investigated and transcriptional analysis of stress- and defense-related genes as well as metabolite profiling of local and systemic maize tissues of KT2440-inoculated were performed. The local and systemic responses differed and more pronounced changes were observed in roots compared to leaves. Early in the interaction roots responded via jasmonic acid- and abscisic acid-dependent signaling. Interestingly, during later steps, the salicylic acid pathway was suppressed. Metabolite profiling revealed the importance of plant phospholipids in KT2440-maize interactions. An additional important maize secondary metabolite, a form of benzoxazinone, was also found to be differently abundant in roots 3 days after KT2440 inoculation. However, the transcriptional and metabolic changes observed in bacterized plants early during the interaction were minor and became even less pronounced with time, indicating an accommodation state of the plant to the presence of KT2440. Since the maize plants reacted to the presence of KT2440 in the rhizosphere, we also investigated the ability of these bacteria to trigger induced systemic resistance (ISR) against the maize anthracnose fungus Colletotrichum graminicola. The observed resistance was expressed as strongly reduced leaf necrosis and fungal growth in infected bacterized plants compared to non-bacterized controls, showing the potential of KT2440 to act as resistance inducers.

Root inoculation with Pseudomonas putida KT2440 induces transcriptional and metabolic changes and systemic resistance in maize plants

PubMed Central

Planchamp, Chantal; Glauser, Gaetan; Mauch-Mani, Brigitte

2014-01-01

Pseudomonas putida KT2440 (KT2440) rhizobacteria colonize a wide range of plants. They have been extensively studied for their capacity to adhere to maize seeds, to tolerate toxic secondary metabolites produced by maize roots and to be attracted by maize roots. However, the response of maize plants to KT2440 colonization has not been investigated yet. Maize roots were inoculated with KT2440 and the local (roots) and systemic (leaves) early plant responses were investigated. The colonization behavior of KT2440 following application to maize seedlings was investigated and transcriptional analysis of stress- and defense-related genes as well as metabolite profiling of local and systemic maize tissues of KT2440-inoculated were performed. The local and systemic responses differed and more pronounced changes were observed in roots compared to leaves. Early in the interaction roots responded via jasmonic acid- and abscisic acid-dependent signaling. Interestingly, during later steps, the salicylic acid pathway was suppressed. Metabolite profiling revealed the importance of plant phospholipids in KT2440-maize interactions. An additional important maize secondary metabolite, a form of benzoxazinone, was also found to be differently abundant in roots 3 days after KT2440 inoculation. However, the transcriptional and metabolic changes observed in bacterized plants early during the interaction were minor and became even less pronounced with time, indicating an accommodation state of the plant to the presence of KT2440. Since the maize plants reacted to the presence of KT2440 in the rhizosphere, we also investigated the ability of these bacteria to trigger induced systemic resistance (ISR) against the maize anthracnose fungus Colletotrichum graminicola. The observed resistance was expressed as strongly reduced leaf necrosis and fungal growth in infected bacterized plants compared to non-bacterized controls, showing the potential of KT2440 to act as resistance inducers. PMID:25628626

Attribution of maize yield increase in China to climate change and technological advancement between 1980 and 2010

NASA Astrophysics Data System (ADS)

Guo, Jianping; Zhao, Junfang; Wu, Dingrong; Mu, Jia; Xu, Yanhong

2014-12-01

Crop yields are affected by climate change and technological advancement. Objectively and quantitatively evaluating the attribution of crop yield change to climate change and technological advancement will ensure sustainable development of agriculture under climate change. In this study, daily climate variables obtained from 553 meteorological stations in China for the period 1961-2010, detailed observations of maize from 653 agricultural meteorological stations for the period 1981-2010, and results using an Agro-Ecological Zones (AEZ) model, are used to explore the attribution of maize (Zea mays L.) yield change to climate change and technological advancement. In the AEZ model, the climatic potential productivity is examined through three step-by-step levels: photosynthetic potential productivity, photosynthetic thermal potential productivity, and climatic potential productivity. The relative impacts of different climate variables on climatic potential productivity of maize from 1961 to 2010 in China are then evaluated. Combined with the observations of maize, the contributions of climate change and technological advancement to maize yield from 1981 to 2010 in China are separated. The results show that, from 1961 to 2010, climate change had a significant adverse impact on the climatic potential productivity of maize in China. Decreased radiation and increased temperature were the main factors leading to the decrease of climatic potential productivity. However, changes in precipitation had only a small effect. The maize yields of the 14 main planting provinces in China increased obviously over the past 30 years, which was opposite to the decreasing trends of climatic potential productivity. This suggests that technological advancement has offset the negative effects of climate change on maize yield. Technological advancement contributed to maize yield increases by 99.6%-141.6%, while climate change contribution was from -41.4% to 0.4%. In particular, the actual maize yields in Shandong, Henan, Jilin, and Inner Mongolia increased by 98.4, 90.4, 98.7, and 121.5 kg hm-2 yr-1 over the past 30 years, respectively. Correspondingly, the maize yields affected by technological advancement increased by 113.7, 97.9, 111.5, and 124.8 kg hm-2 yr-1, respectively. On the contrary, maize yields reduced markedly under climate change, with an average reduction of -9.0 kg hm-2 yr-1. Our findings highlight that agronomic technological advancement has contributed dominantly to maize yield increases in China in the past three decades.

Natural variation in maize aphid resistance is associated with 2,4-Dihydroxy-7-Methoxy-1,4-Benzoxazin-3-One Glucoside Methyltransferase activity

USDA-ARS?s Scientific Manuscript database

Plants differ greatly in their susceptibility to insect herbivory, suggesting both local adaptation and resistance tradeoffs. We used maize (Zea mays) recombinant inbred lines to map a quantitative trait locus (QTL) for the maize leaf aphid (Rhopalosiphum maidis) susceptibility to maize Chromosome 1...

Large scale field inoculation and scoring of maize southern leaf blight and other maize foliar fungal diseases

USDA-ARS?s Scientific Manuscript database

Field-grown maize is inoculated with Cochliobolus heterostrophus, causal agent of Southern Leaf Blight disease, by dropping sorghum grains infested with the fungus into the whorl of each maize plant at an early stage of growth. The initial lesions produce secondary inoculum that is dispersed by wind...

Moisture content, insect pests and mycotoxin levels of maize at harvest and post-harvest in the Middle Belt of Ghana

USDA-ARS?s Scientific Manuscript database

Moisture content, insect pest infestation and mycotoxin contamination of maize are challenges to food safety and security, especially in the tropics where maize is a staple grain. However, very little documentation is available on the impact of these factors on maize in Ghana. This study focused on ...

Physiological and molecular analysis of selected Kenyan maize lines for aluminum tolerance

USDA-ARS?s Scientific Manuscript database

Aluminum (Al) toxicity is an important limitation to maize production in many tropical and sub-tropical acid soil areas. The aim of this study was to survey the variation in Al tolerance in a panel of maize lines adapted for Kenya and look for novel sources of Al tolerance. 112 Kenyan maize accessio...

Seed treatments enhance photosynthesis in maize seedlings by reducing infection with Fusarium spp. and consequent disease development in maize

USDA-ARS?s Scientific Manuscript database

The effects of a seed treatment on early season growth, seedling disease development, incidence Fusarium spp. infection, and photosynthetic performance of maize were evaluated at two locations in Iowa in 2007. Maize seed was either treated with Cruiser 2Extreme 250 ® (fludioxonil + azoxystrobin + me...

MaizeGDB update: New tools, data, and interface for the maize model organism database

USDA-ARS?s Scientific Manuscript database

MaizeGDB is a highly curated, community-oriented database and informatics service to researchers focused on the crop plant and model organism Zea mays ssp. mays. Although some form of the maize community database has existed over the last 25 years, there have only been two major releases. In 1991, ...

Effects of corn fiber gum (CFG) on the pasting and thermal behaviors of maize starch

USDA-ARS?s Scientific Manuscript database

Corn fiber gum (CFG) is a novel arabinoxylan hydrocolloid. Recent research showed its considerable potential in food processing. In this study, the interactions of maize starch and CFG were studied. Maize starch/CFG blend gels were prepared from maize starch suspension mixed with 0.1%, 0.25%, 0.5%, ...

MaizeGDB: The Maize Genetics and Genomics Database.

PubMed

Harper, Lisa; Gardiner, Jack; Andorf, Carson; Lawrence, Carolyn J

2016-01-01

MaizeGDB is the community database for biological information about the crop plant Zea mays. Genomic, genetic, sequence, gene product, functional characterization, literature reference, and person/organization contact information are among the datatypes stored at MaizeGDB. At the project's website ( http://www.maizegdb.org ) are custom interfaces enabling researchers to browse data and to seek out specific information matching explicit search criteria. In addition, pre-compiled reports are made available for particular types of data and bulletin boards are provided to facilitate communication and coordination among members of the community of maize geneticists.

A Single Molecule Scaffold for the Maize Genome

PubMed Central

Zhou, Shiguo; Wei, Fusheng; Nguyen, John; Bechner, Mike; Potamousis, Konstantinos; Goldstein, Steve; Pape, Louise; Mehan, Michael R.; Churas, Chris; Pasternak, Shiran; Forrest, Dan K.; Wise, Roger; Ware, Doreen; Wing, Rod A.; Waterman, Michael S.; Livny, Miron; Schwartz, David C.

2009-01-01

About 85% of the maize genome consists of highly repetitive sequences that are interspersed by low-copy, gene-coding sequences. The maize community has dealt with this genomic complexity by the construction of an integrated genetic and physical map (iMap), but this resource alone was not sufficient for ensuring the quality of the current sequence build. For this purpose, we constructed a genome-wide, high-resolution optical map of the maize inbred line B73 genome containing >91,000 restriction sites (averaging 1 site/∼23 kb) accrued from mapping genomic DNA molecules. Our optical map comprises 66 contigs, averaging 31.88 Mb in size and spanning 91.5% (2,103.93 Mb/∼2,300 Mb) of the maize genome. A new algorithm was created that considered both optical map and unfinished BAC sequence data for placing 60/66 (2,032.42 Mb) optical map contigs onto the maize iMap. The alignment of optical maps against numerous data sources yielded comprehensive results that proved revealing and productive. For example, gaps were uncovered and characterized within the iMap, the FPC (fingerprinted contigs) map, and the chromosome-wide pseudomolecules. Such alignments also suggested amended placements of FPC contigs on the maize genetic map and proactively guided the assembly of chromosome-wide pseudomolecules, especially within complex genomic regions. Lastly, we think that the full integration of B73 optical maps with the maize iMap would greatly facilitate maize sequence finishing efforts that would make it a valuable reference for comparative studies among cereals, or other maize inbred lines and cultivars. PMID:19936062

Bt maize and integrated pest management--a European perspective.

PubMed

Meissle, Michael; Romeis, Jörg; Bigler, Franz

2011-09-01

The European corn borer (Ostrinia nubilalis), the Mediterranean corn borer (Sesamia nonagrioides) and the western corn rootworm (Diabrotica virgifera virgifera) are the main arthropod pests in European maize production. Practised pest control includes chemical control, biological control and cultural control such as ploughing and crop rotation. A pest control option that is available since 1996 is maize varieties that are genetically engineered (GE) to produce insecticidal compounds. GE maize varieties available today express one or several genes from Bacillus thuringiensis (Bt) that target corn borers or corn rootworms. Incentives to growing Bt maize are simplified farm operations, high pest control efficiency, improved grain quality and ecological benefits. Limitations include the risk of resistance evolution in target pest populations, risk of secondary pest outbreaks and increased administration to comply with licence agreements. Growers willing to plant Bt maize in the European Union (EU) often face the problem that authorisation is denied. Only one Bt maize transformation event (MON810) is currently authorised for commercial cultivation, and some national authorities have banned cultivation. Spain is the only EU member state where Bt maize adoption levels are currently delivering farm income gains near full potential levels. In an integrated pest management (IPM) context, Bt maize can be regarded as a preventive (host plant resistance) or a responsive pest control measure. In any case, Bt maize is a highly specific tool that efficiently controls the main pests and allows combination with other preventive or responsive measures to solve other agricultural problems including those with secondary pests. Copyright © 2011 Society of Chemical Industry.

Complete sequence and diversity of a maize-associated Polerovirus in East Africa.

PubMed

Massawe, Deogracious P; Stewart, Lucy R; Kamatenesi, Jovia; Asiimwe, Theodore; Redinbaugh, Margaret G

2018-06-01

Since 2011-2012, Maize lethal necrosis (MLN) has emerged in East Africa, causing massive yield loss and propelling research to identify viruses and virus populations present in maize. As expected, next generation sequencing (NGS) has revealed diverse and abundant viruses from the family Potyviridae, primarily sugarcane mosaic virus (SCMV), and maize chlorotic mottle virus (MCMV) (Tombusviridae), which are known to cause MLN by synergistic co-infection. In addition to these expected viruses, we identified a virus in the genus Polerovirus (family Luteoviridae) in 104/172 samples selected for MLN or other potential virus symptoms from Kenya, Uganda, Rwanda, and Tanzania. This polerovirus (MF974579) nucleotide sequence is 97% identical to maize-associated viruses recently reported in China, termed 'maize yellow mosaic virus' (MaYMV) and maize yellow dwarf virus (MaYMV; KU291101, KU291107, MYDV-RMV2; KT992824); and 99% identical to MaYMV (KY684356) infecting sugarcane and itch grass in Nigeria; 83% identical to a barley-associated polerovirus recently identified in Korea (BVG; KT962089); and 79% identical to the U.S. maize-infecting polerovirus maize yellow dwarf virus (MYDV-RMV; KT992824). Nucleotide sequences from ORF0 of 20 individual East African isolates collected from Kenya, Uganda, Rwanda, and Tanzania shared 98% or higher identity, and were detected in 104/172 (60.5%) of samples collected for virus-like symptoms, indicating extensive prevalence but limited diversity of this virus in East Africa. We refer to this virus as "MYDV-like polerovirus" until symptoms of the virus in maize are known.

Maize Elongin C interacts with the viral genome-linked protein, VPg, of Sugarcane mosaic virus and facilitates virus infection

PubMed Central

Zhu, Min; Chen, Yuting; Ding, Xin Shun; Webb, Stephen L; Zhou, Tao; Nelson, Richard S; Fan, Zaifeng

2014-01-01

The viral genome-linked protein, VPg, of potyviruses is involved in viral genome replication and translation. To determine host proteins that interact with Sugarcane mosaic virus (SCMV) VPg, a yeast two-hybrid screen was used and a maize (Zea mays) Elongin C (ZmElc) protein was identified. ZmELC transcript was observed in all maize organs, but most highly in leaves and pistil extracts, and ZmElc was present in the cytoplasm and nucleus of maize cells in the presence or absence of SCMV. ZmELC expression was increased in maize tissue at 4 and 6 d post SCMV inoculation. When ZmELC was transiently overexpressed in maize protoplasts the accumulation of SCMV RNA was approximately doubled compared with the amount of virus in control protoplasts. Silencing ZmELC expression using a Brome mosaic virus-based gene silencing vector (virus-induced gene silencing) did not influence maize plant growth and development, but did decrease RNA accumulation of two isolates of SCMV and host transcript encoding ZmeIF4E during SCMV infection. Interestingly, Maize chlorotic mottle virus, from outside the Potyviridae, was increased in accumulation after silencing ZmELC expression. Our results describe both the location of ZmElc expression in maize and a new activity associated with an Elc: support of potyvirus accumulation. PMID:24954157

Maize Elongin C interacts with the viral genome-linked protein, VPg, of Sugarcane mosaic virus and facilitates virus infection.

PubMed

Zhu, Min; Chen, Yuting; Ding, Xin Shun; Webb, Stephen L; Zhou, Tao; Nelson, Richard S; Fan, Zaifeng

2014-09-01

The viral genome-linked protein, VPg, of potyviruses is involved in viral genome replication and translation. To determine host proteins that interact with Sugarcane mosaic virus (SCMV) VPg, a yeast two-hybrid screen was used and a maize (Zea mays) Elongin C (ZmElc) protein was identified. ZmELC transcript was observed in all maize organs, but most highly in leaves and pistil extracts, and ZmElc was present in the cytoplasm and nucleus of maize cells in the presence or absence of SCMV. ZmELC expression was increased in maize tissue at 4 and 6 d post SCMV inoculation. When ZmELC was transiently overexpressed in maize protoplasts the accumulation of SCMV RNA was approximately doubled compared with the amount of virus in control protoplasts. Silencing ZmELC expression using a Brome mosaic virus-based gene silencing vector (virus-induced gene silencing) did not influence maize plant growth and development, but did decrease RNA accumulation of two isolates of SCMV and host transcript encoding ZmeIF4E during SCMV infection. Interestingly, Maize chlorotic mottle virus, from outside the Potyviridae, was increased in accumulation after silencing ZmELC expression. Our results describe both the location of ZmElc expression in maize and a new activity associated with an Elc: support of potyvirus accumulation. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

A challenge for the seed mixture refuge strategy in Bt maize: impact of cross-pollination on an ear-feeding pest, corn earworm.

PubMed

Yang, Fei; Kerns, David L; Head, Graham P; Leonard, B Rogers; Levy, Ronnie; Niu, Ying; Huang, Fangneng

2014-01-01

To counter the threat of insect resistance, Bacillus thuringiensis (Bt) maize growers in the U.S. are required to plant structured non-Bt maize refuges. Concerns with refuge compliance led to the introduction of seed mixtures, also called RIB (refuge-in-the-bag), as an alternative approach for implementing refuge for Bt maize products in the U.S. Maize Belt. A major concern in RIB is cross-pollination of maize hybrids that can cause Bt proteins to be present in refuge maize kernels and negatively affect refuge insects. Here we show that a mixed planting of 5% nonBt and 95% Bt maize containing the SmartStax traits expressing Cry1A.105, Cry2Ab2 and Cry1F did not provide an effective refuge for an important above-ground ear-feeding pest, the corn earworm, Helicoverpa zea (Boddie). Cross-pollination in RIB caused a majority (>90%) of refuge kernels to express ≥ one Bt protein. The contamination of Bt proteins in the refuge ears reduced neonate-to-adult survivorship of H. zea to only 4.6%, a reduction of 88.1% relative to larvae feeding on ears of pure non-Bt maize plantings. In addition, the limited survivors on refuge ears had lower pupal mass and took longer to develop to adults.

Reproduction of the whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) B biotype in maize fields (Zea mays L.) in Brazil.

PubMed

Quintela, Eliane D; Abreu, Aluana G; Lima, Julyana F Dos S; Mascarin, Gabriel M; Santos, Jardel B Dos; Brown, Judith K

2016-11-01

Bemisia tabaci (Genn.) (Hemiptera: Aleyrodidae) was observed to have completed its reproductive cycle from the egg to the adult on maize (Zea mays L.). Field and screenhouse studies were carried out to investigate the durability of this putative and unprecedented adaptation to a grass host. Analysis of the mitochondrial COI gene sequence identified the maize-associated B. tabaci as the exotic B biotype (major clade North Africa-Mediterranean-Middle East). Results showed that whiteflies migrated from soybean crops and successfully established in maize plants. Females exhibited a preference for oviposition primarily on the first and second leaves of maize, but were also able to colonise developing leaves. A high, natural infestation on maize (193.3 individuals, all developmental stages) was observed within a 7.1 cm 2 designated 'observation area'. Whiteflies collected from naturally infested maize leaves and allowed to oviposit on maize seedlings grown in a screenhouse developed from egg to adulthood in 28.6 ± 0.2 days. This is the first report of the B biotype completing its development on maize plants. This surprising anomaly indicates that the B biotype is capable of adapting to monocotyledonous host plants, and importantly, broadens the host range to include at least one species in the Poaceae. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Analysis of Nutritional Traits and Aflatoxin Contamination in Selected Maize Varieties from Pakistan.

PubMed

Majeed, Saima; Iqbal, Mazhar; Asi, Muhammad Rafique; Iqbal, Shahzad Zafar; Selamat, Jinap

2017-12-01

Recently, cultivation of high-yielding hybrid maize varieties has revolutionized maize production in Pakistan. Analyses of nutritional traits and aflatoxin (AF) contamination in these varieties can aid in the identification of susceptible and resistant varieties, particularly for cultivation in the Pakistani agro-climatic environment. Five spring maize varieties-Pioneer, Neelam, DK-919, Desi, and Hi-maize-were selected for analyses of their nutritional, tocopherol, and AF contents. Protein, carbohydrate, oil, ash, fiber, and moisture contents ranged between 8.7 and 10.8%, 68 and 71%, 3.72 and 5.56%, 1.09 and 1.81%, 1.1 and 3.1%, and 11.7 and 14.2%, respectively. Tocopherol levels in selected varieties were in the range of 461 to 1,430 μg/g. Hi-maize exhibited significantly higher protein and tocopherol contents than the other varieties, indicating its better suitability for feed and silage applications. The highest mean level of total AFs, 14.5 ± 0.12 μg/kg, was found in Desi, and results showed that the most dominant AF found in the maize varieties was AFB 1 . Furthermore, the results showed that the higher the level of tocopherol, the lower the concentration of total AFs and vice versa in maize varieties. The results can be used to investigate additional susceptible maize varieties that are resistant to fungal attack.

Ecological guild and enzyme activities of rhizosphere soil microbial communities associated with Bt-maize cultivation under field conditions in North West Province of South Africa.

PubMed

van Wyk, Deidré A B; Adeleke, Rasheed; Rhode, Owen H J; Bezuidenhout, Carlos C; Mienie, Charlotte

2017-09-01

Insecticidal proteins expressed by genetically modified Bt maize may alter the enzymatic and microbial communities associated with rhizosphere soil. This study investigated the structure and enzymatic activity of rhizosphere soil microbial communities associated with field grown Bt and non-Bt maize. Rhizosphere soil samples were collected from Bt and non-Bt fields under dryland and irrigated conditions. Samples were subjected to chemical tests, enzyme analyses, and next generation sequencing. Results showed that nitrate and phosphorus concentrations were significantly higher in non-Bt maize dryland soils, while organic carbon was significantly higher in non-Bt maize irrigated field soil. Acid phosphatase and β-glucosidase activities were significantly reduced in soils under Bt maize cultivation. The species diversity differed between fields and Bt and non-Bt maize soils. Results revealed that Actinobacteria, Proteobacteria, and Acidobacteria were the dominant phyla present in these soils. Redundancy analyses indicated that some chemical properties and enzyme activities could explain differences in bacterial community structures. Variances existed in microbial community structures between Bt and non-Bt maize fields. There were also differences between the chemical and biochemical properties of rhizosphere soils under Bt and non-Bt maize cultivation. These differences could be related to agricultural practices and cultivar type. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Spatial pattern characteristics of water footprint for maize production in Northeast China.

PubMed

Duan, Peili; Qin, Lijie; Wang, Yeqiao; He, Hongshi

2016-01-30

Water footprint (WF) methodology is essential for quantifying total water consumption of crop production and making efficient water management policies. This study calculated the green, blue, grey and total WFs of maize production in Northeast China from 1998 to 2012 and compared the values of the provinces. This study also analyzed the spatial variation and structure characteristics of the WFs at the prefecture level. The annual average WF of maize production was 1029 m(3) per ton, which was 51% green, 21% blue and 28% grey. The WF of maize production was highest in Liaoning Province, moderate in Heilongjiang Province and lowest in Jilin Province. The spatial differences of the WFs calculated for the 36 major maize production prefectures were significant in Northeast China. There was a moderate positive spatial autocorrelation among prefectures that had similar WFs. Local indicator of spatial autocorrelation index (LISA) analysis identified prefectures with higher WFs in the southeast region of Liaoning Province and the southwest region of Heilongjiang Province and prefectures with lower WFs in the middle of Jilin Province. Spatial differences in the WF of maize production were caused mainly by variations in climate conditions, soil quality, irrigation facilities and maize yield. The spatial distribution of WFs can help provide a scientific basis for optimizing maize production distribution and then formulate strategies to reduce the WF of maize production. © 2015 Society of Chemical Industry.

The earliest maize from San Marcos Tehuacán is a partial domesticate with genomic evidence of inbreeding

PubMed Central

Vallebueno-Estrada, Miguel; Rodríguez-Arévalo, Isaac; Rougon-Cardoso, Alejandra; Martínez González, Javier; García Cook, Angel; Vielle-Calzada, Jean-Philippe

2016-01-01

Pioneering archaeological expeditions lead by Richard MacNeish in the 1960s identified the valley of Tehuacán as an important center of early Mesoamerican agriculture, providing by far the widest collection of ancient crop remains, including maize. In 2012, a new exploration of San Marcos cave (Tehuacán, Mexico) yielded nonmanipulated maize specimens dating at a similar age of 5,300–4,970 calibrated y B.P. On the basis of shotgun sequencing and genomic comparisons to Balsas teosinte and modern maize, we show herein that the earliest maize from San Marcos cave was a partial domesticate diverging from the landraces and containing ancestral allelic variants that are absent from extant maize populations. Whereas some domestication loci, such as teosinte branched1 (tb1) and brittle endosperm2 (bt2), had already lost most of the nucleotide variability present in Balsas teosinte, others, such as teosinte glume architecture1 (tga1) and sugary1 (su1), conserved partial levels of nucleotide variability that are absent from extant maize. Genetic comparisons among three temporally convergent samples revealed that they were homozygous and identical by descent across their genome. Our results indicate that the earliest maize from San Marcos was already inbred, opening the possibility for Tehuacán maize cultivation evolving from reduced founder populations of isolated and perhaps self-pollinated individuals. PMID:27872313

Managing fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae), with Bt maize and insecticides in southern Brazil.

PubMed

Burtet, Leonardo M; Bernardi, Oderlei; Melo, Adriano A; Pes, Maiquel P; Strahl, Thiago T; Guedes, Jerson Vc

2017-12-01

Maize plants expressing insecticidal proteins of Bacillus thuringiensis are valuable options for managing fall armyworm (FAW), Spodoptera frugiperda, in Brazil. However, control failures were reported, and therefore insecticides have been used to control this species. Based on these, we evaluated the use of Bt maize and its integration with insecticides against FAW in southern Brazil. Early-planted Agrisure TL, Herculex, Optimum Intrasect and non-Bt maize plants were severely damaged by FAW and required up to three insecticidal sprays. In contrast, YieldGard VT Pro, YieldGard VT Pro 3, PowerCore, Agrisure Viptera and Agrisure Viptera 3 showed little damage and did not require insecticides. Late-planted Bt maize plants showed significant damage by FAW and required up to four sprays, with the exceptions of Agrisure Viptera and Agrisure Viptera 3. Exalt (first and second sprays); Lannate + Premio (first spray) and Avatar (second spray); and Karate + Match (first spray) and Ampligo (second spray) were the most effective insecticides against FAW larvae in Bt and non-Bt maize. Maize plants expressing Cry proteins exhibited FAW control failures in southern Brazil, necessitating insecticidal sprays. In contrast, Bt maize containing the Vip3Aa20 protein remained effective against FAW. However, regardless of the insecticide used against FAW surviving on Bt maize, grain yields were similar. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

The earliest maize from San Marcos Tehuacán is a partial domesticate with genomic evidence of inbreeding.

PubMed

Vallebueno-Estrada, Miguel; Rodríguez-Arévalo, Isaac; Rougon-Cardoso, Alejandra; Martínez González, Javier; García Cook, Angel; Montiel, Rafael; Vielle-Calzada, Jean-Philippe

2016-12-06

Pioneering archaeological expeditions lead by Richard MacNeish in the 1960s identified the valley of Tehuacán as an important center of early Mesoamerican agriculture, providing by far the widest collection of ancient crop remains, including maize. In 2012, a new exploration of San Marcos cave (Tehuacán, Mexico) yielded nonmanipulated maize specimens dating at a similar age of 5,300-4,970 calibrated y B.P. On the basis of shotgun sequencing and genomic comparisons to Balsas teosinte and modern maize, we show herein that the earliest maize from San Marcos cave was a partial domesticate diverging from the landraces and containing ancestral allelic variants that are absent from extant maize populations. Whereas some domestication loci, such as teosinte branched1 (tb1) and brittle endosperm2 (bt2), had already lost most of the nucleotide variability present in Balsas teosinte, others, such as teosinte glume architecture1 (tga1) and sugary1 (su1), conserved partial levels of nucleotide variability that are absent from extant maize. Genetic comparisons among three temporally convergent samples revealed that they were homozygous and identical by descent across their genome. Our results indicate that the earliest maize from San Marcos was already inbred, opening the possibility for Tehuacán maize cultivation evolving from reduced founder populations of isolated and perhaps self-pollinated individuals.

Out of America: tracing the genetic footprints of the global diffusion of maize.

PubMed

Mir, C; Zerjal, T; Combes, V; Dumas, F; Madur, D; Bedoya, C; Dreisigacker, S; Franco, J; Grudloyma, P; Hao, P X; Hearne, S; Jampatong, C; Laloë, D; Muthamia, Z; Nguyen, T; Prasanna, B M; Taba, S; Xie, C X; Yunus, M; Zhang, S; Warburton, M L; Charcosset, A

2013-11-01

Maize was first domesticated in a restricted valley in south-central Mexico. It was diffused throughout the Americas over thousands of years, and following the discovery of the New World by Columbus, was introduced into Europe. Trade and colonization introduced it further into all parts of the world to which it could adapt. Repeated introductions, local selection and adaptation, a highly diverse gene pool and outcrossing nature, and global trade in maize led to difficulty understanding exactly where the diversity of many of the local maize landraces originated. This is particularly true in Africa and Asia, where historical accounts are scarce or contradictory. Knowledge of post-domestication movements of maize around the world would assist in germplasm conservation and plant breeding efforts. To this end, we used SSR markers to genotype multiple individuals from hundreds of representative landraces from around the world. Applying a multidisciplinary approach combining genetic, linguistic, and historical data, we reconstructed possible patterns of maize diffusion throughout the world from American "contribution" centers, which we propose reflect the origins of maize worldwide. These results shed new light on introductions of maize into Africa and Asia. By providing a first globally comprehensive genetic characterization of landraces using markers appropriate to this evolutionary time frame, we explore the post-domestication evolutionary history of maize and highlight original diversity sources that may be tapped for plant improvement in different regions of the world.

Carotenoid Stability during Dry Milling, Storage, and Extrusion Processing of Biofortified Maize Genotypes.

PubMed

Ortiz, Darwin; Ponrajan, Amudhan; Bonnet, Juan Pablo; Rocheford, Torbert; Ferruzzi, Mario G

2018-05-09

Translation of the breeding efforts designed to biofortify maize ( Z. mays) genotypes with higher levels of provitamin A carotenoid (pVAC) content for sub-Saharan Africa is dependent in part on the stability of carotenoids during postharvest through industrial and in-home food processing operations. The purpose of this study was to simulate production of commercial milled products by determining the impact of dry milling and extrusion processing on carotenoid stability in three higher pVAC maize genotypes (C17xDE3, Orange ISO, Hi27xCML328). Pericarp and germ removal of biofortified maize kernels resulted in ∼10% loss of total carotenoids. Separating out the maize flour fraction (<212 μm) resulted in an additional ∼15% loss of total carotenoids. Carotenoid degradation was similar across milled maize fractions. Dry-milled products of Orange ISO and Hi27xCML328 genotypes showed ∼28% pVAC loss after 90-days storage. Genotype C17xDE3, with highest levels of all- trans-β-carotene, showed a 68% pVAC loss after 90-day storage. Extrusion processing conditions were optimal at 35% extrusion moisture, producing fully cooked instant maize flours with high pVAC retention (70-93%). These results support the notion that postharvest losses in maize milled fractions may be dependent, in part, on genotype and that extrusion processing may provide an option for preserving biofortified maize products.

Relative contribution of maize and external manure amendment to soil carbon sequestration in a long-term intensive maize cropping system

PubMed Central

Zhang, Wenju; Liu, Kailou; Wang, Jinzhou; Shao, Xingfang; Xu, Minggang; Li, Jianwei; Wang, Xiujun; Murphy, Daniel V.

2015-01-01

We aimed to quantify the relative contributions of plant residue and organic manure to soil carbon sequestration. Using a 27-year-long inorganic fertilizer and manure amendment experiment in a maize (Zea mays L.) double-cropping system, we quantified changes in harvestable maize biomass and soil organic carbon stocks (0–20 cm depth) between 1986-2012. By employing natural 13C tracing techniques, we derived the proportional contributions of below-ground crop biomass return (maize-derived carbon) and external manure amendment (manure-derived carbon) to the total soil organic carbon stock. The average retention of maize-derived carbon plus manure-derived carbon during the early period of the trial (up to 11 years) was relatively high (10%) compared to the later period (22 to 27 years, 5.1–6.3%). About 11% of maize-derived carbon was converted to soil organic carbon, which was double the retention of manure-derived carbon (4.4–5.1%). This result emphasized that organic amendments were necessary to a win-win strategy for both SOC sequestration and maize production. PMID:26039186

Fast-Flowering Mini-Maize: Seed to Seed in 60 Days

PubMed Central

McCaw, Morgan E.; Wallace, Jason G.; Albert, Patrice S.; Buckler, Edward S.; Birchler, James A.

2016-01-01

Two lines of Zea mays were developed as a short-generation model for maize. The Fast-Flowering Mini-Maize (FFMM) lines A and B are robust inbred lines with a significantly shorter generation time, much smaller stature, and better greenhouse adaptation than traditional maize varieties. Five generations a year are typical. FFMM is the result of a modified double-cross hybrid between four fast-flowering lines: Neuffer’s Early ACR (full color), Alexander’s Early Early Synthetic, Tom Thumb Popcorn, and Gaspe Flint, followed by selection for early flowering and desirable morphology throughout an 11-generation selfing regime. Lines A and B were derived from different progeny of the initial hybrid, and crosses between Mini-Maize A and B exhibit heterosis. The ancestry of each genomic region of Mini-Maize A and B was inferred from the four founder populations using genotyping by sequencing. Other genetic and genomic tools for these lines include karyotypes for both lines A and B, kernel genetic markers y1 (white endosperm) and R1-scm2 (purple endosperm and embryo) introgressed into Mini-Maize A, and ∼24× whole-genome resequencing data for Mini-Maize A. PMID:27440866

Growing sensitivity of maize to water scarcity under climate change.

PubMed

Meng, Qingfeng; Chen, Xinping; Lobell, David B; Cui, Zhenling; Zhang, Yi; Yang, Haishun; Zhang, Fusuo

2016-01-25

Climate change can reduce crop yields and thereby threaten food security. The current measures used to adapt to climate change involve avoiding crops yield decrease, however, the limitations of such measures due to water and other resources scarcity have not been well understood. Here, we quantify how the sensitivity of maize to water availability has increased because of the shift toward longer-maturing varieties during last three decades in the Chinese Maize Belt (CMB). We report that modern, longer-maturing varieties have extended the growing period by an average of 8 days and have significantly offset the negative impacts of climate change on yield. However, the sensitivity of maize production to water has increased: maize yield across the CMB was 5% lower with rainfed than with irrigated maize in the 1980s and was 10% lower (and even >20% lower in some areas) in the 2000s because of both warming and the increased requirement for water by the longer-maturing varieties. Of the maize area in China, 40% now fails to receive the precipitation required to attain the full yield potential. Opportunities for water saving in maize systems exist, but water scarcity in China remains a serious problem.

Comparative impact of genetically modified and non modified maize (Zea mays L.) on succeeding crop and associated weed.

PubMed

Ibrahim, Muhammad; Ahmed, Naseer; Ullah, Faizan; Shinwari, Zabta Khan; Bano, Asghari

2016-04-01

This research work documents the comparative impact of genetically modified (GM) (insect resistance) and non modified maize (Zea mays L.) on growth and germination of succeeding crop wheat (Triticum aestivum L.) and associated weed (Avena fatua L.). The aqueous extracts of both the GM and non-GM maize exhibited higher phenolic content than that of methanolic extracts. Germination percentage and germination index of wheat was significantly decreased by GM methanolic extract (10%) as well as that of non-GM maize at 3% aqueous extract. Similarly germination percentage of weed (Avena fatua L.) was significantly reduced by application of 3% and 5% methanolic GM extracts. All extracts of GM maize showed non-significant effect on the number of roots, root length and shoot length per plant but 5% and 10% methanolic extracts of non-GM maize significantly increased the number of roots per plant of wheat seedling. Similarly, 10% methanolic extract of GM maize significantly increased the number of roots per plant of weed seedling. Methanolic extracts of GM and non-GM maize (3% and 5%) significantly decreased the protease activity in wheat as compared to untreated control. © The Author(s) 2013.

Accumulation of Hydrocarbons by Maize (Zea mays L.) in Remediation of Soils Contaminated with Crude Oil.

PubMed

Liao, Changjun; Xu, Wending; Lu, Guining; Liang, Xujun; Guo, Chuling; Yang, Chen; Dang, Zhi

2015-01-01

This study has investigated the use of screened maize for remediation of soil contaminated with crude oil. Pots experiment was carried out for 60 days by transplanting maize seedlings into spiked soils. The results showed that certain amount of crude oil in soil (≤2 147 mg·kg(-1)) could enhance the production of shoot biomass of maize. Higher concentration (6 373 mg·kg(-1)) did not significantly inhibit the growth of plant maize (including shoot and root). Analysis of plant shoot by GC-MS showed that low molecular weight polycyclic aromatic hydrocarbons (PAHs) were detected in maize tissues, but PAHs concentration in the plant did not increase with higher concentration of crude oil in soil. The reduction of total petroleum hydrocarbon in planted soil was up to 52.21-72.84%, while that of the corresponding controls was only 25.85-34.22% in two months. In addition, data from physiological and biochemical indexes demonstrated a favorable adaptability of maize to crude oil pollution stress. This study suggested that the use of maize (Zea mays L.) was a good choice for remediation of soil contaminated with petroleum within a certain range of concentrations.

CERES-Maize model-based simulation of climate change impacts on maize yields and potential adaptive measures in Heilongjiang Province, China.

PubMed

Lin, Yumei; Wu, Wenxiang; Ge, Quansheng

2015-11-01

Climate change would cause negative impacts on future agricultural production and food security. Adaptive measures should be taken to mitigate the adverse effects. The objectives of this study were to simulate the potential effects of climate change on maize yields in Heilongjiang Province and to evaluate two selected typical household-level autonomous adaptive measures (cultivar changes and planting time adjustments) for mitigating the risks of climate change based on the CERES-Maize model. The results showed that flowering duration and maturity duration of maize would be shortened in the future climate and thus maize yield would reduce by 11-46% during 2011-2099 relative to 1981-2010. Increased CO2 concentration would not benefit maize production significantly. However, substituting local cultivars with later-maturing ones and delaying the planting date could increase yields as the climate changes. The results provide insight regarding the likely impacts of climate change on maize yields and the efficacy of selected adaptive measures by presenting evidence-based implications and mitigation strategies for the potential negative impacts of future climate change. © 2014 Society of Chemical Industry.

A transposable element in a NAC gene is associated with drought tolerance in maize seedlings

PubMed Central

Mao, Hude; Wang, Hongwei; Liu, Shengxue; Li, Zhigang; Yang, Xiaohong; Yan, Jianbing; Li, Jiansheng; Tran, Lam-Son Phan; Qin, Feng

2015-01-01

Drought represents a major constraint on maize production worldwide. Understanding the genetic basis for natural variation in drought tolerance of maize may facilitate efforts to improve this trait in cultivated germplasm. Here, using a genome-wide association study, we show that a miniature inverted-repeat transposable element (MITE) inserted in the promoter of a NAC gene (ZmNAC111) is significantly associated with natural variation in maize drought tolerance. The 82-bp MITE represses ZmNAC111 expression via RNA-directed DNA methylation and H3K9 dimethylation when heterologously expressed in Arabidopsis. Increasing ZmNAC111 expression in transgenic maize enhances drought tolerance at the seedling stage, improves water-use efficiency and induces upregulation of drought-responsive genes under water stress. The MITE insertion in the ZmNAC111 promoter appears to have occurred after maize domestication and spread among temperate germplasm. The identification of this MITE insertion provides insight into the genetic basis for natural variation in maize drought tolerance. PMID:26387805

Density equation of bio-coal briquettes and quantity of maize cob in Phitsanulok, Thailand

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patomsok Wilaipon

One of the most important crops in Phitsanulok, a province in Northern Thailand, is maize. BaseD on the calculation, the quantity of maize cob produced in this region was approximately 220 kton year{sup -1}. The net heating value of maize cob was found to be 14.2 MJ kg{sup -1}. Therefore, the total energy over 874 TJ year-1 can be obtained from this agricultural waste. In the experiments, maize cob was utilized as the major ingredient for producing biomass-coal briquettes. The maize cob was treated with sodium hydroxide solution before mixing with coal fine. The ratios of coal:maize were 1:2 andmore » 1:3, respectively. The range of briquetting pressures was from 4-8 MPa. The result showed that the density was strongly affected by both parameters. Finally, the relationship between biomass ratio, briquetting pressures and briquette density was developed and validated by using regression technique. 13 refs., 2 figs.« less

[Dynamics of soil P pool in a long-term fertilizing experiment of wheat-maize rotation. I. Crop yield effect of fertilizer P and dynamics of soil total P and inorganic P].

PubMed

Liu, J; Zhang, F

2000-06-01

The effects of long-term applying fertilizer P and manure on the pools of soil total P and inorganic P and the crop yield in rotation of winter wheat-summer maize-->spring maize were studied. The results showed that the pool of soil total P and inorganic P were increased by applying fertilizer P and manure, and the phosphorus mostly accumulated in soil was inorganic P. The critical amounts of fertilizer P (P2O5) for balancing soil P were 94.7 kg.hm-2 to winter wheat-summer maize and 51.5 kg.hm-2 to spring maize. Based on regression equations, the application rates of fertilizer P (P2O5) for economic optimum and highest yields were 135.8 and 149.8 kg.hm-2 to winter wheat-summer maize, and 88.6 and 95.9 kg.hm-2 to spring maize, respectively.

A comparative study of annealing of waxy, normal and high-amylose maize starches: the role of amylose molecules.

PubMed

Wang, Shujun; Wang, Jinrong; Yu, Jinglin; Wang, Shuo

2014-12-01

The effect of annealing on starch structure and functionality of three maize starches (waxy, normal and high-amylose) was investigated, with the aim of understanding the role of amylose molecules during starch annealing. Amylose content, granular morphology and crystallinity of maize starches were little affected by annealing treatment. Annealing treatment did not alter the swelling power of waxy maize starch, but reduced the swelling power of normal and high-amylose maize starches. The thermal transition temperatures were increased, and the temperature range was decreased, but the enthalpy change was not affected greatly. The pasting viscosities of normal and waxy maize starches were decreased significantly, with the pasting temperature being little affected. The in vitro digestibility of three maize starches was not affected significantly by annealing treatment. Our results demonstrated that amylose molecules play an important role in the structural reorganization of starch granules during annealing treatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effects of Different Forms of Selenium Fertilizers on Se Accumulation, Distribution, and Residual Effect in Winter Wheat-Summer Maize Rotation System.

PubMed

Wang, Qi; Yu, Yao; Li, Jixiang; Wan, Yanan; Huang, Qingqing; Guo, Yanbin; Li, Huafen

2017-02-15

Foliar Se fertilizers were applied to investigate the effects of Se forms on Se accumulation and distribution in the wheat-maize rotation system and residual concentration of Se in subsequent crops. Sodium selenite, sodium selenate, selenomethionine, chemical nano-Se, humic acid + sodium selenite, and compound fertilizer + sodium selenite were applied once at the flowering stage of wheat (30 g ha -1 ) and at the bell stage of maize (60 g ha -1 ). Compared with the control treatment, foliar Se applications significant increased the grain Se concentration of wheat and maize by 0.02-0.31 and 0.07-1.09 mg kg -1 , respectively. Wheat and maize grain Se recoveries were 3.0-10.4 and 4.1-18.5%, respectively. However, Se concentrations in the grain of subsequent wheat and maize significantly decreased by 77.9 and 91.2%, respectively. The change of Se concentration in soil was a dynamic process with Se depletion after harvest of maize.

Genetic Factors Involved in Fumonisin Accumulation in Maize Kernels and Their Implications in Maize Agronomic Management and Breeding

PubMed Central

Santiago, Rogelio; Cao, Ana; Butrón, Ana

2015-01-01

Contamination of maize with fumonisins depends on the environmental conditions; the maize resistance to contamination and the interaction between both factors. Although the effect of environmental factors is a determinant for establishing the risk of kernel contamination in a region, there is sufficient genetic variability among maize to develop resistance to fumonisin contamination and to breed varieties with contamination at safe levels. In addition, ascertaining which environmental factors are the most important in a region will allow the implementation of risk monitoring programs and suitable cultural practices to reduce the impact of such environmental variables. The current paper reviews all works done to address the influence of environmental variables on fumonisin accumulation, the genetics of maize resistance to fumonisin accumulation, and the search for the biochemical and/or structural mechanisms of the maize plant that could be involved in resistance to fumonisin contamination. We also explore the outcomes of breeding programs and risk monitoring of undertaken projects. PMID:26308050

Genetic Factors Involved in Fumonisin Accumulation in Maize Kernels and Their Implications in Maize Agronomic Management and Breeding.

PubMed

Santiago, Rogelio; Cao, Ana; Butrón, Ana

2015-08-20

Contamination of maize with fumonisins depends on the environmental conditions; the maize resistance to contamination and the interaction between both factors. Although the effect of environmental factors is a determinant for establishing the risk of kernel contamination in a region, there is sufficient genetic variability among maize to develop resistance to fumonisin contamination and to breed varieties with contamination at safe levels. In addition, ascertaining which environmental factors are the most important in a region will allow the implementation of risk monitoring programs and suitable cultural practices to reduce the impact of such environmental variables. The current paper reviews all works done to address the influence of environmental variables on fumonisin accumulation, the genetics of maize resistance to fumonisin accumulation, and the search for the biochemical and/or structural mechanisms of the maize plant that could be involved in resistance to fumonisin contamination. We also explore the outcomes of breeding programs and risk monitoring of undertaken projects.

Post-Domestication Selection in the Maize Starch Pathway

PubMed Central

Fan, Longjiang; Bao, Jiandong; Wang, Yu; Yao, Jianqiang; Gui, Yijie; Hu, Weiming; Zhu, Jinqing; Zeng, Mengqian; Li, Yu; Xu, Yunbi

2009-01-01

Modern crops have usually experienced domestication selection and subsequent genetic improvement (post-domestication selection). Chinese waxy maize, which originated from non-glutinous domesticated maize (Zea mays ssp. mays), provides a unique model for investigating the post-domestication selection of maize. In this study, the genetic diversity of six key genes in the starch pathway was investigated in a glutinous population that included 55 Chinese waxy accessions, and a selective bottleneck that resulted in apparent reductions in diversity in Chinese waxy maize was observed. Significant positive selection in waxy (wx) but not amylose extender1 (ae1) was detected in the glutinous population, in complete contrast to the findings in non-glutinous maize, which indicated a shift in the selection target from ae1 to wx during the improvement of Chinese waxy maize. Our results suggest that an agronomic trait can be quickly improved into a target trait with changes in the selection target among genes in a crop pathway. PMID:19859548

Changes in nitrogen metabolism and antioxidant enzyme activities of maize tassel in black soils region of northeast China

PubMed Central

Xu, Hongwen; Lu, Yan; Xie, Zhiming; Song, Fengbin

2014-01-01

Two varieties of maize (Zea mays L.) grown in fields in black soils of northeast China were tested to study the dynamic changes of nitrogen metabolism and antioxidant enzyme activity in tassels of maize. Results showed that antioxidant enzyme activity in tassels of maize increased first and then decreased with the growing of maize, and reached peak value at shedding period. Pattern of proline was consistent with antioxidant enzyme activity, showing that osmotic adjustment could protect many enzymes, which are important for cell metabolism. Continuous reduction of soluble protein content along with the growing of maize was observed in the study, which indicated that quantitative material and energy were provided for pollen formation. Besides, another major cause was that a large proportion of nitrogen was used for the composition of structural protein. Nitrate nitrogen concentrations of tassels were more variable than ammonium nitrogen, which showed that nitrate nitrogen was the favored nitrogen source for maize. PMID:25324855

Practicable group testing method to evaluate weight/weight GMO content in maize grains.

PubMed

Mano, Junichi; Yanaka, Yuka; Ikezu, Yoko; Onishi, Mari; Futo, Satoshi; Minegishi, Yasutaka; Ninomiya, Kenji; Yotsuyanagi, Yuichi; Spiegelhalter, Frank; Akiyama, Hiroshi; Teshima, Reiko; Hino, Akihiro; Naito, Shigehiro; Koiwa, Tomohiro; Takabatake, Reona; Furui, Satoshi; Kitta, Kazumi

2011-07-13

Because of the increasing use of maize hybrids with genetically modified (GM) stacked events, the established and commonly used bulk sample methods for PCR quantification of GM maize in non-GM maize are prone to overestimate the GM organism (GMO) content, compared to the actual weight/weight percentage of GM maize in the grain sample. As an alternative method, we designed and assessed a group testing strategy in which the GMO content is statistically evaluated based on qualitative analyses of multiple small pools, consisting of 20 maize kernels each. This approach enables the GMO content evaluation on a weight/weight basis, irrespective of the presence of stacked-event kernels. To enhance the method's user-friendliness in routine application, we devised an easy-to-use PCR-based qualitative analytical method comprising a sample preparation step in which 20 maize kernels are ground in a lysis buffer and a subsequent PCR assay in which the lysate is directly used as a DNA template. This method was validated in a multilaboratory collaborative trial.

Effect on in vitro starch digestibility of Mexican blue maize anthocyanins.

PubMed

Camelo-Méndez, Gustavo A; Agama-Acevedo, Edith; Sanchez-Rivera, Mirna M; Bello-Pérez, Luis A

2016-11-15

The purpose of this study was to evaluate the effect of blue maize extracts obtained by acid-methanol treatment on the nutritional in vitro starch fractions such as: rapidly digestive starch (RDS), slowly digestive starch (SDS) and resistant starch (RS) of native and gelatinized commercial maize starch. Chromatographic analysis (HPLC-DAD/ESI-MS) of blue maize extracts showed the presence of seven anthocyanins, where cyanidin-3-(6″-malonylglucoside) was the main. Blue maize extracts modified nutritional in vitro starch fractions (decrease of RDS) while RS content increased (1.17 and 2.02 times for native and gelatinized commercial maize starch, respectively) when anthocyanins extracts were added to starch up to 75% (starch weight). This preliminary observation provides the basis for further suitability evaluation of blue maize extract as natural starch-modifier by the possible anthocyanins-starch interaction. Anthocyanin extracts can be a suitable to produce functional foods with higher RS content with potential human health benefits. Copyright © 2016 Elsevier Ltd. All rights reserved.

Maize embryogenesis.

PubMed

Fontanet, Pilar; Vicient, Carlos M

2008-01-01

Plant embryo development is a complex process that includes several coordinated events. Maize mature embryos consist of a well-differentiated embryonic axis surrounded by a single massive cotyledon called scutellum. Mature embryo axis also includes lateral roots and several developed leaves. In contrast to Arabidopsis, in which the orientation of cell divisions are perfectly established, only the first planes of cell division are predictable in maize embryos. These distinctive characteristics joined to the availability of a large collection of embryo mutants, well-developed molecular biology and tissue culture tools, an established genetics and its economical importance make maize a good model plant for grass embryogenesis. Here, we describe basic concepts and techniques necessary for studying maize embryo development: how to grow maize in greenhouses and basic techniques for in vitro embryo culture, somatic embryogenesis and in situ hybridization.

[Presence of pre-Columbian maize in the Old World--an overview].

PubMed

Uchibayashi, Masao

2006-06-01

An overview is presented on the reports available so far on pre-Columbian maize covering the regions of India, Mideast, Africa and Iberia. Frequent observations of maize recorded in the past on the East and the West Coast of Africa and at the ports in the Mideast show that maize was one of the staples of the natives well before 1492. It is also evident that maize in the West Africa was disseminated to Iberia and Lombardy in the pre-Columbian time. An earlier contact between the Old and the New World is strongly suggested.

The MaizeGDB Genome Browser tutorial: one example of database outreach to biologists via video.

PubMed

Harper, Lisa C; Schaeffer, Mary L; Thistle, Jordan; Gardiner, Jack M; Andorf, Carson M; Campbell, Darwin A; Cannon, Ethalinda K S; Braun, Bremen L; Birkett, Scott M; Lawrence, Carolyn J; Sen, Taner Z

2011-01-01

Video tutorials are an effective way for researchers to quickly learn how to use online tools offered by biological databases. At MaizeGDB, we have developed a number of video tutorials that demonstrate how to use various tools and explicitly outline the caveats researchers should know to interpret the information available to them. One such popular video currently available is 'Using the MaizeGDB Genome Browser', which describes how the maize genome was sequenced and assembled as well as how the sequence can be visualized and interacted with via the MaizeGDB Genome Browser. Database

Competitive Expression of Endogenous Wheat CENH3 May Lead to Suppression of Alien ZmCENH3 in Transgenic Wheat × Maize Hybrids.

PubMed

Chen, Wei; Zhu, Qilin; Wang, Haiyan; Xiao, Jin; Xing, Liping; Chen, Peidu; Jin, Weiwei; Wang, Xiu-E

2015-11-20

Uniparental chromosome elimination in wheat × maize hybrid embryos is widely used in double haploid production of wheat. Several explanations have been proposed for this phenomenon, one of which is that the lack of cross-species CENH3 incorporation may act as a barrier to interspecies hybridization. However, it is unknown if this mechanism applies universally. To study the role of CENH3 in maize chromosome elimination of wheat × maize hybrid embryos, maize ZmCENH3 and wheat αTaCENH3-B driven by the constitutive CaMV35S promoter were transformed into wheat variety Yangmai 158. Five transgenic lines for ZmCENH3 and six transgenic lines for αTaCENH3-B were identified. RT-PCR analysis showed that the transgene could be transcribed at a low level in all ZmCENH3 transgenic lines, whereas transcription of endogenous wheat CENH3 was significantly up-regulated. Interestingly, the expression levels of both wheat CENH3 and ZmCENH3 in the ZmCENH3 transgenic wheat × maize hybrid embryos were higher than those in the non-transformed Yangmai 158 × maize hybrid embryos. This indicates that the alien ZmCENH3 in wheat may induce competitive expression of endogenous wheat CENH3, leading to suppression of ZmCENH3 over-expression. Eliminations of maize chromosomes in hybrid embryos of ZmCENH3 transgenic wheat × maize and Yangmai 158 × maize were compared by observations on micronuclei presence, by marker analysis using maize SSRs (simple sequence repeats), and by FISH (fluorescence in situ hybridization) using 45S rDNA as a probe. The results indicate that maize chromosome elimination events in the two crosses are not significantly different. Fusion protein ZmCENH3-YFP could not be detected in ZmCENH3 transgenic wheat by either Western blotting or immnunostaining, whereas accumulation and loading of the αTaCENH3-B-GFP fusion protein was normal in αTaCENH3-B transgenic lines. As ZmCENH3-YFP did not accumulate after AM114 treatment, we speculate that low levels of ZmCENH3 protein in transgenic wheat may be one of the factors that lead to failure of suppression of maize chromatin elimination in ZmCENH3 transgenic wheat × maize hybrids. Copyright © 2015 Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, and Genetics Society of China. Published by Elsevier Ltd. All rights reserved.

Bacterial Communities in the Rhizosphere of Amilaceous Maize (Zea mays L.) as Assessed by Pyrosequencing.

PubMed

Correa-Galeote, David; Bedmar, Eulogio J; Fernández-González, Antonio J; Fernández-López, Manuel; Arone, Gregorio J

2016-01-01

Maize (Zea mays L.) is the staple diet of the native peasants in the Quechua region of the Peruvian Andes who continue growing it in small plots called chacras following ancestral traditions. The abundance and structure of bacterial communities associated with the roots of amilaceous maize has not been studied in Andean chacras. Accordingly, the main objective of this study was to describe the rhizospheric bacterial diversity of amilaceous maize grown either in the presence or the absence of bur clover cultivated in soils from the Quechua maize belt. Three 16S rRNA gene libraries, one corresponding to sequences of bacteria from bulk soil of a chacra maintained under fallow conditions, the second from the rhizosphere of maize-cultivated soils, and the third prepared from rhizospheric soil of maize cultivated in intercropping with bur clover were examined using pyrosequencing tags spanning the V4 and V5 hypervariable regions of the gene. A total of 26031 sequences were found that grouped into 5955 distinct operational taxonomic units which distributed in 309 genera. The numbers of OTUs in the libraries from the maize-cultivated soils were significantly higher than those found in the libraries from bulk soil. One hundred ninety seven genera were found in the bulk soil library and 234 and 203 were in those from the maize and maize/bur clover-cultivated soils. Sixteen out of the 309 genera had a relative abundance higher than 0.5% and the were (in decreasing order of abundance) Gp4, Gp6, Flavobacterium, Subdivision3 genera incertae sedis of the Verrucomicrobia phylum, Gemmatimonas, Dechloromonas, Ohtaekwangia, Rhodoferax, Gaiella, Opitutus, Gp7, Spartobacteria genera incertae sedis, Terrimonas, Gp5, Steroidobacter and Parcubacteria genera incertae sedis. Genera Gp4 and Gp6 of the Acidobacteria, Gemmatimonas and Rhodoferax were the most abundant in bulk soil, whereas Flavobacterium, Dechloromonas and Ohtaekwangia were the main genera in the rhizosphere of maize intercropped with bur clover, and Gp4, Subdivision3 genera incertae sedis of phylum Verrucomicrobia, Gp6 and Rhodoferax were the main genera in the rhizosphere of maize plants. Taken together, our results suggest that bur clover produces specific changes in rhizospheric bacterial diversity of amilaceous maize plants.

Bacterial Communities in the Rhizosphere of Amilaceous Maize (Zea mays L.) as Assessed by Pyrosequencing

PubMed Central

Correa-Galeote, David; Bedmar, Eulogio J.; Fernández-González, Antonio J.; Fernández-López, Manuel; Arone, Gregorio J.

2016-01-01

Maize (Zea mays L.) is the staple diet of the native peasants in the Quechua region of the Peruvian Andes who continue growing it in small plots called chacras following ancestral traditions. The abundance and structure of bacterial communities associated with the roots of amilaceous maize has not been studied in Andean chacras. Accordingly, the main objective of this study was to describe the rhizospheric bacterial diversity of amilaceous maize grown either in the presence or the absence of bur clover cultivated in soils from the Quechua maize belt. Three 16S rRNA gene libraries, one corresponding to sequences of bacteria from bulk soil of a chacra maintained under fallow conditions, the second from the rhizosphere of maize-cultivated soils, and the third prepared from rhizospheric soil of maize cultivated in intercropping with bur clover were examined using pyrosequencing tags spanning the V4 and V5 hypervariable regions of the gene. A total of 26031 sequences were found that grouped into 5955 distinct operational taxonomic units which distributed in 309 genera. The numbers of OTUs in the libraries from the maize-cultivated soils were significantly higher than those found in the libraries from bulk soil. One hundred ninety seven genera were found in the bulk soil library and 234 and 203 were in those from the maize and maize/bur clover-cultivated soils. Sixteen out of the 309 genera had a relative abundance higher than 0.5% and the were (in decreasing order of abundance) Gp4, Gp6, Flavobacterium, Subdivision3 genera incertae sedis of the Verrucomicrobia phylum, Gemmatimonas, Dechloromonas, Ohtaekwangia, Rhodoferax, Gaiella, Opitutus, Gp7, Spartobacteria genera incertae sedis, Terrimonas, Gp5, Steroidobacter and Parcubacteria genera incertae sedis. Genera Gp4 and Gp6 of the Acidobacteria, Gemmatimonas and Rhodoferax were the most abundant in bulk soil, whereas Flavobacterium, Dechloromonas and Ohtaekwangia were the main genera in the rhizosphere of maize intercropped with bur clover, and Gp4, Subdivision3 genera incertae sedis of phylum Verrucomicrobia, Gp6 and Rhodoferax were the main genera in the rhizosphere of maize plants. Taken together, our results suggest that bur clover produces specific changes in rhizospheric bacterial diversity of amilaceous maize plants. PMID:27524985

Response of maize (Zea mays L.) lines carrying Wsm1, Wsm2 and Wsm3 to the potyviruses Johnsongrass mosaic virus and Sorghum mosaic virus

USDA-ARS?s Scientific Manuscript database

Maize dwarf mosaic disease is one of the most important viral diseases of maize throughout the world. It is caused by a set of related viruses in the family Potyviridae, genus Potyvirus, including Maize dwarf mosaic virus (MDMV), Sugarcane mosaic virus (SCMV), Johnsongrass mosaic virus (JGMV), and S...

Metabolic profiling of two maize (Zea mays L.) inbred lines inoculated with the nitrogen fixing plant-interacting bacteria Herbaspirillum seropedicae and Azospirillum brasilense

PubMed Central

Brusamarello-Santos, Liziane Cristina; Gilard, Françoise; Brulé, Lenaïg; Quilleré, Isabelle; Gourion, Benjamin; Ratet, Pascal; Maltempi de Souza, Emanuel; Lea, Peter J.; Hirel, Bertrand

2017-01-01

Maize roots can be colonized by free-living atmospheric nitrogen (N2)-fixing bacteria (diazotrophs). However, the agronomic potential of non-symbiotic N2-fixation in such an economically important species as maize, has still not been fully exploited. A preliminary approach to improve our understanding of the mechanisms controlling the establishment of such N2-fixing associations has been developed, using two maize inbred lines exhibiting different physiological characteristics. The bacterial-plant interaction has been characterized by means of a metabolomic approach. Two established model strains of Nif+ diazotrophic bacteria, Herbaspirillum seropedicae and Azospirillum brasilense and their Nif- couterparts defficient in nitrogenase activity, were used to evaluate the impact of the bacterial inoculation and of N2 fixation on the root and leaf metabolic profiles. The two N2-fixing bacteria have been used to inoculate two genetically distant maize lines (FV252 and FV2), already characterized for their contrasting physiological properties. Using a well-controlled gnotobiotic experimental system that allows inoculation of maize plants with the two diazotrophs in a N-free medium, we demonstrated that both maize lines were efficiently colonized by the two bacterial species. We also showed that in the early stages of plant development, both bacterial strains were able to reduce acetylene, suggesting that they contain functional nitrogenase activity and are able to efficiently fix atmospheric N2 (Fix+). The metabolomic approach allowed the identification of metabolites in the two maize lines that were representative of the N2 fixing plant-bacterial interaction, these included mannitol and to a lesser extend trehalose and isocitrate. Whilst other metabolites such as asparagine, although only exhibiting a small increase in maize roots following bacterial infection, were specific for the two Fix+ bacterial strains, in comparison to their Fix- counterparts. Moreover, a number of metabolites exhibited a maize-genotype specific pattern of accumulation, suggesting that the highly diverse maize genetic resources could be further exploited in terms of beneficial plant-bacterial interactions for optimizing maize growth, with reduced N fertilization inputs. PMID:28362815

Metabolic profiling of two maize (Zea mays L.) inbred lines inoculated with the nitrogen fixing plant-interacting bacteria Herbaspirillum seropedicae and Azospirillum brasilense.

PubMed

Brusamarello-Santos, Liziane Cristina; Gilard, Françoise; Brulé, Lenaïg; Quilleré, Isabelle; Gourion, Benjamin; Ratet, Pascal; Maltempi de Souza, Emanuel; Lea, Peter J; Hirel, Bertrand

2017-01-01

Maize roots can be colonized by free-living atmospheric nitrogen (N2)-fixing bacteria (diazotrophs). However, the agronomic potential of non-symbiotic N2-fixation in such an economically important species as maize, has still not been fully exploited. A preliminary approach to improve our understanding of the mechanisms controlling the establishment of such N2-fixing associations has been developed, using two maize inbred lines exhibiting different physiological characteristics. The bacterial-plant interaction has been characterized by means of a metabolomic approach. Two established model strains of Nif+ diazotrophic bacteria, Herbaspirillum seropedicae and Azospirillum brasilense and their Nif- couterparts defficient in nitrogenase activity, were used to evaluate the impact of the bacterial inoculation and of N2 fixation on the root and leaf metabolic profiles. The two N2-fixing bacteria have been used to inoculate two genetically distant maize lines (FV252 and FV2), already characterized for their contrasting physiological properties. Using a well-controlled gnotobiotic experimental system that allows inoculation of maize plants with the two diazotrophs in a N-free medium, we demonstrated that both maize lines were efficiently colonized by the two bacterial species. We also showed that in the early stages of plant development, both bacterial strains were able to reduce acetylene, suggesting that they contain functional nitrogenase activity and are able to efficiently fix atmospheric N2 (Fix+). The metabolomic approach allowed the identification of metabolites in the two maize lines that were representative of the N2 fixing plant-bacterial interaction, these included mannitol and to a lesser extend trehalose and isocitrate. Whilst other metabolites such as asparagine, although only exhibiting a small increase in maize roots following bacterial infection, were specific for the two Fix+ bacterial strains, in comparison to their Fix- counterparts. Moreover, a number of metabolites exhibited a maize-genotype specific pattern of accumulation, suggesting that the highly diverse maize genetic resources could be further exploited in terms of beneficial plant-bacterial interactions for optimizing maize growth, with reduced N fertilization inputs.

CERES–Maize Model for Determining the Optimum Planting Dates of Early Maturing Maize Varieties in Northern Nigeria

PubMed Central

Adnan, Adnan A.; Jibrin, Jibrin M.; Kamara, Alpha Y.; Abdulrahman, Bassam L.; Shaibu, Abdulwahab S.; Garba, Ismail I.

2017-01-01

Field trials were carried out in the Sudan Savannah of Nigeria to assess the usefulness of CERES–maize crop model as a decision support tool for optimizing maize production through manipulation of plant dates. The calibration experiments comprised of 20 maize varieties planted during the dry and rainy seasons of 2014 and 2015 at Bayero University Kano and Audu Bako College of Agriculture Dambatta. The trials for model evaluation were conducted in 16 different farmer fields across the Sudan (Bunkure and Garun—Mallam) and Northern Guinea (Tudun-Wada and Lere) Savannas using two of the calibrated varieties under four different sowing dates. The model accurately predicted grain yield, harvest index, and biomass of both varieties with low RMSE-values (below 5% of mean), high d-index (above 0.8), and high r-square (above 0.9) for the calibration trials. The time series data (tops weight, stem and leaf dry weights) were also predicted with high accuracy (% RMSEn above 70%, d-index above 0.88). Similar results were also observed for the evaluation trials, where all variables were simulated with high accuracies. Estimation efficiencies (EF)-values above 0.8 were observed for all the evaluation parameters. Seasonal and sensitivity analyses on Typic Plinthiustalfs and Plinthic Kanhaplustults in the Sudan and Northern Guinea Savannas were conducted. Results showed that planting extra early maize varieties in late July and early maize in mid-June leads to production of highest grain yields in the Sudan Savanna. In the Northern Guinea Savanna planting extra-early maize in mid-July and early maize in late July produced the highest grain yields. Delaying planting in both Agro-ecologies until mid-August leads to lower yields. Delaying planting to mid-August led to grain yield reduction of 39.2% for extra early maize and 74.4% for early maize in the Sudan Savanna. In the Northern Guinea Savanna however, delaying planting to mid-August resulted in yield reduction of 66.9 and 94.3% for extra-early and early maize, respectively. PMID:28702039

Negative effects of climate warming on maize yield are reversed by the changing of sowing date and cultivar selection in Northeast China.

PubMed

Liu, Zhijuan; Hubbard, Kenneth G; Lin, Xiaomao; Yang, Xiaoguang

2013-11-01

Northeast China (NEC) accounts for about 30% of the nation's maize production in China. In the past three decades, maize yields in NEC have increased under changes in climate, cultivar selection and crop management. It is important to investigate the contribution of these changing factors to the historical yield increases to improve our understanding of how we can ensure increased yields in the future. In this study, we use phenology observations at six sites from 1981 to 2007 to detect trends in sowing dates and length of maize growing period, and then combine these observations with in situ temperature data to determine the trends of thermal time in the maize growing period, as a measure of changes in maize cultivars. The area in the vicinity of these six sites accounts for 30% of NEC's total maize production. The agricultural production systems simulator, APSIM-Maize model, was used to separate the impacts of changes in climate, sowing dates and thermal time requirements on maize phenology and yields. In NEC, sowing dates trended earlier in four of six sites and maturity dates trended later by 4-21 days. Therefore, the period from sowing to maturity ranged from 2 to 38 days longer in 2007 than it was in 1981. Our results indicate that climate trends alone would have led to a negative impact on maize. However, results from the adaptation assessments indicate that earlier sowing dates increased yields by up to 4%, and adoption of longer season cultivars caused a substantial increase in yield ranging from 13% to 38% over the past 27 years. Therefore, earlier sowing dates and introduction of cultivars with higher thermal time requirements in NEC have overcome the negative effects of climate change and turned what would have otherwise been a loss into a significant increase in maize yield. © 2013 John Wiley & Sons Ltd.

Variation in Yield Gap Induced by Nitrogen, Phosphorus and Potassium Fertilizer in North China Plain

PubMed Central

Dai, Xiaoqin; Ouyang, Zhu; Li, Yunsheng; Wang, Huimin

2013-01-01

A field experiment was conducted under a wheat-maize rotation system from 1990 to 2006 in North China Plain (NCP) to determine the effects of N, P and K on yield and yield gap. There were five treatments: NPK, PK, NK, NP and a control. Average wheat and maize yields were the highest in the NPK treatment, followed by those in the NP plots among all treatments. For wheat and maize yield, a significant increasing trend over time was found in the NPK-treated plots and a decreasing trend in the NK-treated plots. In the absence of N or P, wheat and maize yields were significantly lower than those in the NPK treatment. For both crops, the increasing rate of the yield gap was the highest in the P omission plots, i.e., 189.1 kg ha−1 yr−1 for wheat and 560.6 kg ha−1 yr−1 for maize. The cumulative omission of P fertilizer induced a deficit in the soil available N and extractable P concentrations for maize. The P fertilizer was more pivotal in long-term wheat and maize growth and soil fertility conservation in NCP, although the N fertilizer input was important for both crops growth. The crop response to K fertilizers was much lower than that to N or P fertilizers, but for maize, the cumulative omission of K fertilizer decreased the yield by 26% and increased the yield gap at a rate of 322.7 kg ha−1 yr−1. The soil indigenous K supply was not sufficiently high to meet maize K requirement over a long period. The proper application of K fertilizers is necessary for maize production in the region. Thus, the appropriate application of N and P fertilizers for the growth of both crops, while regularly combining K fertilizers for maize growth, is absolutely necessary for sustainable crop production in the NCP. PMID:24349204

Impact of Climate Variability on Maize Production in Pakistan using Remote Sensing and Machine Learning

NASA Astrophysics Data System (ADS)

Richetti, J.; Ahmad, I.; Aristizabal, F.; Judge, J.

2017-12-01

Determining maize agricultural production under climate variability is valuable to policy makers in Pakistan since maize is the third most produced crop by area after wheat and rice. This study aims to predict the maize production under climate variability. Two-hundred ground truth points of both maize and non-maize land covers were collected from the Faisalabad district during the growing seasons of 2015 and 2016. Landsat-8 images taken in second week of May which correspond spatially and temporally to the local, peak growing season for maize were gathered. For classifying the region training data was constructed for a variety of machine learning algorithms by sampling the second, third, and fourth bands of the Landsat-8 imagery at these reference locations. Cross validation was used for parameter tuning as well as estimating the generalized performances. All the classifiers resulted in overall accuracies of greater than 90% for both years and a support vector machine with a radial basis kernel recorded the maximum accuracy of 97%. The tuned models were used to determine the spatial distribution of maize fields for both growing seasons in the Faisalabad district using parallel processing to improve computation time. The overall classified maize growing area represented 12% difference than that reported by the Crop Reporting Service (CRS) of Punjab Pakistan for both 2015 and 2016. For the agricultural production normalized difference vegetation index from Landsat-8 and climate indicators from ground stations will be used as inputs in a variety of machine learning regression algorithms. The expected results will be compared to actual yield from 64 commercial farms. To verify the impact of climate variability in the maize agricultural production historical climate data from previous 30 years will be used in the developed model to asses the impact of climate variability on the maize production.

Variation in yield gap induced by nitrogen, phosphorus and potassium fertilizer in North China Plain.

PubMed

Dai, Xiaoqin; Ouyang, Zhu; Li, Yunsheng; Wang, Huimin

2013-01-01

A field experiment was conducted under a wheat-maize rotation system from 1990 to 2006 in North China Plain (NCP) to determine the effects of N, P and K on yield and yield gap. There were five treatments: NPK, PK, NK, NP and a control. Average wheat and maize yields were the highest in the NPK treatment, followed by those in the NP plots among all treatments. For wheat and maize yield, a significant increasing trend over time was found in the NPK-treated plots and a decreasing trend in the NK-treated plots. In the absence of N or P, wheat and maize yields were significantly lower than those in the NPK treatment. For both crops, the increasing rate of the yield gap was the highest in the P omission plots, i.e., 189.1 kg ha(-1) yr(-1) for wheat and 560.6 kg ha(-1) yr(-1) for maize. The cumulative omission of P fertilizer induced a deficit in the soil available N and extractable P concentrations for maize. The P fertilizer was more pivotal in long-term wheat and maize growth and soil fertility conservation in NCP, although the N fertilizer input was important for both crops growth. The crop response to K fertilizers was much lower than that to N or P fertilizers, but for maize, the cumulative omission of K fertilizer decreased the yield by 26% and increased the yield gap at a rate of 322.7 kg ha(-1) yr(-1). The soil indigenous K supply was not sufficiently high to meet maize K requirement over a long period. The proper application of K fertilizers is necessary for maize production in the region. Thus, the appropriate application of N and P fertilizers for the growth of both crops, while regularly combining K fertilizers for maize growth, is absolutely necessary for sustainable crop production in the NCP.

Co-expression network analysis of duplicate genes in maize (Zea mays L.) reveals no subgenome bias.

PubMed

Li, Lin; Briskine, Roman; Schaefer, Robert; Schnable, Patrick S; Myers, Chad L; Flagel, Lex E; Springer, Nathan M; Muehlbauer, Gary J

2016-11-04

Gene duplication is prevalent in many species and can result in coding and regulatory divergence. Gene duplications can be classified as whole genome duplication (WGD), tandem and inserted (non-syntenic). In maize, WGD resulted in the subgenomes maize1 and maize2, of which maize1 is considered the dominant subgenome. However, the landscape of co-expression network divergence of duplicate genes in maize is still largely uncharacterized. To address the consequence of gene duplication on co-expression network divergence, we developed a gene co-expression network from RNA-seq data derived from 64 different tissues/stages of the maize reference inbred-B73. WGD, tandem and inserted gene duplications exhibited distinct regulatory divergence. Inserted duplicate genes were more likely to be singletons in the co-expression networks, while WGD duplicate genes were likely to be co-expressed with other genes. Tandem duplicate genes were enriched in the co-expression pattern where co-expressed genes were nearly identical for the duplicates in the network. Older gene duplications exhibit more extensive co-expression variation than younger duplications. Overall, non-syntenic genes primarily from inserted duplications show more co-expression divergence. Also, such enlarged co-expression divergence is significantly related to duplication age. Moreover, subgenome dominance was not observed in the co-expression networks - maize1 and maize2 exhibit similar levels of intra subgenome correlations. Intriguingly, the level of inter subgenome co-expression was similar to the level of intra subgenome correlations, and genes from specific subgenomes were not likely to be the enriched in co-expression network modules and the hub genes were not predominantly from any specific subgenomes in maize. Our work provides a comprehensive analysis of maize co-expression network divergence for three different types of gene duplications and identifies potential relationships between duplication types, duplication ages and co-expression consequences.

Maize and Arabidopsis ARGOS Proteins Interact with Ethylene Receptor Signaling Complex, Supporting a Regulatory Role for ARGOS in Ethylene Signal Transduction[OPEN

PubMed Central

Shi, Jinrui; Wang, Hongyu; Habben, Jeffrey E.

2016-01-01

The phytohormone ethylene regulates plant growth and development as well as plant response to environmental cues. ARGOS genes reduce plant sensitivity to ethylene when overexpressed in transgenic Arabidopsis (Arabidopsis thaliana) and maize (Zea mays). A previous genetic study suggested that the endoplasmic reticulum and Golgi-localized maize ARGOS1 targets the ethylene signal transduction components at or upstream of CONSTITUTIVE TRIPLE RESPONSE1, but the mechanism of ARGOS modulating ethylene signaling is unknown. Here, we demonstrate in Arabidopsis that ZmARGOS1, as well as the Arabidopsis ARGOS homolog ORGAN SIZE RELATED1, physically interacts with Arabidopsis REVERSION-TO-ETHYLENE SENSITIVITY1 (RTE1), an ethylene receptor interacting protein that regulates the activity of ETHYLENE RESPONSE1. The protein-protein interaction was also detected with the yeast split-ubiquitin two-hybrid system. Using the same yeast assay, we found that maize RTE1 homolog REVERSION-TO-ETHYLENE SENSITIVITY1 LIKE4 (ZmRTL4) and ZmRTL2 also interact with maize and Arabidopsis ARGOS proteins. Like AtRTE1 in Arabidopsis, ZmRTL4 and ZmRTL2 reduce ethylene responses when overexpressed in maize, indicating a similar mechanism for ARGOS regulating ethylene signaling in maize. A polypeptide fragment derived from ZmARGOS8, consisting of a Pro-rich motif flanked by two transmembrane helices that are conserved among members of the ARGOS family, can interact with AtRTE1 and maize RTL proteins in Arabidopsis. The conserved domain is necessary and sufficient to reduce ethylene sensitivity in Arabidopsis and maize. Overall, these results suggest a physical association between ARGOS and the ethylene receptor signaling complex via AtRTE1 and maize RTL proteins, supporting a role for ARGOS in regulating ethylene perception and the early steps of signal transduction in Arabidopsis and maize. PMID:27268962

Maize and Arabidopsis ARGOS Proteins Interact with Ethylene Receptor Signaling Complex, Supporting a Regulatory Role for ARGOS in Ethylene Signal Transduction.

PubMed

Shi, Jinrui; Drummond, Bruce J; Wang, Hongyu; Archibald, Rayeann L; Habben, Jeffrey E

2016-08-01

The phytohormone ethylene regulates plant growth and development as well as plant response to environmental cues. ARGOS genes reduce plant sensitivity to ethylene when overexpressed in transgenic Arabidopsis (Arabidopsis thaliana) and maize (Zea mays). A previous genetic study suggested that the endoplasmic reticulum and Golgi-localized maize ARGOS1 targets the ethylene signal transduction components at or upstream of CONSTITUTIVE TRIPLE RESPONSE1, but the mechanism of ARGOS modulating ethylene signaling is unknown. Here, we demonstrate in Arabidopsis that ZmARGOS1, as well as the Arabidopsis ARGOS homolog ORGAN SIZE RELATED1, physically interacts with Arabidopsis REVERSION-TO-ETHYLENE SENSITIVITY1 (RTE1), an ethylene receptor interacting protein that regulates the activity of ETHYLENE RESPONSE1. The protein-protein interaction was also detected with the yeast split-ubiquitin two-hybrid system. Using the same yeast assay, we found that maize RTE1 homolog REVERSION-TO-ETHYLENE SENSITIVITY1 LIKE4 (ZmRTL4) and ZmRTL2 also interact with maize and Arabidopsis ARGOS proteins. Like AtRTE1 in Arabidopsis, ZmRTL4 and ZmRTL2 reduce ethylene responses when overexpressed in maize, indicating a similar mechanism for ARGOS regulating ethylene signaling in maize. A polypeptide fragment derived from ZmARGOS8, consisting of a Pro-rich motif flanked by two transmembrane helices that are conserved among members of the ARGOS family, can interact with AtRTE1 and maize RTL proteins in Arabidopsis. The conserved domain is necessary and sufficient to reduce ethylene sensitivity in Arabidopsis and maize. Overall, these results suggest a physical association between ARGOS and the ethylene receptor signaling complex via AtRTE1 and maize RTL proteins, supporting a role for ARGOS in regulating ethylene perception and the early steps of signal transduction in Arabidopsis and maize. © 2016 American Society of Plant Biologists. All Rights Reserved.

Allocation of Nitrogen and Carbon Is Regulated by Nodulation and Mycorrhizal Networks in Soybean/Maize Intercropping System

PubMed Central

Wang, Guihua; Sheng, Lichao; Zhao, Dan; Sheng, Jiandong; Wang, Xiurong; Liao, Hong

2016-01-01

Soybean/maize intercropping has remarkable advantages in increasing crop yield and nitrogen (N) efficiency. However, little is known about the contributions of rhizobia or arbuscular mycorrhizal fungi (AMF) to yield increases and N acquisition in the intercropping system. Plus, the mechanisms controlling carbon (C) and N allocation in intercropping systems remain unsettled. In the present study, a greenhouse experiment combined with 15N and 13C labeling was conducted using various inoculation and nutrient treatments. The results showed that co-inoculation with AMF and rhizobia dramatically increased biomass and N content of soybean and maize, and moderate application of N and phosphorus largely amplified the effect of co-inoculation. Maize had a competitive advantage over soybean only under co-inoculation and moderate nutrient availability conditions, indicating that the effects of AMF and rhizobia in intercropping systems are closely related to nutrient status. Results from 15N labeling showed that the amount of N transferred from soybean to maize in co-inoculations was 54% higher than that with AMF inoculation alone, with this increased N transfer partly resulting from symbiotic N fixation. The results from 13C labeling showed that 13C content increased in maize shoots and decreased in soybean roots with AMF inoculation compared to uninoculated controls. Yet, with co-inoculation, 13C content increased in soybean. These results indicate that photosynthate assimilation is stimulated by AM symbiosis in maize and rhizobial symbiosis in soybean, but AMF inoculation leads to soybean investing more carbon than maize into common mycorrhizal networks (CMNs). Overall, the results herein demonstrate that the growth advantage of maize when intercropped with soybean is due to acquisition of N by maize via CMNs while this crop contributes less C into CMNs than soybean under co-inoculation conditions. PMID:28018420

Volatiles Emitted from Maize Ears Simultaneously Infected with Two Fusarium Species Mirror the Most Competitive Fungal Pathogen

PubMed Central

Sherif, Mohammed; Becker, Eva-Maria; Herrfurth, Cornelia; Feussner, Ivo; Karlovsky, Petr; Splivallo, Richard

2016-01-01

Along with barley and rice, maize provides staple food for more than half of the world population. Maize ears are regularly infected with fungal pathogens of the Fusarium genus, which, besides reducing yield, also taint grains with toxic metabolites. In an earlier work, we have shown that maize ears infection with single Fusarium strains was detectable through volatile sensing. In nature, infection most commonly occurs with more than a single fungal strain; hence we tested how the interactions of two strains would modulate volatile emission from infected ears. For this purpose, ears of a hybrid and a dwarf maize variety were simultaneously infected with different strains of Fusarium graminearum and F. verticillioides and, the resulting volatile profiles were compared to the ones of ears infected with single strains. Disease severity, fungal biomass, and the concentration of the oxylipin 9-hydroxy octadecadienoic acid, a signaling molecule involved in plant defense, were monitored and correlated to volatile profiles. Our results demonstrate that in simultaneous infections of hybrid and dwarf maize, the most competitive fungal strains had the largest influence on the volatile profile of infected ears. In both concurrent and single inoculations, volatile profiles reflected disease severity. Additionally, the data further indicate that dwarf maize and hybrid maize might emit common (i.e., sesquiterpenoids) and specific markers upon fungal infection. Overall this suggests that volatile profiles might be a good proxy for disease severity regardless of the fungal competition taking place in maize ears. With the appropriate sensitivity and reliability, volatile sensing thus appears as a promising tool for detecting fungal infection of maize ears under field conditions. PMID:27729923

Environmental risk assessment for the small tortoiseshell Aglais urticae and a stacked Bt-maize with combined resistances against Lepidoptera and Chrysomelidae in central European agrarian landscapes.

PubMed

Schuppener, Mechthild; Mühlhause, Julia; Müller, Anne-Katrin; Rauschen, Stefan

2012-09-01

The cultivation of Lepidoptera-resistant Bt-maize may affect nontarget butterflies. We assessed the risk posed by event MON89034 × MON88017 (expressing Cry1A.105 and Cry2Ab2 against corn borers) to nontarget Lepidoptera. Using the small tortoiseshell Aglais urticae, a butterfly species common in central Europe, as a test organism we (i) assessed the toxicity of Bt-maize pollen on butterfly larvae; (ii) measured pollen deposition on leaves of the host plant Urtica dioica; (iii) mapped the occurrence and distribution of host plants and larvae in two arable landscapes in Germany during maize anthesis; and (iv) described the temporal occurrence of a 1-year population of A. urticae. (i) Larvae-fed 200 Bt-maize pollen grains/cm(2) had a reduced feeding activity. Significant differences in developmental time existed at pollen densities of 300 Bt-maize pollen grains/cm(2) and in survival at 400 grains/cm(2). (ii) The highest pollen amount found was 212 grains/cm(2) at the field margin. Mean densities were much lower. (iii) In one region, over 50% of A. urticae nests were located within 5 m of a maize field, while in the other, all nests were found in more than 25 m distance to a maize field. (iv) The percentage of larvae developing during maize anthesis was 19% in the study area. The amount of pollen from maize MON89034 × MON88017 found on host plants is unlikely to adversely affect a significant proportion of larvae of A. urticae. This paper concludes that the risk of event MON89034 × MON88017 to populations of this species is negligible. © 2012 Blackwell Publishing Ltd.

Allocation of Nitrogen and Carbon Is Regulated by Nodulation and Mycorrhizal Networks in Soybean/Maize Intercropping System.

PubMed

Wang, Guihua; Sheng, Lichao; Zhao, Dan; Sheng, Jiandong; Wang, Xiurong; Liao, Hong

2016-01-01

Soybean/maize intercropping has remarkable advantages in increasing crop yield and nitrogen (N) efficiency. However, little is known about the contributions of rhizobia or arbuscular mycorrhizal fungi (AMF) to yield increases and N acquisition in the intercropping system. Plus, the mechanisms controlling carbon (C) and N allocation in intercropping systems remain unsettled. In the present study, a greenhouse experiment combined with 15 N and 13 C labeling was conducted using various inoculation and nutrient treatments. The results showed that co-inoculation with AMF and rhizobia dramatically increased biomass and N content of soybean and maize, and moderate application of N and phosphorus largely amplified the effect of co-inoculation. Maize had a competitive advantage over soybean only under co-inoculation and moderate nutrient availability conditions, indicating that the effects of AMF and rhizobia in intercropping systems are closely related to nutrient status. Results from 15 N labeling showed that the amount of N transferred from soybean to maize in co-inoculations was 54% higher than that with AMF inoculation alone, with this increased N transfer partly resulting from symbiotic N fixation. The results from 13 C labeling showed that 13 C content increased in maize shoots and decreased in soybean roots with AMF inoculation compared to uninoculated controls. Yet, with co-inoculation, 13 C content increased in soybean. These results indicate that photosynthate assimilation is stimulated by AM symbiosis in maize and rhizobial symbiosis in soybean, but AMF inoculation leads to soybean investing more carbon than maize into common mycorrhizal networks (CMNs). Overall, the results herein demonstrate that the growth advantage of maize when intercropped with soybean is due to acquisition of N by maize via CMNs while this crop contributes less C into CMNs than soybean under co-inoculation conditions.

Genome-wide identification and characterisation of F-box family in maize.

PubMed

Jia, Fengjuan; Wu, Bingjiang; Li, Hui; Huang, Jinguang; Zheng, Chengchao

2013-11-01

F-box-containing proteins, as the key components of the protein degradation machinery, are widely distributed in higher plants and are considered as one of the largest known families of regulatory proteins. The F-box protein family plays a crucial role in plant growth and development and in response to biotic and abiotic stresses. However, systematic analysis of the F-box family in maize (Zea mays) has not been reported yet. In this paper, we identified and characterised the maize F-box genes in a genome-wide scale, including phylogenetic analysis, chromosome distribution, gene structure, promoter analysis and gene expression profiles. A total of 359 F-box genes were identified and divided into 15 subgroups by phylogenetic analysis. The F-box domain was relatively conserved, whereas additional motifs outside the F-box domain may indicate the functional diversification of maize F-box genes. These genes were unevenly distributed in ten maize chromosomes, suggesting that they expanded in the maize genome because of tandem and segmental duplication events. The expression profiles suggested that the maize F-box genes had temporal and spatial expression patterns. Putative cis-acting regulatory DNA elements involved in abiotic stresses were observed in maize F-box gene promoters. The gene expression profiles under abiotic stresses also suggested that some genes participated in stress responsive pathways. Furthermore, ten genes were chosen for quantitative real-time PCR analysis under drought stress and the results were consistent with the microarray data. This study has produced a comparative genomics analysis of the maize ZmFBX gene family that can be used in further studies to uncover their roles in maize growth and development.

A functional antigen in a practical crop: LT-B producing maize protects mice against Escherichia coli heat labile enterotoxin (LT) and cholera toxin (CT).

PubMed

Chikwamba, Rachel; Cunnick, Joan; Hathaway, Diane; McMurray, Jennifer; Mason, Hugh; Wang, Kan

2002-10-01

We have produced a functional heat labile enterotoxin (LT-) B subunit of Escherichia coli in maize. LT-B is a multimeric protein that presents an ideal model for an edible vaccine, displaying stability in the gut and inducing mucosal and systemic immune responses. Transgenic maize was engineered to synthesize the LT-B polypeptides, which assembled into oligomeric structures with affinity for G(M1) gangliosides. We orally immunized BALB/c mice by feeding transgenic maize meal expressing LT-B or non-transgenic maize meal spiked with bacterial LT-B. Both treatments stimulated elevated IgA and IgG antibodies against LT-B and the closely related cholera toxin B subunit (CT-B) in serum, and elevated IgA in fecal pellets. The transgenic maize induced a higher anti-LT-B and anti-CT-B mucosal and serum IgA response compared to the equivalent amount of bacterial LT-B spiked into maize. Following challenge by oral administration of the diarrhea inducing toxins LT and CT, transgenic maize-fed mice displayed reduced fluid accumulation in the gut compared to non-immunized mice. Moreover, the gut to carcass ratio of immunized mice was not significantly different from the PBS (non-toxin) challenged control group. We concluded that maize-synthesized LT-B had features of the native bacterial LT-B such as molecular weight, G(M1) binding ability, and induction of serum and mucosal immunity. We have demonstrated that maize, a major food and feed ingredient, can be efficiently transformed to produce, accumulate, and store a fully assembled and functional candidate vaccine antigen.

Fate of Transgenic DNA from Orally Administered Bt MON810 Maize and Effects on Immune Response and Growth in Pigs

PubMed Central

Walsh, Maria C.; Buzoianu, Stefan G.; Gardiner, Gillian E.; Rea, Mary C.; Gelencsér, Eva; Jánosi, Anna; Epstein, Michelle M.; Ross, R. Paul; Lawlor, Peadar G.

2011-01-01

We assessed the effect of short-term feeding of genetically modified (GM: Bt MON810) maize on immune responses and growth in weanling pigs and determined the fate of the transgenic DNA and protein in-vivo. Pigs were fed a diet containing 38.9% GM or non-GM isogenic parent line maize for 31 days. We observed that IL-12 and IFNγ production from mitogenic stimulated peripheral blood mononuclear cells decreased (P<0.10) following 31 days of GM maize exposure. While Cry1Ab-specific IgG and IgA were not detected in the plasma of GM maize-fed pigs, the detection of the cry1Ab gene and protein was limited to the gastrointestinal digesta and was not found in the kidneys, liver, spleen, muscle, heart or blood. Feeding GM maize to weanling pigs had no effect on growth performance or body weight. IL-6 and IL-4 production from isolated splenocytes were increased (P<0.05) in response to feeding GM maize while the proportion of CD4+ T cells in the spleen decreased. In the ileum, the proportion of B cells and macrophages decreased while the proportion of CD4+ T cells increased in GM maize-fed pigs. IL-8 and IL-4 production from isolated intraepithelial and lamina propria lymphocytes were also increased (P<0.05) in response to feeding GM maize. In conclusion, there was no evidence of cry1Ab gene or protein translocation to the organs and blood of weaning pigs. The growth of pigs was not affected by feeding GM maize. Alterations in immune responses were detected; however, their biologic relevance is questionable. PMID:22132091

Provitamin A retention and sensory acceptability of amahewu, a non-alcoholic cereal-based beverage made with provitamin A-biofortified maize.

PubMed

Awobusuyi, Temitope D; Siwela, Muthulisi; Kolanisi, Unathi; Amonsou, Eric O

2016-03-15

Vitamin A deficiency is a major public health problem in sub-Saharan Africa. Amahewu is a popular southern African lactic acid fermented non-alcoholic maize-based beverage, which is deficient in vitamin A. In this study, provitamin A retention and sensory acceptability of amahewu processed using provitamin A-biofortified maize and three types of inoculums during fermentation (malted maize, wheat bran and Lactobacillus starter culture) were investigated. The total provitamin A content of amahewu samples, estimated as β-carotene, β-cryptoxanthin and α-carotene content, ranged from 3.3 to 3.8 g kg(-1) (dry weight). Provitamin A was substantially retained (79- 90% β-carotene equivalent) in amahewu after fermentation. Amahewu samples prepared with added starter cultures had the lowest retention of provitamin A. Consumers (approx. 69%) liked provitamin A-biofortified amahewu either moderately or very much. Principal component analysis of amahewu sensory data showed that 71% of variation was due to maize types and 18% of variation could be due to the inoculum used during fermentation. Amahewu samples prepared using provitamin A-biofortified maize were slightly more liked (mean score: 7.0 ± 1.2) compared to those of white maize reference samples. The use of starter culture combined with either malted maize or wheat bran as inoculum during fermentation improved the taste and aroma of amahewu and hence its acceptability. Provitamin A is substantially retained in amahewu after fermentation. The slightly high acceptability of amahewu prepared using provitamin A-biofortified maize compared to that of white maize thus suggests that fermented product like amahewu can potentially be used to deliver provitamin A to vulnerable individuals. © 2015 Society of Chemical Industry.

Field-Evolved Resistance to Bt Maize by Western Corn Rootworm

PubMed Central

Gassmann, Aaron J.; Petzold-Maxwell, Jennifer L.; Keweshan, Ryan S.; Dunbar, Mike W.

2011-01-01

Background Crops engineered to produce insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt) are planted on millions of hectares annually, reducing the use of conventional insecticides and suppressing pests. However, the evolution of resistance could cut short these benefits. A primary pest targeted by Bt maize in the United States is the western corn rootworm Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae). Methodology/Principal Findings We report that fields identified by farmers as having severe rootworm feeding injury to Bt maize contained populations of western corn rootworm that displayed significantly higher survival on Cry3Bb1 maize in laboratory bioassays than did western corn rootworm from fields not associated with such feeding injury. In all cases, fields experiencing severe rootworm feeding contained Cry3Bb1 maize. Interviews with farmers indicated that Cry3Bb1 maize had been grown in those fields for at least three consecutive years. There was a significant positive correlation between the number of years Cry3Bb1 maize had been grown in a field and the survival of rootworm populations on Cry3Bb1 maize in bioassays. However, there was no significant correlation among populations for survival on Cry34/35Ab1 maize and Cry3Bb1 maize, suggesting a lack of cross resistance between these Bt toxins. Conclusions/Significance This is the first report of field-evolved resistance to a Bt toxin by the western corn rootworm and by any species of Coleoptera. Insufficient planting of refuges and non-recessive inheritance of resistance may have contributed to resistance. These results suggest that improvements in resistance management and a more integrated approach to the use of Bt crops may be necessary. PMID:21829470

Cry1F Resistance in Fall Armyworm Spodoptera frugiperda: Single Gene versus Pyramided Bt Maize

PubMed Central

Huang, Fangneng; Qureshi, Jawwad A.; Meagher, Robert L.; Reisig, Dominic D.; Head, Graham P.; Andow, David A.; Ni, Xinzi; Kerns, David; Buntin, G. David; Niu, Ying; Yang, Fei; Dangal, Vikash

2014-01-01

Evolution of insect resistance to transgenic crops containing Bacillus thuringiensis (Bt) genes is a serious threat to the sustainability of this technology. However, field resistance related to the reduced efficacy of Bt maize has not been documented in any lepidopteran pest in the mainland U.S. after 18 years of intensive Bt maize planting. Here we report compelling evidence of field resistance in the fall armyworm, Spodoptera frugiperda (J.E. Smith), to Cry1F maize (TC 3507) in the southeastern region of the U.S. An F2 screen showed a surprisingly high (0.293) Cry1F resistance allele frequency in a population collected in 2011 from non-Bt maize in south Florida. Field populations from non-Bt maize in 2012–2013 exhibited 18.8-fold to >85.4-fold resistance to purified Cry1F protein and those collected from unexpectedly damaged Bt maize plants at several locations in Florida and North Carolina had >85.4-fold resistance. In addition, reduced efficacy and control failure of Cry1F maize against natural populations of S. frugiperda were documented in field trials using Cry1F-based and pyramided Bt maize products in south Florida. The Cry1F-resistant S. frugiperda also showed a low level of cross-resistance to Cry1A.105 and related maize products, but not to Cry2Ab2 or Vip3A. The occurrence of Cry1F resistance in the U.S. mainland populations of S. frugiperda likely represents migration of insects from Puerto Rico, indicating the great challenges faced in achieving effective resistance management for long-distance migratory pests like S. frugiperda. PMID:25401494

Nitrogen transporter and assimilation genes exhibit developmental stage-selective expression in maize (Zea mays L.) associated with distinct cis-acting promoter motifs.

PubMed

Liseron-Monfils, Christophe; Bi, Yong-Mei; Downs, Gregory S; Wu, Wenqing; Signorelli, Tara; Lu, Guangwen; Chen, Xi; Bondo, Eddie; Zhu, Tong; Lukens, Lewis N; Colasanti, Joseph; Rothstein, Steven J; Raizada, Manish N

2013-10-01

Nitrogen is considered the most limiting nutrient for maize (Zea mays L.), but there is limited understanding of the regulation of nitrogen-related genes during maize development. An Affymetrix 82K maize array was used to analyze the expression of ≤ 46 unique nitrogen uptake and assimilation probes in 50 maize tissues from seedling emergence to 31 d after pollination. Four nitrogen-related expression clusters were identified in roots and shoots corresponding to, or overlapping, juvenile, adult, and reproductive phases of development. Quantitative real time PCR data was consistent with the existence of these distinct expression clusters. Promoters corresponding to each cluster were screened for over-represented cis-acting elements. The 8-bp distal motif of the Arabidopsis 43-bp nitrogen response element (NRE) was over-represented in nitrogen-related maize gene promoters. This conserved motif, referred to here as NRE43-d8, was previously shown to be critical for nitrate-activated transcription of nitrate reductase (NIA1) and nitrite reductase (NIR1) by the NIN-LIKE PROTEIN 6 (NLP6) in Arabidopsis. Here, NRE43-d8 was over-represented in the promoters of maize nitrate and ammonium transporter genes, specifically those that showed peak expression during early-stage vegetative development. This result predicts an expansion of the NRE-NLP6 regulon and suggests that it may have a developmental component in maize. We also report leaf expression of putative orthologs of nitrite transporters (NiTR1), a transporter not previously reported in maize. We conclude by discussing how each of the four transcriptional modules may be responsible for the different nitrogen uptake and assimilation requirements of leaves and roots at different stages of maize development.

Cry1F resistance in fall armyworm Spodoptera frugiperda: single gene versus pyramided Bt maize.

PubMed

Huang, Fangneng; Qureshi, Jawwad A; Meagher, Robert L; Reisig, Dominic D; Head, Graham P; Andow, David A; Ni, Xinzi; Kerns, David; Buntin, G David; Niu, Ying; Yang, Fei; Dangal, Vikash

2014-01-01

Evolution of insect resistance to transgenic crops containing Bacillus thuringiensis (Bt) genes is a serious threat to the sustainability of this technology. However, field resistance related to the reduced efficacy of Bt maize has not been documented in any lepidopteran pest in the mainland U.S. after 18 years of intensive Bt maize planting. Here we report compelling evidence of field resistance in the fall armyworm, Spodoptera frugiperda (J.E. Smith), to Cry1F maize (TC 3507) in the southeastern region of the U.S. An F2 screen showed a surprisingly high (0.293) Cry1F resistance allele frequency in a population collected in 2011 from non-Bt maize in south Florida. Field populations from non-Bt maize in 2012-2013 exhibited 18.8-fold to >85.4-fold resistance to purified Cry1F protein and those collected from unexpectedly damaged Bt maize plants at several locations in Florida and North Carolina had >85.4-fold resistance. In addition, reduced efficacy and control failure of Cry1F maize against natural populations of S. frugiperda were documented in field trials using Cry1F-based and pyramided Bt maize products in south Florida. The Cry1F-resistant S. frugiperda also showed a low level of cross-resistance to Cry1A.105 and related maize products, but not to Cry2Ab2 or Vip3A. The occurrence of Cry1F resistance in the U.S. mainland populations of S. frugiperda likely represents migration of insects from Puerto Rico, indicating the great challenges faced in achieving effective resistance management for long-distance migratory pests like S. frugiperda.

Individual detection of genetically modified maize varieties in non-identity-preserved maize samples.

PubMed

Akiyama, Hiroshi; Sakata, Kozue; Kondo, Kazunari; Tanaka, Asako; Liu, Ming S; Oguchi, Taichi; Furui, Satoshi; Kitta, Kazumi; Hino, Akihiro; Teshima, Reiko

2008-03-26

In many countries, the labeling of grains and feed- and foodstuffs is mandatory if the genetically modified organism (GMO) content exceeds a certain level of approved GM varieties. The GMO content in a maize sample containing the combined-trait (stacked) GM maize as determined by the currently available methodology is likely to be overestimated. However, there has been little information in the literature on the mixing level and varieties of stacked GM maize in real sample grains. For the first time, the GMO content of non-identity-preserved (non-IP) maize samples imported from the United States has been successfully determined by using a previously developed individual kernel detection system coupled to a multiplex qualitative PCR method followed by multichannel capillary gel electrophoresis system analysis. To clarify the GMO content in the maize samples imported from the United States, determine how many stacked GM traits are contained therein, and which GM trait varieties frequently appeared in 2005, the GMO content (percent) on a kernel basis and the varieties of the GM kernels in the non-IP maize samples imported from the United States were investigated using the individual kernel analysis system. The average (+/-standard deviation) of the GMO contents on a kernel basis in five non-IP sample lots was determined to be 51.0+/-21.6%, the percentage of a single GM trait grains was 39%, and the percentage of the stacked GM trait grains was 12%. The MON810 grains and NK603 grains were the most frequent varieties in the single GM traits. The most frequent stacked GM traits were the MON810xNK603 grains. In addition, the present study would provide the answer and impact for the quantification of GM maize content in the GM maize kernels on labeling regulation.

The Optical Absorption Coefficient of Maize Grains Investigated by Photoacoustic Spectroscopy

NASA Astrophysics Data System (ADS)

Rodríguez-Páez, C. L.; Carballo-Carballo, A.; Rico-Molina, R.; Hernández-Aguilar, C.; Domínguez-Pacheco, A.; Cruz-Orea, A.; Moreno-Martínez, E.

2017-01-01

In the maize and tortilla industry, it is important to characterize the color of maize ( Zea mays L.) grain, as it is one of the attributes that directly affect the quality of the tortillas consumed by the population. For this reason, the availability of alternative techniques for assessing and improving the quality of grain is valued. Photoacoustic spectroscopy has proven to be a useful tool for characterizing maize grain. So, the objective of the present study was to determine the optical absorption coefficient β of the maize grain used to make tortillas from two regions of Mexico: (a) Valles Altos, 2012-2013 production cycle and (b) Guasave, Sinaloa, 2013-2014 production cycle. Traditional reflectance measurements, physical characteristics of the grain and nutrient content were also calculated. The experimental results show different characteristics for maize grains.

The proteome and phosphoproteome of maize pollen uncovers fertility candidate proteins.

PubMed

Chao, Qing; Gao, Zhi-Fang; Wang, Yue-Feng; Li, Zhe; Huang, Xia-He; Wang, Ying-Chun; Mei, Ying-Chang; Zhao, Biligen-Gaowa; Li, Liang; Jiang, Yu-Bo; Wang, Bai-Chen

2016-06-01

Maize is unique since it is both monoecious and diclinous (separate male and female flowers on the same plant). We investigated the proteome and phosphoproteome of maize pollen containing modified proteins and here we provide a comprehensive pollen proteome and phosphoproteome which contain 100,990 peptides from 6750 proteins and 5292 phosphorylated sites corresponding to 2257 maize phosphoproteins, respectively. Interestingly, among the total 27 overrepresented phosphosite motifs we identified here, 11 were novel motifs, which suggested different modification mechanisms in plants compared to those of animals. Enrichment analysis of pollen phosphoproteins showed that pathways including DNA synthesis/chromatin structure, regulation of RNA transcription, protein modification, cell organization, signal transduction, cell cycle, vesicle transport, transport of ions and metabolisms, which were involved in pollen development, the following germination and pollen tube growth, were regulated by phosphorylation. In this study, we also found 430 kinases and 105 phosphatases in the maize pollen phosphoproteome, among which calcium dependent protein kinases (CDPKs), leucine rich repeat kinase, SNF1 related protein kinases and MAPK family proteins were heavily enriched and further analyzed. From our research, we also uncovered hundreds of male sterility-associated proteins and phosphoproteins that might influence maize productivity and serve as targets for hybrid maize seed production. At last, a putative complex signaling pathway involving CDPKs, MAPKs, ubiquitin ligases and multiple fertility proteins was constructed. Overall, our data provides new insight for further investigation of protein phosphorylation status in mature maize pollen and construction of maize male sterile mutants in the future.

Sporophytic control of pollen tube growth and guidance in maize.

PubMed

Lausser, Andreas; Kliwer, Irina; Srilunchang, Kanok-orn; Dresselhaus, Thomas

2010-03-01

Pollen tube germination, growth, and guidance (progamic phase) culminating in sperm discharge is a multi-stage process including complex interactions between the male gametophyte as well as sporophytic tissues and the female gametophyte (embryo sac), respectively. Inter- and intra-specific crossing barriers in maize and Tripsacum have been studied and a precise description of progamic pollen tube development in maize is reported here. It was found that pollen germination and initial tube growth are rather unspecific, but an early, first crossing barrier was detected before arrival at the transmitting tract. Pollination of maize silks with Tripsacum pollen and incompatible pollination of Ga1s/Ga1s-maize silks with ga1-maize pollen revealed another two incompatibility barriers, namely transmitting tract mistargeting and insufficient growth support. Attraction and growth support by the transmitting tract seem to play key roles for progamic pollen tube growth. After leaving transmitting tracts, pollen tubes have to navigate across the ovule in the ovular cavity. Pollination of an embryo sac-less maize RNAi-line allowed the role of the female gametophyte for pollen tube guidance to be determined in maize. It was found that female gametophyte controlled guidance is restricted to a small region around the micropyle, approximately 50-100 microm in diameter. This area is comparable to the area of influence of previously described ZmEA1-based short-range female gametophyte signalling. In conclusion, the progamic phase is almost completely under sporophytic control in maize.

Sporophytic control of pollen tube growth and guidance in maize

PubMed Central

Lausser, Andreas; Kliwer, Irina; Srilunchang, Kanok-orn; Dresselhaus, Thomas

2010-01-01

Pollen tube germination, growth, and guidance (progamic phase) culminating in sperm discharge is a multi-stage process including complex interactions between the male gametophyte as well as sporophytic tissues and the female gametophyte (embryo sac), respectively. Inter- and intra-specific crossing barriers in maize and Tripsacum have been studied and a precise description of progamic pollen tube development in maize is reported here. It was found that pollen germination and initial tube growth are rather unspecific, but an early, first crossing barrier was detected before arrival at the transmitting tract. Pollination of maize silks with Tripsacum pollen and incompatible pollination of Ga1s/Ga1s-maize silks with ga1-maize pollen revealed another two incompatibility barriers, namely transmitting tract mistargeting and insufficient growth support. Attraction and growth support by the transmitting tract seem to play key roles for progamic pollen tube growth. After leaving transmitting tracts, pollen tubes have to navigate across the ovule in the ovular cavity. Pollination of an embryo sac-less maize RNAi-line allowed the role of the female gametophyte for pollen tube guidance to be determined in maize. It was found that female gametophyte controlled guidance is restricted to a small region around the micropyle, approximately 50–100 μm in diameter. This area is comparable to the area of influence of previously described ZmEA1-based short-range female gametophyte signalling. In conclusion, the progamic phase is almost completely under sporophytic control in maize. PMID:19926683

Production and economic performance of F1-crossbred dairy cattle fed non-conventional protein supplements in Zimbabwe.

PubMed

Gusha, Jacob; Manyuchi, Clive Rolex; Imbayarwo-Chikosi, Venancio Edward; Hamandishe, Vimbayi Rangaridzo; Katsande, Simbarashe; Zvinorova, Plaxedis Ivy

2014-01-01

The effects of supplementing crossbred cows with non-conventional protein sources on dry matter intake, milk yield parameters and economic returns were investigated. Twenty-five lactating F1 Holstein-Mashona crossbreds averaging 115 ± 24 days in milk were used. Five treatments, total mixed ration (TMR), urea-treated maize stover, untreated maize stover, Macroptilium atropurpureum (Siratro) hay and veld hay, were randomly assigned to cows and replicated five times in a completely randomised design. Nutrient composition, intake, milk yield and economic returns were determined. M. atropurpureum hay, urea-treated maize stover and TMR had equal crude protein content. Daily dry matter intake and yield differed significantly among the treatment diets (P < 0.05). Cows on TMR, urea-treated maize stover and M. atropurpureum consumed more (P < 0.05) than cows on untreated maize stover and veld hay. Supplementing with TMR, urea-treated maize stover and M. atropurpureum hay increased (P < 0.05) milk yields. Mean daily milk yield was highest for cows supplemented with urea-treated maize stover. Percent fat, protein and total solids in milk from cows fed urea-treated stover compared favourably to that of milk for cows supplemented with TMR. Income over supplement cost was highest for cows supplemented with M. atropurpureum hay and urea-treated maize stover. Urea-treated maize stover and M. atropurpureum can therefore be used as a replacer protein supplements for dairy cattle in Zimbabwe.

Comparative analysis of maize (Zea mays) crop performance: natural variation, incremental improvements and economic impacts.

PubMed

Leibman, Mark; Shryock, Jereme J; Clements, Michael J; Hall, Michael A; Loida, Paul J; McClerren, Amanda L; McKiness, Zoe P; Phillips, Jonathan R; Rice, Elena A; Stark, Steven B

2014-09-01

Grain yield from maize hybrids continues to improve through advances in breeding and biotechnology. Despite genetic improvements to hybrid maize, grain yield from distinct maize hybrids is expected to vary across growing locations due to numerous environmental factors. In this study, we examine across-location variation in grain yield among maize hybrids in three case studies. The three case studies examine hybrid improvement through breeding, introduction of an insect protection trait or introduction of a transcription factor trait associated with increased yield. In all cases, grain yield from each hybrid population had a Gaussian distribution. Across-location distributions of grain yield from each hybrid partially overlapped. The hybrid with a higher mean grain yield typically outperformed its comparator at most, but not all, of the growing locations (a 'win rate'). These results suggest that a broad set of environmental factors similarly impacts grain yields from both conventional- and biotechnology-derived maize hybrids and that grain yields among two or more hybrids should be compared with consideration given to both mean yield performance and the frequency of locations at which each hybrid 'wins' against its comparators. From an economic standpoint, growers recognize the value of genetically improved maize hybrids that outperform comparators in the majority of locations. Grower adoption of improved maize hybrids drives increases in average U.S. maize grain yields and contributes significant value to the economy. © 2014 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

Effect of seed blends and soil-insecticide on western and northern corn rootworm emergence from mCry3A + eCry3.1Ab Bt maize

USDA-ARS?s Scientific Manuscript database

Blended seed mixtures containing various ratios of transgenic Bt maize expressing the mCry3A + eCry3.1Ab proteins and non-Bt maize (near-isoline maize) were deployed alone and in combination with a soil applied insecticide (Force CS) to evaluate the survivorship of the western corn rootworm, Diabrot...

Genetically engineered crops and pesticide use in U.S. maize and soybeans

PubMed Central

Perry, Edward D.; Ciliberto, Federico; Hennessy, David A.; Moschini, GianCarlo

2016-01-01

The widespread adoption of genetically engineered (GE) crops has clearly led to changes in pesticide use, but the nature and extent of these impacts remain open questions. We study this issue with a unique, large, and representative sample of plot-level choices made by U.S. maize and soybean farmers from 1998 to 2011. On average, adopters of GE glyphosate-tolerant (GT) soybeans used 28% (0.30 kg/ha) more herbicide than nonadopters, adopters of GT maize used 1.2% (0.03 kg/ha) less herbicide than nonadopters, and adopters of GE insect-resistant (IR) maize used 11.2% (0.013 kg/ha) less insecticide than nonadopters. When pesticides are weighted by the environmental impact quotient, however, we find that (relative to nonadopters) GE adopters used about the same amount of soybean herbicides, 9.8% less of maize herbicides, and 10.4% less of maize insecticides. In addition, the results indicate that the difference in pesticide use between GE and non-GE adopters has changed significantly over time. For both soybean and maize, GT adopters used increasingly more herbicides relative to nonadopters, whereas adopters of IR maize used increasingly less insecticides. The estimated pattern of change in herbicide use over time is consistent with the emergence of glyphosate weed resistance. PMID:27652335

Distinct gene networks modulate floral induction of autonomous maize and photoperiod-dependent teosinte.

PubMed

Minow, Mark A A; Ávila, Luis M; Turner, Katie; Ponzoni, Elena; Mascheretti, Iride; Dussault, Forest M; Lukens, Lewis; Rossi, Vincenzo; Colasanti, Joseph

2018-05-25

Temperate maize was domesticated from its tropical ancestor, teosinte. Whereas temperate maize is an autonomous day-neutral plant, teosinte is an obligate short-day plant that requires uninterrupted long nights to induce flowering. Leaf-derived florigenic signals trigger reproductive growth in both teosinte and temperate maize. To study the genetic mechanisms underlying floral inductive pathways in maize and teosinte, mRNA and small RNA genome-wide expression analyses were conducted on leaf tissue from plants that were induced or not induced to flower. Transcriptome profiles reveal common differentially expressed genes during floral induction, but a comparison of candidate flowering time genes indicates that photoperiod and autonomous pathways act independently. Expression differences in teosinte are consistent with the current paradigm for photoperiod-induced flowering, where changes in circadian clock output trigger florigen production. Conversely, differentially expressed genes in temperate maize link carbon partitioning and flowering, but also show altered expression of circadian clock genes that are distinct from those altered upon photoperiodic induction in teosinte. Altered miRNA399 levels in both teosinte and maize suggest a novel common connection between flowering and phosphorus perception. These findings provide insights into the molecular mechanisms underlying a strengthened autonomous pathway that enabled maize growth throughout temperate regions.

Quality of maize for sale in markets in Benin and Niger.

PubMed

Bakoye, O N; Baoua, I B; Seyni, H; Amadou, L; Murdock, L L; Baributsa, D

2017-03-01

A follow-up study on the quality of maize for sale in West African public markets was carried out in Benin and Niger from August 15-28, 2013. Complementing the earlier study, this present assessment included not only retailers but also wholesalers and maize producers. Samples were evaluated for parameters related to the physical quality of the maize and for aflatoxin contamination. Most maize value chain actors process their offered grain using traditional methods for threshing, winnowing and drying. Maize for sale in the markets surveyed had an average moisture content ranging between 12 and 14%. Non-grain impurities amounted to 0-2.3% while mouldy grains ranged between 0.2 and 0.8%. The impurity level in grain was three times higher among wholesalers compared to retailers and producers. An insect pest, the Larger Grain Borer ( Prostephanus truncatus (Horn) was found only in Benin but Sitophilus zeamais Motschulsky, Cryptolestes ferrugineus Stephens, and Tribolium castaneum Herbst, were present in maize for sale in the markets in of both countries. Insect pest frequency was 16 times higher in wholesalers' grain compared to that of retailers and producers. Aflatoxin levels exceeding the accepted standard of 20 ppb were noted in markets in both countries. The highest proportion of aflatoxin-contaminated maize was in wholesalers' grain in Malanville market.

Advances in Maize Genomics and Their Value for Enhancing Genetic Gains from Breeding

PubMed Central

Xu, Yunbi; Skinner, Debra J.; Wu, Huixia; Palacios-Rojas, Natalia; Araus, Jose Luis; Yan, Jianbing; Gao, Shibin; Warburton, Marilyn L.; Crouch, Jonathan H.

2009-01-01

Maize is an important crop for food, feed, forage, and fuel across tropical and temperate areas of the world. Diversity studies at genetic, molecular, and functional levels have revealed that, tropical maize germplasm, landraces, and wild relatives harbor a significantly wider range of genetic variation. Among all types of markers, SNP markers are increasingly the marker-of-choice for all genomics applications in maize breeding. Genetic mapping has been developed through conventional linkage mapping and more recently through linkage disequilibrium-based association analyses. Maize genome sequencing, initially focused on gene-rich regions, now aims for the availability of complete genome sequence. Conventional insertion mutation-based cloning has been complemented recently by EST- and map-based cloning. Transgenics and nutritional genomics are rapidly advancing fields targeting important agronomic traits including pest resistance and grain quality. Substantial advances have been made in methodologies for genomics-assisted breeding, enhancing progress in yield as well as abiotic and biotic stress resistances. Various genomic databases and informatics tools have been developed, among which MaizeGDB is the most developed and widely used by the maize research community. In the future, more emphasis should be given to the development of tools and strategic germplasm resources for more effective molecular breeding of tropical maize products. PMID:19688107

Effects of temperature changes on maize production in Mozambique

USGS Publications Warehouse

Harrison, L.; Michaelsen, J.; Funk, Chris; Husak, G.

2011-01-01

We examined intraseasonal changes in maize phenology and heat stress exposure over the 1979-2008 period, using Mozambique meteorological station data and maize growth requirements in a growing degree-day model. Identifying historical effects of warming on maize growth is particularly important in Mozambique because national food security is highly dependent on domestic food production, most of which is grown in already warm to hot environments. Warming temperatures speed plant development, shortening the length of growth periods necessary for optimum plant and grain size. This faster phenological development also alters the timing of maximum plant water demand. In hot growing environments, temperature increases during maize pollination threaten to make midseason crop failure the norm. In addition to creating a harsher thermal environment, we find that early season temperature increases have caused the maize reproductive period to start earlier, increasing the risk of heat and water stress. Declines in time to maize maturation suggest that, independent of effects to water availability, yield potential is becoming increasingly limited by warming itself. Regional variations in effects are a function of the timing and magnitude of temperature increases and growing season characteristics. Continuation of current climatic trends could induce substantial yield losses in some locations. Farmers could avoid some losses through simple changes to planting dates and maize varietal types.

Impact of living mulches on the physical properties of Planosol in monocropped maize cultivation

NASA Astrophysics Data System (ADS)

Romaneckas, Kęstutis; Adamavičienė, Aida; Šarauskis, Egidijus; Kriaučiūnienė, Zita; Marks, Marek; Vaitauskienė, Kristina

2018-04-01

The complex mutual interactions between soil properties and plants in high-biodiversity mono-cropping agro ecosystems have not been widely investigated. For this purpose, during 2009-2011, a stationary field experiment was conducted at the Experimental Station of the Aleksandras Stulginskis University to establish the effect of a multi-component agrocenose (maize, living mulch, weeds) on the physical properties of the soil. Spring oilseed rape, white mustard, spring barley, Italian ryegrass, black medic, Persian clover and red clover were sown as living mulch into maize inter-rows. The stability of >1.0 mm aggregates increased between the beginning and end of the maize vegetative period in almost all of the crops containing living mulch. The greatest competition for moisture content between the inter-crops and maize was observed at the beginning of the vegetative period because of living mulches of long growing seasons using the most moisture. In many cases, the shear strength of the soil was significantly reduced by the living mulch in the middle of summer, when it covered the maize inter-rows. These findings show that the monocropping of maize with living mulch stabilises or improves the physical characteristics of the soil, highlighting its potential for sustainable maize growing.

Effect on Soil Properties of BcWRKY1 Transgenic Maize with Enhanced Salinity Tolerance

PubMed Central

Zeng, Xing; Zhou, Yu; Zhu, Zhongjia; Zu, Hongyue

2016-01-01

Maize (Zea mays L.) is the most important cereal crop in the world. However, soil salinity has become a major problem affecting plant productivity due to arable field degradation. Thus, transgenic maize transformed with a salinity tolerance gene has been developed to further evaluate its salt tolerance and effects on agronomic traits. It is necessary to analyze the potential environmental risk of transgenic maize before further commercialization. Enzyme activities, physicochemical properties, and microbial populations were evaluated in saline and nonsaline rhizosphere soils from a transgenic maize line (WL-73) overexpressing BcWRKY1 and from wild-type (WT) maize LH1037. Measurements were taken at four growth stages (V3, V9, R1, and R6) and repeated in three consecutive years (2012–2014). There was no change in the rhizosphere soils of either WL-73 or WT plants in the four soil enzyme activities, seven soil physicochemical properties, and the populations of three soil organisms. The results of this study suggested that salinity tolerant transgenic maize had no adverse impact on soil properties in soil rhizosphere during three consecutive years at two different locations and provided a theoretical basis for environmental impact monitoring of salinity tolerant transgenic maize. PMID:27990421

The MaizeGDB Genome Browser tutorial: one example of database outreach to biologists via video

PubMed Central

Harper, Lisa C.; Schaeffer, Mary L.; Thistle, Jordan; Gardiner, Jack M.; Andorf, Carson M.; Campbell, Darwin A.; Cannon, Ethalinda K.S.; Braun, Bremen L.; Birkett, Scott M.; Lawrence, Carolyn J.; Sen, Taner Z.

2011-01-01

Video tutorials are an effective way for researchers to quickly learn how to use online tools offered by biological databases. At MaizeGDB, we have developed a number of video tutorials that demonstrate how to use various tools and explicitly outline the caveats researchers should know to interpret the information available to them. One such popular video currently available is ‘Using the MaizeGDB Genome Browser’, which describes how the maize genome was sequenced and assembled as well as how the sequence can be visualized and interacted with via the MaizeGDB Genome Browser. Database URL: http://www.maizegdb.org/ PMID:21565781

Genomic variation in recently collected maize landraces from Mexico

PubMed Central

Arteaga, María Clara; Moreno-Letelier, Alejandra; Mastretta-Yanes, Alicia; Vázquez-Lobo, Alejandra; Breña-Ochoa, Alejandra; Moreno-Estrada, Andrés; Eguiarte, Luis E.; Piñero, Daniel

2015-01-01

The present dataset comprises 36,931 SNPs genotyped in 46 maize landraces native to Mexico as well as the teosinte subspecies Zea maiz ssp. parviglumis and ssp. mexicana. These landraces were collected directly from farmers mostly between 2006 and 2010. We accompany these data with a short description of the variation within each landrace, as well as maps, principal component analyses and neighbor joining trees showing the distribution of the genetic diversity relative to landrace, geographical features and maize biogeography. High levels of genetic variation were detected for the maize landraces (HE = 0.234 to 0.318 (mean 0.311), while slightly lower levels were detected in Zea m. mexicana and Zea m. parviglumis (HE = 0.262 and 0.234, respectively). The distribution of genetic variation was better explained by environmental variables given by the interaction of altitude and latitude than by landrace identity. This dataset is a follow up product of the Global Native Maize Project, an initiative to update the data on Mexican maize landraces and their wild relatives, and to generate information that is necessary for implementing the Mexican Biosafety Law. PMID:26981357

Genome-Wide Identification, Evolution and Expression Analysis of mTERF Gene Family in Maize

PubMed Central

Zhao, Yanxin; Cai, Manjun; Zhang, Xiaobo; Li, Yurong; Zhang, Jianhua; Zhao, Hailiang; Kong, Fei; Zheng, Yonglian; Qiu, Fazhan

2014-01-01

Plant mitochondrial transcription termination factor (mTERF) genes comprise a large family with important roles in regulating organelle gene expression. In this study, a comprehensive database search yielded 31 potential mTERF genes in maize (Zea mays L.) and most of them were targeted to mitochondria or chloroplasts. Maize mTERF were divided into nine main groups based on phylogenetic analysis, and group IX represented the mitochondria and species-specific clade that diverged from other groups. Tandem and segmental duplication both contributed to the expansion of the mTERF gene family in the maize genome. Comprehensive expression analysis of these genes, using microarray data and RNA-seq data, revealed that these genes exhibit a variety of expression patterns. Environmental stimulus experiments revealed differential up or down-regulation expression of maize mTERF genes in seedlings exposed to light/dark, salts and plant hormones, respectively, suggesting various important roles of maize mTERF genes in light acclimation and stress-related responses. These results will be useful for elucidating the roles of mTERF genes in the growth, development and stress response of maize. PMID:24718683

Ustilago maydis populations tracked maize through domestication and cultivation in the Americas

PubMed Central

Munkacsi, Andrew B; Stoxen, Sam; May, Georgiana

2008-01-01

The domestication of crops and the development of agricultural societies not only brought about major changes in human interactions with the environment but also in plants' interactions with the diseases that challenge them. We evaluated the impact of the domestication of maize from teosinte and the widespread cultivation of maize on the historical demography of Ustilago maydis, a fungal pathogen of maize. To determine the evolutionary response of the pathogen's populations, we obtained multilocus genotypes for 1088 U. maydis diploid individuals from two teosinte subspecies in Mexico and from maize in Mexico and throughout the Americas. Results identified five major U. maydis populations: two in Mexico; two in South America; and one in the United States. The two populations in Mexico diverged from the other populations at times comparable to those for the domestication of maize at 6000–10 000 years before present. Maize domestication and agriculture enforced sweeping changes in U. maydis populations such that the standing variation in extant pathogen populations reflects evolution only since the time of the crop's domestication. PMID:18252671

Effects of feeding Mediterranean buffalo sorghum silage versus maize silage on the rumen microbiota and milk fatty acid content.

PubMed

Ann Huws, Sharon; Chiariotti, Antonella; Sarubbi, Fiorella; Carfì, Francesca; Pace, Vilma

2012-01-01

Sorghum presents a sustainable feedstock for Mediterranean buffaloes due to its reduced water and nitrogen requirements compared with maize, which is currently fed primarily. We investigated the effects of feeding sorghum as opposed to maize on Mediterranean buffalo rumen microbial diversity and milk fatty acid content. Four cannulated lactating Mediterranean buffalo cows were fed a basal diet for one month before switching either to maize or sorghum-silage based diets for a 3-month period. Buffaloes were then changed over to the contrasting diet for a further one month. Rumen and milk samples were collected at the end of each month. DGGE- and T-RFLP-based dendrograms generated from rumen samples did not show an effect of diet on rumen bacterial diversity. Milk samples also did not differ in terms of their fatty acid content post sorghum feeding as compared with maize feeding. Thus, sorghum provides an environmentally beneficial alternative to maize for feeding Mediterranean buffalo with little effect on rumen microbial diversity or milk fatty acid composition compared with maize feeding.

Multiple Pesticides Detoxification Function of Maize (Zea mays) GST34.

PubMed

Li, Dongzhi; Xu, Li; Pang, Sen; Liu, Zhiqian; Zhao, Weisong; Wang, Chengju

2017-03-08

ZmGST34 is a maize Tau class GST gene and was found to be differently expressed between two maize cultivars differing in tolerance to herbicide metolachlor. To explore the possible role of ZmGST34 in maize development, the expression pattern and substrate specificity of ZmGST34 were characterized by quantitative RT-PCR and heterologous expression system, respectively. The results indicated that the expression level of ZmGST34 was increased ∼2-5-fold per day during the second-leaf stage of maize seedling. Chloroacetanilide herbicides or phytohormone treatments had no influence on the expression level of ZmGST34, suggesting that ZmGST34 is a constitutively expressed gene in maize seedling. Heterologous expression in Escherichia coli and in Arabidopsis thaliana proved that ZmGST34 can metabolize most chloroacetanilide herbicides and increase tolerance to these herbicides in transgenic Arabidopsis thaliana. The constitutive expression pattern and broad substrate activity of ZmGST34 suggested that this gene may play an important role in maize development in addition to the detoxification of pesticides.

Genomic variation in recently collected maize landraces from Mexico.

PubMed

Arteaga, María Clara; Moreno-Letelier, Alejandra; Mastretta-Yanes, Alicia; Vázquez-Lobo, Alejandra; Breña-Ochoa, Alejandra; Moreno-Estrada, Andrés; Eguiarte, Luis E; Piñero, Daniel

2016-03-01

The present dataset comprises 36,931 SNPs genotyped in 46 maize landraces native to Mexico as well as the teosinte subspecies Zea maiz ssp. parviglumis and ssp. mexicana. These landraces were collected directly from farmers mostly between 2006 and 2010. We accompany these data with a short description of the variation within each landrace, as well as maps, principal component analyses and neighbor joining trees showing the distribution of the genetic diversity relative to landrace, geographical features and maize biogeography. High levels of genetic variation were detected for the maize landraces (H E = 0.234 to 0.318 (mean 0.311), while slightly lower levels were detected in Zea m. mexicana and Zea m. parviglumis (H E = 0.262 and 0.234, respectively). The distribution of genetic variation was better explained by environmental variables given by the interaction of altitude and latitude than by landrace identity. This dataset is a follow up product of the Global Native Maize Project, an initiative to update the data on Mexican maize landraces and their wild relatives, and to generate information that is necessary for implementing the Mexican Biosafety Law.

Maize rhabdovirus-vector transmission

USDA-ARS?s Scientific Manuscript database

oth of the plant-infecting rhabdovirus genera, Nucleorhabdovirus and Cytorhabdovirus, contain viruses that infect maize (Zea mays L.). The maize infecting rhabdoviruses are transmitted by hemipteran insects in the families Cicadellidae and Delphacidae in a persistent propagative manner. This chapt...

Genomic estimation of complex traits reveals ancient maize adaptation to temperate North America.

PubMed

Swarts, Kelly; Gutaker, Rafal M; Benz, Bruce; Blake, Michael; Bukowski, Robert; Holland, James; Kruse-Peeples, Melissa; Lepak, Nicholas; Prim, Lynda; Romay, M Cinta; Ross-Ibarra, Jeffrey; Sanchez-Gonzalez, Jose de Jesus; Schmidt, Chris; Schuenemann, Verena J; Krause, Johannes; Matson, R G; Weigel, Detlef; Buckler, Edward S; Burbano, Hernán A

2017-08-04

By 4000 years ago, people had introduced maize to the southwestern United States; full agriculture was established quickly in the lowland deserts but delayed in the temperate highlands for 2000 years. We test if the earliest upland maize was adapted for early flowering, a characteristic of modern temperate maize. We sequenced fifteen 1900-year-old maize cobs from Turkey Pen Shelter in the temperate Southwest. Indirectly validated genomic models predicted that Turkey Pen maize was marginally adapted with respect to flowering, as well as short, tillering, and segregating for yellow kernel color. Temperate adaptation drove modern population differentiation and was selected in situ from ancient standing variation. Validated prediction of polygenic traits improves our understanding of ancient phenotypes and the dynamics of environmental adaptation. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Ancient maize from Chacoan great houses: Where was it grown?

PubMed Central

Benson, Larry; Cordell, Linda; Vincent, Kirk; Taylor, Howard; Stein, John; Farmer, G. Lang; Futa, Kiyoto

2003-01-01

In this article, we compare chemical (87Sr/86Sr and elemental) analyses of archaeological maize from dated contexts within Pueblo Bonito, Chaco Canyon, New Mexico, to potential agricultural sites on the periphery of the San Juan Basin. The oldest maize analyzed from Pueblo Bonito probably was grown in an area located 80 km to the west at the base of the Chuska Mountains. The youngest maize came from the San Juan or Animas river floodplains 90 km to the north. This article demonstrates that maize, a dietary staple of southwestern Native Americans, was transported over considerable distances in pre-Columbian times, a finding fundamental to understanding the organization of pre-Columbian southwestern societies. In addition, this article provides support for the hypothesis that major construction events in Chaco Canyon were made possible because maize was brought in to support extra-local labor forces. PMID:14563925

Temperature, Sowing and Harvest Dates, and Yield of Maize in the Southwestern US

NASA Astrophysics Data System (ADS)

Kafatos, M.; Stack, D.; Myoung, B.; Kim, S. H.; Kim, J.

2014-12-01

Since sowing date of maize is sensitive to climate variability and changes, it is of a practical importance to examine how sowing dates affect maize yields in various temperature regimes in the southwestern US. A 21-year (1991-2011) simulation of maize yield using Agricultural Production Systems sIMulator (APSIM) with observed meteorological forcing, shows that earlier sowing dates are favorable for higher yields primarily by increasing the length of growing season in cold mountaineous regions. In these regions, warmer conditions in the sowing period tend to advance the sowing date and then enhance yield. Over low-elevation warm regions, yields are less correlated with sowing dates and the length of growing season, perhaps because growing season temperatures are high enough for fast growth. Instead, in the warm regions, maize yields are sensitive to temperature variations during the late growing season due to adverse effects of extreme high temperature events on maize development.

Ancient maize from Chacoan great houses: Where was it grown?

USGS Publications Warehouse

Benson, L.; Cordell, L.; Vincent, K.; Taylor, Howard E.; Stein, J.; Farmer, G.L.; Futa, K.

2003-01-01

In this article, we compare chemical (87Sr/86Sr and elemental) analyses of archaeological maize from dated contexts within Pueblo Bonito, Chaco Canyon, New Mexico, to potential agricultural sites on the periphery of the San Juan Basin. The oldest maize analyzed from Pueblo Bonito probably was grown in an area located 80 km to the west at the base of the Chuska Mountains. The youngest maize came from the San Juan or Animas river floodplains 90 km to the north. This article demonstrates that maize, a dietary staple of southwestern Native Americans, was transported over considerable distances in pre-Columbian times, a finding fundamental to understanding the organization of pre-Columbian southwestern societies. In addition, this article provides support for the hypothesis that major construction events in Chaco Canyon were made possible because maize was brought in to support extra-local labor forces.

Quality characteristics of bread produced from wheat, rice and maize flours.

PubMed

Rai, Sweta; Kaur, Amarjeet; Singh, Baljit; Minhas, K S

2012-12-01

Rice (Oryza sativa) flour and maize (Zea mays) meal substitution in wheat (Triticum aestivum) flour, from 0 to 100% each, for the production of bread was investigated. The proximate analysis, pasting properties, bread making qualities of raw materials and sensory evaluation of the bread samples were determined. The pasting temperature increased with increased percentage of rice flour and maize meal. But the other pasting characters decreased with the higher proportion of rice flour. The baking absorption was observed to increase with higher level of maize meal but it decreased when level of rice flour was increased. Loaf weight (g) decreased with progressive increase in the proportion of maize meal but increased when rice flour incorporation was increased. Loaf volume, loaf height and specific volume decreased for progressively higher level of maize meal and rice flour. The sensory evaluation revealed that 25% replacement of wheat flour was found to be more acceptable than control sample.

Use of Drought Index and Crop Modelling for Drought Impacts Analysis on Maize (Zea mays L.) Yield Loss in Bandung District

NASA Astrophysics Data System (ADS)

Kurniasih, E.; Impron; Perdinan

2017-03-01

Drought impacts on crop yield loss depend on drought magnitude and duration and on plant genotype at every plant growth stages when droughts occur. This research aims to assess the difference calculation results of 2 drought index methods and to study the maize yield loss variability impacted by drought magnitude and duration during maize growth stages in Bandung district, province of West Java, Indonesia. Droughts were quantified by the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI) at 1- to 3-month lags for the January1986-December 2015 period data. Maize yield responses to droughts were simulated by AquaCrop for the January 1986-May 2016 period of growing season. The analysis showed that the SPI and SPEI methods provided similar results in quantifying drought event. Droughts during maize reproductive stages caused the highest maize yield loss.

Root exudates drive interspecific facilitation by enhancing nodulation and N2 fixation

PubMed Central

Li, Bai; Li, Yu-Ying; Wu, Hua-Mao; Zhang, Fang-Fang; Li, Chun-Jie; Li, Xue-Xian; Lambers, Hans; Li, Long

2016-01-01

Plant diversity in experimental systems often enhances ecosystem productivity, but the mechanisms causing this overyielding are only partly understood. Intercropping faba beans (Vicia faba L.) and maize (Zea mays L.) result in overyielding and also, enhanced nodulation by faba beans. By using permeable and impermeable root barriers in a 2-y field experiment, we show that root–root interactions between faba bean and maize significantly increase both nodulation and symbiotic N2 fixation in intercropped faba bean. Furthermore, root exudates from maize promote faba bean nodulation, whereas root exudates from wheat and barley do not. Thus, a decline of soil nitrate concentrations caused by intercropped cereals is not the sole mechanism for maize promoting faba bean nodulation. Intercropped maize also caused a twofold increase in exudation of flavonoids (signaling compounds for rhizobia) in the systems. Roots of faba bean treated with maize root exudates exhibited an immediate 11-fold increase in the expression of chalcone–flavanone isomerase (involved in flavonoid synthesis) gene together with a significantly increased expression of genes mediating nodulation and auxin response. After 35 d, faba beans treated with maize root exudate continued to show up-regulation of key nodulation genes, such as early nodulin 93 (ENOD93), and promoted nitrogen fixation. Our results reveal a mechanism for how intercropped maize promotes nitrogen fixation of faba bean, where maize root exudates promote flavonoid synthesis in faba bean, increase nodulation, and stimulate nitrogen fixation after enhanced gene expression. These results indicate facilitative root–root interactions and provide a mechanism for a positive relationship between species diversity and ecosystem productivity. PMID:27217575

High IgE sensitization to maize and rice pollen in the highlands of Madagascar

PubMed Central

Ramavovololona; Sénéchal, Hélène; Andrianarisoa, Ange; Rakotoarimanana, Vololona; Godfrin, Dominique; Peltre, Gabriel; Poncet, Pascal; Sutra, Jean-Pierre

2014-01-01

Introduction Maize and rice are two crops constituting the main food supply in many under-developed and developing countries. Despite the large area devoted to the culture, the sensitization to the pollen from these plants is reported to be low and often considered as an occupational allergy. Methods Sixty five Malagasy pollen allergic patients were clinically and immunochemically investigated with regard to maize and rice pollen allergens. Pollen extracts were electrophoretically separated in 1 and 2 dimensions and IgE and IgG reactivities detected upon immunoblotting. Results When exploring the sensitization profile of Malagasy allergic patients to maize and rice pollen, it appears that a high proportion of these patients consulting during grass pollinating season were sensitized to both pollen as revealed by skin prick testing (62 vs. 59%) and IgE immunoblotting (85 vs. 40%). Several clinically relevant allergens were recognized by patients’ serum IgE in maize and rice pollen extracts. Conclusion The high levels of maize and rice pollen sensitization should be related, in this tropical region, to a specific environmental exposure including i) a proximity of the population to the allergenic sources and ii) a putative exacerbating effect of a highly polluted urban atmosphere on pollen allergenicity. Cross-reactivities between wild and cultivated grasses and also between rice and maize pollen are involved as well as some specific maize sensitizations. The presence of dense urban and peri-urban agriculture, in various African regions and worldwide, could be a high environmental risk factor for people sensitive to maize pollen. PMID:25870739

Accumulation and phytotoxicity of technical hexabromocyclododecane in maize.

PubMed

Wu, Tong; Huang, Honglin; Zhang, Shuzhen

2016-04-01

To investigate the accumulation and phytotoxicity of technical hexabromocyclododecane (HBCD) in maize, young seedlings were exposed to solutions of technical HBCD at different concentrations. The uptake kinetics showed that the HBCD concentration reached an apparent equilibrium within 96hr, and the accumulation was much higher in roots than in shoots. HBCD accumulation in maize had a positive linear correlation with the exposure concentration. The accumulation of different diastereoisomers followed the order γ-HBCD>β-HBCD>α-HBCD. Compared with their proportions in the technical HBCD exposure solution, the diastereoisomer contribution increased for β-HBCD and decreased for γ-HBCD in both maize roots and shoots with exposure time, whereas the contribution of α-HBCD increased in roots and decreased in shoots throughout the experimental period. These results suggest the diastereomer-specific accumulation and translocation of HBCD in maize. Inhibitory effects of HBCD on the early development of maize followed the order of germination rate>root biomass≥root elongation>shoot biomass≥shoot elongation. Hydroxyl radical (OH) and histone H2AX phosphorylation (γ-H2AX) were induced in maize by HBCD exposure, indicative of the generation of oxidative stress and DNA double-strand breaks in maize. An OH scavenger inhibited the expression of γ-H2AX foci in both maize roots and shoots, which suggests the involvement of OH generation in the HBCD-induced DNA damage. The results of this study will offer useful information for a more comprehensive assessment of the environmental behavior and toxicity of technical HBCD. Copyright © 2015. Published by Elsevier B.V.

Biological interactions to select biocontrol agents against toxigenic strains of Aspergillus flavus and Fusarium verticillioides from maize.

PubMed

Etcheverry, Miriam G; Scandolara, Andrea; Nesci, Andrea; Vilas Boas Ribeiro, Marta Sofia; Pereira, Paola; Battilani, Paola

2009-05-01

Biological control represent an alternative to the use of pesticides in crop protection. A key to progress in biological control to protect maize against Fusarium verticillioides and Aspergillus flavus maize pathogens are, to select in vitro, the best agent to be applied in the field. The aim of this study was to examine the antagonistic activity of bacterial and yeast isolates against F.verticillioides and A. flavus toxigenic strains. The first study showed the impact of Bacillus amyloliquefaciens BA-S13, Microbacterium oleovorans DMS 16091, Enterobacter hormomaechei EM-562T, and Kluyveromyces spp. L14 and L16 isolates on mycelial growth of two strains of A. flavus MPVPA 2092, 2094 and three strains of F. verticillioides MPVPA 285, 289, and 294 on 3% maize meal extract agar at different water activities (0.99, 0.97, 0.95, and 0.93). From this first assay antagonistics isolates M. oleovorans, B. amyloliquefaciens and Kluyveromyces sp. (L16) produced an increase of lag phase of growth and decreased a growth rate of all fungal strains. These isolates were selected for futher studies. In vitro non-rhizospheric maize soil (centrally and sprayed inoculated) and in vitro maize (ears apex and base inoculated) were treated with antagonistics and pathogenic strains alone in co-inoculated cultures. Bacillus amyloliquefaciens significantly reduced F. verticillioides and A. flavus count in maize soil inoculated centrally. Kluyveromyces sp. L16 reduced F. verticillioides and A. flavus count in maize soil inoculated by spray. Kluyveromyces sp. L16 was the most effective treatment limiting percent infections by F. verticillioides on the maize ears.

Evolution of US maize (Zea mays L.) root architectural and anatomical phenes over the past 100 years corresponds to increased tolerance of nitrogen stress

PubMed Central

York, Larry M.; Galindo-Castañeda, Tania; Schussler, Jeffrey R.; Lynch, Jonathan P.

2015-01-01

Increasing the nitrogen use efficiency of maize is an important goal for food security and agricultural sustainability. In the past 100 years, maize breeding has focused on yield and above-ground phenes. Over this period, maize cultivation has changed from low fertilizer inputs and low population densities to intensive fertilization and dense populations. The authors hypothesized that through indirect selection the maize root system has evolved phenotypes suited to more intense competition for nitrogen. Sixteen maize varieties representing commercially successful lines over the past century were planted at two nitrogen levels and three planting densities. Root systems of the most recent material were 7 º more shallow, had one less nodal root per whorl, had double the distance from nodal root emergence to lateral branching, and had 14% more metaxylem vessels, but total mextaxylem vessel area remained unchanged because individual metaxylem vessels had 12% less area. Plasticity was also observed in cortical phenes such as aerenchyma, which increased at greater population densities. Simulation modelling with SimRoot demonstrated that even these relatively small changes in root architecture and anatomy could increase maize shoot growth by 16% in a high density and high nitrogen environment. The authors concluded that evolution of maize root phenotypes over the past century is consistent with increasing nitrogen use efficiency. Introgression of more contrasting root phene states into the germplasm of elite maize and determination of the functional utility of these phene states in multiple agronomic conditions could contribute to future yield gains. PMID:25795737

Effect of particle size distribution of maize and soybean meal on the precaecal amino acid digestibility in broiler chickens.

PubMed

Siegert, W; Ganzer, C; Kluth, H; Rodehutscord, M

2018-02-01

1. Herein, it was investigated whether different particle size distributions of feed ingredients achieved by grinding through a 2- or 3-mm grid would have an effect on precaecal (pc) amino acid (AA) digestibility. Maize and soybean meal were used as the test ingredients. 2. Maize and soybean meal was ground with grid sizes of 2 or 3 mm. Nine diets were prepared. The basal diet contained 500 g/kg of maize starch. The other experimental diets contained maize or soybean meal samples at concentrations of 250 and 500, and 150 and 300 g/kg, respectively, instead of maize starch. Each diet was tested using 6 replicate groups of 10 birds each. The regression approach was applied to calculate the pc AA digestibility of the test ingredients. 3. The reduction of the grid size from 3 to 2 mm reduced the average particle size of both maize and soybean meal, mainly by reducing the proportion of coarse particles. Reducing the grid size significantly (P < 0.050) increased the pc digestibility of all AA in the soybean meal. In maize, reducing the grid size decreased the pc digestibility of all AA numerically, but not significantly (P > 0.050). The mean numerical differences in pc AA digestibility between the grid sizes were 0.045 and 0.055 in maize and soybean meal, respectively. 4. Future studies investigating the pc AA digestibility should specify the particle size distribution and should investigate the test ingredients ground similarly for practical applications.

A(maize)ing attraction: gravid Anopheles arabiensis are attracted and oviposit in response to maize pollen odours.

PubMed

Wondwosen, Betelehem; Hill, Sharon R; Birgersson, Göran; Seyoum, Emiru; Tekie, Habte; Ignell, Rickard

2017-01-23

Maize cultivation contributes to the prevalence of malaria mosquitoes and exacerbates malaria transmission in sub-Saharan Africa. The pollen from maize serves as an important larval food source for Anopheles mosquitoes, and females that are able to detect breeding sites where maize pollen is abundant may provide their offspring with selective advantages. Anopheles mosquitoes are hypothesized to locate, discriminate among, and select such sites using olfactory cues, and that synthetic volatile blends can mimic these olfactory-guided behaviours. Two-port olfactometer and two-choice oviposition assays were used to assess the attraction and oviposition preference of gravid Anopheles arabiensis to the headspace of the pollen from two maize cultivars (BH-660 and ZM-521). Bioactive compounds were identified using combined gas chromatography and electroantennographic detection from the headspace of the cultivar found to be most attractive (BH-660). Synthetic blends of the volatile compounds were then assessed for attraction and oviposition preference of gravid An. arabiensis, as above. Here the collected headspace volatiles from the pollen of two maize cultivars was shown to differentially attract and stimulate oviposition in gravid An. arabiensis. Furthermore, a five-component synthetic maize pollen odour blend was identified, which elicited the full oviposition behavioural repertoire of the gravid mosquitoes. The cues identified from maize pollen provide important substrates for the development of novel control measures that modulate gravid female behaviour. Such measures are irrespective of indoor or outdoor feeding and resting patterns, thus providing a much-needed addition to the arsenal of tools that currently target indoor biting mosquitoes.

Genetic architecture of domestication-related traits in maize

USDA-ARS?s Scientific Manuscript database

Strong directional selection occurred during the domestication of maize from its wild ancestor teosinte, reducing its genetic diversity, particularly at genes controlling domestication-related traits. Nevertheless, variability for some domestication-related traits is maintained in maize. The genet...

Modelling of maize production in Croatia: present and future climate

PubMed Central

VUČETIĆ, V.

2011-01-01

SUMMARY Maize is one of the most important agricultural crops in Croatia, and was selected for research of the effect of climate warming on yields. The Decision Support System for the Agrotechnology Transfer model (DSSAT) is one of the most utilized crop–weather models in the world, and was used in this paper for the investigation of maize growth and production in the present and future climate. The impact of present climate on maize yield was studied using DSSAT 4.0 with meteorological data from the Zagreb–Maksimir station covering the period 1949–2004. Pedological, physiological and genetic data from a 1999 field maize experiment at the same location were added. The location is representative of the continental climate in central Croatia. The linear trends of model outputs and the non-parametric Mann–Kendall test indicate that the beginning of silking has advanced significantly by 1·4 days/decade since the mid-1990s, and maturity by 4·5 days/decade. It also shows a decrease in biomass by 122 kg/ha and in maize yield by 216 kg/ha in 10 years. Estimates of the sensitivity of maize growth and yield in future climates were made by changing the initial weather and CO2 conditions of the DSSAT 4.0 model according to the different climatic scenarios for Croatia at the end of the 21st century. Changed climate suggests increases in global solar radiation, minimal temperature and maximal temperature (×1·07, 2 and 4°C, respectively), but a decrease in the amount of precipitation (×0·92), compared with weather data from the period 1949–2004. The reduction of maize yield was caused by the increase in minimal and maximal temperature and the decrease in precipitation amount, related to the present climate, is 6, 12 and 3%, respectively. A doubling of CO2 concentration stimulates leaf assimilation, but maize yield is only 1% higher, while global solar radiation growth by 7% increases evapotranspiration by 3%. Simultaneous application of all these climate changes suggested that the maize growth period would shorten by c. 1 month and maize yield would decrease by 9%, with the main reason for maize yield reduction in Croatia being due to extremely warm conditions in the future climate. PMID:22505771

A Maize Cystatin Suppresses Host Immunity by Inhibiting Apoplastic Cysteine Proteases[C][W

PubMed Central

van der Linde, Karina; Hemetsberger, Christoph; Kastner, Christine; Kaschani, Farnusch; van der Hoorn, Renier A.L.; Kumlehn, Jochen; Doehlemann, Gunther

2012-01-01

Ustilago maydis is a biotrophic pathogen causing maize (Zea mays) smut disease. Transcriptome profiling of infected maize plants indicated that a gene encoding a putative cystatin (CC9) is induced upon penetration by U. maydis wild type. By contrast, cc9 is not induced after infection with the U. maydis effector mutant Δpep1, which elicits massive plant defenses. Silencing of cc9 resulted in a strongly induced maize defense gene expression and a hypersensitive response to U. maydis wild-type infection. Consequently, fungal colonization was strongly reduced in cc9-silenced plants, while recombinant CC9 prevented salicylic acid (SA)–induced defenses. Protease activity profiling revealed a strong induction of maize Cys proteases in SA-treated leaves, which could be inhibited by addition of CC9. Transgenic maize plants overexpressing cc9-mCherry showed an apoplastic localization of CC9. The transgenic plants showed a block in Cys protease activity and SA-dependent gene expression. Moreover, activated apoplastic Cys proteases induced SA-associated defense gene expression in naïve plants, which could be suppressed by CC9. We show that apoplastic Cys proteases play a pivotal role in maize defense signaling. Moreover, we identified cystatin CC9 as a novel compatibility factor that suppresses Cys protease activity to allow biotrophic interaction of maize with the fungal pathogen U. maydis. PMID:22454455

A New Method for in Situ Measurement of Bt-Maize Pollen Deposition on Host-Plant Leaves.

PubMed

Hofmann, Frieder; Otto, Mathias; Kuhn, Ulrike; Ober, Steffi; Schlechtriemen, Ulrich; Vögel, Rudolph

2011-02-21

Maize is wind pollinated and produces huge amounts of pollen. In consequence, the Cry toxins expressed in the pollen of Bt maize will be dispersed by wind in the surrounding vegetation leading to exposure of non-target organisms (NTO). NTO like lepidopteran larvae may be affected by the uptake of Bt-pollen deposited on their host plants. Although some information is available to estimate pollen deposition on host plants, recorded data are based on indirect measurements such as shaking or washing off pollen, or removing pollen with adhesive tapes. These methods often lack precision and they do not include the necessary information such as the spatial and temporal variation of pollen deposition on the leaves. Here, we present a new method for recording in situ the amount and the distribution of Bt-maize pollen deposited on host plant leaves. The method is based on the use of a mobile digital microscope (Dino-Lite Pro, including DinoCapture software), which can be used in combination with a notebook in the field. The method was evaluated during experiments in 2008 to 2010. Maize pollen could be correctly identified and pollen deposition as well as the spatial heterogeneity of maize pollen deposition was recorded on maize and different lepidopteran host plants (Centaurea scabiosa, Chenopodium album, Rumex spp., Succina pratensis and Urtica dioica) growing adjacent to maize fields.

A New Method for in Situ Measurement of Bt-Maize Pollen Deposition on Host-Plant Leaves

PubMed Central

Hofmann, Frieder; Otto, Mathias; Kuhn, Ulrike; Ober, Steffi; Schlechtriemen, Ulrich; Vögel, Rudolph

2011-01-01

Maize is wind pollinated and produces huge amounts of pollen. In consequence, the Cry toxins expressed in the pollen of Bt maize will be dispersed by wind in the surrounding vegetation leading to exposure of non-target organisms (NTO). NTO like lepidopteran larvae may be affected by the uptake of Bt-pollen deposited on their host plants. Although some information is available to estimate pollen deposition on host plants, recorded data are based on indirect measurements such as shaking or washing off pollen, or removing pollen with adhesive tapes. These methods often lack precision and they do not include the necessary information such as the spatial and temporal variation of pollen deposition on the leaves. Here, we present a new method for recording in situ the amount and the distribution of Bt-maize pollen deposited on host plant leaves. The method is based on the use of a mobile digital microscope (Dino-Lite Pro, including DinoCapture software), which can be used in combination with a notebook in the field. The method was evaluated during experiments in 2008 to 2010. Maize pollen could be correctly identified and pollen deposition as well as the spatial heterogeneity of maize pollen deposition was recorded on maize and different lepidopteran host plants (Centaurea scabiosa, Chenopodium album, Rumex spp., Succina pratensis and Urtica dioica) growing adjacent to maize fields. PMID:26467496

Chloroplasts in anther endothecium of Zea mays (Poaceae).

PubMed

Murphy, Katherine M; Egger, Rachel L; Walbot, Virginia

2015-11-01

Although anthers of Zea mays, Oryza sativa, and Arabidopsis thaliana have been studied intensively using genetic and biochemical analyses in the past 20 years, few updates to anther anatomical and ultrastructural descriptions have been reported. For example, no transmission electron microscopy (TEM) images of the premeiotic maize anther have been published. Here we report the presence of chloroplasts in maize anthers. TEM imaging, electron acceptor photosynthesis assay, in planta photon detection, microarray analysis, and light and fluorescence microscopy were used to investigate the presence of chloroplasts in the maize anther. Most cells of the maize subepidermal endothecium have starch-containing chloroplasts that do not conduct measurable photosynthesis in vitro. The maize anther contains chloroplasts in most subepidermal, endothecial cells. Although maize anthers receive sufficient light to photosynthesize in vivo and the maize anther transcribes >96% of photosynthesis-associated genes found in the maize leaf, no photosynthetic light reaction activity was detected in vitro. The endothecial cell layer should no longer be defined as a complete circle viewed transversely in anther lobes, because chloroplasts are observed only in cells directly beneath the epidermis and not those adjacent to the connective tissue. We propose that chloroplasts be a defining characteristic of differentiated endothecial cells and that nonsubepidermal endothecial cells that lack chloroplasts be defined as a separate cell type, the interendothecium. © 2015 Botanical Society of America.

Maize root lectins mediate the interaction with Herbaspirillum seropedicae via N-acetyl glucosamine residues of lipopolysaccharides.

PubMed

Balsanelli, Eduardo; Tuleski, Thalita Regina; de Baura, Valter Antonio; Yates, Marshall Geoffrey; Chubatsu, Leda Satie; Pedrosa, Fabio de Oliveira; de Souza, Emanuel Maltempi; Monteiro, Rose Adele

2013-01-01

Herbaspirillum seropedicae is a plant growth-promoting diazotrophic betaproteobacterium which associates with important crops, such as maize, wheat, rice and sugar-cane. We have previously reported that intact lipopolysaccharide (LPS) is required for H. seropedicae attachment and endophytic colonization of maize roots. In this study, we present evidence that the LPS biosynthesis gene waaL (codes for the O-antigen ligase) is induced during rhizosphere colonization by H. seropedicae. Furthermore a waaL mutant strain lacking the O-antigen portion of the LPS is severely impaired in colonization. Since N-acetyl glucosamine inhibits H. seropedicae attachment to maize roots, lectin-like proteins from maize roots (MRLs) were isolated and mass spectrometry (MS) analysis showed that MRL-1 and MRL-2 correspond to maize proteins with a jacalin-like lectin domain, while MRL-3 contains a B-chain lectin domain. These proteins showed agglutination activity against wild type H. seropedicae, but failed to agglutinate the waaL mutant strain. The agglutination reaction was severely diminished in the presence of N-acetyl glucosamine. Moreover addition of the MRL proteins as competitors in H. seropedicae attachment assays decreased 80-fold the adhesion of the wild type to maize roots. The results suggest that N-acetyl glucosamine residues of the LPS O-antigen bind to maize root lectins, an essential step for efficient bacterial attachment and colonization.

Maize Root Lectins Mediate the Interaction with Herbaspirillum seropedicae via N-Acetyl Glucosamine Residues of Lipopolysaccharides

PubMed Central

Balsanelli, Eduardo; Tuleski, Thalita Regina; de Baura, Valter Antonio; Yates, Marshall Geoffrey; Chubatsu, Leda Satie; de Oliveira Pedrosa, Fabio; de Souza, Emanuel Maltempi; Monteiro, Rose Adele

2013-01-01

Herbaspirillum seropedicae is a plant growth-promoting diazotrophic betaproteobacterium which associates with important crops, such as maize, wheat, rice and sugar-cane. We have previously reported that intact lipopolysaccharide (LPS) is required for H. seropedicae attachment and endophytic colonization of maize roots. In this study, we present evidence that the LPS biosynthesis gene waaL (codes for the O-antigen ligase) is induced during rhizosphere colonization by H. seropedicae. Furthermore a waaL mutant strain lacking the O-antigen portion of the LPS is severely impaired in colonization. Since N-acetyl glucosamine inhibits H. seropedicae attachment to maize roots, lectin-like proteins from maize roots (MRLs) were isolated and mass spectrometry (MS) analysis showed that MRL-1 and MRL-2 correspond to maize proteins with a jacalin-like lectin domain, while MRL-3 contains a B-chain lectin domain. These proteins showed agglutination activity against wild type H. seropedicae, but failed to agglutinate the waaL mutant strain. The agglutination reaction was severely diminished in the presence of N-acetyl glucosamine. Moreover addition of the MRL proteins as competitors in H. seropedicae attachment assays decreased 80-fold the adhesion of the wild type to maize roots. The results suggest that N-acetyl glucosamine residues of the LPS O-antigen bind to maize root lectins, an essential step for efficient bacterial attachment and colonization. PMID:24130823

Magnesium deficiency results in damage of nitrogen and carbon cross-talk of maize and improvement by cerium addition.

PubMed

Zhao, Haiquan; Zhou, Qiuping; Zhou, Min; Li, Chunxiao; Gong, Xiaolan; Liu, Chao; Qu, Chunxiang; Si, Wenhui; Hong, Fashui

2012-07-01

Magnesium (Mg) deficiency has been reported to affect plant photosynthesis and growth, and cerium (Ce) was considered to be able to improve plant growth. However, the mechanisms of Mg deficiency and Ce on plant growth remain poorly understood. The main aim of this work is to identify whether or not Mg deprivation affects the interdependent nitrogen and carbon assimilations in the maize leaves and whether or not Ce modulates the assimilations in the maize leaves under Mg deficiency. Maize plants were cultivated in Hoagland’s solution. They were subjected to Mg deficiency and to cerium chloride administration in the Mg-present Hoagland’s media and Mg-deficient Hoagland’s media.After 2 weeks,we measured chlorophyll (Chl) a fluorescence and the activities of nitrate reductase (NR), sucrose-phosphate synthase(SPS), and phosphoenolpyruvate carboxylase (PEPCase)in metabolic checkpoints coordinating primary nitrogen and carbon assimilations in the maize leaves. The results showed that Mg deficiency significantly inhibited plant growth and decreased the activities of NR, SPS, and PEPCase and the synthesis of Chl and protein. Mg deprivation in maize also significantly decreased the oxygen evolution, electron transport,and efficiency of photochemical energy conversion by photosystem II (PSII). However, Ce addition may promote nitrogen and carbon assimilations, increase PSII activities,and improve maize growth under Mg deficiency. Moreover,our findings would help promote usage of Mg or Ce fertilizers in maize production.

Resistance to dual-gene Bt maize in Spodoptera frugiperda: selection, inheritance, and cross-resistance to other transgenic events

PubMed Central

Santos-Amaya, Oscar F.; Rodrigues, João V. C.; Souza, Thadeu C.; Tavares, Clébson S.; Campos, Silverio O.; Guedes, Raul N.C.; Pereira, Eliseu J.G.

2015-01-01

Transgenic crop “pyramids” producing two or more Bacillus thuringiensis (Bt) toxins active against the same pest are used to delay evolution of resistance in insect pest populations. Laboratory and greenhouse experiments were performed with fall armyworm, Spodoptera frugiperda, to characterize resistance to Bt maize producing Cry1A.105 and Cry2Ab and test some assumptions of the “pyramid” resistance management strategy. Selection of a field-derived strain of S. frugiperda already resistant to Cry1F maize with Cry1A.105 + Cry2Ab maize for ten generations produced resistance that allowed the larvae to colonize and complete the life cycle on these Bt maize plants. Greenhouse experiments revealed that the resistance was completely recessive (Dx = 0), incomplete, autosomal, and without maternal effects or cross-resistance to the Vip3Aa20 toxin produced in other Bt maize events. This profile of resistance supports some of the assumptions of the pyramid strategy for resistance management. However, laboratory experiments with purified Bt toxin and plant leaf tissue showed that resistance to Cry1A.105 + Cry2Ab2 maize further increased resistance to Cry1Fa, which indicates that populations of fall armyworm have high potential for developing resistance to some currently available pyramided maize used against this pest, especially where resistance to Cry1Fa was reported in the field. PMID:26675246

Resistance to dual-gene Bt maize in Spodoptera frugiperda: selection, inheritance, and cross-resistance to other transgenic events.

PubMed

Santos-Amaya, Oscar F; Rodrigues, João V C; Souza, Thadeu C; Tavares, Clébson S; Campos, Silverio O; Guedes, Raul N C; Pereira, Eliseu J G

2015-12-17

Transgenic crop "pyramids" producing two or more Bacillus thuringiensis (Bt) toxins active against the same pest are used to delay evolution of resistance in insect pest populations. Laboratory and greenhouse experiments were performed with fall armyworm, Spodoptera frugiperda, to characterize resistance to Bt maize producing Cry1A.105 and Cry2Ab and test some assumptions of the "pyramid" resistance management strategy. Selection of a field-derived strain of S. frugiperda already resistant to Cry1F maize with Cry1A.105 + Cry2Ab maize for ten generations produced resistance that allowed the larvae to colonize and complete the life cycle on these Bt maize plants. Greenhouse experiments revealed that the resistance was completely recessive (Dx = 0), incomplete, autosomal, and without maternal effects or cross-resistance to the Vip3Aa20 toxin produced in other Bt maize events. This profile of resistance supports some of the assumptions of the pyramid strategy for resistance management. However, laboratory experiments with purified Bt toxin and plant leaf tissue showed that resistance to Cry1A.105 + Cry2Ab2 maize further increased resistance to Cry1Fa, which indicates that populations of fall armyworm have high potential for developing resistance to some currently available pyramided maize used against this pest, especially where resistance to Cry1Fa was reported in the field.

Association analysis of single nucleotide polymorphisms in candidate genes with root traits in maize (Zea mays L.) seedlings.

PubMed

Kumar, Bharath; Abdel-Ghani, Adel H; Pace, Jordon; Reyes-Matamoros, Jenaro; Hochholdinger, Frank; Lübberstedt, Thomas

2014-07-01

Several genes involved in maize root development have been isolated. Identification of SNPs associated with root traits would enable the selection of maize lines with better root architecture that might help to improve N uptake, and consequently plant growth particularly under N deficient conditions. In the present study, an association study (AS) panel consisting of 74 maize inbred lines was screened for seedling root traits in 6, 10, and 14-day-old seedlings. Allele re-sequencing of candidate root genes Rtcl, Rth3, Rum1, and Rul1 was also carried out in the same AS panel lines. All four candidate genes displayed different levels of nucleotide diversity, haplotype diversity and linkage disequilibrium. Gene based association analyses were carried out between individual polymorphisms in candidate genes, and root traits measured in 6, 10, and 14-day-old maize seedlings. Association analyses revealed several polymorphisms within the Rtcl, Rth3, Rum1, and Rul1 genes associated with seedling root traits. Several nucleotide polymorphisms in Rtcl, Rth3, Rum1, and Rul1 were significantly (P<0.05) associated with seedling root traits in maize suggesting that all four tested genes are involved in the maize root development. Thus considerable allelic variation present in these root genes can be exploited for improving maize root characteristics. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

γ-Aminobutyric Acid Imparts Partial Protection from Salt Stress Injury to Maize Seedlings by Improving Photosynthesis and Upregulating Osmoprotectants and Antioxidants

PubMed Central

Wang, Yongchao; Gu, Wanrong; Meng, Yao; Xie, Tenglong; Li, Lijie; Li, Jing; Wei, Shi

2017-01-01

γ-Aminobutyric acid (GABA) has high physiological activity in plant stress physiology. This study showed that the application of exogenous GABA by root drenching to moderately (MS, 150 mM salt concentration) and severely salt-stressed (SS, 300 mM salt concentration) plants significantly increased endogenous GABA concentration and improved maize seedling growth but decreased glutamate decarboxylase (GAD) activity compared with non-treated ones. Exogenous GABA alleviated damage to membranes, increased in proline and soluble sugar content in leaves, and reduced water loss. After the application of GABA, maize seedling leaves suffered less oxidative damage in terms of superoxide anion (O2·−) and malondialdehyde (MDA) content. GABA-treated MS and SS maize seedlings showed increased enzymatic antioxidant activity compared with that of untreated controls, and GABA-treated MS maize seedlings had a greater increase in enzymatic antioxidant activity than SS maize seedlings. Salt stress severely damaged cell function and inhibited photosynthesis, especially in SS maize seedlings. Exogenous GABA application could reduce the accumulation of harmful substances, help maintain cell morphology, and improve the function of cells during salt stress. These effects could reduce the damage to the photosynthetic system from salt stress and improve photosynthesis and chlorophyll fluorescence parameters. GABA enhanced the salt tolerance of maize seedlings. PMID:28272438

High bioavailability iron maize (Zea mays L.) developed through molecular breeding provides more absorbable iron in vitro (Caco-2 model) and in vivo (Gallus gallus).

PubMed

Tako, Elad; Hoekenga, Owen A; Kochian, Leon V; Glahn, Raymond P

2013-01-04

Iron (Fe) deficiency is the most common micronutrient deficiency worldwide. Iron biofortification is a preventative strategy that alleviates Fe deficiency by improving the amount of absorbable Fe in crops. In the present study, we used an in vitro digestion/Caco 2 cell culture model as the guiding tool for breeding and development of two maize (Zea mays L.) lines with contrasting Fe bioavailability (ie. Low and High). Our objective was to confirm and validate the in vitro results and approach. Also, to compare the capacities of our two maize hybrid varieties to deliver Fe for hemoglobin (Hb) synthesis and to improve the Fe status of Fe deficient broiler chickens. We compared the Fe-bioavailability between these two maize varieties with the presence or absence of added Fe in the maize based-diets. Diets were made with 75% (w/w) maize of either low or high Fe-bioavailability maize, with or without Fe (ferric citrate). Chicks (Gallus gallus) were fed the diets for 6 wk. Hb, liver ferritin and Fe related transporter/enzyme gene-expression were measured. Hemoglobin maintenance efficiency (HME) and total body Hb Fe values were used to estimate Fe bioavailability from the diets. DMT-1, DcytB and ferroportin expressions were higher (P<0.05) in the "Low Fe" group than in the "High Fe" group (no added Fe), indicating lower Fe status and adaptation to less Fe-bioavailability. At times, Hb concentrations (d 21,28,35), HME (d 21), Hb-Fe (as from d 14) and liver ferritin were higher in the "High Fe" than in the "Low Fe" groups (P<0.05), indicating greater Fe absorption from the diet and improved Fe status. We conclude that the High Fe-bioavailability maize contains more bioavailable Fe than the Low Fe-bioavailability maize, presumably due to a more favorable matrix for absorption. Maize shows promise for Fe biofortification; therefore, human trials should be conducted to determine the efficacy of consuming the high bioavailable Fe maize to reduce Fe deficiency.

Conservation Agriculture Improves Soil Quality, Crop Yield, and Incomes of Smallholder Farmers in North Western Ghana

PubMed Central

Naab, Jesse B.; Mahama, George Y.; Yahaya, Iddrisu; Prasad, P. V. V.

2017-01-01

Conservation agriculture (CA) practices are being widely promoted in many areas in sub-Saharan Africa to recuperate degraded soils and improve ecosystem services. This study examined the effects of three tillage practices [conventional moldboard plowing (CT), hand hoeing (MT) and no-tillage (NT)], and three cropping systems (continuous maize, soybean–maize annual rotation, and soybean/maize intercropping) on soil quality, crop productivity, and profitability in researcher and farmer managed on-farm trials from 2010 to 2013 in northwestern Ghana. In the researcher managed mother trial, the CA practices of NT, residue retention and crop rotation/intercropping maintained higher soil organic carbon, and total soil N compared to conventional tillage practices after 4 years. Soil bulk density was higher under NT than under CT soils in the researcher managed mother trails or farmers managed baby trials after 4 years. In the researcher managed mother trial, there was no significant difference between tillage systems or cropping systems in maize or soybean yields in the first three seasons. In the fourth season, crop rotation had the greatest impact on maize yields with CT maize following soybean increasing yields by 41 and 49% compared to MT and NT maize, respectively. In the farmers’ managed trials, maize yield ranged from 520 to 2700 kg ha-1 and 300 to 2000 kg ha-1 for CT and NT, respectively, reflecting differences in experience of farmers with NT. Averaged across farmers, CT cropping systems increased maize and soybean yield ranging from 23 to 39% compared with NT cropping systems. Partial budget analysis showed that the cost of producing maize or soybean is 20–29% cheaper with NT systems and gives higher returns to labor compared to CT practice. Benefit-to-cost ratios also show that NT cropping systems are more profitable than CT systems. We conclude that with time, implementation of CA practices involving NT, crop rotation, intercropping of maize and soybean along with crop residue retention presents a win–win scenario due to improved crop yield, increased economic return, and trends of increasing soil fertility. The biggest challenge, however, remains with producing enough biomass and retaining same on the field. PMID:28680427

Effects of biochar and maize straw on the short-term carbon and nitrogen dynamics in a cultivated silty loam in China.

PubMed

Zhu, Li-Xia; Xiao, Qian; Shen, Yu-Fang; Li, Shi-Qing

2017-01-01

Application of maize straw and biochar can potentially improve soil fertility and sequester carbon (C) in the soil, but little information is available about the effects of maize straw and biochar on the mineralization of soil C and nitrogen (N). We conducted a laboratory incubation experiment with five treatments of a cultivated silty loam, biochar produced from maize straw and/or maize straw: soil only (control), soil + 1 % maize straw (S), soil + 4 % biochar (B1), soil + 4 % biochar + 1 % maize straw (B1S), and soil + 8 % biochar + 1 % maize straw (B2S). CO 2 emissions, soil organic C, dissolved organic C, easily oxidized C, total N, mineral N, net N mineralization, and microbial biomass C and N of three replicates were measured periodically during the 60-day incubation using destructive sampling method. C mineralization was highest in treatment S, followed by B2S, B1S, the control, and B1. Total net CO 2 emissions suggested that negative or positive priming effect may occur between the biochar and straw according to the biochar addition rate, and biochar mineralization was minimal. By day 35, maize straw, irrespective of the rate of biochar addition, significantly increased microbial biomass C and N but decreased dissolved organic N. Biochar alone, however, had no significant effect on either microbial biomass C or N but decreased dissolved organic N. Mixing the soil with biochar and/or straw significantly increased soil organic C, easily oxidized C and total N contents, and decreased dissolved organic N content. Dissolved organic C contents showed mixed results. Notably, N was immobilized in soil mixed with straw and/or biochar, but the effect was stronger for soil mixed with straw, which may cause N deficiency for plant growth. The application of biochar and maize straw can thus affect soil C and N cycles, and the appropriate proportion of biochar and maize straw need further studies to increase C sequestration.

Water use efficiency and evapotranspiration in maize-soybean relay strip intercrop systems as affected by planting geometries.

PubMed

Rahman, Tanzeelur; Liu, Xin; Hussain, Sajad; Ahmed, Shoaib; Chen, Guopeng; Yang, Feng; Chen, Lilian; Du, Junbo; Liu, Weiguo; Yang, Wenyu

2017-01-01

Optimum planting geometries have been shown to increase crop yields in maize-soybean intercrop systems. However, little is known about whether changes in planting geometry improve the seasonal water use of maize and soybean intercrops. We conducted two different field experiments in 2013 and 2014 to investigate the effects of changes in planting geometry on water use efficiency (WUE) and evapotranspiration (ETc) of maize (Zea mays L.) and soybean [Glycine max (L.) Merr.] relay strip intercrop systems. Our results showed that the leaf area index of maize for both years where intercropping occurred was notably greater compared to sole maize, thus the soil water content (SWC), soil evaporation (E), and throughfall followed a decreasing trend in the following order: central row of maize strip (CRM) < adjacent row between maize and soybean strip (AR) < central row of soybean strip (CRS). When intercropped, the highest grain yield for maize and total yields were recorded for the 40:120 cm and 40:160 cm planting geometries using 160 cm and 200 cm bandwidth, respectively. By contrast, the highest grain yield of intercropped soybean was appeared for the 20:140 cm and 20:180 cm planting geometries. The largest land equivalent ratios were 1.62 for the 40:120 cm planting geometry and 1.79 for the 40:160 cm planting geometry, indicating that both intercropping strategies were advantageous. Changes in planting geometries did not show any significant effect on the ETc of the maize and soybean intercrops. WUEs in the different planting geometries of intercrop systems were lower compared to sole cropping. However, the highest group WUEs of 23.06 and 26.21 kg ha-1 mm-1 for the 40:120 cm and 40:160 cm planting geometries, respectively, were 39% and 23% higher than those for sole cropping. Moreover, the highest water equivalent ratio values of 1.66 and 1.76 also appeared for the 40:120 cm and 40:160 cm planting geometries. We therefore suggest that an optimum planting geometry of 40:160 cm and bandwidth of 200 cm could be a viable planting pattern management method for attaining high group WUE in maize-soybean intercrop systems.

High bioavailablilty iron maize (Zea mays L.) developed through molecular breeding provides more absorbable iron in vitro (Caco-2 model) and in vivo (Gallus gallus)

PubMed Central

2013-01-01

Background Iron (Fe) deficiency is the most common micronutrient deficiency worldwide. Iron biofortification is a preventative strategy that alleviates Fe deficiency by improving the amount of absorbable Fe in crops. In the present study, we used an in vitro digestion/Caco 2 cell culture model as the guiding tool for breeding and development of two maize (Zea mays L.) lines with contrasting Fe bioavailability (ie. Low and High). Our objective was to confirm and validate the in vitro results and approach. Also, to compare the capacities of our two maize hybrid varieties to deliver Fe for hemoglobin (Hb) synthesis and to improve the Fe status of Fe deficient broiler chickens. Methods We compared the Fe-bioavailability between these two maize varieties with the presence or absence of added Fe in the maize based-diets. Diets were made with 75% (w/w) maize of either low or high Fe-bioavailability maize, with or without Fe (ferric citrate). Chicks (Gallus gallus) were fed the diets for 6 wk. Hb, liver ferritin and Fe related transporter/enzyme gene-expression were measured. Hemoglobin maintenance efficiency (HME) and total body Hb Fe values were used to estimate Fe bioavailability from the diets. Results DMT-1, DcytB and ferroportin expressions were higher (P < 0.05) in the "Low Fe" group than in the "High Fe" group (no added Fe), indicating lower Fe status and adaptation to less Fe-bioavailability. At times, Hb concentrations (d 21,28,35), HME (d 21), Hb-Fe (as from d 14) and liver ferritin were higher in the "High Fe" than in the "Low Fe" groups (P < 0.05), indicating greater Fe absorption from the diet and improved Fe status. Conclusions We conclude that the High Fe-bioavailability maize contains more bioavailable Fe than the Low Fe-bioavailability maize, presumably due to a more favorable matrix for absorption. Maize shows promise for Fe biofortification; therefore, human trials should be conducted to determine the efficacy of consuming the high bioavailable Fe maize to reduce Fe deficiency. PMID:23286295

Comparison of broiler performance and carcass yields when fed transgenic maize grain containing event DP-O9814O-6 and processed fractions from transgenic soybeans containing event DP-356O43-5.

PubMed

McNaughton, J; Roberts, M; Rice, D; Smith, B; Hinds, M; Delaney, B; Iiams, C; Sauber, T

2011-08-01

The performance of broilers fed diets containing maize grain from event DP-Ø9814Ø-6 (98140; gat4621 and zm-hra genes) and processed fractions (meal, hulls, and oil) from soybeans containing event DP-356Ø43-5 (356043; gat4601 and gm-hra genes) was evaluated in a 42-d feeding study. Diets were produced with nontransgenic maize grain and soybean fractions from controls with comparable genetic backgrounds to 98140 and 356043 (control), 98140 maize and 356043 soybean (98140 + 356043), or 3 commercially available nontransgenic maize and soybean combinations. Ross 708 broilers (n = 120/group; 50% male, 50% female) were fed diets in 3 phases: starter (d 0 to 21), grower (d 22 to 35), and finisher (d 36 to 42). Starter diets contained (on average) 63% maize and 28% soybean meal, grower diets 66% maize and 26% soybean meal, and finisher diets 72% maize and 21% soybean meal; soybean hulls and oils were held constant at 1.0 and 0.5%, respectively, across all diets in all phases. Weight gain, feed intake, and mortality-adjusted feed efficiency were calculated for d 0 to 42. Standard organ and carcass yield data were collected on d 42. Data were analyzed using a mixed model ANOVA with differences between control and 98140 + 356043 group means considered significant at P < 0.05. Reference group data were used only to estimate experimental variability and to generate tolerance intervals. No significant differences were observed in weight gain, mortality, mortality-adjusted feed efficiency, organ yields, or carcass yields between broilers consuming diets produced with 98140 + 356043 and those consuming diets produced with control maize and soybean fractions. All values of response variables evaluated in the control and 98140 + 356043 groups fell within calculated tolerance intervals. Based on these results, it was concluded that the combination of genetically modified 98140 maize and 356043 soybean fractions was nutritionally equivalent to nontransgenic maize and soybean controls with comparable genetic backgrounds.

[Evolution of maize climate productivity and its response to climate change in Heilongjiang Province, China.

PubMed

Li, Xiu Fen; Zhao, Hui Ying; Zhu, Hai Xia; Wang, Ping; Wang, Qiu Jing; Wang, Ming; Li, Yu Guang

2016-08-01

Under the background of climate change, revealing the change trend and spatial diffe-rence of maize climate productivity in-depth and understanding the regularity of maize climatic resources utilization can provide scientific basis for the macro-decision of agricultural production in Heilongjiang Province. Based on the 1981-2014 meteorological data of 72 weather stations and the corresponding maize yield data in Heilongjiang Province, by the methods of step by step revisal, spatial interpolation and linear trend analysis, this paper studied the photosynthetic productivity (PP), light-temperature productivity (LTP), and climatic productivity (CP) of spring maize, and their temporal and spatial variation characteristics, main influencing factors and light energy utilization efficiency, and evaluated the maize climate productivities under different climate scenarios in the future. The results showed that during the study period, the mean PP, LTP and CP in Heilongjiang Province were 26558, 19953, 18742 kg·hm -2 , respectively. Maize PP, LTP and CP were high in plains and low in mountains, and gradually decreased from southwest to northeast. PP, LTP and CP presented significantly increasing trends, and the increase rates were 378, 723 and 560 kg·hm -2 ·(10 a) -1 , respectively. The increase of radiation and temperature had positive effect on maize production in Heilongjiang Province. The potential productivity of maize presented significant response to climate change. The decrease of solar radiation led to the decline of PP in western Songnen Plain, but the increased temperature compensated the negative effect of solar radiation, so the downward trend of LTP was slowed. The response to climate warming was particularly evident in North and East, and LTP was significantly increased, which was sensitive to the change of precipitation in southwest of Songnen Plain and part of Sanjiang Plain. The average ratio of maize actual yield to its climate productivity was only 24.1%, there was still 75.9% to be developed. In the future, the warm and wet climate would benefit the improvement of maize climate productivity, while the cold and dry climate would make an adverse impact.

Bt-maize (MON810) and Non-GM Soybean Meal in Diets for Atlantic Salmon (Salmo salar L.) Juveniles – Impact on Survival, Growth Performance, Development, Digestive Function, and Transcriptional Expression of Intestinal Immune and Stress Responses

PubMed Central

Gu, Jinni; Bakke, Anne Marie; Valen, Elin C.; Lein, Ingrid; Krogdahl, Åshild

2014-01-01

Responses in Atlantic salmon (Salmo salar L.) juveniles (fry) fed diets containing genetically modified maize (Bt-maize, MON810) expressing Cry1Ab protein from first-feeding were investigated during a 99-day feeding trial. Four experimental diets were made; each diet contained ∼20% maize, either Bt-maize or its near-isogenic maternal line (non-GM maize). One pair was fishmeal-based while the other pair included standard (extracted) soybean meal (SBM; 16.7% inclusion level), with the intention of investigating responses to the maize varieties in healthy fish as well as in immunologically challenged fish with SBM-induced distal intestinal inflammation, respectively. Three replicate tanks of fry (0.17±0.01 g; initial mean weight ± SEM) were fed one of the four diets and samples were taken on days 15, 36, 48 and 99. Survival, growth performance, whole body composition, digestive function, morphology of intestine, liver and skeleton, and mRNA expression of some immune and stress response parameters in the distal intestine were evaluated. After 99 days of feeding, survival was enhanced and the intended SBM-induced inflammatory response in the distal intestine of the two groups of SBM-fed fish was absent, indicating that the juvenile salmon were tolerant to SBM. Mortality, growth performance and body composition were similar in fish fed the two maize varieties. The Bt-maize fed fish, however, displayed minor but significantly decreased digestive enzyme activities of leucine aminopeptidase and maltase, as well as decreased concentration of gut bile salts, but significantly increased amylase activity at some sampling points. Histomorphological, radiographic and mRNA expression evaluations did not reveal any biologically relevant effects of Bt-maize in the gastrointestinal tract, liver or skeleton. The results suggest that the Cry1Ab protein or other compositional differences in GM Bt-maize may cause minor alterations in intestinal responses in juvenile salmon, but without affecting overall survival, growth performance, development or health. PMID:24923786

Bt-maize (MON810) and non-GM soybean meal in diets for Atlantic salmon (Salmo salar L.) juveniles--impact on survival, growth performance, development, digestive function, and transcriptional expression of intestinal immune and stress responses.

PubMed

Gu, Jinni; Bakke, Anne Marie; Valen, Elin C; Lein, Ingrid; Krogdahl, Åshild

2014-01-01

Responses in Atlantic salmon (Salmo salar L.) juveniles (fry) fed diets containing genetically modified maize (Bt-maize, MON810) expressing Cry1Ab protein from first-feeding were investigated during a 99-day feeding trial. Four experimental diets were made; each diet contained ∼20% maize, either Bt-maize or its near-isogenic maternal line (non-GM maize). One pair was fishmeal-based while the other pair included standard (extracted) soybean meal (SBM; 16.7% inclusion level), with the intention of investigating responses to the maize varieties in healthy fish as well as in immunologically challenged fish with SBM-induced distal intestinal inflammation, respectively. Three replicate tanks of fry (0.17±0.01 g; initial mean weight ± SEM) were fed one of the four diets and samples were taken on days 15, 36, 48 and 99. Survival, growth performance, whole body composition, digestive function, morphology of intestine, liver and skeleton, and mRNA expression of some immune and stress response parameters in the distal intestine were evaluated. After 99 days of feeding, survival was enhanced and the intended SBM-induced inflammatory response in the distal intestine of the two groups of SBM-fed fish was absent, indicating that the juvenile salmon were tolerant to SBM. Mortality, growth performance and body composition were similar in fish fed the two maize varieties. The Bt-maize fed fish, however, displayed minor but significantly decreased digestive enzyme activities of leucine aminopeptidase and maltase, as well as decreased concentration of gut bile salts, but significantly increased amylase activity at some sampling points. Histomorphological, radiographic and mRNA expression evaluations did not reveal any biologically relevant effects of Bt-maize in the gastrointestinal tract, liver or skeleton. The results suggest that the Cry1Ab protein or other compositional differences in GM Bt-maize may cause minor alterations in intestinal responses in juvenile salmon, but without affecting overall survival, growth performance, development or health.

Leaf transpiration efficiency of some drought-resistant maize lines

USDA-ARS?s Scientific Manuscript database

Field measurements of leaf gas exchange in maize often indicate stomatal conductances higher than required to provide substomatal carbon dioxide concentrations saturating to photosynthesis. Thus maize leaves often operate at lower transpiration efficiency (TE) than potentially achievable for specie...

Effect of Stacked Insecticidal Cry Proteins from Maize Pollen on Nurse Bees (Apis mellifera carnica) and Their Gut Bacteria

PubMed Central

Härtel, Stephan; Näther, Astrid; Dohrmann, Anja B.; Steffan-Dewenter, Ingolf; Tebbe, Christoph C.

2013-01-01

Honey bee pollination is a key ecosystem service to nature and agriculture. However, biosafety research on genetically modified crops rarely considers effects on nurse bees from intact colonies, even though they receive and primarily process the largest amount of pollen. The objective of this study was to analyze the response of nurse bees and their gut bacteria to pollen from Bt maize expressing three different insecticidal Cry proteins (Cry1A.105, Cry2Ab2, and Cry3Bb1). Naturally Cry proteins are produced by bacteria (Bacillus thuringiensis). Colonies of Apis mellifera carnica were kept during anthesis in flight cages on field plots with the Bt maize, two different conventionally bred maize varieties, and without cages, 1-km outside of the experimental maize field to allow ad libitum foraging to mixed pollen sources. During their 10-days life span, the consumption of Bt maize pollen had no effect on their survival rate, body weight and rates of pollen digestion compared to the conventional maize varieties. As indicated by ELISA-quantification of Cry1A.105 and Cry3Bb1, more than 98% of the recombinant proteins were degraded. Bacterial population sizes in the gut were not affected by the genetic modification. Bt-maize, conventional varieties and mixed pollen sources selected for significantly different bacterial communities which were, however, composed of the same dominant members, including Proteobacteria in the midgut and Lactobacillus sp. and Bifidobacterium sp. in the hindgut. Surprisingly, Cry proteins from natural sources, most likely B. thuringiensis, were detected in bees with no exposure to Bt maize. The natural occurrence of Cry proteins and the lack of detectable effects on nurse bees and their gut bacteria give no indication for harmful effects of this Bt maize on nurse honey bees. PMID:23533634

Effect of stacked insecticidal Cry proteins from maize pollen on nurse bees (Apis mellifera carnica) and their gut bacteria.

PubMed

Hendriksma, Harmen P; Küting, Meike; Härtel, Stephan; Näther, Astrid; Dohrmann, Anja B; Steffan-Dewenter, Ingolf; Tebbe, Christoph C

2013-01-01

Honey bee pollination is a key ecosystem service to nature and agriculture. However, biosafety research on genetically modified crops rarely considers effects on nurse bees from intact colonies, even though they receive and primarily process the largest amount of pollen. The objective of this study was to analyze the response of nurse bees and their gut bacteria to pollen from Bt maize expressing three different insecticidal Cry proteins (Cry1A.105, Cry2Ab2, and Cry3Bb1). Naturally Cry proteins are produced by bacteria (Bacillus thuringiensis). Colonies of Apis mellifera carnica were kept during anthesis in flight cages on field plots with the Bt maize, two different conventionally bred maize varieties, and without cages, 1-km outside of the experimental maize field to allow ad libitum foraging to mixed pollen sources. During their 10-days life span, the consumption of Bt maize pollen had no effect on their survival rate, body weight and rates of pollen digestion compared to the conventional maize varieties. As indicated by ELISA-quantification of Cry1A.105 and Cry3Bb1, more than 98% of the recombinant proteins were degraded. Bacterial population sizes in the gut were not affected by the genetic modification. Bt-maize, conventional varieties and mixed pollen sources selected for significantly different bacterial communities which were, however, composed of the same dominant members, including Proteobacteria in the midgut and Lactobacillus sp. and Bifidobacterium sp. in the hindgut. Surprisingly, Cry proteins from natural sources, most likely B. thuringiensis, were detected in bees with no exposure to Bt maize. The natural occurrence of Cry proteins and the lack of detectable effects on nurse bees and their gut bacteria give no indication for harmful effects of this Bt maize on nurse honey bees.

Efficacy of fungal and bacterial antagonists for controlling growth, FUM1 gene expression and fumonisin B1 production by Fusarium verticillioides on maize cobs of different ripening stages.

PubMed

Samsudin, Nik Iskandar Putra; Rodriguez, Alicia; Medina, Angel; Magan, Naresh

2017-04-04

This study was carried out to examine the efficacy of two biocontrol agents (Clonostachys rosea 016, BCA1; Gram-negative bacterium, BCA5) for control of FUM1 gene expression and fumonisin B 1 (FB 1 ) production by F. verticillioides FV1 on maize cobs of different ripening stages: R 3 , Milk (0.985 a w ); R 4 , Dough (0.976 a w ); R 5 , Dent (0.958 a w ). Initially, temporal studies on FUM1 gene expression and FB 1 production were performed on maize kernels for up to 14days. This revealed that day 10 was optimum for both parameters, and was used in the biocontrol studies. Maize cobs were inoculated with 50:50 mixtures of the pathogen:antagonist inoculum and incubated in environmental chambers to maintain the natural a w conditions for ten days at 25 and 30°C. The growth rates of F. verticillioides FV1, the relative expression of the FUM1 gene and FB 1 production were quantified. It was found that, a w ×temp had significant impacts on growth, FUM1 gene expression and FB 1 production by F. verticillioides FV1 on maize cobs of different maturities. The fungal antagonist (BCA1) significantly reduced FB 1 contamination on maize cobs by >70% at 25°C, and almost 60% at 30°C regardless of maize ripening stage. For the bacterial antagonist (BCA5) however, FB 1 levels on maize cobs were significantly decreased only in some treatments. These results suggest that efficacy of antagonists to control mycotoxin production in ripening maize cobs needs to take account of the ecophysiology of the pathogen and the antagonists, as well as the physiological status of the maize during silking to ensure effective control. Copyright © 2017 Elsevier B.V. All rights reserved.

Ectopic expression of bacterial amylopullulanase enhances bioethanol production from maize grain.

PubMed

Nahampun, Hartinio N; Lee, Chang Joo; Jane, Jay-Lin; Wang, Kan

2013-09-01

Heterologous expression of amylopullulanase in maize seeds leads to partial starch degradation into fermentable sugars, which enhances direct bioethanol production from maize grain. Utilization of maize in bioethanol industry in the United States reached ±13.3 billion gallons in 2012, most of which was derived from maize grain. Starch hydrolysis for bioethanol industry requires the addition of thermostable alpha amylase and amyloglucosidase (AMG) enzymes to break down the α-1,4 and α-1,6 glucosidic bonds of starch that limits the cost effectiveness of the process on an industrial scale due to its high cost. Transgenic plants expressing a thermostable starch-degrading enzyme can overcome this problem by omitting the addition of exogenous enzymes during the starch hydrolysis process. In this study, we generated transgenic maize plants expressing an amylopullulanase (APU) enzyme from the bacterium Thermoanaerobacter thermohydrosulfuricus. A truncated version of the dual functional APU (TrAPU) that possesses both alpha amylase and pullulanase activities was produced in maize endosperm tissue using a seed-specific promoter of 27-kD gamma zein. A number of analyses were performed at 85 °C, a temperature typically used for starch processing. Firstly, enzymatic assay and thin layer chromatography analysis showed direct starch hydrolysis into glucose. In addition, scanning electron microscopy illustrated porous and broken granules, suggesting starch autohydrolysis. Finally, bioethanol assay demonstrated that a 40.2 ± 2.63 % (14.7 ± 0.90 g ethanol per 100 g seed) maize starch to ethanol conversion was achieved from the TrAPU seeds. Conversion efficiency was improved to reach 90.5 % (33.1 ± 0.66 g ethanol per 100 g seed) when commercial amyloglucosidase was added after direct hydrolysis of TrAPU maize seeds. Our results provide evidence that enzymes for starch hydrolysis can be produced in maize seeds to enhance bioethanol production.

Maize and resistant starch enriched breads reduce postprandial glycemic responses in rats.

PubMed

Brites, Carla M; Trigo, Maria J; Carrapiço, Belmira; Alviña, Marcela; Bessa, Rui J

2011-04-01

White wheat bread is a poor source of dietary fiber, typically containing less than 2%. A demand exists for the development of breads with starch that is slowly digestible or partially resistant to the digestive process. The utilization of maize flour and resistant starch is expected to reduce the release and absorption of glucose and, hence, lower the glycemic index of bread. This study was undertaken to investigate the hypothesis that a diet of maize bread, as produced and consumed in Portugal, would have beneficial metabolic effects on rats compared to white wheat bread. We also hypothesized that the effect of resistant starch on glycemic response could be altered by the use of different formulations and breadmaking processes for wheat and maize breads. Resistant starch (RS) was incorporated into formulations of breads at 20% of the inclusion rate of wheat and maize flours. Assays were conducted with male Wistar rats (n = 36), divided into four groups and fed either wheat bread, RS-wheat bread, maize bread, and RS-maize bread to evaluate feed intake, body weight gain, fecal pH, and postprandial blood glucose response (glycemic response). Blood triglycerides, total cholesterol concentrations, and liver weights were also determined. The maize bread group presented higher body weight gain and cholesterol level, lower fecal pH, and postprandial blood glucose response than the wheat bread group. The RS-wheat bread group showed significant reductions in feed intake, fecal pH, postprandial blood glucose response, and total cholesterol. The RS-maize group displayed significant reductions of body weight gain, fecal pH, and total cholesterol levels; however, for the glycemic response, only a reduction in fasting level was observed. These results suggest that maize bread has a lower glycemic index than wheat bread, and the magnitude of the effect of RS on glycemic response depends of type of bread. Copyright © 2011 Elsevier Inc. All rights reserved.

Nutritional value and acceptability of homemade maize/sorghum-based weaning mixtures supplemented with rojo bean flour, ground sardines and peanut paste.

PubMed

Mosha, Theobald C E; Vicent, Mary M

2004-06-01

Low nutrient density in weaning foods is the major cause of under-nutrition among infants and young children in developing countries. Ten types of composite weaning diets (namely, maize-rojo beans-peanut, maize-peanut-sardines, maize-peanut-sardine-rojo beans, maize-peanut-soaked rojo beans, maize-peanut-germinated rojo beans, sorghum-rojo beans-peanut, sorghum-peanut-sardines, sorghum-peanut-sardine-rojo beans, sorghum-peanut-soaked rojo beans, and sorghum-peanut-germinated rojo beans) were formulated and assayed for proximate composition, energy, mineral density, tannin content and residual urease activity. The diets were also evaluated for storage stability under ambient conditions, sensory quality and overall acceptability. Results of the study indicated that, concentrations of protein, fat, ash, calcium, iron, zinc and copper were significantly (P<0.05) increased when plain maize and sorghum gruels were enriched with rojo beans, peanut paste and/or ground sardines. Soaking and germinating the rojo beans and dehulling the sorghum reduced the concentration of tannins in the gruels significantly (P<0.05). Residual urease activity ranged between 0.00 and 0.07 units, about 10-fold lower than the maximum level (0.8 units) allowed in weaning foods. Both maize and sorghum-based composite gruels had a short shelf-life under ambient conditions (26.4 degrees C) ranging between 4 and 6 h, with gruels containing ground sardines showing a tendency to spoil faster. All composite gruels except those containing germinated rojo beans were highly liked and accepted by consumers (P<0.05), similar to the plain maize and sorghum gruels. The maize and sorghum-based composite products therefore have a potential for use as weaning and/or supplementary foods for older infants and young children. Further investigations are suggested to extend the shelf-life of the composite products and improve the organoleptic quality of the diets containing germinated rojo beans.

Definition and feasibility of isolation distances for transgenic maize cultivation.

PubMed

Sanvido, Olivier; Widmer, Franco; Winzeler, Michael; Streit, Bernhard; Szerencsits, Erich; Bigler, Franz

2008-06-01

A major concern related to the adoption of genetically modified (GM) crops in agricultural systems is the possibility of unwanted GM inputs into non-GM crop production systems. Given the increasing commercial cultivation of GM crops in the European Union (EU), there is an urgent need to define measures to prevent mixing of GM with non-GM products during crop production. Cross-fertilization is one of the various mechanisms that could lead to GM-inputs into non-GM crop systems. Isolation distances between GM and non-GM fields are widely accepted to be an effective measure to reduce these inputs. However, the question of adequate isolation distances between GM and non-GM maize is still subject of controversy both amongst scientists and regulators. As several European countries have proposed largely differing isolation distances for maize ranging from 25 to 800 m, there is a need for scientific criteria when using cross-fertilization data of maize to define isolation distances between GM and non-GM maize. We have reviewed existing cross-fertilization studies in maize, established relevant criteria for the evaluation of these studies and applied these criteria to define science-based isolation distances. To keep GM-inputs in the final product well below the 0.9% threshold defined by the EU, isolation distances of 20 m for silage and 50 m for grain maize, respectively, are proposed. An evaluation using statistical data on maize acreage and an aerial photographs assessment of a typical agricultural landscape by means of Geographic Information Systems (GIS) showed that spatial resources would allow applying the defined isolation distances for the cultivation of GM maize in the majority of the cases under actual Swiss agricultural conditions. The here developed approach, using defined criteria to consider the agricultural context of maize cultivation, may be of assistance for the analysis of cross-fertilization data in other countries.

The Bacterial Community Structure and Dynamics of Carbon and Nitrogen when Maize (Zea mays L.) and Its Neutral Detergent Fibre Were Added to Soil from Zimbabwe with Contrasting Management Practices.

PubMed

De la Cruz-Barrón, Magali; Cruz-Mendoza, Alejandra; Navarro-Noya, Yendi E; Ruiz-Valdiviezo, Victor M; Ortíz-Gutiérrez, Daniel; Ramírez-Villanueva, Daniel A; Luna-Guido, Marco; Thierfelder, Cristian; Wall, Patrick C; Verhulst, Nele; Govaerts, Bram; Dendooven, Luc

2017-01-01

Water infiltration, soil carbon content, aggregate stability and yields increased in conservation agriculture practices compared to conventionally ploughed control treatments at the Henderson research station near Mazowe (Zimbabwe). How these changes in soil characteristics affect the bacterial community structure and the bacteria involved in the degradation of applied organic material remains unanswered. Soil was sampled from three agricultural systems at Henderson, i.e. (1) conventional mouldboard ploughing with continuous maize (conventional tillage), (2) direct seeding with a Fitarelli jab planter and continuous maize (direct seeding with continuous maize) and (3) direct seeding with a Fitarelli jab planter with rotation of maize sunn hemp (direct seeding with crop rotation). Soil was amended with young maize plants or their neutral detergent fibre (NDF) and incubated aerobically for 56 days, while C and N mineralization and the bacterial community structure were monitored. Bacillus (Bacillales), Micrococcaceae (Actinomycetales) and phylotypes belonging to the Pseudomonadales were first degraders of the applied maize plants. At day 3, Streptomyces (Actinomycetales), Chitinophagaceae ([Saprospirales]) and Dyella (Xanthomonadales) participated in the degradation of the applied maize and at day 7 Oxalobacteraceae (Burkholderiales). Phylotypes belonging to Halomonas (Oceanospirillales) were the first degraders of NDF and were replaced by Phenylobacterium (Caulobacterales) and phylotypes belonging to Pseudomonadales at day 3. Afterwards, similar bacterial groups were favoured by application of NDF as they were by the application of maize plants, but there were also clear differences. Phylotypes belonging to the Micrococcaceae and Bacillus did not participate in the degradation of NDF or its metabolic products, while phylotypes belonging to the Acidobacteriaceae participated in the degradation of NDF but not in that of maize plants. It was found that agricultural practices had a limited effect on the bacterial community structure, but application of organic material altered it substantially.

Weed Dynamics during Transition to Conservation Agriculture in Western Kenya Maize Production

PubMed Central

Odhiambo, Judith A.; Norton, Urszula; Ashilenje, Dennis; Omondi, Emmanuel C.; Norton, Jay B.

2015-01-01

Weed competition is a significant problem in maize (Zea mays, L.) production in Sub-Saharan Africa. Better understanding of weed management and costs in maize intercropped with beans (Phaseolus vulgaris, L.) during transition to conservation agricultural systems is needed. Changes in weed population and maize growth were assessed for a period of three years at Bungoma where crops are grown twice per year and at Trans-Nzoia where crops are grown once per year. Treatments included three tillage practices: minimum (MT), no-till (NT) and conventional (CT) applied to three cropping systems: continuous maize/bean intercropping (TYPICAL), maize/bean intercropping with relayed mucuna after bean harvest (RELAY) and maize, bean and mucuna planted in a strip intercropping arrangement (STRIP). Herbicides were used in NT, shallow hand hoeing and herbicides were used in MT and deep hoeing with no herbicides were used in CT. Weed and maize performance in the maize phase of each cropping system were assessed at both locations and costs of weed control were estimated at Manor House only. Weed density of grass and forb species declined significantly under MT and NT at Manor House and of grass species only at Mabanga. The greatest declines of more than 50% were observed as early as within one year of the transition to MT and NT in STRIP and TYPICAL cropping systems at Manor House. Transitioning to conservation based systems resulted in a decline of four out of five most dominant weed species. At the same time, no negative impact of MT or NT on maize growth was observed. Corresponding costs of weed management were reduced by $148.40 ha-1 in MT and $149.60 ha-1 in NT compared with CT. In conclusion, farmers can benefit from effective and less expensive weed management alternatives early in the process of transitioning to reduced tillage operations. PMID:26237404

Weed Dynamics during Transition to Conservation Agriculture in Western Kenya Maize Production.

PubMed

Odhiambo, Judith A; Norton, Urszula; Ashilenje, Dennis; Omondi, Emmanuel C; Norton, Jay B

2015-01-01

Weed competition is a significant problem in maize (Zea mays, L.) production in Sub-Saharan Africa. Better understanding of weed management and costs in maize intercropped with beans (Phaseolus vulgaris, L.) during transition to conservation agricultural systems is needed. Changes in weed population and maize growth were assessed for a period of three years at Bungoma where crops are grown twice per year and at Trans-Nzoia where crops are grown once per year. Treatments included three tillage practices: minimum (MT), no-till (NT) and conventional (CT) applied to three cropping systems: continuous maize/bean intercropping (TYPICAL), maize/bean intercropping with relayed mucuna after bean harvest (RELAY) and maize, bean and mucuna planted in a strip intercropping arrangement (STRIP). Herbicides were used in NT, shallow hand hoeing and herbicides were used in MT and deep hoeing with no herbicides were used in CT. Weed and maize performance in the maize phase of each cropping system were assessed at both locations and costs of weed control were estimated at Manor House only. Weed density of grass and forb species declined significantly under MT and NT at Manor House and of grass species only at Mabanga. The greatest declines of more than 50% were observed as early as within one year of the transition to MT and NT in STRIP and TYPICAL cropping systems at Manor House. Transitioning to conservation based systems resulted in a decline of four out of five most dominant weed species. At the same time, no negative impact of MT or NT on maize growth was observed. Corresponding costs of weed management were reduced by $148.40 ha(-1) in MT and $149.60 ha(-1) in NT compared with CT. In conclusion, farmers can benefit from effective and less expensive weed management alternatives early in the process of transitioning to reduced tillage operations.

Detection of the 35S promoter in transgenic maize via various isothermal amplification techniques: a practical approach.

PubMed

Zahradnik, Celine; Kolm, Claudia; Martzy, Roland; Mach, Robert L; Krska, Rudolf; Farnleitner, Andreas H; Brunner, Kurt

2014-11-01

In 2003 the European Commission introduced a 0.9% threshold for food and feed products containing genetically modified organism (GMO)-derived components. For commodities containing GMO contents higher than this threshold, labelling is mandatory. To provide a DNA-based rapid and simple detection method suitable for high-throughput screening of GMOs, several isothermal amplification approaches for the 35S promoter were tested: strand displacement amplification, nicking-enzyme amplification reaction, rolling circle amplification, loop-mediated isothermal amplification (LAMP) and helicase-dependent amplification (HDA). The assays developed were tested for specificity in order to distinguish between samples containing genetically modified (GM) maize and non-GM maize. For those assays capable of this discrimination, tests were performed to determine the lower limit of detection. A false-negative rate was determined to rule out whether GMO-positive samples were incorrectly classified as GMO-negative. A robustness test was performed to show reliable detection independent from the instrument used for amplification. The analysis of three GM maize lines showed that only LAMP and HDA were able to differentiate between the GMOs MON810, NK603, and Bt11 and non-GM maize. Furthermore, with the HDA assay it was possible to realize a detection limit as low as 0.5%. A false-negative rate of only 5% for 1% GM maize for all three maize lines shows that HDA has the potential to be used as an alternative strategy for the detection of transgenic maize. All results obtained with the LAMP and HDA assays were compared with the results obtained with a previously reported real-time PCR assay for the 35S promoter in transgenic maize. This study presents two new screening assays for detection of the 35S promoter in transgenic maize by applying the isothermal amplification approaches HDA and LAMP.

Acid phosphatase role in chickpea/maize intercropping.

PubMed

Li, S M; Li, L; Zhang, F S; Tang, C

2004-08-01

Organic P comprises 30-80 % of the total P in most agricultural soils. It has been proven that chickpea facilitates P uptake from an organic P source by intercropped wheat. In this study, acid phosphatase excreted from chickpea roots is quantified and the contribution of acid phosphatase to the facilitation of P uptake by intercropped maize receiving phytate is examined. For the first experiment using hydroponics, maize (Zea mays 'Zhongdan No. 2') and chickpea (Cicer arietinum 'Sona') were grown in either the same or separate containers, and P was supplied as phytate, KH2PO4 at 0.25 mmol P L(-1), or not at all. The second experiment involved soil culture with three types of root separation between the two species: (1) plastic sheet, (2) nylon mesh, and (3) no barrier. Maize plants were grown in one compartment and chickpea in the other. Phosphorus was supplied as phytate, Ca(H2PO4)2 at 50 mg P kg(-1), or no P added. In the hydroponics study, the total P uptake by intercropped maize supplied with phytate was 2.1-fold greater than when it was grown as a monoculture. In the soil experiment, when supplied with phytate, total P uptake by maize with mesh barrier and without root barrier was 2.2 and 1.5 times, respectively, as much as that with solid barrier. In both experiments, roots of both maize and chickpea supplied with phytate and no P secreted more acid phosphatase than those with KH2PO4 or Ca(H2PO4)2. However, average acid phosphatase activity of chickpea roots supplied with phytate was 2-3-fold as much as maize. Soil acid phosphatase activity in the rhizosphere of chickpea was also significantly higher than maize regardless of P sources. Chickpea can mobilize organic P in both hydroponic and soil cultures, leading to an interspecific facilitation in utilization of organic P in maize/chickpea intercropping.

The Effects of B, K10, and AR Chromosomes on the Resistance of Maize to Viral Infection

PubMed Central

McGirr, Scott C.; Endrizzi, J. E.

1978-01-01

Studies were conducted to determine if accessory (B) chromosomes, the abnormal tenth (K10) chromosome or the aberrant ratio (AR) phenomenon of maize (Zea mays L.) affect the resistance of the plants to viral infection. Genetically similar stocks of maize with and without these elements were compared to determine what effect they would have on the plants response to Brome Mosaic Virus (BMV), Maize Dwarf Mosaic Virus (MDMV), Wheat Streak Mosaic Virus (WSMV) and Barley Stripe Mosaic Virus (BSMV).—The test results with BSMV were not found to be conclusive. With BMV and MDMV, neither the B orK10 chromosomes were found to alter infections; however, these chromosomes were found to affect the resistance of the plants to WSMV infection. The B chromosomes were found to delay the onset of leaf necrosis by 15%, while the K10 chromosome was found to increase the susceptibility to necrosis by 100%. The AR phenomenon was not found to alter the resistance of maize to BMV infection. However, it was found to increase the susceptibility of maize to MDMV infection by 36% and to decrease the susceptibility of maize to WSMV infection by 92%. PMID:17248865

The Effects of B, K10, and AR Chromosomes on the Resistance of Maize to Viral Infection.

PubMed

McGirr, S C; Endrizzi, J E

1978-10-01

Studies were conducted to determine if accessory (B) chromosomes, the abnormal tenth (K10) chromosome or the aberrant ratio (AR) phenomenon of maize (Zea mays L.) affect the resistance of the plants to viral infection. Genetically similar stocks of maize with and without these elements were compared to determine what effect they would have on the plants response to Brome Mosaic Virus (BMV), Maize Dwarf Mosaic Virus (MDMV), Wheat Streak Mosaic Virus (WSMV) and Barley Stripe Mosaic Virus (BSMV).-The test results with BSMV were not found to be conclusive. With BMV and MDMV, neither the B orK10 chromosomes were found to alter infections; however, these chromosomes were found to affect the resistance of the plants to WSMV infection. The B chromosomes were found to delay the onset of leaf necrosis by 15%, while the K10 chromosome was found to increase the susceptibility to necrosis by 100%. The AR phenomenon was not found to alter the resistance of maize to BMV infection. However, it was found to increase the susceptibility of maize to MDMV infection by 36% and to decrease the susceptibility of maize to WSMV infection by 92%.

Utilizing virus-induced gene silencing for the functional characterization of maize genes during infection with the fungal pathogen Ustilago maydis.

PubMed

van der Linde, Karina; Doehlemann, Gunther

2013-01-01

While in dicotyledonous plants virus-induced gene silencing (VIGS) is well established to study plant-pathogen interaction, in monocots only few examples of efficient VIGS have been reported so far. One of the available systems is based on the brome mosaic virus (BMV) which allows gene silencing in different cereals including barley (Hordeum vulgare), wheat (Triticum aestivum), and maize (Zea mays).Infection of maize plants by the corn smut fungus Ustilago maydis leads to the formation of large tumors on stem, leaves, and inflorescences. During this biotrophic interaction, plant defense responses are actively suppressed by the pathogen, and previous transcriptome analyses of infected maize plants showed comprehensive and stage-specific changes in host gene expression during disease progression.To identify maize genes that are functionally involved in the interaction with U. maydis, we adapted a VIGS system based on the Brome mosaic virus (BMV) to maize at conditions that allow successful U. maydis infection of BMV pre-infected maize plants. This setup enables quantification of VIGS and its impact on U. maydis infection using a quantitative real-time PCR (q(RT)-PCR)-based readout.

Biofortified orange maize enhances β-cryptoxanthin concentrations in egg yolks of laying hens better than tangerine peel fortificant.

PubMed

Heying, Emily K; Tanumihardjo, Jacob P; Vasic, Vedran; Cook, Mark; Palacios-Rojas, Natalia; Tanumihardjo, Sherry A

2014-12-10

The xanthophyll β-cryptoxanthin provides vitamin A and has other purported health benefits. Laying hens deposit xanthophyll carotenoids into egg yolk. Hens (n = 8/group) were fed conventional-bred high β-cryptoxanthin biofortified (orange) maize, tangerine peel-fortified white maize, lutein-fortified yellow maize, or white maize for 40 d to investigate yolk color changes using L*a*b* scales, yolk carotenoid enhancement, and hen vitamin A status. Yolks from hens fed orange maize had scores indicating a darker, orange color and mean higher β-cryptoxanthin, zeaxanthin, and β-carotene concentrations (8.43 ± 1.82, 23.1 ± 4.8, 0.16 ± 0.08 nmol/g, respectively) than other treatments (P < 0.0001). Yolk retinol concentrations (mean: 14.4 ± 3.42 nmol/g) were similar among groups and decreased with time (P < 0.0001). Hens fed orange maize had higher liver retinol (0.53 ± 0.20 μmol/g liver) than other groups (P < 0.0001). β-Cryptoxanthin-biofortified eggs could be another choice for consumers, providing enhanced color through a provitamin A carotenoid and supporting eggs' status as a functional food.

Economic viability of phytoremediation of a cadmium contaminated agricultural area using energy maize. Part II: economics of anaerobic digestion of metal contaminated maize in Belgium.

PubMed

Thewys, T; Witters, N; Meers, E; Vangronsveld, J

2010-09-01

This paper deals with remediation of the Campine soil, an agricultural area diffusely contaminated with metals where most farmers raise dairy cattle and grow fodder maize. In a previous study, we calculated the effect of switching from fodder to energy maize on the farmer's income. Selling this energy maize as feedstock for anaerobic digestion to produce renewable energy could lead to a significant increase in his income. This paper explores the economic opportunities for the farmer of digesting the harvested contaminated biomass himself, by performing a Net Present Value (NPV) analysis on the digestion activity and by calculating the probability of a positive NPV of income resulting from the digestion installation. We investigate the trade off between the maximum price for energy maize that can be paid by the digestion activity and the minimum price that the farming activity needs to compensate for covering its production costs. Integrating the previous study in the current analysis results in an increase of total extra income for the farmer (i.e., from both growing energy maize and performing digestion).

Gibberella ear rot of maize (Zea mays) in Nepal: distribution of the mycotoxins nivalenol and deoxynivalenol in naturally and experimentally infected maize.

PubMed

Desjardins, Anne E; Busman, Mark; Manandhar, Gyanu; Jarosz, Andrew M; Manandhar, Hira K; Proctor, Robert H

2008-07-09

The fungus Fusarium graminearum (sexual stage Gibberella zeae) causes ear rot of maize (Zea mays) and contamination with the 8-ketotrichothecenes nivalenol (1) or 4-deoxynivalenol (2), depending on diversity of the fungal population for the 4-oxygenase gene (TRI13). To determine the importance of 1 and 2 in maize ear rot, a survey of naturally contaminated maize in Nepal was combined with experiments in the field and in a plant growth room. In the survey, 1 contamination was 4-fold more frequent than 2 contamination and 1-producers (TRI13) were isolated more than twice as frequently as 2-producers (Psi TRI13). In maize ear rot experiments, genetically diverse 1-producers and 2-producers caused ear rot and trichothecene contamination. Among strains with the same genetic background, however, 1-producers caused less ear rot and trichothecene contamination than did 2-producers. The high frequency of 1 contamination and the high virulence of many 1-producers are of concern because maize is a staple food of rural populations in Nepal and because 1 has proven to be more toxic than 2 to animals.

Retrogradation of Maize Starch after High Hydrostatic Pressure Gelation: Effect of Amylose Content and Depressurization Rate.

PubMed

Yang, Zhi; Swedlund, Peter; Gu, Qinfen; Hemar, Yacine; Chaieb, Sahraoui

2016-01-01

High hydrostatic pressure (HHP) has been employed to gelatinize or physically modify starch dispersions. In this study, waxy maize starch, normal maize starch, and two high amylose content starch were processed by a HHP of the order of 600 MPa, at 25°C for 15min. The effect of HHP processing on the crystallization of maize starches with various amylose content during storage at 4°C was investigated. Crystallization kinetics of HHP treated starch gels were investigated using rheology and FTIR. The effect of crystallization on the mechanical properties of starch gel network were evaluated in terms of dynamic complex modulus (G*). The crystallization induced increase of short-range helices structures were investigated using FTIR. The pressure releasing rate does not affect the starch retrogradation behaviour. The rate and extent of retrogradation depends on the amylose content of amylose starch. The least retrogradation was observed in HHP treated waxy maize starch. The rate of retrogradation is higher for HHP treated high amylose maize starch than that of normal maize starch. A linear relationship between the extent of retrogradation (phase distribution) measured by FTIR and G* is proposed.

Retrogradation of Maize Starch after High Hydrostatic Pressure Gelation: Effect of Amylose Content and Depressurization Rate

PubMed Central

Yang, Zhi; Swedlund, Peter; Gu, Qinfen; Hemar, Yacine; Chaieb, Sahraoui

2016-01-01

High hydrostatic pressure (HHP) has been employed to gelatinize or physically modify starch dispersions. In this study, waxy maize starch, normal maize starch, and two high amylose content starch were processed by a HHP of the order of 600 MPa, at 25°C for 15min. The effect of HHP processing on the crystallization of maize starches with various amylose content during storage at 4°C was investigated. Crystallization kinetics of HHP treated starch gels were investigated using rheology and FTIR. The effect of crystallization on the mechanical properties of starch gel network were evaluated in terms of dynamic complex modulus (G*). The crystallization induced increase of short-range helices structures were investigated using FTIR. The pressure releasing rate does not affect the starch retrogradation behaviour. The rate and extent of retrogradation depends on the amylose content of amylose starch. The least retrogradation was observed in HHP treated waxy maize starch. The rate of retrogradation is higher for HHP treated high amylose maize starch than that of normal maize starch. A linear relationship between the extent of retrogradation (phase distribution) measured by FTIR and G* is proposed. PMID:27219066

Susceptibility and aversion of Spodoptera frugiperda (Lepidoptera: Noctuidae) to Cry1F Bt maize and considerations for insect resistance management.

PubMed

Binning, Rachel R; Coats, Joel; Kong, Xiaoxiao; Hellmich, Richard L

2014-02-01

Bacillus thuringiensis (Bt) maize was developed primarily for North American pests such as European corn borer (Ostrinia nubilalis (Hübner)). However, most Bt maize products are also cultivated outside of North America, where the primary pests may be different and may have lower susceptibility to Bt toxins. Fall armyworm (Spodoptera frugiperda JE Smith) is an important pest and primary target of Bt maize in Central and South America. S. frugiperda susceptibility to Cry1F (expressed in event TC1507) is an example of a pest-by-toxin interaction that does not meet the high-dose definition. In this study, the behavioral and toxic response of S. frugiperda to Cry1F maize was investigated by measuring the percentage of time naive third instars spent feeding during a 3-min exposure. S. frugiperda also were exposed as third instars to Cry1F maize for 14 d to measure weight gain and survival. S. frugiperda demonstrated an initial, postingestive aversive response to Cry1F maize, and few larvae survived the 14 d exposure. The role of susceptibility and avoidance are discussed in the context of global IRM refuge strategy development for Bt products.

The maize (Zea mays ssp. mays var. B73) genome encodes 33 members of the purple acid phosphatase family

PubMed Central

González-Muñoz, Eliécer; Avendaño-Vázquez, Aida-Odette; Montes, Ricardo A. Chávez; de Folter, Stefan; Andrés-Hernández, Liliana; Abreu-Goodger, Cei; Sawers, Ruairidh J. H.

2015-01-01

Purple acid phosphatases (PAPs) play an important role in plant phosphorus nutrition, both by liberating phosphorus from organic sources in the soil and by modulating distribution within the plant throughout growth and development. Furthermore, members of the PAP protein family have been implicated in a broader role in plant mineral homeostasis, stress responses and development. We have identified 33 candidate PAP encoding gene models in the maize (Zea mays ssp. mays var. B73) reference genome. The maize Pap family includes a clear single-copy ortholog of the Arabidopsis gene AtPAP26, shown previously to encode both major intracellular and secreted acid phosphatase activities. Certain groups of PAPs present in Arabidopsis, however, are absent in maize, while the maize family contains a number of expansions, including a distinct radiation not present in Arabidopsis. Analysis of RNA-sequencing based transcriptome data revealed accumulation of maize Pap transcripts in multiple plant tissues at multiple stages of development, and increased accumulation of specific transcripts under low phosphorus availability. These data suggest the maize PAP family as a whole to have broad significance throughout the plant life cycle, while highlighting potential functional specialization of individual family members. PMID:26042133

Evolutionary divergence of phytochrome protein function in Zea mays PIF3 signaling.

PubMed

Kumar, Indrajit; Swaminathan, Kankshita; Hudson, Karen; Hudson, Matthew E

2016-07-01

Two maize phytochrome-interacting factor (PIF) basic helix-loop-helix (bHLH) family members, ZmPIF3.1 and ZmPIF3.2, were identified, cloned and expressed in vitro to investigate light-signaling interactions. A phylogenetic analysis of sequences of the maize bHLH transcription factor gene family revealed the extent of the PIF family, and a total of seven predicted PIF-encoding genes were identified from genes encoding bHLH family VIIa/b proteins in the maize genome. To investigate the role of maize PIFs in phytochrome signaling, full-length cDNAs for phytochromes PhyA2, PhyB1, PhyB2 and PhyC1 from maize were cloned and expressed in vitro as chromophorylated holophytochromes. We showed that ZmPIF3.1 and ZmPIF3.2 interact specifically with the Pfr form of maize holophytochrome B1 (ZmphyB1), showing no detectable affinity for the Pr form. Maize holophytochrome B2 (ZmphyB2) showed no detectable binding affinity for PIFs in either Pr or Pfr forms, but phyB Pfr from Arabidopsis interacted with ZmPIF3.1 similarly to ZmphyB1 Pfr. We conclude that subfunctionalization at the protein-protein interaction level has altered the role of phyB2 relative to that of phyB1 in maize. Since the phyB2 mutant shows photomorphogenic defects, we conclude that maize phyB2 is an active photoreceptor, without the binding of PIF3 seen in other phyB family proteins. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Evolution of US maize (Zea mays L.) root architectural and anatomical phenes over the past 100 years corresponds to increased tolerance of nitrogen stress.

PubMed

York, Larry M; Galindo-Castañeda, Tania; Schussler, Jeffrey R; Lynch, Jonathan P

2015-04-01

Increasing the nitrogen use efficiency of maize is an important goal for food security and agricultural sustainability. In the past 100 years, maize breeding has focused on yield and above-ground phenes. Over this period, maize cultivation has changed from low fertilizer inputs and low population densities to intensive fertilization and dense populations. The authors hypothesized that through indirect selection the maize root system has evolved phenotypes suited to more intense competition for nitrogen. Sixteen maize varieties representing commercially successful lines over the past century were planted at two nitrogen levels and three planting densities. Root systems of the most recent material were 7 º more shallow, had one less nodal root per whorl, had double the distance from nodal root emergence to lateral branching, and had 14% more metaxylem vessels, but total mextaxylem vessel area remained unchanged because individual metaxylem vessels had 12% less area. Plasticity was also observed in cortical phenes such as aerenchyma, which increased at greater population densities. Simulation modelling with SimRoot demonstrated that even these relatively small changes in root architecture and anatomy could increase maize shoot growth by 16% in a high density and high nitrogen environment. The authors concluded that evolution of maize root phenotypes over the past century is consistent with increasing nitrogen use efficiency. Introgression of more contrasting root phene states into the germplasm of elite maize and determination of the functional utility of these phene states in multiple agronomic conditions could contribute to future yield gains. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Computing the biomass potentials for maize and two alternative energy crops, triticale and cup plant (Silphium perfoliatum L.), with the crop model BioSTAR in the region of Hannover (Germany).

PubMed

Bauböck, Roland; Karpenstein-Machan, Marianne; Kappas, Martin

2014-01-01

Lower Saxony (Germany) has the highest installed electric capacity from biogas in Germany. Most of this electricity is generated with maize. Reasons for this are the high yields and the economic incentive. In parts of Lower Saxony, an expansion of maize cultivation has led to ecological problems and a negative image of bioenergy as such. Winter triticale and cup plant have both shown their suitability as alternative energy crops for biogas production and could help to reduce maize cultivation. The model Biomass Simulation Tool for Agricultural Resources (BioSTAR) has been validated with observed yield data from the region of Hannover for the cultures maize and winter wheat. Predicted yields for the cultures show satisfactory error values of 9.36% (maize) and 11.5% (winter wheat). Correlations with observed data are significant ( P  < 0.01) with R  = 0.75 for maize and 0.6 for winter wheat. Biomass potential calculations for triticale and cup plant have shown both crops to be high yielding and a promising alternative to maize in the region of Hanover and other places in Lower Saxony. The model BioSTAR simulated yields for maize and winter wheat in the region of Hannover at a good overall level of accuracy (combined error 10.4%). Due to input data aggregation, individual years show high errors though (up to 30%). Nevertheless, the BioSTAR crop model has proven to be a functioning tool for the prediction of agricultural biomass potentials under varying environmental and crop management frame conditions.

Humoral and cellular immune response in Wistar Han RCC rats fed two genetically modified maize MON810 varieties for 90 days (EU 7th Framework Programme project GRACE).

PubMed

Tulinská, Jana; Adel-Patient, Karine; Bernard, Hervé; Líšková, Aurélia; Kuricová, Miroslava; Ilavská, Silvia; Horváthová, Mira; Kebis, Anton; Rollerová, Eva; Babincová, Júlia; Aláčová, Radka; Wal, Jean-Michel; Schmidt, Kerstin; Schmidtke, Jörg; Schmidt, Paul; Kohl, Christian; Wilhelm, Ralf; Schiemann, Joachim; Steinberg, Pablo

2018-07-01

The genetically modified maize event MON810 expresses a Bacillus thuringiensis-derived gene, which encodes the insecticidal protein Cry1Ab to control some lepidopteran insect pests such as the European corn borer. It has been claimed that the immune system may be affected following the oral/intragastric administration of the MON810 maize in various different animal species. In the frame of the EU-funded project GRACE, two 90-day feeding trials, the so-called studies D and E, were performed to analyze the humoral and cellular immune responses of male and female Wistar Han RCC rats fed the MON810 maize. A MON810 maize variety of Monsanto was used in the study D and a MON810 maize variety of Pioneer Hi-Bred was used in the study E. The total as well as the maize protein- and Cry1Ab-serum-specific IgG, IgM, IgA and IgE levels, the proliferative activity of the lymphocytes, the phagocytic activity of the granulocytes and monocytes, the respiratory burst of the phagocytes, a phenotypic analysis of spleen, thymus and lymph node cells as well as the in vitro production of cytokines by spleen cells were analyzed. No specific Cry1Ab immune response was observed in MON810 rats, and anti-maize protein antibody responses were similar in MON810 and control rats. Single parameters were sporadically altered in rats fed the MON810 maize when compared to control rats, but these alterations are considered to be of no immunotoxicological significance.

Maize Chlorotic Mottle Virus Induces Changes in Host Plant Volatiles that Attract Vector Thrips Species.

PubMed

Mwando, Nelson L; Tamiru, Amanuel; Nyasani, Johnson O; Obonyo, Meshack A O; Caulfield, John C; Bruce, Toby J A; Subramanian, Sevgan

2018-06-02

Maize lethal necrosis is one of the most devastating diseases of maize causing yield losses reaching up to 90% in sub-Saharan Africa. The disease is caused by a combination of maize chlorotic mottle virus (MCMV) and any one of cereal viruses in the Potyviridae group such as sugarcane mosaic virus. MCMV has been reported to be transmitted mainly by maize thrips (Frankliniella williamsi) and onion thrips (Thrips tabaci). To better understand the role of thrips vectors in the epidemiology of the disease, we investigated behavioral responses of F. williamsi and T. tabaci, to volatiles collected from maize seedlings infected with MCMV in a four-arm olfactometer bioassay. Volatile profiles from MCMV-infected and healthy maize plants were compared by gas chromatography (GC) and GC coupled mass spectrometry analyses. In the bioassays, both sexes of F. williamsi and male T. tabaci were significantly attracted to volatiles from maize plants infected with MCMV compared to healthy plants and solvent controls. Moreover, volatile analysis revealed strong induction of (E)-4,8-dimethyl-1,3,7-nonatriene, methyl salicylate and (E,E)-4,8,12-trimethyltrideca-1,3,7,11-tetraene in MCMV-infected maize seedlings. Our findings demonstrate MCMV induces changes in volatile profiles of host plants to elicit attraction of thrips vectors. The increased vector contact rates with MCMV-infected host plants could enhance virus transmission if thrips feed on the infected plants and acquire the pathogen prior to dispersal. Uncovering the mechanisms mediating interactions between vectors, host plants and pathogens provides useful insights for understanding the vector ecology and disease epidemiology, which in turn may contribute in designing integrated vector management strategies.

In vitro evaluation of different varieties of maize fodder for their methane generation potential and digestibility with goat rumen liquor.

PubMed

Vaswani, Shalini; Kumar, Ravindra; Kumar, Vinod; Roy, Debashis; Kumar, Muneendra

2016-11-01

To evaluate the methane generation potential and digestibility of different (normal and three high-quality protein maize [HQPM]) varieties of maize fodder with goat rumen liquor in vitro . Methane production potential and digestibility of different varieties of maize fodder were tested in in vitro gas production test. Seven varieties of maize, four normal (HTHM 5101, DHM 117, HM 5, and Shaktiman/900 M Gold), and three high-quality protein (HQPM 5, HQPM 7, and HQPM 9/Vivek) were grown in different plots under the same environmental and agro-climatic conditions. Fodders were harvested at 45-50 days of sowing, and the representative samples of fodder from different varieties of maize were collected for analysis. Dried and grinded form of these maize fodder varieties was tested for gas, methane, and digestibility using goat rumen microflora in in vitro gas syringes. Gas production (ml/g dry matter [DM]) was highest for HM5 variety (97.66, whereas lowest for HQPM 9 variety (64.22). Gas production (ml/g degraded DM [DDM]) and methane (%) were statistically similar in different varieties of maize fodder. The methane production expressed as ml/g DM and ml/g DDM was significantly (p<0.05) highest for HM 5 (14.22 and 26.62) and lowest for DHM 117 variety (7.47 and 14.13). The in vitro DM digestibility (%) and in vitro organic matter digestibility (%) varied from 47.48 (HQPM 5) to 52.05 (HQPM 9) and 50.03 (HQPM 7) to 54.22 (HM 5), respectively. The present study concluded that DHM 117 maize variety fodder has lowest methane generation potential and incorporating it in the dietary regime of ruminants may contribute to lower methane production.

In vitro evaluation of different varieties of maize fodder for their methane generation potential and digestibility with goat rumen liquor

PubMed Central

Vaswani, Shalini; Kumar, Ravindra; Kumar, Vinod; Roy, Debashis; Kumar, Muneendra

2016-01-01

Aim: To evaluate the methane generation potential and digestibility of different (normal and three high-quality protein maize [HQPM]) varieties of maize fodder with goat rumen liquor in vitro. Materials and Methods: Methane production potential and digestibility of different varieties of maize fodder were tested in in vitro gas production test. Seven varieties of maize, four normal (HTHM 5101, DHM 117, HM 5, and Shaktiman/900 M Gold), and three high-quality protein (HQPM 5, HQPM 7, and HQPM 9/Vivek) were grown in different plots under the same environmental and agro-climatic conditions. Fodders were harvested at 45-50 days of sowing, and the representative samples of fodder from different varieties of maize were collected for analysis. Dried and grinded form of these maize fodder varieties was tested for gas, methane, and digestibility using goat rumen microflora in in vitro gas syringes. Results: Gas production (ml/g dry matter [DM]) was highest for HM5 variety (97.66, whereas lowest for HQPM 9 variety (64.22). Gas production (ml/g degraded DM [DDM]) and methane (%) were statistically similar in different varieties of maize fodder. The methane production expressed as ml/g DM and ml/g DDM was significantly (p<0.05) highest for HM 5 (14.22 and 26.62) and lowest for DHM 117 variety (7.47 and 14.13). The in vitro DM digestibility (%) and in vitro organic matter digestibility (%) varied from 47.48 (HQPM 5) to 52.05 (HQPM 9) and 50.03 (HQPM 7) to 54.22 (HM 5), respectively. Conclusion: The present study concluded that DHM 117 maize variety fodder has lowest methane generation potential and incorporating it in the dietary regime of ruminants may contribute to lower methane production. PMID:27956770

Characterization and distribution of a maize cDNA encoding a peptide similar to the catalytic region of second messenger dependent protein kinases

NASA Technical Reports Server (NTRS)

Biermann, B.; Johnson, E. M.; Feldman, L. J.

1990-01-01

Maize (Zea mays) roots respond to a variety of environmental stimuli which are perceived by a specialized group of cells, the root cap. We are studying the transduction of extracellular signals by roots, particularly the role of protein kinases. Protein phosphorylation by kinases is an important step in many eukaryotic signal transduction pathways. As a first phase of this research we have isolated a cDNA encoding a maize protein similar to fungal and animal protein kinases known to be involved in the transduction of extracellular signals. The deduced sequence of this cDNA encodes a polypeptide containing amino acids corresponding to 33 out of 34 invariant or nearly invariant sequence features characteristic of protein kinase catalytic domains. The maize cDNA gene product is more closely related to the branch of serine/threonine protein kinase catalytic domains composed of the cyclic-nucleotide- and calcium-phospholipid-dependent subfamilies than to other protein kinases. Sequence identity is 35% or more between the deduced maize polypeptide and all members of this branch. The high structural similarity strongly suggests that catalytic activity of the encoded maize protein kinase may be regulated by second messengers, like that of all members of this branch whose regulation has been characterized. Northern hybridization with the maize cDNA clone shows a single 2400 base transcript at roughly similar levels in maize coleoptiles, root meristems, and the zone of root elongation, but the transcript is less abundant in mature leaves. In situ hybridization confirms the presence of the transcript in all regions of primary maize root tissue.

Safety and Quality Assessment of Smallholder Farmers' Maize in the Western Highlands of Guatemala.

PubMed

Mendoza, José Rodrigo; Rodas, Ana; Oliva, Ana; Sabillón, Luis; Colmenares, Ana; Clarke, Jennifer; Hallen-Adams, Heather E; Campabadal, Carlos; Bianchini, Andréia

2018-05-01

Maize ( Zea mays) is a staple in many developing countries but is known to be prone to pest (insects, birds, and rodents) and fungal infestation. In Guatemala, mycotoxin contamination of cultivated products may occur owing to such factors as environmental conditions and the use of traditional agriculture operations. To assess the current maize conditions in Guatemala, a small-scale study was performed. Mold and insect counts and mycotoxin (aflatoxin and fumonisin) concentrations were determined on 25 farms in two townships (Chiantla and Todos Santos) of the Huehuetenango Department. Total fungal counts were 3.6 to 6.83 log CFU/g with no significant differences ( P > 0.05) across farms at different altitudes. Farms where maize was not produced but was purchased were at higher risk of fumonisin contamination, whereas local producers were mostly affected by aflatoxins. Aflatoxin was present in maize from 100% of farms at 1.0 to 85.3 ppb, and fumonisin was detected on 52% of farms at 0.4 to 31.0 ppm. Average mycotoxin consumption amounts were above the recommended maximum intake for aflatoxin in both produced and purchased maize and above the provisional maximum tolerable daily intake for fumonisin in purchased maize. Estimated daily intake was 0.01 to 0.85 μg/kg of body weight per day for aflatoxin and 2.9 to 310.0 μg/kg of body weight per day for fumonisin. An entomological analysis revealed overall 32% prevalence of Ephestia kuehniella (flour moth), 16% prevalence of Sitophilus zeamais (maize weevil), and 8% prevalence of Tribolium sp. (flour beetle) on the analyzed farms. This study highlighted poor agricultural practices used in the highlands of Guatemala. Current practices should be revised for the production of maize that is safe for consumption by the population in this region.

A Proteinaceous Elicitor Sm1 from the Beneficial Fungus Trichoderma virens Is Required for Induced Systemic Resistance in Maize1[W

PubMed Central

Djonović, Slavica; Vargas, Walter A.; Kolomiets, Michael V.; Horndeski, Michelle; Wiest, Aric; Kenerley, Charles M.

2007-01-01

We have previously shown that the beneficial filamentous fungus Trichoderma virens secretes the highly effective hydrophobin-like elicitor Sm1 that induces systemic disease resistance in the dicot cotton (Gossypium hirsutum). In this study we tested whether colonization of roots by T. virens can induce systemic protection against a foliar pathogen in the monocot maize (Zea mays), and we further demonstrated the importance of Sm1 during maize-fungal interactions using a functional genomics approach. Maize seedlings were inoculated with T. virens Gv29-8 wild type and transformants in which SM1 was disrupted or constitutively overexpressed in a hydroponic system or in soil-grown maize seedlings challenged with the pathogen Colletotrichum graminicola. We show that similar to dicot plants, colonization of maize roots by T. virens induces systemic protection of the leaves inoculated with C. graminicola. This protection was associated with notable induction of jasmonic acid- and green leaf volatile-biosynthetic genes. Neither deletion nor overexpression of SM1 affected normal growth or development of T. virens, conidial germination, production of gliotoxin, hyphal coiling, hydrophobicity, or the ability to colonize maize roots. Plant bioassays showed that maize grown with SM1-deletion strains exhibited the same levels of systemic protection as non-Trichoderma-treated plants. Moreover, deletion and overexpression of SM1 resulted in significantly reduced and enhanced levels of disease protection, respectively, compared to the wild type. These data together indicate that T. virens is able to effectively activate systemic disease protection in maize and that the functional Sm1 elicitor is required for this activity. PMID:17885089

Strategies to reduce exposure of fumonisins from complementary foods in rural Tanzania.

PubMed

Kimanya, Martin E; De Meulenaer, Bruno; Van Camp, John; Baert, Katleen; Kolsteren, Patrick

2012-10-01

Feeding infants with maize can expose them to fumonisin mycotoxins. We assessed fumonisin exposure from complementary foods in rural Tanzania and determined strategies to reduce the exposure. We conducted a cross-sectional study in four villages of Tarakea division, Northern Tanzania. We used a repeat 24-hour dietary recall to collect data of maize consumption as complementary food for 254 infants aged 6-8 months. Fumonisin concentrations in the maize were also estimated. Fumonisin exposure was assessed using @risk analysis software. With the software, several maximum fumonisin contamination and maize consumption patterns were combined in order to determine effective strategies for minimizing fumonisin exposure. Of the infants, 89% consumed maize at amounts up to 158g/person/day (mean; 43g/person/day±28). The maize was contaminated with fumonisins at levels up to 3201µgkg(-1) . Risk of fumonisin intake above the provisional maximum tolerable daily limit of 2µgkg(-1) body weight was 15% (95% confidence interval; 10-19). The risk was minimized when the maximum contamination was set at 150µgkg(-1) . The risk was also minimized when the maximum consumption was set at 20g/child/day while keeping the maximum contamination at the European Union (EU) maximum tolerated limit (MTL) of 1000µgkg(-1) . Considering the economical and technological limitations of adopting good agricultural practices in rural Tanzania, it is practically difficult to reduce contamination in maize to 150µgkg(-1) . We suggest adoption of the EU MTL of 1000µgkg(-1) for fumonisins in maize and reduction, by replacement with another cereal, of the maize component in complementary foods to a maximum intake of 20g/child/day. © 2011 Blackwell Publishing Ltd.

Effect of hormonal synchronisation and/or short-term supplementation with maize on follicular dynamics and hormone profiles in goats during the non-breeding season.

PubMed

Nogueira, D M; Cavalieri, J; Fitzpatrick, L A; Gummow, B; Blache, D; Parker, A J

2016-08-01

This study aimed to evaluate the reproductive response of anoestrous goats that were either hormonally treated and/or supplemented with maize for 9days to determine which treatment combination was the most effective in enhancing follicular development and ovulation rate, and whether these responses were associated with increases in metabolic hormones. The experiment was carried out using 28 does, using a 2×2 factorial design with seven does in each group to test the effect of synchronisation of oestrus, supplementation with maize and their interactions. Synchronisation of oestrous cycles (P<0.001) but not supplementation with maize or the interaction between the two (P>0.05) increased the number of codominant follicles, the diameter of the largest follicle on Day 9 and growth rate of follicles during the period of supplementation. Compared with non-supplemented animals, supplementation with maize increased the total number of follicles observed between Days 7 and 9 (P=0.039). In addition, nutritional supplementation with maize in combination with synchronisation of oestrus increased the ovulation rate by 43% (P=0.074). Interactions between time and supplementation with maize showed that plasma concentrations of insulin, leptin and IGF-1 were greater in does supplemented with maize compared with non-supplemented does (P<0.001). The findings show that hormonal synchronisation had the most influence on modifying follicular development and ovulation in anoestrous goats. Supplementation with maize increased the concentrations of insulin, leptin and IGF-1, which could potentially modify the sensitivity of follicles to gonadotrophins and reduce rates of atresia. Copyright © 2016 Elsevier B.V. All rights reserved.

Bitrophic and Tritrophic Effects of Transgenic cry1Ab/cry2Aj Maize on the Beneficial, Nontarget Harmonia axyridis (Coleoptera: Coccinellidae).

PubMed

Chang, Xue; Lu, Zengbin; Shen, Zhicheng; Peng, Yufa; Ye, Gongyin

2017-10-01

Harmonia axyridis (Pallas) is a common and abundant predator in China and may be exposed to Cry toxins that are produced in Bt crops either by feeding on plant parts or by feeding on target or nontarget herbivorous insects. A new Bt maize line, expressing the Cry1Ab/Cry2Aj fused protein, has been developed and should be rigorously assessed for the ecological risks on the natural enemy. Laboratory experiments were carried out to study the effects of this Bt maize on nontarget predator H. axyridis via bitrophic interaction of adult H. axyridis feeding on Bt maize pollen and tritrophic interaction of H. axyridis consuming the lepidopteran prey. Spodoptera exigua (Hübner) neonate larvae were used to transfer Bt protein because they could survive after ingesting transgenic cry1Ab/cry2Aj maize kernels in the previous study. ELISA bioassays confirmed that the Bt protein could be transferred, but diluted through Bt maize-prey-predator. Life history parameters such as survival, development, weight, fecundity, and egg hatching rate were not significantly different when H. axyridis consumed prey that had been reared on Bt maize compared with prey reared on a nontransformed parental control. Furthermore, feeding directly on Bt maize pollen also had no detrimental effects on fitness, survival, and weight of female and male adults. In conclusion, our results indicate that transgenic cry1Ab/cry2Aj maize poses no ecological risks on the nontarget predator H. axyridis. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

In vitro utilization of amylopectin and high-amylose maize (Amylomaize) starch granules by human colonic bacteria.

PubMed

Wang, X; Conway, P L; Brown, I L; Evans, A J

1999-11-01

It has been well established that a certain amount of ingested starch can escape digestion in the human small intestine and consequently enters the large intestine, where it may serve as a carbon source for bacterial fermentation. Thirty-eight types of human colonic bacteria were screened for their capacity to utilize soluble starch, gelatinized amylopectin maize starch, and high-amylose maize starch granules by measuring the clear zones on starch agar plates. The six cultures which produced clear zones on amylopectin maize starch- containing plates were selected for further studies for utilization of amylopectin maize starch and high-amylose maize starch granules A (amylose; Sigma) and B (Culture Pro 958N). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was used to detect bacterial starch-degrading enzymes. It was demonstrated that Bifidobacterium spp., Bacteroides spp., Fusobacterium spp., and strains of Eubacterium, Clostridium, Streptococcus, and Propionibacterium could hydrolyze the gelatinized amylopectin maize starch, while only Bifidobacterium spp. and Clostridium butyricum could efficiently utilize high-amylose maize starch granules. In fact, C. butyricum and Bifidobacterium spp. had higher specific growth rates in the autoclaved medium containing high-amylose maize starch granules and hydrolyzed 80 and 40% of the amylose, respectively. Starch-degrading enzymes were cell bound on Bifidobacterium and Bacteroides cells and were extracellular for C. butyricum. Active staining for starch-degrading enzymes on SDS-PAGE gels showed that the Bifidobacterium cells produced several starch-degrading enzymes with high relative molecular (M(r)) weights (>160,000), medium-sized relative molecular weights (>66,000), and low relative molecular weights (<66,000). It was concluded that Bifidobacterium spp. and C. butyricum degraded and utilized granules of amylomaize starch.

In Vitro Utilization of Amylopectin and High-Amylose Maize (Amylomaize) Starch Granules by Human Colonic Bacteria

PubMed Central

Wang, Xin; Conway, Patricia Lynne; Brown, Ian Lewis; Evans, Anthony John

1999-01-01

It has been well established that a certain amount of ingested starch can escape digestion in the human small intestine and consequently enters the large intestine, where it may serve as a carbon source for bacterial fermentation. Thirty-eight types of human colonic bacteria were screened for their capacity to utilize soluble starch, gelatinized amylopectin maize starch, and high-amylose maize starch granules by measuring the clear zones on starch agar plates. The six cultures which produced clear zones on amylopectin maize starch- containing plates were selected for further studies for utilization of amylopectin maize starch and high-amylose maize starch granules A (amylose; Sigma) and B (Culture Pro 958N). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was used to detect bacterial starch-degrading enzymes. It was demonstrated that Bifidobacterium spp., Bacteroides spp., Fusobacterium spp., and strains of Eubacterium, Clostridium, Streptococcus, and Propionibacterium could hydrolyze the gelatinized amylopectin maize starch, while only Bifidobacterium spp. and Clostridium butyricum could efficiently utilize high-amylose maize starch granules. In fact, C. butyricum and Bifidobacterium spp. had higher specific growth rates in the autoclaved medium containing high-amylose maize starch granules and hydrolyzed 80 and 40% of the amylose, respectively. Starch-degrading enzymes were cell bound on Bifidobacterium and Bacteroides cells and were extracellular for C. butyricum. Active staining for starch-degrading enzymes on SDS-PAGE gels showed that the Bifidobacterium cells produced several starch-degrading enzymes with high relative molecular (Mr) weights (>160,000), medium-sized relative molecular weights (>66,000), and low relative molecular weights (<66,000). It was concluded that Bifidobacterium spp. and C. butyricum degraded and utilized granules of amylomaize starch. PMID:10543795

MicroRNA528 Affects Lodging Resistance of Maize by Regulating Lignin Biosynthesis under Nitrogen-Luxury Conditions.

PubMed

Sun, Qing; Liu, Xiaogang; Yang, Juan; Liu, Wenwen; Du, Qingguo; Wang, Hongqiu; Fu, Chunxiang; Li, Wen-Xue

2018-06-04

Lodging under nitrogen (N)-luxury conditions substantially reduces crop yield and seed quality. However, the molecular mechanisms of plant lodging resistance remain largely unclear, especially in maize. We report here that the expression of ZmmiR528, a monocot-specific microRNA, is induced by N luxury but reduced by N deficiency. We show by the thioacidolysis and acetyl bromide analysis that N luxury significantly reduces the generation of H, G, and S monomers of the lignin as well as its total content in maize shoots. We further demonstrate that ZmLACCASE3 (ZmLAC3) and ZmLACCASE5 (ZmLAC5), which encode the copper-containing laccases, are the targets of ZmmiR528. In situ hybridization showed that ZmmiR528 is mainly expressed in maize vascular tissues. Knockdown of ZmmiR528 or overexpression of ZmLAC3 significantly increased the lignin content and rind penetrometer resistance of maize stems. In contrast, transgenic maize plants overexpressing ZmmiR528 had reduced lignin content and rind penetrometer resistance and were prone to lodging under N-luxury conditions. RNA-sequencing analysis revealed that ZmPAL7 and ZmPAL8 are upregulated in transgenic maize lines downregulating ZmmiR528. Under N-luxury conditions, the expression levels of ZmPALs were much higher in ZmmiR528-knockdown lines than in the wild type and transgenic maize lines overexpressing ZmmiR528. Taken together, these results indicate that, by regulating the expression of ZmLAC3 and ZmLAC5, ZmmiR528 affects maize lodging resistance under N-luxury conditions. Copyright © 2018 The Author. Published by Elsevier Inc. All rights reserved.

Systematic Analysis of Sequences and Expression Patterns of Drought-Responsive Members of the HD-Zip Gene Family in Maize

PubMed Central

Zhao, Yang; Zhou, Yuqiong; Jiang, Haiyang; Li, Xiaoyu; Gan, Defang; Peng, Xiaojian; Zhu, Suwen; Cheng, Beijiu

2011-01-01

Background Members of the homeodomain-leucine zipper (HD-Zip) gene family encode transcription factors that are unique to plants and have diverse functions in plant growth and development such as various stress responses, organ formation and vascular development. Although systematic characterization of this family has been carried out in Arabidopsis and rice, little is known about HD-Zip genes in maize (Zea mays L.). Methods and Findings In this study, we described the identification and structural characterization of HD-Zip genes in the maize genome. A complete set of 55 HD-Zip genes (Zmhdz1-55) were identified in the maize genome using Blast search tools and categorized into four classes (HD-Zip I-IV) based on phylogeny. Chromosomal location of these genes revealed that they are distributed unevenly across all 10 chromosomes. Segmental duplication contributed largely to the expansion of the maize HD-ZIP gene family, while tandem duplication was only responsible for the amplification of the HD-Zip II genes. Furthermore, most of the maize HD-Zip I genes were found to contain an overabundance of stress-related cis-elements in their promoter sequences. The expression levels of the 17 HD-Zip I genes under drought stress were also investigated by quantitative real-time PCR (qRT-PCR). All of the 17 maize HD-ZIP I genes were found to be regulated by drought stress, and the duplicated genes within a sister pair exhibited the similar expression patterns, suggesting their conserved functions during the process of evolution. Conclusions Our results reveal a comprehensive overview of the maize HD-Zip gene family and provide the first step towards the selection of Zmhdz genes for cloning and functional research to uncover their roles in maize growth and development. PMID:22164299

Systematic analysis of sequences and expression patterns of drought-responsive members of the HD-Zip gene family in maize.

PubMed

Zhao, Yang; Zhou, Yuqiong; Jiang, Haiyang; Li, Xiaoyu; Gan, Defang; Peng, Xiaojian; Zhu, Suwen; Cheng, Beijiu

2011-01-01

Members of the homeodomain-leucine zipper (HD-Zip) gene family encode transcription factors that are unique to plants and have diverse functions in plant growth and development such as various stress responses, organ formation and vascular development. Although systematic characterization of this family has been carried out in Arabidopsis and rice, little is known about HD-Zip genes in maize (Zea mays L.). In this study, we described the identification and structural characterization of HD-Zip genes in the maize genome. A complete set of 55 HD-Zip genes (Zmhdz1-55) were identified in the maize genome using Blast search tools and categorized into four classes (HD-Zip I-IV) based on phylogeny. Chromosomal location of these genes revealed that they are distributed unevenly across all 10 chromosomes. Segmental duplication contributed largely to the expansion of the maize HD-ZIP gene family, while tandem duplication was only responsible for the amplification of the HD-Zip II genes. Furthermore, most of the maize HD-Zip I genes were found to contain an overabundance of stress-related cis-elements in their promoter sequences. The expression levels of the 17 HD-Zip I genes under drought stress were also investigated by quantitative real-time PCR (qRT-PCR). All of the 17 maize HD-ZIP I genes were found to be regulated by drought stress, and the duplicated genes within a sister pair exhibited the similar expression patterns, suggesting their conserved functions during the process of evolution. Our results reveal a comprehensive overview of the maize HD-Zip gene family and provide the first step towards the selection of Zmhdz genes for cloning and functional research to uncover their roles in maize growth and development.

Maize Endophytic Bacterial Diversity as Affected by Soil Cultivation History.

PubMed

Correa-Galeote, David; Bedmar, Eulogio J; Arone, Gregorio J

2018-01-01

The bacterial endophytic communities residing within roots of maize ( Zea mays L.) plants cultivated by a sustainable management in soils from the Quechua maize belt (Peruvian Andes) were examined using tags pyrosequencing spanning the V4 and V5 hypervariable regions of the 16S rRNA. Across four replicate libraries, two corresponding to sequences of endophytic bacteria from long time maize-cultivated soils and the other two obtained from fallow soils, 793 bacterial sequences were found that grouped into 188 bacterial operational taxonomic units (OTUs, 97% genetic similarity). The numbers of OTUs in the libraries from the maize-cultivated soils were significantly higher than those found in the libraries from fallow soils. A mean of 30 genera were found in the fallow soil libraries and 47 were in those from the maize-cultivated soils. Both alpha and beta diversity indexes showed clear differences between bacterial endophytic populations from plants with different soil cultivation history and that the soils cultivated for long time requires a higher diversity of endophytes. The number of sequences corresponding to main genera Sphingomonas, Herbaspirillum, Bradyrhizobium and Methylophilus in the maize-cultivated libraries were statistically more abundant than those from the fallow soils. Sequences of genera Dyella and Sreptococcus were significantly more abundant in the libraries from the fallow soils. Relative abundance of genera Burkholderia, candidatus Glomeribacter, Staphylococcus, Variovorax, Bacillus and Chitinophaga were similar among libraries. A canonical correspondence analysis of the relative abundance of the main genera showed that the four libraries distributed in two clearly separated groups. Our results suggest that cultivation history is an important driver of endophytic colonization of maize and that after a long time of cultivation of the soil the maize plants need to increase the richness of the bacterial endophytes communities.

Maize Endophytic Bacterial Diversity as Affected by Soil Cultivation History

PubMed Central

Correa-Galeote, David; Bedmar, Eulogio J.; Arone, Gregorio J.

2018-01-01

The bacterial endophytic communities residing within roots of maize (Zea mays L.) plants cultivated by a sustainable management in soils from the Quechua maize belt (Peruvian Andes) were examined using tags pyrosequencing spanning the V4 and V5 hypervariable regions of the 16S rRNA. Across four replicate libraries, two corresponding to sequences of endophytic bacteria from long time maize-cultivated soils and the other two obtained from fallow soils, 793 bacterial sequences were found that grouped into 188 bacterial operational taxonomic units (OTUs, 97% genetic similarity). The numbers of OTUs in the libraries from the maize-cultivated soils were significantly higher than those found in the libraries from fallow soils. A mean of 30 genera were found in the fallow soil libraries and 47 were in those from the maize-cultivated soils. Both alpha and beta diversity indexes showed clear differences between bacterial endophytic populations from plants with different soil cultivation history and that the soils cultivated for long time requires a higher diversity of endophytes. The number of sequences corresponding to main genera Sphingomonas, Herbaspirillum, Bradyrhizobium and Methylophilus in the maize-cultivated libraries were statistically more abundant than those from the fallow soils. Sequences of genera Dyella and Sreptococcus were significantly more abundant in the libraries from the fallow soils. Relative abundance of genera Burkholderia, candidatus Glomeribacter, Staphylococcus, Variovorax, Bacillus and Chitinophaga were similar among libraries. A canonical correspondence analysis of the relative abundance of the main genera showed that the four libraries distributed in two clearly separated groups. Our results suggest that cultivation history is an important driver of endophytic colonization of maize and that after a long time of cultivation of the soil the maize plants need to increase the richness of the bacterial endophytes communities. PMID:29662471

Sequence of Changes in Maize Responding to Soil Water Deficit and Related Critical Thresholds

PubMed Central

Ma, Xueyan; He, Qijin; Zhou, Guangsheng

2018-01-01

The sequence of changes in crop responding to soil water deficit and related critical thresholds are essential for better drought damage classification and drought monitoring indicators. This study was aimed to investigate the critical thresholds of maize growth and physiological characteristics responding to changing soil water and to reveal the sequence of changes in maize responding to soil water deficit both in seedling and jointing stages based on 2-year’s maize field experiment responding to six initial soil water statuses conducted in 2013 and 2014. Normal distribution tolerance limits were newly adopted to identify critical thresholds of maize growth and physiological characteristics to a wide range of soil water status. The results showed that in both stages maize growth characteristics related to plant water status [stem moisture content (SMC) and leaf moisture content (LMC)], leaf gas exchange [net photosynthetic rate (Pn), transpiration rate (Tr), and stomatal conductance (Gs)], and leaf area were sensitive to soil water deficit, while biomass-related characteristics were less sensitive. Under the concurrent weather conditions and agronomic managements, the critical soil water thresholds in terms of relative soil moisture of 0–30 cm depth (RSM) of maize SMC, LMC, net Pn, Tr, Gs, and leaf area were 72, 65, 62, 60, 58, and 46%, respectively, in seedling stage, and 64, 64, 51, 53, 48, and 46%, respectively, in jointing stage. It indicated that there is a sequence of changes in maize responding to soil water deficit, i.e., their response sequences as soil water deficit intensified: SMC ≥ LMC > leaf gas exchange > leaf area in both stages. This sequence of changes in maize responding to soil water deficit and related critical thresholds may be better indicators of damage classification and drought monitoring. PMID:29765381

Assessment of Climate Suitability of Maize in South Korea

NASA Astrophysics Data System (ADS)

Hyun, S.; Choi, D.; Seo, B.

2017-12-01

Assessing suitable areas for crops would be useful to design alternate cropping systems as an adaptation option to climate change adaptation. Although suitable areas could be identified by using a crop growth model, it would require a number of input parameters including cultivar and soil. Instead, a simple climate suitability model, e.g., EcoCrop model, could be used for an assessment of climate suitability for a major grain crop. The objective of this study was to assess of climate suitability for maize using the EcoCrop model under climate change conditions in Korea. A long term climate data from 2000 - 2100 were compiled from weather data source. The EcoCrop model implemented in R was used to determine climate suitability index at each grid cell. Overall, the EcoCrop model tended to identify suitable areas for maize production near the coastal areas whereas the actual major production areas located in inland areas. It is likely that the discrepancy between assessed and actual crop production areas would result from the socioeconomic aspects of maize production. Because the price of maize is considerably low, maize has been grown in an area where moisture and temperature conditions would be less than optimum. In part, a simple algorithm to predict climate suitability for maize would caused a relatively large error in climate suitability assessment under the present climate conditions. In 2050s, the climate suitability for maize increased in a large areas in southern and western part of Korea. In particular, the plain areas near the coastal region had considerably greater suitability index in the future compared with mountainous areas. The expansion of suitable areas for maize would help crop production policy making such as the allocation of rice production area for other crops due to considerably less demand for the rice in Korea.

Arbuscular mycorrhizal fungi differ in their ability to regulate the expression of phosphate transporters in maize (Zea mays L.).

PubMed

Tian, Hui; Drijber, Rhae A; Li, Xiaolin; Miller, Daniel N; Wienhold, Brian J

2013-08-01

Previous studies have found that some phosphate (Pi) starvation inducible transporter genes are downregulated and arbuscular mycorrhizal (AM) inducible Pi transporter genes are upregulated in maize roots associated with the fungus Glomus intraradices. However, little is known about the functional diversity of different AM fungal species in influencing the expression of Pi transporters in maize roots. Here, we studied the expression of two Pi transporter genes ZEAma:Pht1;3 (Pi starvation inducible) and ZEAma:Pht1;6 (AM inducible) in maize root colonized by different AM fungal inoculants. Non-mycorrhizal maize, maize colonized by Glomus deserticola (CA113), Glomus intraradices (IA506), Glomus mosseae (CA201), Gigaspora gigantea (MN922A) and the co-inoculation of all four species were established. The expression patterns of the two genes were quantified using real-time, reverse transcription polymerase chain reaction. The expression level of ZEAma:Pht1;6 was 26-135 times higher in AM plants than in non-mycorrhizal maize roots, whereas the expression level of ZEAma:Pht1;3 was five to 44 times lower in AM plants than in non-mycorrhizal plants. Expression of the two genes differed with inoculation treatment, and increasing the diversity of AM fungi in maize roots led to greater expression of ZEAma:Pht1;6 as well as Pi uptake in shoots. The expression of ZEAma:Pht1;6 was significantly positively correlated with AM colonization rate, concentration of AM biomarkers in maize roots, Pi uptake and dry weight of shoot, but negatively correlated with the expression of ZEAma:Pht1;3. Addition of Pi fertilizer at a low concentration significantly increased the expression of ZEAma:Pht1;6 but had no effect on the expression of ZEAma:Pht1;3.

Dynamic Maize Responses to Aphid Feeding Are Revealed by a Time Series of Transcriptomic and Metabolomic Assays1[OPEN

PubMed Central

Tzin, Vered; Fernandez-Pozo, Noe; Richter, Annett; Schmelz, Eric A.; Schoettner, Matthias; Schäfer, Martin; Ahern, Kevin R.; Meihls, Lisa N.; Kaur, Harleen; Huffaker, Alisa; Mori, Naoki; Degenhardt, Joerg; Mueller, Lukas A.; Jander, Georg

2015-01-01

As a response to insect attack, maize (Zea mays) has inducible defenses that involve large changes in gene expression and metabolism. Piercing/sucking insects such as corn leaf aphid (Rhopalosiphum maidis) cause direct damage by acquiring phloem nutrients as well as indirect damage through the transmission of plant viruses. To elucidate the metabolic processes and gene expression changes involved in maize responses to aphid attack, leaves of inbred line B73 were infested with corn leaf aphids for 2 to 96 h. Analysis of infested maize leaves showed two distinct response phases, with the most significant transcriptional and metabolic changes occurring in the first few hours after the initiation of aphid feeding. After 4 d, both gene expression and metabolite profiles of aphid-infested maize reverted to being more similar to those of control plants. Although there was a predominant effect of salicylic acid regulation, gene expression changes also indicated prolonged induction of oxylipins, although not necessarily jasmonic acid, in aphid-infested maize. The role of specific metabolic pathways was confirmed using Dissociator transposon insertions in maize inbred line W22. Mutations in three benzoxazinoid biosynthesis genes, Bx1, Bx2, and Bx6, increased aphid reproduction. In contrast, progeny production was greatly decreased by a transposon insertion in the single W22 homolog of the previously uncharacterized B73 terpene synthases TPS2 and TPS3. Together, these results show that maize leaves shift to implementation of physical and chemical defenses within hours after the initiation of aphid feeding and that the production of specific metabolites can have major effects in maize-aphid interactions. PMID:26378100

Carbon isotopic constraints on the contribution of plant material to the natural precursors of trihalomethanes

USGS Publications Warehouse

Bergamaschi, B.A.; Fram, M.S.; Kendall, C.; Silva, S.R.; Aiken, G.R.; Fujii, R.

1999-01-01

The ??13C values of individual trihalomethanes (THM) formed on reaction of chlorine with dissolved organic carbon (DOC) leached from maize (corn, Zea maize L) and Scirpus acutus (an aquatic bulrush), and with DOC extracted from agricultural drainage waters were determined using purge and trap introduction into a gas chromatograph-combustion-isotope ratio monitoring mass spectrometer. We observed a 1-6.8??? difference between the ??13C values of THM produced from the maize and Scirpus leachates, similar to the isotopic difference between the whole plant materials. Both maize and Scirpus formed THM 12??? lower in 13C than whole plant material. We suggest that the low value of the THM relative to the whole plant material is evidence of distinct pools of THM-forming DOC, representing different biochemical types or chemical structures, and possessing different environmental reactivity Humic extracts of waters draining an agricultural field containing Scirpus peat soils and planted with maize formed THM with isotopic values intermediate between those of maize and Scirpus leachates, indicating maize may contribute significantly to the THM-forming DOC. The difference between the ??13C values of the whole isolate and that of the THM it yielded was 3 9???, however, suggesting diagenesis plays a role in determining the ??13C value of THM-forming DOC in the drainage waters, and precluding the direct use of isotopic mixing models to quantitatively attribute sources.The ??13C values of individual trihalomethanes (THM) formed on reaction of chlorine with dissolved organic carbon (DOC) leached from maize (corn; Zea maize L.) and Scirpus acutus (an aquatic bulrush), and with DOC extracted from agricultural drainage waters were determined using purge and trap introduction into a gas chromatograph-combustion-isotope ratio monitoring mass spectrometer. We observed a 16.8qq difference between the ??13C values of THM produced from the maize and Scirpus leachates, similar to the isotopic difference between the whole plant materials. Both maize and Scirpus formed THM 12qq lower in 13C than whole plant material. We suggest that the low value of the THM relative to the whole plant material is evidence of distinct pools of THM-forming DOC, representing different biochemical types or chemical structures, and possessing different environmental reactivity. Humic extracts of waters draining an agricultural field containing Scirpus peat soils and planted with maize formed THM with isotopic values intermediate between those of maize and Scirpus leachates, indicating maize may contribute significantly to the THM-forming DOC. The difference between the ??13C values of the whole isolate and that of the THM it yielded was 3.9qq, however, suggesting diagenesis plays a role in determining the ??13C value of THM-forming DOC in the drainage waters, and precluding the direct use of isotopic mixing models to quantitatively attribute sources.

Early allelic selection in maize as revealed by ancient DNA.

PubMed

Jaenicke-Després, Viviane; Buckler, Ed S; Smith, Bruce D; Gilbert, M Thomas P; Cooper, Alan; Doebley, John; Pääbo, Svante

2003-11-14

Maize was domesticated from teosinte, a wild grass, by approximately 6300 years ago in Mexico. After initial domestication, early farmers continued to select for advantageous morphological and biochemical traits in this important crop. However, the timing and sequence of character selection are, thus far, known only for morphological features discernible in corn cobs. We have analyzed three genes involved in the control of plant architecture, storage protein synthesis, and starch production from archaeological maize samples from Mexico and the southwestern United States. The results reveal that the alleles typical of contemporary maize were present in Mexican maize by 4400 years ago. However, as recently as 2000 years ago, allelic selection at one of the genes may not yet have been complete.

Plant host range and leafhopper transmission of Maize fine streak virus

USDA-ARS?s Scientific Manuscript database

Maize fine streak virus (MFSV), an emerging rhabdovirus species in the genus Nucleorhabdovirus, is persistently transmitted by the black-faced leafhopper, Graminella nigrifrons (Forbes). MFSV was transmitted to maize, wheat, oats, rye, barley, foxtail, annual ryegrass and quackgrass by G. nigrifron...

Aflatoxin contamination of groundnut and maize in Zambia: observed and potential concentrations

USDA-ARS?s Scientific Manuscript database

Maize and groundnut, important staples in Zambia, are susceptible to aflatoxin-producing fungi. Aflatoxins are potent human carcinogens also associated with stunting and immunosuppression. Although health and economic burdens of aflatoxins are well known, patterns of contamination in maize and grou...

The art and design of genetic screens: maize

USDA-ARS?s Scientific Manuscript database

Maize (Zea mays) is an excellent model for basic research. Genetic screens have informed our understanding of developmental processes, meiosis, epigenetics and biochemical pathways--not only in maize but also in other cereal crops. We discuss the forward and reverse genetic screens that are possible...

Sequencing, assembly, and annotation of Maize B104 : A maize transformation resource

USDA-ARS?s Scientific Manuscript database

Maize transformation is complicated. Most lines are not readily cultured and transformed, making the germplasm available for genome engineering extremely limited. Developing a better understanding of the genomic regions responsible for differences in culturability and transformability would be a goo...

Interaction of F. verticillioides and Talaromyces sp. in maize seeds

USDA-ARS?s Scientific Manuscript database

We conducted studies in maize fields (Illinois, USA, 2013) to observe the interactions of Talaromyces species with fumonisin producing Fusarium verticillioides in corn seeds. Maize ears were inoculated during the milk phase using sterile wooden toothpicks dipped in conidium suspensions, or sterile d...

A Gene-Oriented Haplotype Comparison Reveals Recently Selected Genomic Regions in Temperate and Tropical Maize Germplasm

PubMed Central

Zhang, Jie; Li, Yongxiang; Zheng, Jun; Zhang, Hongwei; Yang, Xiaohong; Wang, Jianhua; Wang, Guoying

2017-01-01

The extensive genetic variation present in maize (Zea mays) germplasm makes it possible to detect signatures of positive artificial selection that occurred during temperate and tropical maize improvement. Here we report an analysis of 532,815 polymorphisms from a maize association panel consisting of 368 diverse temperate and tropical inbred lines. We developed a gene-oriented approach adapting exonic polymorphisms to identify recently selected alleles by comparing haplotypes across the maize genome. This analysis revealed evidence of selection for more than 1100 genomic regions during recent improvement, and included regulatory genes and key genes with visible mutant phenotypes. We find that selected candidate target genes in temperate maize are enriched in biosynthetic processes, and further examination of these candidates highlights two cases, sucrose flux and oil storage, in which multiple genes in a common pathway can be cooperatively selected. Finally, based on available parallel gene expression data, we hypothesize that some genes were selected for regulatory variations, resulting in altered gene expression. PMID:28099470

Fusarium species and fumonisins in subsistence maize in the former Transkei region, South Africa: a multi-year study in rural villages.

PubMed

Rheeder, J P; Van der Westhuizen, L; Imrie, G; Shephard, G S

2016-09-01

Fumonisin occurrence was investigated in subsistence maize in four rural villages in each of Mbizana and Centane areas, South Africa. Samples (total 211) were analysed morphologically for Fusarium species and by high performance liquid chromatography for fumonisins. The mean incidence levels of Fusarium verticillioides in Centane good maize were 16% for both 1997 and 2000, but increased to 32% in 2003, whereas Mbizana good maize contained levels of 17% and 11% (2000 and 2003 seasons, respectively). The mean total fumonisin level in good maize in Centane for 1997 and 2000 was 575 and 975 µg/kg and 2150 µg/kg in 2003. In Mbizana, the mean total fumonisin level in good maize for 2000 was 950 µg/kg, but decreased to 610 µg/kg in 2003. The 2003 drought conditions led to a substantial increase in fumonisin levels in dry subhumid Centane, compared to humid subtropical Mbizana. This study emphasises the seasonal fluctuation in fumonisin levels.

Comparison of the efficiency between two sampling plans for aflatoxins analysis in maize

PubMed Central

Mallmann, Adriano Olnei; Marchioro, Alexandro; Oliveira, Maurício Schneider; Rauber, Ricardo Hummes; Dilkin, Paulo; Mallmann, Carlos Augusto

2014-01-01

Variance and performance of two sampling plans for aflatoxins quantification in maize were evaluated. Eight lots of maize were sampled using two plans: manual, using sampling spear for kernels; and automatic, using a continuous flow to collect milled maize. Total variance and sampling, preparation, and analysis variance were determined and compared between plans through multifactor analysis of variance. Four theoretical distribution models were used to compare aflatoxins quantification distributions in eight maize lots. The acceptance and rejection probabilities for a lot under certain aflatoxin concentration were determined using variance and the information on the selected distribution model to build the operational characteristic curves (OC). Sampling and total variance were lower at the automatic plan. The OC curve from the automatic plan reduced both consumer and producer risks in comparison to the manual plan. The automatic plan is more efficient than the manual one because it expresses more accurately the real aflatoxin contamination in maize. PMID:24948911

Performance of draught cattle in communal farming areas in Zimbabwe after dry season supplementation.

PubMed

Ndlovu, L R; Francis, J; Hove, E

1996-11-01

Sixty-four pairs of oxen owned by smallholders were randomly allocated to one of 3 supplementary treatments offered at one kg per head per day from July to October or to a control where no supplement was offered. The supplements were maize stover plus silverleaf hay (2:1 w/w), urea-treated maize stover (50 g urea/kg stover) and plain maize stover. Animals fed plain maize stover or no supplement lost weight (6 to 7% of initial weight), whilst those fed the other 2 supplements maintained their liveweights. Supplementation reduced time spent on feeding activities by 10 per cent. Animals fed on urea-treated maize stover or maize stover plus silverleaf hay ploughed at speeds that were 29% faster than oxen on the other treatments and covered 45% more area. Blood parameters indicated a general deficiency of nitrogen intake throughout the dry season. It was concluded that supplements of good quality have the potential to improve the working ability of communal area oxen.

Application of superabsorbent polymers (SAP) as desiccants to dry maize and reduce aflatoxin contamination.

PubMed

Mbuge, Duncan O; Negrini, Renata; Nyakundi, Livine O; Kuate, Serge P; Bandyopadhyay, Ranajit; Muiru, William M; Torto, Baldwyn; Mezzenga, Raffaele

2016-08-01

The ability of superabsorbent polymers (SAP) in drying maize and controlling aflatoxin contamination was studied under different temperatures, drying times and SAP-to-maize ratios. Temperature and drying time showed significant influence on the aflatoxin formation. SAP-to-maize ratios between 1:1 and 1:5 showed little or no aflatoxin contamination after drying to the optimal moisture content (MC) of 13 %, while for ratios 1:10 and 1:20, aflatoxin contamination was not well controlled due to the overall higher MC and drying time, which made these ratios unsuitable for the drying process. Results clearly show that temperature, frequency of SAP change, drying time and SAP-to-maize ratio influenced the drying rate and aflatoxin contamination. Furthermore, it was shown that SAP had good potential for grain drying and can be used iteratively, which can make this system an optimal solution to reduce aflatoxin contamination in maize, particular for developing countries and resource-lacking areas.

Between myth and reality: genetically modified maize, an example of a sizeable scientific controversy.

PubMed

Wisniewski, Jean-Pierre; Frangne, Nathalie; Massonneau, Agnès; Dumas, Christian

2002-11-01

Maize is a major crop plant with essential agronomical interests and a model plant for genetic studies. With the development of plant genetic engineering technology, many transgenic strains of this monocotyledonous plant have been produced over the past decade. In particular, field-cultivated insect-resistant Bt-maize hybrids are at the centre of an intense debate between scientists and organizations recalcitrant to genetically modified organisms (GMOs). This debate, which addresses both safety and ethical aspects, has raised questions about the impact of genetically modified (GM) crops on the biodiversity of traditional landraces and on the environment. Here, we review some of the key points of maize genetic history as well as the methods used to stably transform this cereal. We describe the genetically engineered Bt-maizes available for field cultivation and we investigate the controversial reports on their impacts on non-target insects such as the monarch butterfly and on the flow of transgenes into Mexican maize landraces.

Effect of glucose and cellulase addition on wet-storage of excessively wilted maize stover and biogas production.

PubMed

Guo, Jianbin; Cui, Xian; Sun, Hui; Zhao, Qian; Wen, Xiaoyu; Pang, Changle; Dong, Renjie

2018-07-01

In north China, large amounts of excessively wilted maize stover are produced annually. Maize stover wet storage strategies and subsequent biogas production was examined in this study. Firstly, wet storage performances of harvested maize stover, air-dried for different time durations, were evaluated. Results showed that optimal storage performance was obtained when the initial water soluble carbohydrate (WSC) content after air-drying was higher than 8.0%. Therefore, cellulase and glucose were added to the excessively wilted maize stover to achieve the targeted pre-storage WSC levels. Good storage performances were observed in treatments with addition of 76.4 g/kg DM glucose and 12.5 g/kg DM of cellulase; the specific methane yield increased by 23.7% and 19.2%, respectively. However, use of glucose as additive or co-storing with high WSC substrates can serve as economically feasible options to adapt wet storage of excessively wilted maize stover. Copyright © 2018 Elsevier Ltd. All rights reserved.

Estimating plant distance in maize using Unmanned Aerial Vehicle (UAV).

PubMed

Zhang, Jinshui; Basso, Bruno; Price, Richard F; Putman, Gregory; Shuai, Guanyuan

2018-01-01

Distance between rows and plants are essential parameters that affect the final grain yield in row crops. This paper presents the results of research intended to develop a novel method to quantify the distance between maize plants at field scale using an Unmanned Aerial Vehicle (UAV). Using this method, we can recognize maize plants as objects and calculate the distance between plants. We initially developed our method by training an algorithm in an indoor facility with plastic corn plants. Then, the method was scaled up and tested in a farmer's field with maize plant spacing that exhibited natural variation. The results of this study demonstrate that it is possible to precisely quantify the distance between maize plants. We found that accuracy of the measurement of the distance between maize plants depended on the height above ground level at which UAV imagery was taken. This study provides an innovative approach to quantify plant-to-plant variability and, thereby final crop yield estimates.

DNA extraction techniques compared for accurate detection of genetically modified organisms (GMOs) in maize food and feed products.

PubMed

Turkec, Aydin; Kazan, Hande; Karacanli, Burçin; Lucas, Stuart J

2015-08-01

In this paper, DNA extraction methods have been evaluated to detect the presence of genetically modified organisms (GMOs) in maize food and feed products commercialised in Turkey. All the extraction methods tested performed well for the majority of maize foods and feed products analysed. However, the highest DNA content was achieved by the Wizard, Genespin or the CTAB method, all of which produced optimal DNA yield and purity for different maize food and feed products. The samples were then screened for the presence of GM elements, along with certified reference materials. Of the food and feed samples, 8 % tested positive for the presence of one GM element (NOS terminator), of which half (4 % of the total) also contained a second element (the Cauliflower Mosaic Virus 35S promoter). The results obtained herein clearly demonstrate the presence of GM maize in the Turkish market, and that the Foodproof GMO Screening Kit provides reliable screening of maize food and feed products.

Involvement of an antioxidant defense system in the adaptive response to cadmium in maize seedlings (Zea mays L.).

PubMed

Xu, Xianghua; Liu, Cuiying; Zhao, Xiaoyan; Li, Renying; Deng, Wenjing

2014-11-01

Chemical and biological analyses were used to investigate the growth response and antioxidant defense mechanism of maize seedlings (Zea mays L.) grown in soils with 0-100 mg kg(-1) Cd. Results showed that maize seedlings have strong abilities to accumulate and tolerate high concentrations of Cd. For soil with 50 mg kg(-1) Cd, the Cd contents in roots and shoots of maize seedlings are as large as 295.6 and 153.0 mg kg(-1) DW, respectively, without visible symptoms of toxicity. Lower soil Cd concentrations lead to a decrease in reduced glutathione (GSH) content in leaves of maize seedlings, whereas higher soil Cd concentrations resulted in an increase in the activities of superoxide dismutase, guaiacol peroxidase, catalase, and ascorbate peroxidase. Maize seedlings have strong capacities to adapt to low concentrations of Cd by consuming GSH and to develop an antioxidative enzyme system to defend against high-Cd stress.

Construction and functional analysis of Trichoderma harzianum mutants that modulate maize resistance to the pathogen Curvularia lunata.

PubMed

Fan, Lili; Fu, Kehe; Yu, Chuanjin; Ma, Jia; Li, Yaqian; Chen, Jie

2014-01-01

Agrobacterium tumefaciens-mediated transformation (ATMT) was used to generate an insertional mutant library of the mycelial fungus Trichoderma harzianum. From a total of 450 mutants, six mutants that showed significant influence on maize resistance to C. lunata were analyzed in detail. Maize coated with these mutants was more susceptible to C. lunata compared with those coated with a wild-type (WT) strain. Similar to other fungal ATMT libraries, all six mutants were single copy integrations, which occurred preferentially in noncoding regions (except two mutants) and were frequently accompanied by the loss of border sequences. Two mutants (T66 and T312) that were linked to resistance were characterized further. Maize seeds coated with T66 and T312 were more susceptible to C. lunata than those treated with WT. Moreover, the mutants affected the resistance of maize to C. lunata by enhancing jasmonate-responsive gene expression. T66 and T312 induced maize resistance to C. lunata infection through a jasmonic acid-dependent pathway.

Very high expander processing of maize on animal performance, digestibility and product quality of finishing pigs and broilers.

PubMed

Puntigam, R; Schedle, K; Schwarz, C; Wanzenböck, E; Eipper, J; Lechner, E-M; Yin, L; Gierus, M

2018-07-01

The present study investigated the effect of hydrothermic maize processing and supplementation of amino acids (AA) in two experiments. In total, 60 barrows and 384 broilers were fed four diets including either unprocessed (T1), or hydrothermically processed maize, that is short- (T2), or long-term conditioned (LC) (T3), and subsequently expanded maize of the same batch. Assuming a higher metabolizable energy (ME) content after processing, the fourth diet (T4) contains maize processed as treatment T3, but AA were supplemented to maintain the ideal protein value. Performance, digestibility and product quality in both species were assessed. Results show that in pigs receiving T4 the average daily feed intake was lower compared with the other treatments, whereas no difference was observed in broilers. The T3 improved the feed conversion rate compared with T1 (P<0.10) for both species. In contrast, average daily gain (ADG) (1277 g/day for T2 and 1267 g/day for T3 v. 971 g/day for T1) was only altered in pigs. The hydrothermic maize processing increased the apparent total tract digestibility (ATTD) of dry matter, starch and ether extract after acid hydrolysis. This may be a consequence of higher ATTD of gross energy in the finishing phase for both animal species, suggesting a higher ME content in diets with processed maize. The higher ME content of diets with processed maize is supported also by measurements of product quality. Supplementation of AA in T4 enhanced the loin depth in pigs as well as the amount of breast meat in broilers. Further effects of processing maize on meat quality were the reduced yellowness and antioxidative capacity (P<0.10) for broilers, likely due to the heat damage of xanthophylls and tocopherols. Processing also increased springiness and chewiness (P<0.10) of the broilers breast meat, whereas the loin meat of pigs showed a decreased lightness and yellowness (P<0.10) in meat when hydrothermic processed maize was used (for T2, T3 and T4). LC processed maize (T3) showed the lowest springiness in pork, however the supplementation of AA in T4 did not show differences between the treatments. Shown results demonstrated positive effects of hydrothermic processing of maize on animal performance and digestibility in both species. However, effects on carcass characteristics and product quality differed. The negative effects on product quality could be partly compensated with the AA supplementation, whereas a change in meat colour and reduced antioxidative capacity was observed in all groups fed hydrothermic maize processing.

Impact of Cry3Bb1-expressing Bt maize on adults of the western corn rootworm, Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae).

PubMed

Meissle, Michael; Hellmich, Richard L; Romeis, Jörg

2011-07-01

Genetically engineered maize producing insecticidal Cry3Bb1 protein from Bacillus thuringiensis (Bt) is protected from root damage by corn rootworm larvae. An examination was made to establish whether western corn rootworm (Diabrotica virgifera virgifera) adults are affected by Cry3Bb1-expressing maize (MON88017) when feeding on above-ground tissue. In laboratory bioassays, adult D. v. virgifera were fed for 7 weeks with silk, leaves or pollen from Bt maize or the corresponding near-isoline. Male, but not female, survival was reduced in the Bt-leaf treatment compared with the control. Female weight was lower when fed Bt maize, and egg production was reduced in the Bt-silk treatment. ELISA measurements demonstrated that beetles feeding on silk were exposed to higher Cry3Bb1 concentrations than beetles collected from Bt-maize fields in the United States. In contrast to silk and pollen, feeding on leaves resulted in high mortality and low fecundity. Females feeding on pollen produced more eggs than on silk. C:N ratios indicated that silk does not provide enough nitrogen for optimal egg production. Direct effects of Cry3Bb1 on adult beetles could explain the observed effects, but varietal differences between Bt and control maize are also possible. The impact of Bt maize on adult populations, however, is likely to be limited. Copyright © 2011 Society of Chemical Industry.

Assessment of Inheritance and Fitness Costs Associated with Field-Evolved Resistance to Cry3Bb1 Maize by Western Corn Rootworm.

PubMed

Paolino, Aubrey R; Gassmann, Aaron J

2017-05-11

The western corn rootworm, Diabrotica virgifera virgifera LeConte, is among the most serious insect pests of maize in North America. One strategy used to manage this pest is transgenic maize that produces one or more crystalline (Cry) toxins derived from the bacterium Bacillus thuringiensis (Bt). To delay Bt resistance by insect pests, refuges of non-Bt maize are grown in conjunction with Bt maize. Two factors influencing the success of the refuge strategy to delay resistance are the inheritance of resistance and fitness costs, with greater delays in resistance expected when inheritance of resistance is recessive and fitness costs are present. We measured inheritance and fitness costs of resistance for two strains of western corn rootworm with field-evolved resistance to Cry3Bb1 maize. Plant-based and diet-based bioassays revealed that the inheritance of resistance was non-recessive. In a greenhouse experiment, in which larvae were reared on whole maize plants in field soil, no fitness costs of resistance were detected. In a laboratory experiment, in which larvae experienced intraspecific and interspecific competition for food, a fitness cost of delayed larval development was identified, however, no other fitness costs were found. These findings of non-recessive inheritance of resistance and minimal fitness costs, highlight the potential for the rapid evolution of resistance to Cry3Bb1 maize by western corn rootworm, and may help to improve resistance management strategies for this pest.

High-precision chronology for Central American maize diversification from El Gigante rockshelter, Honduras.

PubMed

Kennett, Douglas J; Thakar, Heather B; VanDerwarker, Amber M; Webster, David L; Culleton, Brendan J; Harper, Thomas K; Kistler, Logan; Scheffler, Timothy E; Hirth, Kenneth

2017-08-22

The first steps toward maize ( Zea mays subspecies mays ) domestication occurred in the Balsas region of Mexico by ∼9,000 calendar years B.P. (cal B.P.), but it remains unclear when maize was productive enough to be a staple grain in the Americas. Molecular and microbotanical data provide a partial picture of the timing and nature of morphological change, with genetic data indicating that alleles for some domestication traits were not yet fixed by 5,300 cal B.P. in the highlands of Mexico. Here, we report 88 radiocarbon dates on the botanical remains from El Gigante rockshelter (Honduras) to establish a Bayesian chronology over the past ∼11,000 y spanning the transition to maize-based food production. Botanical remains are remarkably well preserved and include over 10,000 maize macrofossils. We directly dated 37 maize cobs to establish the appearance and local change of maize at the site. Cobs are common in deposits dating between 4,340 and 4,020 cal B.P., and again between 2,350 and 980 cal B.P. The earliest cobs appear robustly domesticated, having 10-14 rows, suggesting strong selection for increased yield. The later cobs are comparable to these earliest ones, but show clear emergence of diverse traits, including increased cob width, rachis segment length, and cupule width. Our results indicate that domesticated landraces of maize productive enough to be a staple grain existed in Central America by 4,300 cal B.P.

Directly dated starch residues document early formative maize (Zea mays L.) in tropical Ecuador

PubMed Central

Zarrillo, Sonia; Pearsall, Deborah M.; Raymond, J. Scott; Tisdale, Mary Ann; Quon, Dugane J.

2008-01-01

The study of maize (Zea mays L.) domestication has advanced from questions of its origins to the study—and debate—of its dietary role and the timing of its dispersal from Mexico. Because the investigation of maize's spread is hampered by poor preservation of macrobotanical remains in the Neotropics, research has focused on microbotanical remains whose contexts are often dated by association, leading some to question the dates assigned. Furthermore, some scholars have argued that maize was not introduced to southwestern Ecuador until ≈4150–3850 calendar years before the present (cal B.P.), that it was used first and foremost as a fermented beverage in ceremonial contexts, and that it was not important in everyday subsistence, challenging previous studies based on maize starch and phytoliths. To further investigate these questions, we analyzed every-day cooking vessels, food-processing implements, and sediments for starch and phytoliths from an archaeological site in southwestern Ecuador constituting a small Early Formative village. Employing a new technique to recover starch granules from charred cooking-pot residues we show that maize was present, cultivated, and consumed here in domestic contexts by at least 5300–4950 cal B.P. Directly dating the residues by accelerator mass spectrometry (AMS) radiocarbon measurement, our results represent the earliest direct dates for maize in Early Formative Ecuadorian sites and provide further support that, once domesticated ≈9000 calendar years ago, maize spread rapidly from southwestern Mexico to northwestern South America. PMID:18362336

New strategy for the determination of gliadins in maize- or rice-based foods matrix-assisted laser desorption/ionization time-of-flight mass spectrometry: fractionation of gliadins from maize or rice prolamins by acidic treatment.

PubMed

Hernando, Alberto; Valdes, Israel; Méndez, Enrique

2003-08-01

A procedure for determining small quantities of gliadins by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) in gluten-free foods containing relatively large amounts of prolamin proteins from maize or rice is described. We report for the first time that gliadins, the ethanol-soluble wheat prolamin fraction, can be quantitatively solubilized in 1.0 M acetic acid, while the corresponding ethanol-soluble maize or rice prolamin fraction remains insoluble in acetic acid. We describe a methodology for the detection of gliadins in maize and rice foods based on a two-step procedure of extraction (60% aqueous ethanol followed by 1 M acetic acid). Subsequent MALDI-TOFMS analysis of the resulting acidic extract from these gluten-free foods clearly confirms the presence of a typical mass pattern corresponding to gliadin components, ranging from 30 to 45 kDa. Depending on the percentages of maize or rice flours employed in the elaboration of these foods, the combined procedure enables levels of gliadins from 100 to 400 ppm to be detected. The efficiency of this combined procedure corroborates enzyme-linked immunosorbent assay data for a large number of maize/rice gluten-free foods by means of direct visualization of the characteristic gliadin mass pattern in maize or rice foods. Copyright 2003 John Wiley & Sons, Ltd.

Mapping of a major QTL for salt tolerance of mature field-grown maize plants based on SNP markers.

PubMed

Luo, Meijie; Zhao, Yanxin; Zhang, Ruyang; Xing, Jinfeng; Duan, Minxiao; Li, Jingna; Wang, Naishun; Wang, Wenguang; Zhang, Shasha; Chen, Zhihui; Zhang, Huasheng; Shi, Zi; Song, Wei; Zhao, Jiuran

2017-08-15

Salt stress significantly restricts plant growth and production. Maize is an important food and economic crop but is also a salt sensitive crop. Identification of the genetic architecture controlling salt tolerance facilitates breeders to select salt tolerant lines. However, the critical quantitative trait loci (QTLs) responsible for the salt tolerance of field-grown maize plants are still unknown. To map the main genetic factors contributing to salt tolerance in mature maize, a double haploid population (240 individuals) and 1317 single nucleotide polymorphism (SNP) markers were employed to produce a genetic linkage map covering 1462.05 cM. Plant height of mature maize cultivated in the saline field (SPH) and plant height-based salt tolerance index (ratio of plant height between saline and control fields, PHI) were used to evaluate salt tolerance of mature maize plants. A major QTL for SPH was detected on Chromosome 1 with the LOD score of 22.4, which explained 31.2% of the phenotypic variation. In addition, the major QTL conditioning PHI was also mapped at the same position on Chromosome 1, and two candidate genes involving in ion homeostasis were identified within the confidence interval of this QTL. The detection of the major QTL in adult maize plant establishes the basis for the map-based cloning of genes associated with salt tolerance and provides a potential target for marker assisted selection in developing maize varieties with salt tolerance.

Factors Controlling Pre-Columbian and Early Historic Maize Productivity in the American Southwest, Part 1: The Southern Colorado Plateau and Rio Grande Regions

USGS Publications Warehouse

Benson, L.V.

2011-01-01

Maize is the New World's preeminent grain crop and it provided the economic basis for human culture in many regions within the Americas. To flourish, maize needs water, sunlight (heat), and nutrients (e. g., nitrogen). In this paper, climate and soil chemistry data are used to evaluate the potential for dryland (rainon-field) agriculture in the semiarid southeastern Colorado Plateau and Rio Grande regions. Processes that impact maize agriculture such as nitrogen mineralization, infiltration of precipitation, bare soil evaporation, and transpiration are discussed and evaluated. Most of the study area, excepting high-elevation regions, receives sufficient solar radiation to grow maize. The salinities of subsurface soils in the central San Juan Basin are very high and their nitrogen concentrations are very low. In addition, soils of the central San Juan Basin are characterized by pH values that exceed 8.0, which limit the availability of both nitrogen and phosphorous. In general, the San Juan Basin, including Chaco Canyon, is the least promising part of the study area in terms of dryland farming. Calculations of field life, using values of organic nitrogen for the upper 50 cm of soil in the study area, indicate that most of the study area could not support a 10-bushel/acre crop of maize. The concepts, methods, and calculations used to quantify maize productivity in this study are applicable to maize cultivation in other environmental settings across the Americas. ?? 2010 US Government.

Genomic resources for gene discovery, functional genome annotation, and evolutionary studies of maize and its close relatives.

PubMed

Wang, Chao; Shi, Xue; Liu, Lin; Li, Haiyan; Ammiraju, Jetty S S; Kudrna, David A; Xiong, Wentao; Wang, Hao; Dai, Zhaozhao; Zheng, Yonglian; Lai, Jinsheng; Jin, Weiwei; Messing, Joachim; Bennetzen, Jeffrey L; Wing, Rod A; Luo, Meizhong

2013-11-01

Maize is one of the most important food crops and a key model for genetics and developmental biology. A genetically anchored and high-quality draft genome sequence of maize inbred B73 has been obtained to serve as a reference sequence. To facilitate evolutionary studies in maize and its close relatives, much like the Oryza Map Alignment Project (OMAP) (www.OMAP.org) bacterial artificial chromosome (BAC) resource did for the rice community, we constructed BAC libraries for maize inbred lines Zheng58, Chang7-2, and Mo17 and maize wild relatives Zea mays ssp. parviglumis and Tripsacum dactyloides. Furthermore, to extend functional genomic studies to maize and sorghum, we also constructed binary BAC (BIBAC) libraries for the maize inbred B73 and the sorghum landrace Nengsi-1. The BAC/BIBAC vectors facilitate transfer of large intact DNA inserts from BAC clones to the BIBAC vector and functional complementation of large DNA fragments. These seven Zea Map Alignment Project (ZMAP) BAC/BIBAC libraries have average insert sizes ranging from 92 to 148 kb, organellar DNA from 0.17 to 2.3%, empty vector rates between 0.35 and 5.56%, and genome equivalents of 4.7- to 8.4-fold. The usefulness of the Parviglumis and Tripsacum BAC libraries was demonstrated by mapping clones to the reference genome. Novel genes and alleles present in these ZMAP libraries can now be used for functional complementation studies and positional or homology-based cloning of genes for translational genomics.

Population Level Purifying Selection and Gene Expression Shape Subgenome Evolution in Maize.

PubMed

Pophaly, Saurabh D; Tellier, Aurélien

2015-12-01

The maize ancestor experienced a recent whole-genome duplication (WGD) followed by gene erosion which generated two subgenomes, the dominant subgenome (maize1) experiencing fewer deletions than maize2. We take advantage of available extensive polymorphism and gene expression data in maize to study purifying selection and gene expression divergence between WGD retained paralog pairs. We first report a strong correlation in nucleotide diversity between duplicate pairs, except for upstream regions. We then show that maize1 genes are under stronger purifying selection than maize2. WGD retained genes have higher gene dosage and biased Gene Ontologies consistent with previous studies. The relative gene expression of paralogs across tissues demonstrates that 98% of duplicate pairs have either subfunctionalized in a tissuewise manner or have diverged consistently in their expression thereby preventing functional complementation. Tissuewise subfunctionalization seems to be a hallmark of transcription factors, whereas consistent repression occurs for macromolecular complexes. We show that dominant gene expression is a strong determinant of the strength of purifying selection, explaining the inferred stronger negative selection on maize1 genes. We propose a novel expression-based classification of duplicates which is more robust to explain observed polymorphism patterns than the subgenome location. Finally, upstream regions of repressed genes exhibit an enrichment in transposable elements which indicates a possible mechanism for expression divergence. © The Author 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Absence of detectable transgenes in local landraces of maize in Oaxaca, Mexico (2003–2004)

PubMed Central

Ortiz-García, S.; Ezcurra, E.; Schoel, B.; Acevedo, F.; Soberón, J.; Snow, A. A.

2005-01-01

In 2000, transgenes were detected in local maize varieties (landraces) in the mountains of Oaxaca, Mexico [Quist, D. & Chapela, I. H. (2001) Nature 414, 541–543]. This region is part of the Mesoamerican center of origin for maize (Zea mays L.), and the genetic diversity that is maintained in open-pollinated landraces is recognized as an important genetic resource of great cultural value. The presence of transgenes in landraces was significant because transgenic maize has never been approved for cultivation in Mexico. Here we provide a systematic survey of the frequency of transgenes in currently grown landraces. We sampled maize seeds from 870 plants in 125 fields and 18 localities in the state of Oaxaca during 2003 and 2004. We then screened 153,746 sampled seeds for the presence of two transgene elements from the 35S promoter of the cauliflower mosaic virus and the nopaline synthase gene (nopaline synthase terminator) from Agrobacterium tumefaciens. One or both of these transgene elements are present in all transgenic commercial varieties of maize. No transgenic sequences were detected with highly sensitive PCR-based markers, appropriate positive and negative controls, and duplicate samples for DNA extraction. We conclude that transgenic maize seeds were absent or extremely rare in the sampled fields. This study provides a much-needed preliminary baseline for understanding the biological, socioeconomic, and ethical implications of the inadvertent dispersal of transgenes from the United States and elsewhere to local landraces of maize in Mexico. PMID:16093316

Absence of detectable transgenes in local landraces of maize in Oaxaca, Mexico (2003-2004).

PubMed

Ortiz-García, S; Ezcurra, E; Schoel, B; Acevedo, F; Soberón, J; Snow, A A

2005-08-30

In 2000, transgenes were detected in local maize varieties (landraces) in the mountains of Oaxaca, Mexico [Quist, D. & Chapela, I. H. (2001) Nature 414, 541-543]. This region is part of the Mesoamerican center of origin for maize (Zea mays L.), and the genetic diversity that is maintained in open-pollinated landraces is recognized as an important genetic resource of great cultural value. The presence of transgenes in landraces was significant because transgenic maize has never been approved for cultivation in Mexico. Here we provide a systematic survey of the frequency of transgenes in currently grown landraces. We sampled maize seeds from 870 plants in 125 fields and 18 localities in the state of Oaxaca during 2003 and 2004. We then screened 153,746 sampled seeds for the presence of two transgene elements from the 35S promoter of the cauliflower mosaic virus and the nopaline synthase gene (nopaline synthase terminator) from Agrobacterium tumefaciens. One or both of these transgene elements are present in all transgenic commercial varieties of maize. No transgenic sequences were detected with highly sensitive PCR-based markers, appropriate positive and negative controls, and duplicate samples for DNA extraction. We conclude that transgenic maize seeds were absent or extremely rare in the sampled fields. This study provides a much-needed preliminary baseline for understanding the biological, socioeconomic, and ethical implications of the inadvertent dispersal of transgenes from the United States and elsewhere to local landraces of maize in Mexico.

[Spatial-temporal variations of spring maize potential yields in a changing climate in Northeast China.

PubMed

Liu, Zhi Juan; Yang, Xiao Guang; Lyu, Shuo; Wang, Jing; Lin, Xiao Mao

2018-01-01

Based on meteorological data, agro-meteorological observations, and agricultural statistical data in Northeast China (NEC), by using the validated Agricultural Production System sIMulator (APSIM-maize), the potential, attainable, potential farmers' and actual farmers' yields of spring maize during the period 1961 to 2015 were analyzed, and the effects of climate variation on maize potential yield in NEC were quantified. Results indicated that the potential yield of spring maize was 12.2 t·hm -2 during the period 1961 to 2015, with those in northeast being lower than southwest within the study region. The attainable yield of spring maize was 11.3 t·hm -2 , and showed a similar spatial distribution with potential yield. Under the current farmers' management practices, mean simulated potential and actual farmers' yields were 6.5 and 4.5 t·hm -2 , respectively. Assuming there were no changes in cultivars and management practices in NEC, the mean potential, attainable, and potential farmers' yields of spring maize would decrease by 0.34, 0.25 and 0.10 t·hm -2 per decade in NEC. However, the actual farmers' yields increased with the value of 1.27 t·hm -2 per decade averaged over NEC. Due to climate variation, year-to-year variations of spring maize potential, attainable, and potential farmers' yields were significant, ranging from 10.0 to 14.4, 9.8 to 13.3, 4.4 to 8.5 t·hm -2 , respectively.

High-precision chronology for Central American maize diversification from El Gigante rockshelter, Honduras

PubMed Central

Kennett, Douglas J.; Thakar, Heather B.; VanDerwarker, Amber M.; Webster, David L.; Culleton, Brendan J.; Harper, Thomas K.; Kistler, Logan; Scheffler, Timothy E.; Hirth, Kenneth

2017-01-01

The first steps toward maize (Zea mays subspecies mays) domestication occurred in the Balsas region of Mexico by ∼9,000 calendar years B.P. (cal B.P.), but it remains unclear when maize was productive enough to be a staple grain in the Americas. Molecular and microbotanical data provide a partial picture of the timing and nature of morphological change, with genetic data indicating that alleles for some domestication traits were not yet fixed by 5,300 cal B.P. in the highlands of Mexico. Here, we report 88 radiocarbon dates on the botanical remains from El Gigante rockshelter (Honduras) to establish a Bayesian chronology over the past ∼11,000 y spanning the transition to maize-based food production. Botanical remains are remarkably well preserved and include over 10,000 maize macrofossils. We directly dated 37 maize cobs to establish the appearance and local change of maize at the site. Cobs are common in deposits dating between 4,340 and 4,020 cal B.P., and again between 2,350 and 980 cal B.P. The earliest cobs appear robustly domesticated, having 10–14 rows, suggesting strong selection for increased yield. The later cobs are comparable to these earliest ones, but show clear emergence of diverse traits, including increased cob width, rachis segment length, and cupule width. Our results indicate that domesticated landraces of maize productive enough to be a staple grain existed in Central America by 4,300 cal B.P. PMID:28784803

Unconventional P-35S sequence identified in genetically modified maize

PubMed Central

Al-Hmoud, Nisreen; Al-Husseini, Nawar; Ibrahim-Alobaide, Mohammed A; Kübler, Eric; Farfoura, Mahmoud; Alobydi, Hytham; Al-Rousan, Hiyam

2014-01-01

The Cauliflower Mosaic Virus 35S promoter sequence, CaMV P-35S, is one of several commonly used genetic targets to detect genetically modified maize and is found in most GMOs. In this research we report the finding of an alternative P-35S sequence and its incidence in GM maize marketed in Jordan. The primer pair normally used to amplify a 123 bp DNA fragment of the CaMV P-35S promoter in GMOs also amplified a previously undetected alternative sequence of CaMV P-35S in GM maize samples which we term V3. The amplified V3 sequence comprises 386 base pairs and was not found in the standard wild-type maize, MON810 and MON 863 GM maize. The identified GM maize samples carrying the V3 sequence were found free of CaMV when compared with CaMV infected brown mustard sample. The data of sequence alignment analysis of the V3 genetic element showed 90% similarity with the matching P-35S sequence of the cauliflower mosaic virus isolate CabbB-JI and 99% similarity with matching P-35S sequences found in several binary plant vectors, of which the binary vector locus JQ693018 is one example. The current study showed an increase of 44% in the incidence of the identified 386 bp sequence in GM maize sold in Jordan’s markets during the period 2009 and 2012. PMID:24495911

Fermentation Kinetic of Maize Straw-Gliricidia Feed Mixture Supplemented by Fermentable Carbohydrate Measured by In Vitro Gas Production

NASA Astrophysics Data System (ADS)

Yulistiani, D.; Nurhayati

2018-02-01

Utilization of crop by-products such as maize straw mixed with legume is expected to be able to overcome the limitation of forage availability during dry season and have similar nutritional value with grass. Addition of fermentable carbohydrate in this diet can be improved fermentability and reduced methane production. The objective of this study was to evaluate supplementation of ground corn grain or rice bran as fermentable carbohydrate in maize straw-gliricidiamixture. Treatment diets evaluated were: Maize straw + gliricidialeaf meal (Control/RO); Control + 10% ground maize grain (ROC); Control + 10% rice bran (RORB). Maize straw was chopped and ground then mixed with gliricidia leaf meal at ratio 60:40% DM. Maize straw-gliricidia mixture then supplemented either with ground corn grain or rice bran at 10% of DM basal diet (control). Sample was incubated for 48 hours, gas production was recorded at 4, 8,12, 16, 24, 36 and 48 hours. Study was conducted in randomized complete design. Results of the study showed that supplementation of fermentable carbohydrate from corn grain or rice bran was able to increased (P<0.05) rate of gas production by 24 and 18% respectively. However only in ROC potential gas production was increased (P<0.05) by 32% and percentage of methane production was decreased. From this study it can be concluded that supplementation of ground corn grain at 10% in maize straw-gliricidia mixture was able to improve diet fermentation and reduced methane production.

In situ nitrogen mineralization, nitrification, and ammonia volatilization in maize field fertilized with urea in Huanghuaihai region of northern China.

PubMed

Zhang, Xuelin; Wang, Qun; Xu, Jun; Gilliam, Frank S; Tremblay, Nicolas; Li, Chaohai

2015-01-01

Nitrogen (N) fertilization potentially affects soil N mineralization and leaching, and can enhance NH3 volatilization, thus impacting crop production. A fertilizer experiment with five levels of N addition (0, 79, 147, 215 and 375 kg N ha(-1)) was performed in 2009 and 2010 in a maize field in Huanghuaihai region, China, where > 300 kg N ha(-1) has been routinely applied to soil during maize growth period of 120 days. Responses of net N mineralization, inorganic N flux (0-10 cm), NH3 volatilization, and maize yield to N fertilization were measured. During the growth period, net N mineralization and nitrification varied seasonally, with higher rates occurring in August and coinciding with the R1 stage of maize growth. Soil NO3(-)-N contributed to more than 60% of inorganic N flux during maize growth. Cumulative NH3 volatilization increased with N additions, with total NH3 volatilization during maize growth accounting for about 4% of added N. Relative to the control, mean maize yield in the fertilizer treatments increased by 17% and 20% in 2009 and 2010, respectively. However, grain yield, aboveground biomass, and plant N accumulation did not increase with added N at levels > 215 kg N ha(-1). These results suggest that the current N rate of 300 kg N ha(-1) is not only excessive, but also reduces fertilizer efficacy and may contribute to environmental problems such as global warming and eutrophication of ground water and streams.

Genotype by environment interaction for plant density response in maize

USDA-ARS?s Scientific Manuscript database

Increased adaptation to high plant density has been an important factor in improvements in grain yield in maize. Despite extensive public literature on variation in plant density response among maize varieties, almost no public information is available on environmental effects on plant density respo...

Comparative histological and transcriptional analysis of maize kernels infected with Aspergillus flavus and Fusarium verticillioides

USDA-ARS?s Scientific Manuscript database

Aspergillus flavus and Fusarium verticillioides infect maize kernels and contaminate them with the mycotoxins aflatoxin and fumonisin, respectively. Combined histological examination of fungal colonization and transcriptional changes in maize kernels at 4, 12, 24, 48, and 72 hours post inoculation (...

Use of tropical maize for bioethanol production

USDA-ARS?s Scientific Manuscript database

Tropical maize is an alternative energy crop being considered as a feedstock for bioethanol production in the North Central and Midwest United States. Tropical maize is advantageous because it produces large amounts of soluble sugars in its stalks, creates a large amount of biomass, and requires lo...

Comparative population genomics of maize domestication and improvement

USDA-ARS?s Scientific Manuscript database

Domestication and modern breeding represent exemplary case studies of evolution in action. Maize is an outcrossing species with a complex genome, and an understanding of maize evolution is thus relevant for both plant and animal systems. This study is the largest plant resequencing effort to date, ...

Rapid defense responses in maize leaves induced by Spodoptera exigua caterpillar feeding

USDA-ARS?s Scientific Manuscript database

Insects such as beet armyworm caterpillars (Spodoptera exigua) cause extensive damage to maize (Zea mays) by consuming foliar tissue. Maize plants respond to insect attack by triggering defense mechanisms that involve massive changes in gene expression, biosynthesis of specialized metabolites and de...

Ear leaf photosynthesis and related parameters of transgenic and non-GMO maize hybrids

USDA-ARS?s Scientific Manuscript database

Hybrid maize (Zea mays L.) has undergone transformation by using transgenic technology to include d-endotoxins for insect control and tolerance for the herbicides glyphosate and glufosinate . Maize hybrids are being grown with multiple transgenic traits into their genotype (stacked-gene). Limited...

Evaluation of Atoxigenic Strains of Aspergillus flavus as Potential Biocontrol Agents for Aflatoxin in Maize

USDA-ARS?s Scientific Manuscript database

Aflatoxin contamination resulting from maize infection by Aspergillus flavus is both an economic concern and public health concern. Therefore, strategies for controlling maize contamination are being investigated. Abilities of 11 naturally occurring atoxigenic strains in Nigeria to reduce aflatox...

Effects of elevated [CO2] on maize defense against mycotoxigenic Fusarium verticillioides

USDA-ARS?s Scientific Manuscript database

Maize is by quantity the most important C4 cereal crop; however, future climate changes are expected to increase maize susceptibility to mycotoxigenic fungal pathogens and reduce productivity. While rising atmospheric [CO2] is a driving force behind the warmer temperatures and drought, which aggrava...

Complete sequence and diversity of a maize-associated Polerovirus in East Africa

USDA-ARS?s Scientific Manuscript database

Since 2011-2012, Maize lethal necrosis (MLN) has emerged in East Africa, causing massive yield loss and propelling research to identify viruses and virus populations present in maize. As expected, next generation sequencing (NGS) has revealed diverse and abundant viruses from the family Potyviridae,...

The Effect of Five Biomass Cropping Systems on Soil-Saturated Hydraulic Conductivity Across a Topographic Gradient

Treesearch

Usman Anwar; Lisa A. Schulte; Matthew Helmers; Randall K. Kolka

2017-01-01

Understanding the environmental impact of bioenergy crops is needed to inform bioenergy policy development. We determined the effects of five biomass cropping systems—continuous maize (Zea mays), soybean (Glycine max)-triticale (Triticosecale ×)/soybean-maize, maize-switchgrass (Panicum virgatum...

A meteorologically driven maize stress indicator model

NASA Technical Reports Server (NTRS)

Taylor, T. W.; Ravet, F. W. (Principal Investigator)

1981-01-01

A maize soil moisture and temperature stress model is described which was developed to serve as a meteorological data filter to alert commodity analysts to potential stress conditions in the major maize-producing areas of the world. The model also identifies optimum climatic conditions and planting/harvest problems associated with poor tractability.

Maize Haploid Induction and Doubling II – Experience with Exotic and Elite Maize Populations

USDA-ARS?s Scientific Manuscript database

As a follow-up to our previous study, second year information will be presented addressing questions on haploid induction and doubling, utilizing exotic and elite maize. These projects result from collaborations between Iowa State Doubled Haploid Facility (http://www.plantbreeding.iastate.edu/DHF/D...

Maize Haploid Induction and Doubling – Recent Experience with Exotic and Elite Maize Populations

USDA-ARS?s Scientific Manuscript database

Experience from three maize research projects utilizing the haploid inducer RWS x RWK-76 from the University of Hohenheim will be summarized. These projects result from collaborations between Iowa State Doubled Haploid Facility (http://www.plantbreeding.iastate.edu/DHF/DHF.htm) researchers and USDA...

Genetic, evoluntionary and plant breedinginsights from the domestication of maize

USDA-ARS?s Scientific Manuscript database

The natural history of maize began nine thousand years ago when Mexican farmers started to collect the seeds of the wild grass, teosinte. Invaluable as a food source, maize permeated Mexican culture and religion. Its domestication eventually led to its adoption as a model organism, aided in large pa...

Evaluation of maize inbred lines for resistance to pre-harvest aflatoxin and fumonisin contamination in the field

USDA-ARS?s Scientific Manuscript database

Two important mycotoxins, aflatoxin and fumonisin, are among the most potent naturally occurring carcinogens, contaminating maize (Zea mays L.) and affecting the crop yield and quality. Resistance of maize to pre-harvest mycotoxin contamination, specifically aflatoxin produced by Aspergillus flavus ...

Intraplant communication in maize contributes to defense against insects

USDA-ARS?s Scientific Manuscript database

The vasculature of plants act as a channel for transport of signal(s) that facilitate long-distance intraplant communication. In maize, Maize insect resistance1-Cysteine Protease (Mir1-CP), which has homology to papain-like proteases, provides defense to different feeding guilds of insect pests. Fur...

REDUCTION OF WATER CONSUMPTION AND POLLUTION IN THE CORN MASA PRODUCTION PROCESS

EPA Science Inventory

Maize (corn) is the principle food source in Mexico accounting for approximately 70 percent of the total calorie intake and 50 percent of the total protein intake (Paredes and Saharopulos, 1983). Maize is primarily used to produce masa, a maize based dough. In Mexico there ...

Genetic analysis of teosinte alleles for kernel composition traits in maize

USDA-ARS?s Scientific Manuscript database

Teosinte (Zea mays ssp. parviglumis) is the wild ancestor of modern maize (Zea mays ssp. mays). Teosinte contains greater genetic diversity compared to maize inbreds and landraces, but its use is limited by insufficient genetic resources to evaluate its value. A population of teosinte near isogenic ...

Brassinosteroid and Gibberellin control of seedling traits in maize (Zea mays L.)

USDA-ARS?s Scientific Manuscript database

Brassinosteroids (BRs) and gibberellins (GAs) are two major plant hormones regulating various plant developmental processes. In maize, BRs and GAs have been shown to regulate field traits such as plant height and sex determination. This study used 207 doubled haploid maize lines and measured respons...

Nitric oxide detoxification by Fusarium verticillioides flavohemoglobin and role in pathogenicity of maize

USDA-ARS?s Scientific Manuscript database

Fusarium verticillioides is a non-obligate plant pathogen of maize causing a number of specific diseases, including root rot, kernel rot, seed rot, stalk rot, and seedling blight. The saprophytic nature of this fungus, its production of the mycotoxin fumonisin, and complex relationship maize puts t...

Predicting maize phenology: Intercomparison of functions for developmental response to temperature

USDA-ARS?s Scientific Manuscript database

Accurate prediction of phenological development in maize is fundamental to determining crop adaptation and yield potential. A number of thermal functions are used in crop models, but their relative precision in predicting maize development has not been quantified. The objectives of this study were t...

Fumonisin biomarkers in maize eaters and implications for human disease

USDA-ARS?s Scientific Manuscript database

Maize is the predominant food source contaminated by fumonisins and this has particular health risks for communities consuming maize as a staple diet. The main biochemical effect of fumonisins is the inhibition of ceramide biosynthesis causing an increase in sphingoid bases and sphingoid base 1-pho...

Grain and nutritional quality traits of Southwestern U.S. blue maize landraces

USDA-ARS?s Scientific Manuscript database

Anthocyanin-rich pigmented maize has been a key component in socio-cultural life of Native American communities for many centuries. Our research characterizes the grain and nutritional quality traits of southwestern U.S. blue maize landraces. During 2013, six representative accessions and two improv...

Evaluation of the expression genes associated with resistance to Aspergillus flavus colonization and aflatoxin production in different maize lines.

USDA-ARS?s Scientific Manuscript database

Aflatoxins are carcinogenic toxic compounds produced by Aspergillus flavus during infection of crops including maize (Zea mays L.). Contamination of maize with aflatoxin is exacerbated by late season drought stress. Previous studies have implicated numerous resistance-associated proteins (RAPs) that...

Interpreting diplodiosis: bioactive metabolites in Stenocarpella maydis ear rot of maize

USDA-ARS?s Scientific Manuscript database

Stenocarpella maydis is a fungal pathogen of major importance that causes a dry-rot of maize ears and is associated with a neuromycotoxicosis in cattle grazing harvested maize fields in southern Africa and Argentina. Chemical investigations of S. maydis rotted kernels at harvest in Illinois led to t...

Diplodiatoxin, chaetoglobosins, and diplonine associated with a field outbreak of Stenocarpella ear rot in Illinois

USDA-ARS?s Scientific Manuscript database

Stenocarpella maydis causes a fungal dry-rot of maize ears and is associated with diplodiosis, a neuromycotoxicosis in cattle grazing harvested maize fields in southern Africa and Argentina. There have been no reports of Stenocarpella metabolites in maize crop residues. Chemical investigations of S....

Stewardship of the Maize B73 feference genome assembly

USDA-ARS?s Scientific Manuscript database

The release of version 4 of the B73 reference genome assembly is imminent. However, continued improvement of the assembly is likely to fall to the maize research community. Toward this end, and recognizing the importance of an accurate and well-curated reference genome, MaizeGDB, Gramene, and the Ge...

C3 versus C4 cavitation resistance and embolism repair under different levels of soil moisture availability

USDA-ARS?s Scientific Manuscript database

Comparison of maize and sunflower (Helianthus) under deficit irrigation indicates that maize has more conservative water use with lower maximum hydraulic conductance than Helianthus. We observe that maize under deficit irrigation dramatically reduces transpiration while Helianthus maintains high wat...

Maize development: Cell wall changes in leaves and sheaths

USDA-ARS?s Scientific Manuscript database

Developmental changes occur in maize (Zea mays L.) as it transitions from juvenile stages to the mature plant. Changes also occur as newly formed cells mature into adult cells. Maize leaf blades, including the midribs and sheaths, undergo cell wall changes as cells transition to fully mature cell ty...

Rapid cycling genomic selection in a multiparental tropical maize population

USDA-ARS?s Scientific Manuscript database

Genomic selection (GS) increases genetic gain by reducing the length of the selection cycle, as has been exemplified in maize using rapid cycling recombination of biparental populations. However, no results of GS applied to maize multi-parental populations have been reported so far. This study is th...

Genomic, transcriptomic and phenomic variation reveals the complex adaptation to stress response of modern maize breeding

USDA-ARS?s Scientific Manuscript database

Early maize adaptation to different agricultural environments was an important process associated with the creation of a stable food supply that allowed the evolution of human civilization in the Americas. To explore the mechanisms of maize adaptation, genomic, transcriptomic and phenomic data were ...

Molecular breeding for developing drought tolerant and disease resistant maize in sub Saharan Africa

USDA-ARS?s Scientific Manuscript database

The International Maize and Wheat Improvement Center (CIMMYT), in collaboration with public and private partners, is working on developing and disseminating drought tolerant maize for sub Saharan Africa (SSA) using pedigree selection and molecular breeding. In this paper, we provide an overview of ...

Toward Cost-Effective Fingerprinting Methodology to Distinguish Maize Open-Pollinated Varieties

USDA-ARS?s Scientific Manuscript database

In Africa, many smallholder farmers grow open pollinated maize varieties (OPVs), as they allow seed recycling and out-yield traditional farmer’s (unimproved) landraces. One popular OPV, ZM521 released by the International Maize and Wheat Improvement Center (CIMMYT), has been provided to farmers, o...

Determining density of maize canopy. 1: Digitized photography

NASA Technical Reports Server (NTRS)

Stoner, E. R.; Baumgardner, M. F.; Swain, P. H.

1972-01-01

The relationship between different densities of maize (Zea mays L.) canopies and the energy reflected by these canopies was studied. Field plots were laid out, representing four growth stages of maize, on a dark soil and on a very light colored surface soil. Spectral and spatial data were obtained from color and color infrared photography taken from a vertical distance of 10 m above the maize canopies. Estimates of ground cover were related to field measurements of leaf area index. Ground cover was predicted from leaf area index measurements by a second order equation. Color infrared photography proved helpful in determining the density of maize canopy on dark soils. Color photography was useful for determining canopy density on light colored soils. The near infrared dye layer is the most valuable in canopy density determinations.

A G protein alpha null mutation confers prolificacy potential in maize

DOE PAGES

Urano, Daisuke; Jackson, David; Jones, Alan M.

2015-05-06

Plasticity in plant development is controlled by environmental signals through largely unknown signalling networks. Signalling coupled by the heterotrimeric G protein complex underlies various developmental pathways in plants. The morphology of two plastic developmental pathways, root system architecture and female inflorescence formation, was quantitatively assessed in a mutant compact plant 2 (ct2) lacking the alpha subunit of the heterotrimeric G protein complex in maize. The ct2 mutant partially compensated for a reduced shoot height by increased total leaf number, and had far more ears, even in the presence of pollination signals. Lastly, the maize heterotrimeric G protein complex is importantmore » in some plastic developmental traits in maize. In particular, the maize Gα subunit is required to dampen the overproduction of female inflorescences.« less

Construction of the third-generation Zea mays haplotype map.

PubMed

Bukowski, Robert; Guo, Xiaosen; Lu, Yanli; Zou, Cheng; He, Bing; Rong, Zhengqin; Wang, Bo; Xu, Dawen; Yang, Bicheng; Xie, Chuanxiao; Fan, Longjiang; Gao, Shibin; Xu, Xun; Zhang, Gengyun; Li, Yingrui; Jiao, Yinping; Doebley, John F; Ross-Ibarra, Jeffrey; Lorant, Anne; Buffalo, Vince; Romay, M Cinta; Buckler, Edward S; Ware, Doreen; Lai, Jinsheng; Sun, Qi; Xu, Yunbi

2018-04-01

Characterization of genetic variations in maize has been challenging, mainly due to deterioration of collinearity between individual genomes in the species. An international consortium of maize research groups combined resources to develop the maize haplotype version 3 (HapMap 3), built from whole-genome sequencing data from 1218 maize lines, covering predomestication and domesticated Zea mays varieties across the world. A new computational pipeline was set up to process more than 12 trillion bp of sequencing data, and a set of population genetics filters was applied to identify more than 83 million variant sites. We identified polymorphisms in regions where collinearity is largely preserved in the maize species. However, the fact that the B73 genome used as the reference only represents a fraction of all haplotypes is still an important limiting factor.

A N2-fixing endophytic Burkholderia sp. associated with maize plants cultivated in Mexico.

PubMed

Estrada, Paulina; Mavingui, Patrick; Cournoyer, Benoit; Fontaine, Fanette; Balandreau, Jacques; Caballero-Mellado, Jesus

2002-04-01

In the frame of a survey of potentially endophytic N2-fixing Burkholderia associated with maize in Mexico, its country of origin, the soil of an indigenous maize field near Oaxaca was studied. Under laboratory conditions, plant seedlings of two ancient maize varieties were used as a trap to select endophyte candidates from the soil sample. Among the N2 fixers isolated from inside plant tissues and able to grow on PCAT medium, the most abundant isolates belonged to genus Burkholderia (API 20NE, rrs sequences). Representative isolates obtained from roots and shoots of different plants appeared identical (rrs and nifH RFLP), showing that they were closely related. In addition, their 16S rDNA sequences differed from described Burkholderia species and, phylogenetically, they constituted a separate deep-branching new lineage in genus Burkholderia. This indicated that these isolates probably constituted a new species. An inoculation experiment confirmed that these N2-fixing Burkholderia isolates could densely colonize the plant tissues of maize. More isolates of this group were subsequently obtained from field-grown maize and teosinte plants. It was hypothesized that strains of this species had developed a sort of primitive symbiosis with one of their host plants, teosinte, which persisted during the domestication of teosinte into maize.

A Secreted Effector Protein of Ustilago maydis Guides Maize Leaf Cells to Form Tumors

PubMed Central

Redkar, Amey; Hoser, Rafal; Schilling, Lena; Zechmann, Bernd; Krzymowska, Magdalena; Walbot, Virginia; Doehlemann, Gunther

2015-01-01

The biotrophic smut fungus Ustilago maydis infects all aerial organs of maize (Zea mays) and induces tumors in the plant tissues. U. maydis deploys many effector proteins to manipulate its host. Previously, deletion analysis demonstrated that several effectors have important functions in inducing tumor expansion specifically in maize leaves. Here, we present the functional characterization of the effector See1 (Seedling efficient effector1). See1 is required for the reactivation of plant DNA synthesis, which is crucial for tumor progression in leaf cells. By contrast, See1 does not affect tumor formation in immature tassel floral tissues, where maize cell proliferation occurs independent of fungal infection. See1 interacts with a maize homolog of SGT1 (Suppressor of G2 allele of skp1), a factor acting in cell cycle progression in yeast (Saccharomyces cerevisiae) and an important component of plant and human innate immunity. See1 interferes with the MAPK-triggered phosphorylation of maize SGT1 at a monocot-specific phosphorylation site. We propose that See1 interferes with SGT1 activity, resulting in both modulation of immune responses and reactivation of DNA synthesis in leaf cells. This identifies See1 as a fungal effector that directly and specifically contributes to the formation of leaf tumors in maize. PMID:25888589

Effects of amaranth addition on the pro-vitamin A content, and physical and antioxidant properties of extruded pro-vitamin A-biofortified maize snacks.

PubMed

Beswa, Daniso; Dlamini, Nomusa R; Amonsou, Eric O; Siwela, Muthulisi; Derera, John

2016-01-15

Pro-vitamin A-biofortified maize snacks with added leafy vegetable may have a potential as nutritious and health-promoting products, especially in addressing vitamin A deficiency, which is prevalent in developing regions. The objective of the study was to determine the effects of adding amaranth leaf powder on the physical, antioxidant properties and pro-vitamin A content of extruded pro-vitamin A-biofortified maize snacks. Extruded snacks were processed using four pro-vitamin A-biofortified maize varieties that were composited with amaranth leaf powder at 0%, 1% and 3% (w/w) substitution levels. At higher amaranth concentration, the expansion ratio of the snacks decreased, while their hardness increased by as much as 93%. The physical quality of the snacks may therefore need improvement. As amaranth was increased, the phenolic content and antioxidant activity of the snacks increased as well as the pro-vitamin A content. Pro-vitamin A-biofortified maize with added amaranth has a potential for use in nutritious and healthy extruded snacks. There are limited studies reporting on processing pro-vitamin A maize with complementary plant foods, which is common with white maize in southern Africa; thus the current study serves as a baseline. © 2015 Society of Chemical Industry.

Gene Coexpression Network Alignment and Conservation of Gene Modules between Two Grass Species: Maize and Rice[C][W][OA

PubMed Central

Ficklin, Stephen P.; Feltus, F. Alex

2011-01-01

One major objective for plant biology is the discovery of molecular subsystems underlying complex traits. The use of genetic and genomic resources combined in a systems genetics approach offers a means for approaching this goal. This study describes a maize (Zea mays) gene coexpression network built from publicly available expression arrays. The maize network consisted of 2,071 loci that were divided into 34 distinct modules that contained 1,928 enriched functional annotation terms and 35 cofunctional gene clusters. Of note, 391 maize genes of unknown function were found to be coexpressed within modules along with genes of known function. A global network alignment was made between this maize network and a previously described rice (Oryza sativa) coexpression network. The IsoRankN tool was used, which incorporates both gene homology and network topology for the alignment. A total of 1,173 aligned loci were detected between the two grass networks, which condensed into 154 conserved subgraphs that preserved 4,758 coexpression edges in rice and 6,105 coexpression edges in maize. This study provides an early view into maize coexpression space and provides an initial network-based framework for the translation of functional genomic and genetic information between these two vital agricultural species. PMID:21606319

Gene coexpression network alignment and conservation of gene modules between two grass species: maize and rice.

PubMed

Ficklin, Stephen P; Feltus, F Alex

2011-07-01

One major objective for plant biology is the discovery of molecular subsystems underlying complex traits. The use of genetic and genomic resources combined in a systems genetics approach offers a means for approaching this goal. This study describes a maize (Zea mays) gene coexpression network built from publicly available expression arrays. The maize network consisted of 2,071 loci that were divided into 34 distinct modules that contained 1,928 enriched functional annotation terms and 35 cofunctional gene clusters. Of note, 391 maize genes of unknown function were found to be coexpressed within modules along with genes of known function. A global network alignment was made between this maize network and a previously described rice (Oryza sativa) coexpression network. The IsoRankN tool was used, which incorporates both gene homology and network topology for the alignment. A total of 1,173 aligned loci were detected between the two grass networks, which condensed into 154 conserved subgraphs that preserved 4,758 coexpression edges in rice and 6,105 coexpression edges in maize. This study provides an early view into maize coexpression space and provides an initial network-based framework for the translation of functional genomic and genetic information between these two vital agricultural species.

Systemic virus-induced gene silencing allows functional characterization of maize genes during biotrophic interaction with Ustilago maydis.

PubMed

van der Linde, Karina; Kastner, Christine; Kumlehn, Jochen; Kahmann, Regine; Doehlemann, Gunther

2011-01-01

Infection of maize (Zea mays) plants with the corn smut fungus Ustilago maydis leads to the formation of large tumors on the stem, leaves and inflorescences. In this biotrophic interaction, plant defense responses are actively suppressed by the pathogen, and previous transcriptome analyses of infected maize plants showed massive and stage-specific changes in host gene expression during disease progression. To identify maize genes that are functionally involved in the interaction with U. maydis, we adapted a virus-induced gene silencing (VIGS) system based on the brome mosaic virus (BMV) for maize. Conditions were established that allowed successful U. maydis infection of BMV-preinfected maize plants. This set-up enabled quantification of VIGS and its impact on U. maydis infection using a quantitative real-time PCR (qRT-PCR)-based readout. In proof-of-principle experiments, an U. maydis-induced terpene synthase was shown to negatively regulate disease development while a protein involved in cell death inhibition was required for full virulence of U. maydis. The results suggest that this system is a versatile tool for the rapid identification of maize genes that determine compatibility with U. maydis. © (2010) Max Planck Society. Journal compilation © New Phytologist Trust (2010).

Emissions of volatile organic compounds from maize residue open burning in the northern region of Thailand

NASA Astrophysics Data System (ADS)

Sirithian, Duanpen; Thepanondh, Sarawut; Sattler, Melanie L.; Laowagul, Wanna

2018-03-01

Emission factors for speciated volatile organic compounds (VOCs) from maize residue burning were determined in this study based on chamber experiments. Thirty-six VOC species were identified by Gas Chromatography/Mass Spectrometer (GC/MS). They were classified into six groups, including alkanes, alkenes, oxygenated VOCs, halogenated VOCs, aromatics and other. The emission factor for total VOCs was estimated as about 148 mg kg-1 dry mass burned. About 68.4% of the compounds were aromatics. Field samplings of maize residues were conducted to acquire the information of fuel characteristics including fuel loading, fraction of maize residues that were actually burned as well as proximate and elemental analysis of maize residues. The emission factors were then applied to estimate speciated VOC emissions from maize residue open burning at the provincial level in the upper-northern region of Thailand for the year 2014. Total burned area of maize covered an area of about 500,000 ha which was about 4.7% of the total area of upper-northern region of the country. It was found that total VOC emissions released during the burning season (January-April) was about 79.4 tons. Ethylbenzene, m,p-xylene, 1,2,4-trimethylbenzene, acetaldehyde and o-xylene were the major contributors, accounting for more than 65% of total speciated VOC emissions.

Health risk assessment and growth characteristics of wheat and maize crops irrigated with contaminated wastewater.

PubMed

Farahat, Emad A; Galal, Tarek M; Elawa, Omar E; Hassan, Loutfy M

2017-10-02

The present study evaluated the effect of untreated wastewater irrigation and its health risks in Triticum aestivum (wheat) and Zea mays (maize) cultivated at south Cairo, Egypt. Morphological measurements (stem and root lengths, number of leaves per plant, and dry weights of main organs) as well as soil, irrigation water, and plant analyses for nutrients and heavy metals were conducted in polluted and unpolluted sites. Wastewater irrigations leads to reduction in the morphological traits of the plants and reduced its vegetative biomass and yield production, with more negative impacts on maize than wheat. The concentrations of Pb, Cd, Cr, and Fe in roots and leaves of wheat were above the phytotoxic limits. Conversely, Pb, Cd, and Fe were significantly high and at phytotoxic concentrations in the leaves of maize at polluted site. The present study indicated that wheat plants tend to phytostabilize heavy metals in their roots, while maize accumulates it more in their leaves. Maize and wheat had toxic concentrations of Pb and Cd in their grains under wastewater irrigation. The health risk index showed values > 1 for Pb and Cd in polluted site for both crops, in addition to maize in unpolluted site. Consequently, this will have greatest potential to pose health risk to the consumers.

Design and Development of Maize Dehusker cum Sheller: A Technology for Northern Transition Zone of Karnataka, India

NASA Astrophysics Data System (ADS)

Chilur, Rudragouda; Kumar, Sushilendra

2018-06-01

The Maize ( Zea mays L.) crop is one of the most important cereal in agricultural production systems of Northern Transition Zone (Hyderabad-Karnataka region) in India. These Hyderabad Karnataka farmers (small-medium) are lack of economic technologies with maize dehusking and shelling, which fulfils the two major needs as crops and as livestock in farming. The portable medium size (600 kg/h capacity) electric motor (2.23 kW) operated Maize Dehusker cum Sheller (MDS) was designed to resolve the issue by considering engineering properties of maize. The developed trapezium shaped MDS machine having overall dimensions (length × (top and bottom) × height) of 1200 × (500 and 610) × 810 mm. The selected operational parameters viz, cylinder peripheral speed (7.1 m/s), concave clearance (25 mm) and feed rate (600 kg/h) were studied for machine-performance and seed-quality parameters. The performance of machine under these parameters showed the dehusking efficiency of 99.56%, shelling efficiency of 98.01%, cleaning efficiency of 99.11%, total loss of 3.63% machine capacity of 527.11 kg/kW-h and germination percentage of 98.93%. Overall machine performance was found satisfactory for maize dehusking cum shelling operation as well as to produce the maize grains for seeding purpose.

A field study on heavy metals phytoattenuation potential of monocropping and intercropping of maize and/or legumes in weakly alkaline soils.

PubMed

Zhu, Saiyong; Ma, Xinwang; Guo, Rui; Ai, Shiwei; Liu, Bailin; Zhang, Wenya; Zhang, Yingmei

2016-10-02

The study focused on the phytoattenuation effects of monocropping and intercropping of maize (Zea mays) and/or legumes on Cu, Zn, Pb, and Cd in weakly alkaline soils. Nine growth stages of monocropping maize were chosen to study the dynamic process of extraction of heavy metals. The total content of heavy metals extracted by the aerial part of monocropped maize increased in a sigmoidal pattern over the effective accumulative temperature. The biggest biomass, highest extraction content, and lowest heavy metals bioaccumulation level occurred at physiological maturity. Among the different planting patterns, including monocropping and intercropping of maize and/or soybean (Glycine max), pea (Pisum sativum), and alfalfa (Medicago sativa), the extraction efficiency of Cu, Zn, Pb, and Cd varied greatly. Only intercropping of maize and soybean yielded relatively higher extraction efficiency for the four metals with no significant difference in the total biomass. Moreover, the heavy metals concentrations in dry biomass from all the planting patterns in the present study were within China's national legal thresholds for fodder use. Therefore, slightly polluted alkaline soils can be safely used through monocropping and intercropping of maize and/or legumes for a range of purposes. In particular, this study indicated that intercropping improves soil ecosystems polluted by heavy metals compared with monocropping.

Design and Development of Maize Dehusker cum Sheller: A Technology for Northern Transition Zone of Karnataka, India

NASA Astrophysics Data System (ADS)

Chilur, Rudragouda; Kumar, Sushilendra

2018-02-01

The Maize (Zea mays L.) crop is one of the most important cereal in agricultural production systems of Northern Transition Zone (Hyderabad-Karnataka region) in India. These Hyderabad Karnataka farmers (small-medium) are lack of economic technologies with maize dehusking and shelling, which fulfils the two major needs as crops and as livestock in farming. The portable medium size (600 kg/h capacity) electric motor (2.23 kW) operated Maize Dehusker cum Sheller (MDS) was designed to resolve the issue by considering engineering properties of maize. The developed trapezium shaped MDS machine having overall dimensions (length × (top and bottom) × height) of 1200 × (500 and 610) × 810 mm. The selected operational parameters viz, cylinder peripheral speed (7.1 m/s), concave clearance (25 mm) and feed rate (600 kg/h) were studied for machine-performance and seed-quality parameters. The performance of machine under these parameters showed the dehusking efficiency of 99.56%, shelling efficiency of 98.01%, cleaning efficiency of 99.11%, total loss of 3.63% machine capacity of 527.11 kg/kW-h and germination percentage of 98.93%. Overall machine performance was found satisfactory for maize dehusking cum shelling operation as well as to produce the maize grains for seeding purpose.

Mixing of maize and wheat genomic DNA by somatic hybridization in regenerated sterile maize plants.

PubMed

Szarka, B.; Göntér, I.; Molnár-Láng, M.; Mórocz, S.; Dudits, D.

2002-07-01

Intergeneric somatic hybridization was performed between albino maize ( Zea mays L.) protoplasts and mesophyll protoplasts of wheat ( Triticum aestivum L.) by polyethylene glycol (PEG) treatments. None of the parental protoplasts were able to produce green plants without fusion. The maize cells regenerated only rudimentary albino plantlets of limited viability, and the wheat mesophyll protoplasts were unable to divide. PEG-mediated fusion treatments resulted in hybrid cells with mixed cytoplasm. Six months after fusion green embryogenic calli were selected as putative hybrids. The first-regenerates were discovered as aborted embryos. Regeneration of intact, green, maize-like plants needed 6 months of further subcultures on hormone-free medium. These plants were sterile, although had both male and female flowers. The cytological analysis of cells from callus tissues and root tips revealed 56 chromosomes, but intact wheat chromosomes were not observed. Using total DNA from hybrid plants, three RAPD primer combinations produced bands resembling the wheat profile. Genomic in situ hybridization (GISH) using total wheat DNA as a probe revealed the presence of wheat DNA islands in the maize chromosomal background. The increased viability and the restored green color were the most-significant new traits as compared to the original maize parent. Other intermediate morphological traits of plants with hybrid origin were not found.

Analysis and expression of the alpha-expansin and beta-expansin gene families in maize

NASA Technical Reports Server (NTRS)

Wu, Y.; Meeley, R. B.; Cosgrove, D. J.

2001-01-01

Expansins comprise a multigene family of proteins in maize (Zea mays). We isolated and characterized 13 different maize expansin cDNAs, five of which are alpha-expansins and eight of which are beta-expansins. This paper presents an analysis of these 13 expansins, as well as an expression analysis by northern blotting with materials from young and mature maize plants. Some expansins were expressed in restricted regions, such as the beta-expansins ExpB1 (specifically expressed in maize pollen) and ExpB4 (expressed principally in young husks). Other expansins such as alpha-expansin Exp1 and beta-expansin ExpB2 were expressed in several organs. The expression of yet a third group was not detected in the selected organs and tissues. An analysis of expansin sequences from the maize expressed sequence tag collection is also presented. Our results indicate that expansin genes may have general, overlapping expression in some instances, whereas in other cases the expression may be highly specific and limited to a single organ or cell type. In contrast to the situation in Arabidopsis, beta-expansins in maize seem to be more numerous and more highly expressed than are alpha-expansins. The results support the concept that beta-expansins multiplied and evolved special functions in the grasses.

Determination of chlorimuron and metsulfuron residues in two soils of Argentina using a rapid seed-bioassay.

PubMed

Castro, M C; Bedmar, F; Monterubbianesi, M G; Peretti, A; Barassi, C A

2002-10-01

The presence of chlorimuron ethyl and metsulfuron methyl in two soils was determined by a modified petri dish bioassay. Pregerminated seeds of maize and sunflower were placed in petri dishes containing 85 to 100 g of treated soil. Radicle root lengths were measured after 24 h. Chlorimuron had no effect on maize on the Balcarce soil, however 0.007 microg g(-1) decreased sunflower root length. Chlorimuron decreased maize and sunflower root length regardless application dose on the San Cayetano soil. Metsulfuron decreased maize root length at 0.04 microg g(-1) and sunflower at 0.021 microg g(-1) on the Balcarce soil. On the San Cayetano soil metsulfuron at 0.001 microg g(-1) decreased maize and sunflower root length. The phytotoxicity of chlorimuron and metsulfuron changed according to soil type and dose. Maize and sunflower were 1.3-1.5 and 1.3-1.8 times respectively more sensitive to chlorimuron on the San Cayetano soil than on the Balcarce soil. In the case of metsulfuron, maize was similarly sensitive on both soils but sunflower was 1.7-2.0 times more sensitive on the San Cayetano soil than on the Balcarce soil. Phytotoxicity increased as organic matter (OM) content decreased and/or when the soil pH and concentration increased.

Evaluation of the transfer of soil arsenic to maize crops in suburban areas of San Luis Potosi, Mexico.

PubMed

Rosas-Castor, J M; Guzmán-Mar, J L; Alfaro-Barbosa, J M; Hernández-Ramírez, A; Pérez-Maldonado, I N; Caballero-Quintero, A; Hinojosa-Reyes, L

2014-11-01

The presence of arsenic (As) in agricultural food products is a matter of concern because it can cause adverse health effects at low concentrations. Agricultural-product intake constitutes a principal source for As exposure in humans. In this study, the contribution of the chemical-soil parameters in As accumulation and translocation in the maize crop from a mining area of San Luis Potosi was evaluated. The total arsenic concentration and arsenic speciation were determined by HG-AFS and IC-HG-AFS, respectively. The data analysis was conducted by cluster analysis (CA) and principal component analysis (PCA). The soil pH presented a negative correlation with the accumulated As in each maize plant part, and parameters such as iron (Fe) and manganese (Mn) presented a higher correlation with the As translocation in maize. Thus, the metabolic stress in maize may induce organic acid exudation leading a higher As bioavailability. A high As inorganic/organic ratio in edible maize plant tissues suggests a substantial risk of poisoning by this metalloid. Careful attention to the chemical changes in the rhizosphere of the agricultural zones that can affect As transfer through the food chain could reduce the As-intoxication risk of maize consumers. Copyright © 2014 Elsevier B.V. All rights reserved.

Candidate Loci for Yield-Related Traits in Maize Revealed by a Combination of MetaQTL Analysis and Regional Association Mapping

PubMed Central

Chen, Lin; An, Yixin; Li, Yong-xiang; Li, Chunhui; Shi, Yunsu; Song, Yanchun; Zhang, Dengfeng; Wang, Tianyu; Li, Yu

2017-01-01

Maize grain yield and related traits are complex and are controlled by a large number of genes of small effect or quantitative trait loci (QTL). Over the years, a large number of yield-related QTLs have been identified in maize and deposited in public databases. However, integrating and re-analyzing these data and mining candidate loci for yield-related traits has become a major issue in maize. In this study, we collected information on QTLs conferring maize yield-related traits from 33 published studies. Then, 999 of these QTLs were iteratively projected and subjected to meta-analysis to obtain metaQTLs (MQTLs). A total of 76 MQTLs were found across the maize genome. Based on a comparative genomics strategy, several maize orthologs of rice yield-related genes were identified in these MQTL regions. Furthermore, three potential candidate genes (Gene ID: GRMZM2G359974, GRMZM2G301884, and GRMZM2G083894) associated with kernel size and weight within three MQTL regions were identified using regional association mapping, based on the results of the meta-analysis. This strategy, combining MQTL analysis and regional association mapping, is helpful for functional marker development and rapid identification of candidate genes or loci. PMID:29312420

Randomly Detected Genetically Modified (GM) Maize (Zea mays L.) near a Transport Route Revealed a Fragile 45S rDNA Phenotype

PubMed Central

Waminal, Nomar Espinosa; Ryu, Ki Hyun; Choi, Sun-Hee; Kim, Hyun Hee

2013-01-01

Monitoring of genetically modified (GM) crops has been emphasized to prevent their potential effects on the environment and human health. Monitoring of the inadvertent dispersal of transgenic maize in several fields and transport routes in Korea was carried out by qualitative multiplex PCR, and molecular analyses were conducted to identify the events of the collected GM maize. Cytogenetic investigations through fluorescence in situ hybridization (FISH) of the GM maize were performed to check for possible changes in the 45S rDNA cluster because this cluster was reported to be sensitive to replication and transcription stress. Three GM maize kernels were collected from a transport route near Incheon port, Korea, and each was found to contain NK603, stacked MON863 x NK603, and stacked NK603 x MON810 inserts, respectively. Cytogenetic analysis of the GM maize containing the stacked NK603 x MON810 insert revealed two normal compact 5S rDNA signals, but the 45S rDNA showed a fragile phenotype, demonstrating a “beads-on-a-string” fragmentation pattern, which seems to be a consequence of genetic modification. Implications of the 45S rDNA cluster fragility in GM maize are also discussed. PMID:24040165

Development of a decision support system for crop disease monitoring, surveillance and prediction in Bomet county, Kenya

NASA Astrophysics Data System (ADS)

Otieno, O. M.

2015-12-01

The study proposes to use Geographic Information Systems and Remote Sensing techniques to spatially model Maize Lethal Necrosis (MLN) disease in maize growing areas in Kenya. Results from this work will be used for prediction, monitoring and to guide intervention on MLN. This will minimize maize yield losses resulting from MLN infestation and thus safeguard the livelihoods of maize farmers in Kenya. MLN was first reported in Kenya in September 2011 in Bomet county. It then subsequently spread to other parts in Kenya. Maize crops are susceptible to MLN at all growth stages. Once infected the only option left for the farmers is to burn their maize plantations. Infection rate and damage is very high affecting yields and sometimes causing complete loss of maize yield.The modelling exercise will cover the period prior to and after the incidence of MLN. Specifically, the analysis will integrate spatio-temporal information on maize phenology and field surveys with the intention of delineating the extent of MLN infestation and the degree of damage as a result of MLN. Additionally, the task will identify potential predisposing factors leading to MLN resurgence and spread and to predict potential areas where MLN is likely to spread and to estimate the potential impact of MLN on the farm holders. The area of study for this task will be Bomet County. Historical and current environmental and spatial indicators including temperature, rainfall, soil moisture, vegetation health and crop cover will be fed into a model in order to determine the main factors that aide the occurrence and the spread of MLN. Multi-spectral image processing will be used to produce indices to study maize crop health whilst image classification techniques will be used to identify crop cover clusters by differentiating the variations in spectral signatures in the area of study and hence distinguish infected, unaffected maize crops and other crop cover classes. Variables from these indicators will then be weighted in a spatial model and be used as a basis for generating site-specific MLN prediction maps that will guide policy on MLN management in Kenya. The broaderobjective is to document a model that can be up-scaled and replicated in other maize producing areas in Kenya affected by MLN.

Effects of variety and storage duration on the nutrient digestibility and the digestible and metabolisable energy content of maize fed to growing pigs.

PubMed

Zhang, Lei; Liu, Ling; Li, Defa; Li, Quanfeng; Piao, Xiangshu; Thacker, Philip A; Brown, Michael A; Lai, Changhua

2017-02-01

The objective of this research was to determine the effects of variety and storage duration on the nutrient digestibility and the digestible (DE) and metabolisable (ME) energy content in maize when fed to growing pigs. Four maize varieties (LS1, LS2, LS3 and LS4) were hand-harvested from the same growing area in China in early October of 2012. The samples were sun dried to about 14% moisture content and then stored in the warehouse of the Fengning Pig Experiment Base at China Agricultural University for 0, 3 or 10 months. Twenty-four barrows of about 33 kg body weight were used and allotted to a completely randomised block design with four diets and six replicate pigs per diet. Pigs were individually housed in metabolic crates. The four experimental diets were formulated by mixing 96.8% of each variety of maize with 3.2% vitamins and minerals. A 5-day collection period followed a 7-day diet acclimation period. The results indicated that the DE and ME contents of maize and the apparent total tract digestibility (ATTD) of organic matter (OM), dry matter, gross energy (GE), neutral detergent fibre, acid detergent fibre (ADF), crude protein (CP) and ether extract (EE) were significantly (p < 0.05) influenced by maize variety and storage duration. With an extension of storage duration from 0 to 10 months, the DE and ME of maize and the ATTD of OM, GE, ADF, CP and EE changed in a quadratic manner (p < 0.05), and 3 months of storage exceeded 0 months of storage by 1.84%, 1.43%, 0.31%, 0.32%, 15.37%, 2.11% and 5.02%, respectively. The DE, ME of maize and the ATTD of OM, GE, ADF, CP and EE decreased by 3.67%, 6.00%, 0.97%, 1.40%, 30.54%, 3.92% and 20.93%, respectively, at 10 months of storage compared to 3 months of storage. No interaction was observed between maize variety and storage duration in DE and ME contents in maize. In conclusion, under the conditions of this study, most of the nutrient digestibility and the DE and ME contents of maize increased from 0 to 3 months and decreased from 3 to 10 months.

Effect of Bt-176 maize pollen on first instar larvae of the Peacock butterfly (Inachis io) (Lepidoptera; Nymphalidae).

PubMed

Felke, Martin; Langenbruch, Gustav-Adolf; Feiertag, Simon; Kassa, Adane

2010-01-01

More than 10 years after registration of the first Bt maize cultivar in Europe, there still exists a remarkable lack of data on effects on Lepidoptera which would be necessary for a complete and comprehensive environmental risk assessment. So far only very few European butterfly species have been tested in this aspect. In our study the effect of transgenic Bacillus thuringiensis (Bt) maize pollen (event Bt-176) on the development and survival of neonate larvae of the Peacock butterfly, Inachis io (L.) was for the first time shown. The results of our study suggest that the Peacock butterfly may serve as a model organism for assessing potential side effects of new developed transgenic Bt crops on non-target butterflies in a GMO environmental risk assessment. The study was done under laboratory conditions by exposing larvae of the Peacock butterfly to various pollen doses of transgenic maize event Bt-176 (cv. PACTOL CB) or the conventional isogenic maize (cv. PACTOL) using a no-choice test. Larvae feeding for 48 h on nettle plants (Urtica dioica) that were contaminated with higher pollen concentrations from Bt-176 maize (205 and 388 applied pollen.cm⁻²) suffered a significantly higher mortality rate (68 and 85% respectively) compared to larvae feeding on leaves with no pollen (11%), or feeding on leaves with pollen from conventional maize (6 to 25%). At lower Bt maize pollen doses (23-104 applied pollen.cm⁻²),mortality ranged from 11-25% and there were no apparent differences among treatments. The corresponding LC₅₀-and LC₉₀-values for neonate larvae of the Peacock butterfly were 187 and 448 applied pollen grains.cm⁻² of Bt-176, respectively.Weight of larvae surviving consumption of Bt-176 maize pollen declined between 10 and 81% with increased pollen doses (r = -0.95). The highest weight reduction (81%) corresponded to the highest pollen concentration (388 pollen grains applied.cm⁻²). Ingestion of pollen from the conventional maize hybrid did not have negative effects on larval weight gain or survival rate.

Fusarium diseases of maize associated with mycotoxin contamination of agricultural products intended to be used for food and feed.

PubMed

Oldenburg, Elisabeth; Höppner, Frank; Ellner, Frank; Weinert, Joachim

2017-08-01

Infections of maize with phytopathogenic and toxinogenic Fusarium spp. may occur throughout the cultivation period. This can cause different types of diseases in vegetative and generative organs of the plant. Along with these infections, mycotoxins are often produced and accumulated in affected tissues, which could pose a significant risk on human and animal health when entering the food and feed chain. Most important fungal species infecting European maize belong to the Fusarium sections Discolour and Liseola, the first being more prevalent in cooler and humid climate regions than the second predominating in warmer and dryer areas. Coexistence of several Fusarium spp. pathogens in growing maize under field conditions is the usual case and may lead to multi-contamination with mycotoxins like trichothecenes, zearalenone and fumonisins. The pathways how the fungi gain access to the target organs of the plant are extensively described in relation to specific symptoms of typical rot diseases regarding ears, kernels, rudimentary ears, roots, stem, leaves, seed and seedlings. Both Gibberella and Fusarium ear rots are of major importance in affecting the toxinogenic quality of grain or ear-based products as well as forage maize used for human or animal nutrition. Although rudimentary ears may contain high amounts of Fusarium toxins, the contribution to the contamination of forage maize is minor due to their small proportion on the whole plant dry matter yield. The impact of foliar diseases on forage maize contamination is regarded to be low, as Fusarium infections are restricted to some parts on the leaf sheaths and husks. Mycotoxins produced in rotted basal part of the stem may contribute to forage maize contamination, but usually remain in the stubbles after harvest. As the probability of a more severe disease progression is increasing with a prolonged cultivation period, maize should be harvested at the appropriate maturity stage to keep Fusarium toxin contamination as low as possible. Ongoing surveillance and research is needed to recognise changes in the spectrum of dominating Fusarium pathogens involved in mycotoxin contamination of maize to ensure safety in the food and feed chain.

Analysis of agro-climatic parameters and their influence on maize production in South Africa

NASA Astrophysics Data System (ADS)

Adisa, Omolola M.; Botai, Christina M.; Botai, Joel O.; Hassen, Abubeker; Darkey, Daniel; Tesfamariam, Eyob; Adisa, Alex F.; Adeola, Abiodun M.; Ncongwane, Katlego P.

2017-11-01

This study analyzed the variability of the agro-climatic parameters that impact maize production across different seasons in South Africa. To achieve this, four agro-climatic variables (precipitation, potential evapotranspiration, minimum, and maximum temperatures) were considered for the period spanning 1986-2015, covering the North West, Free State, Mpumalanga, and KwaZulu-Natal (KZN) provinces. Results illustrate that there is a negative trend in precipitation for North West and Free State provinces and positive trend in maximum temperature for all the provinces over the study period. Furthermore, the results showed that among other agro-climatic parameters, minimum temperature had the most influence on maize production in North West, potential evapotranspiration (combination of the agro-climatic parameters), minimum and maximum temperature influenced maize production in KZN while maximum temperature influenced maize production in Mpumalanga and Free State. In general, the agro-climatic parameters were found to contribute 7.79, 21.85, 32.52, and 44.39% to variation in maize production during the study period in North West, Free State, Mpumalanga, and KZN, respectively. The variation in maize production among the provinces under investigation could most likely attribute to the variation in the size of the cultivated land among other factors including soil type and land tenure system. There were also difference in yield per hectare between the provinces; KZN and Mpumalanga being located in the humid subtropical areas of South Africa had the highest yield per hectare 5.61 and 4.99 tons, respectively, while Free State and North West which are in the semi-arid region had the lowest yield per hectare 3.86 and 3.03 tons, respectively. Understanding the nature and interaction of the dominant agro-climatic parameters discussed in the present study as well as their impact on maize production will help farmers and agricultural policy makers to understand how climate change exerts its influence on maize production within the study area so as to better adapt to the major climate element that either increases or decreases maize production in their respective provinces.

Physiological basis for isoxadifen-ethyl induction of nicosulfuron detoxification in maize hybrids.

PubMed

Sun, Lanlan; Wu, Renhai; Su, Wangcang; Gao, Zenggui; Lu, Chuantao

2017-01-01

Isoxadifen-ethyl can effectively alleviate nicosulfuron injury in the maize. However, the effects of safener isoxadifen-ethyl on detoxifying enzymes in maize is unknown. The individual and combined effects of the sulfonylurea herbicide nicosulfuron and the safener isoxadifen-ethyl on the growth and selected physiological processes of maize were evaluated. Bioassays showed that the EC50 values of nicosulfuron and nicosulfuron plus isoxadifen-ethyl for maize cultivar Zhengdan958 were 18.87 and 249.28 mg kg-1, respectively, and were 24.8 and 275.51 mg kg-1, respectively, for Zhenghuangnuo No. 2 cultivar. Evaluations of the target enzyme of acetolactate synthase showed that the I50 values of nicosulfuron and nicosulfuron plus isoxadifen-ethyl for the ALS of Zhengdan958 were 15.46 and 28.56 μmol L-1, respectively, and were 0.57 and 2.17 μmol L-1, respectively, for the acetolactate synthase of Zhenghuangnuo No. 2. The safener isoxadifen-ethyl significantly enhanced tolerance of maize to nicosulfuron. The enhanced tolerance of maize to nicosulfuron in the presence of the safener, coupled with the enhanced injury observed in the presence of piperonyl butoxide, 1-aminobenzotriazole, and malathion, suggested cytochrome P450 monooxygenases may be involved in metabolism of nicosulfuron. We proposed that isoxadifen-ethyl increases plant metabolism of nicosulfuron through non-P450-catalyzed routes or through P450 monooxygenases not inhibited by piperonyl butoxide, 1-aminobenzotriazole, and malathion. Isoxadifen-ethyl, at a rate of 33 mg kg-1, completely reversed the effects of all doses (37.5-300 mg kg-1) of nicosulfuron on both of the maize cultivars. When the two compounds were given simultaneously, isoxadifen-ethyl enhanced activity of glutathione S-transferases (GSTs) and acetolactate synthase activity in maize. The free acid 4,5-dihydro-5,5-diphenyl-1,2-oxazole-3-carboxylic was equally effective at inducing GSTs as the parent ester and appeared to be the active safener. GST induction in the maize Zhenghuangnuo No. 2 was faster than in Zhengdan 958.

Physiological basis for isoxadifen-ethyl induction of nicosulfuron detoxification in maize hybrids

PubMed Central

Sun, Lanlan; Wu, Renhai; Su, Wangcang; Gao, Zenggui; Lu, Chuantao

2017-01-01

Isoxadifen-ethyl can effectively alleviate nicosulfuron injury in the maize. However, the effects of safener isoxadifen-ethyl on detoxifying enzymes in maize is unknown. The individual and combined effects of the sulfonylurea herbicide nicosulfuron and the safener isoxadifen-ethyl on the growth and selected physiological processes of maize were evaluated. Bioassays showed that the EC50 values of nicosulfuron and nicosulfuron plus isoxadifen-ethyl for maize cultivar Zhengdan958 were 18.87 and 249.28 mg kg-1, respectively, and were 24.8 and 275.51 mg kg-1, respectively, for Zhenghuangnuo No. 2 cultivar. Evaluations of the target enzyme of acetolactate synthase showed that the I50 values of nicosulfuron and nicosulfuron plus isoxadifen-ethyl for the ALS of Zhengdan958 were 15.46 and 28.56 μmol L-1, respectively, and were 0.57 and 2.17 μmol L-1, respectively, for the acetolactate synthase of Zhenghuangnuo No. 2. The safener isoxadifen-ethyl significantly enhanced tolerance of maize to nicosulfuron. The enhanced tolerance of maize to nicosulfuron in the presence of the safener, coupled with the enhanced injury observed in the presence of piperonyl butoxide, 1-aminobenzotriazole, and malathion, suggested cytochrome P450 monooxygenases may be involved in metabolism of nicosulfuron. We proposed that isoxadifen-ethyl increases plant metabolism of nicosulfuron through non-P450-catalyzed routes or through P450 monooxygenases not inhibited by piperonyl butoxide, 1-aminobenzotriazole, and malathion. Isoxadifen-ethyl, at a rate of 33 mg kg-1, completely reversed the effects of all doses (37.5–300 mg kg-1) of nicosulfuron on both of the maize cultivars. When the two compounds were given simultaneously, isoxadifen-ethyl enhanced activity of glutathione S-transferases (GSTs) and acetolactate synthase activity in maize. The free acid 4,5-dihydro-5,5-diphenyl-1,2-oxazole-3-carboxylic was equally effective at inducing GSTs as the parent ester and appeared to be the active safener. GST induction in the maize Zhenghuangnuo No. 2 was faster than in Zhengdan 958. PMID:28267798

Assessing spatiotemporal variation of drought and its impact on maize yield in Northeast China

NASA Astrophysics Data System (ADS)

Guo, Enliang; Liu, Xingpeng; Zhang, Jiquan; Wang, Yongfang; Wang, Cailin; Wang, Rui; Li, Danjun

2017-10-01

In the context of global climate change, drought has become an important factor that affects the maize yield in China. To analyse the impact of drought on maize yield loss in Northeast China in current and future climate scenarios, the Composite Meteorological Drought Index (CI) is introduced to reconstruct the following drought indicators: drought accumulative days (DAD), drought accumulative intensity (DAI), and consecutive drought days (CDD). These three drought indicators are used to describe the three-dimensional characteristics of drought in this study. Sen's slope method and three-dimensional copula functions are adopted to analyse the variety of drought features, and Ensemble Empirical Mode Decomposition (EEMD) is used to analyse the variations in maize yield. A temporal assessment of the standardized yield residuals series (SYRS) of maize from 1961 to 2014 is conducted. A panel regression model is applied to demonstrate the drought impact on maize yield at various growth stages under the RCP4.5 scenario. The results show that the drought risk level for midwest Jilin Province, western Liaoning, and eastern Heilongjiang increase with global warming in the current scenario. The shorter three-dimensional joint return periods, 44-80 yr, were mainly located in western Jilin Province, Liaodong Peninsula, and northwestern Liaoning. Eastern Heilongjiang has a slightly longer joint return period of 80-100 yr. The SYRS shows a strong statistical correlation with drought indicator variations; drought-prone regions exhibit strong positive correlations. In comparison, excess precipitation regions show strong negative correlations with drought indicators in most growth stages. Drought indicators have a relatively strong association with SYRS at the milky-mature maize growth stage, and the occurrence of drought during this period primarily determines the maize yield changes in the future. Maize yield changes are -2.04%, -2.65% and -1.57% for Liaoning, Jilin, and Heilongjiang Province under the RCP4.5 scenario. These results can be used as a tool for early warning of drought risk to maize, and will accelerate the progress of drought disaster risk management.

A powerful tool for genome analysis in maize: development and evaluation of the high density 600 k SNP genotyping array.

PubMed

Unterseer, Sandra; Bauer, Eva; Haberer, Georg; Seidel, Michael; Knaak, Carsten; Ouzunova, Milena; Meitinger, Thomas; Strom, Tim M; Fries, Ruedi; Pausch, Hubert; Bertani, Christofer; Davassi, Alessandro; Mayer, Klaus Fx; Schön, Chris-Carolin

2014-09-29

High density genotyping data are indispensable for genomic analyses of complex traits in animal and crop species. Maize is one of the most important crop plants worldwide, however a high density SNP genotyping array for analysis of its large and highly dynamic genome was not available so far. We developed a high density maize SNP array composed of 616,201 variants (SNPs and small indels). Initially, 57 M variants were discovered by sequencing 30 representative temperate maize lines and then stringently filtered for sequence quality scores and predicted conversion performance on the array resulting in the selection of 1.2 M polymorphic variants assayed on two screening arrays. To identify high-confidence variants, 285 DNA samples from a broad genetic diversity panel of worldwide maize lines including the samples used for sequencing, important founder lines for European maize breeding, hybrids, and proprietary samples with European, US, semi-tropical, and tropical origin were used for experimental validation. We selected 616 k variants according to their performance during validation, support of genotype calls through sequencing data, and physical distribution for further analysis and for the design of the commercially available Affymetrix® Axiom® Maize Genotyping Array. This array is composed of 609,442 SNPs and 6,759 indels. Among these are 116,224 variants in coding regions and 45,655 SNPs of the Illumina® MaizeSNP50 BeadChip for study comparison. In a subset of 45,974 variants, apart from the target SNP additional off-target variants are detected, which show only a minor bias towards intermediate allele frequencies. We performed principal coordinate and admixture analyses to determine the ability of the array to detect and resolve population structure and investigated the extent of LD within a worldwide validation panel. The high density Affymetrix® Axiom® Maize Genotyping Array is optimized for European and American temperate maize and was developed based on a diverse sample panel by applying stringent quality filter criteria to ensure its suitability for a broad range of applications. With 600 k variants it is the largest currently publically available genotyping array in crop species.

The genetic architecture of maize height.

PubMed

Peiffer, Jason A; Romay, Maria C; Gore, Michael A; Flint-Garcia, Sherry A; Zhang, Zhiwu; Millard, Mark J; Gardner, Candice A C; McMullen, Michael D; Holland, James B; Bradbury, Peter J; Buckler, Edward S

2014-04-01

Height is one of the most heritable and easily measured traits in maize (Zea mays L.). Given a pedigree or estimates of the genomic identity-by-state among related plants, height is also accurately predictable. But, mapping alleles explaining natural variation in maize height remains a formidable challenge. To address this challenge, we measured the plant height, ear height, flowering time, and node counts of plants grown in >64,500 plots across 13 environments. These plots contained >7300 inbreds representing most publically available maize inbreds in the United States and families of the maize Nested Association Mapping (NAM) panel. Joint-linkage mapping of quantitative trait loci (QTL), fine mapping in near isogenic lines (NILs), genome-wide association studies (GWAS), and genomic best linear unbiased prediction (GBLUP) were performed. The heritability of maize height was estimated to be >90%. Mapping NAM family-nested QTL revealed the largest explained 2.1 ± 0.9% of height variation. The effects of two tropical alleles at this QTL were independently validated by fine mapping in NIL families. Several significant associations found by GWAS colocalized with established height loci, including brassinosteroid-deficient dwarf1, dwarf plant1, and semi-dwarf2. GBLUP explained >80% of height variation in the panels and outperformed bootstrap aggregation of family-nested QTL models in evaluations of prediction accuracy. These results revealed maize height was under strong genetic control and had a highly polygenic genetic architecture. They also showed that multiple models of genetic architecture differing in polygenicity and effect sizes can plausibly explain a population's variation in maize height, but they may vary in predictive efficacy.

Complex structure of knob DNA on maize chromosome 9. Retrotransposon invasion into heterochromatin.

PubMed Central

Ananiev, E V; Phillips, R L; Rines, H W

1998-01-01

The recovery of maize (Zea mays L.) chromosome addition lines of oat (Avena sativa L.) from oat x maize crosses enables us to analyze the structure and composition of specific regions, such as knobs, of individual maize chromosomes. A DNA hybridization blot panel of eight individual maize chromosome addition lines revealed that 180-bp repeats found in knobs are present in each of these maize chromosomes, but the copy number varies from approximately 100 to 25, 000. Cosmid clones with knob DNA segments were isolated from a genomic library of an oat-maize chromosome 9 addition line with the help of the 180-bp knob-associated repeated DNA sequence used as a probe. Cloned knob DNA segments revealed a complex organization in which blocks of tandemly arranged 180-bp repeating units are interrupted by insertions of other repeated DNA sequences, mostly represented by individual full size copies of retrotransposable elements. There is an obvious preference for the integration of retrotransposable elements into certain sites (hot spots) of the 180-bp repeat. Sequence microheterogeneity including point mutations and duplications was found in copies of 180-bp repeats. The 180-bp repeats within an array all had the same polarity. Restriction maps constructed for 23 cloned knob DNA fragments revealed the positions of polymorphic sites and sites of integration of insertion elements. Discovery of the interspersion of retrotransposable elements among blocks of tandem repeats in maize and some other organisms suggests that this pattern may be basic to heterochromatin organization for eukaryotes. PMID:9691055

Ethylene Contributes to maize insect resistance1-Mediated Maize Defense against the Phloem Sap-Sucking Corn Leaf Aphid1[OPEN

PubMed Central

Louis, Joe; Basu, Saumik; Varsani, Suresh; Castano-Duque, Lina; Jiang, Victoria; Williams, W. Paul; Felton, Gary W.; Luthe, Dawn S.

2015-01-01

Signaling networks among multiple phytohormones fine-tune plant defense responses to insect herbivore attack. Previously, it was reported that the synergistic combination of ethylene (ET) and jasmonic acid (JA) was required for accumulation of the maize insect resistance1 (mir1) gene product, a cysteine (Cys) proteinase that is a key defensive protein against chewing insect pests in maize (Zea mays). However, this study suggests that mir1-mediated resistance to corn leaf aphid (CLA; Rhopalosiphum maidis), a phloem sap-sucking insect pest, is independent of JA but regulated by the ET-signaling pathway. Feeding by CLA triggers the rapid accumulation of mir1 transcripts in the resistant maize genotype, Mp708. Furthermore, Mp708 provided elevated levels of antibiosis (limits aphid population)- and antixenosis (deters aphid settling)-mediated resistance to CLA compared with B73 and Tx601 maize susceptible inbred lines. Synthetic diet aphid feeding trial bioassays with recombinant Mir1-Cys Protease demonstrates that Mir1-Cys Protease provides direct toxicity to CLA. Furthermore, foliar feeding by CLA rapidly sends defensive signal(s) to the roots that trigger belowground accumulation of the mir1, signifying a potential role of long-distance signaling in maize defense against the phloem-feeding insects. Collectively, our data indicate that ET-regulated mir1 transcript accumulation, uncoupled from JA, contributed to heightened resistance to CLA in maize. In addition, our results underscore the significance of ET acting as a central node in regulating mir1 expression to different feeding guilds of insect herbivores. PMID:26253737

Genome-wide identification, splicing, and expression analysis of the myosin gene family in maize (Zea mays)

PubMed Central

Wang, Guifeng; Zhong, Mingyu; Wang, Gang; Song, Rentao

2014-01-01

The actin-based myosin system is essential for the organization and dynamics of the endomembrane system and transport network in plant cells. Plants harbour two unique myosin groups, class VIII and class XI, and the latter is structurally and functionally analogous to the animal and fungal class V myosin. Little is known about myosins in grass, even though grass includes several agronomically important cereal crops. Here, we identified 14 myosin genes from the genome of maize (Zea mays). The relatively larger sizes of maize myosin genes are due to their much longer introns, which are abundant in transposable elements. Phylogenetic analysis indicated that maize myosin genes could be classified into class VIII and class XI, with three and 11 members, respectively. Apart from subgroup XI-F, the remaining subgroups were duplicated at least in one analysed lineage, and the duplication events occurred more extensively in Arabidopsis than in maize. Only two pairs of maize myosins were generated from segmental duplication. Expression analysis revealed that most maize myosin genes were expressed universally, whereas a few members (XI-1, -6, and -11) showed an anther-specific pattern, and many underwent extensive alternative splicing. We also found a short transcript at the O1 locus, which conceptually encoded a headless myosin that most likely functions at the transcriptional level rather than via a dominant-negative mechanism at the translational level. Together, these data provide significant insights into the evolutionary and functional characterization of maize myosin genes that could transfer to the identification and application of homologous myosins of other grasses. PMID:24363426

Estimation of the fraction of absorbed photosynthetically active radiation (fPAR) in maize canopies using LiDAR data and hyperspectral imagery.

PubMed

Qin, Haiming; Wang, Cheng; Zhao, Kaiguang; Xi, Xiaohuan

2018-01-01

Accurate estimation of the fraction of absorbed photosynthetically active radiation (fPAR) for maize canopies are important for maize growth monitoring and yield estimation. The goal of this study is to explore the potential of using airborne LiDAR and hyperspectral data to better estimate maize fPAR. This study focuses on estimating maize fPAR from (1) height and coverage metrics derived from airborne LiDAR point cloud data; (2) vegetation indices derived from hyperspectral imagery; and (3) a combination of these metrics. Pearson correlation analyses were conducted to evaluate the relationships among LiDAR metrics, hyperspectral metrics, and field-measured fPAR values. Then, multiple linear regression (MLR) models were developed using these metrics. Results showed that (1) LiDAR height and coverage metrics provided good explanatory power (i.e., R2 = 0.81); (2) hyperspectral vegetation indices provided moderate interpretability (i.e., R2 = 0.50); and (3) the combination of LiDAR metrics and hyperspectral metrics improved the LiDAR model (i.e., R2 = 0.88). These results indicate that LiDAR model seems to offer a reliable method for estimating maize fPAR at a high spatial resolution and it can be used for farmland management. Combining LiDAR and hyperspectral metrics led to better performance of maize fPAR estimation than LiDAR or hyperspectral metrics alone, which means that maize fPAR retrieval can benefit from the complementary nature of LiDAR-detected canopy structure characteristics and hyperspectral-captured vegetation spectral information.

Inbreeding drives maize centromere evolution.

PubMed

Schneider, Kevin L; Xie, Zidian; Wolfgruber, Thomas K; Presting, Gernot G

2016-02-23

Functional centromeres, the chromosomal sites of spindle attachment during cell division, are marked epigenetically by the centromere-specific histone H3 variant cenH3 and typically contain long stretches of centromere-specific tandem DNA repeats (∼1.8 Mb in maize). In 23 inbreds of domesticated maize chosen to represent the genetic diversity of maize germplasm, partial or nearly complete loss of the tandem DNA repeat CentC precedes 57 independent cenH3 relocation events that result in neocentromere formation. Chromosomal regions with newly acquired cenH3 are colonized by the centromere-specific retrotransposon CR2 at a rate that would result in centromere-sized CR2 clusters in 20,000-95,000 y. Three lines of evidence indicate that CentC loss is linked to inbreeding, including (i) CEN10 of temperate lineages, presumed to have experienced a genetic bottleneck, contain less CentC than their tropical relatives; (ii) strong selection for centromere-linked genes in domesticated maize reduced diversity at seven of the ten maize centromeres to only one or two postdomestication haplotypes; and (iii) the centromere with the largest number of haplotypes in domesticated maize (CEN7) has the highest CentC levels in nearly all domesticated lines. Rare recombinations introduced one (CEN2) or more (CEN5) alternate CEN haplotypes while retaining a single haplotype at domestication loci linked to these centromeres. Taken together, this evidence strongly suggests that inbreeding, favored by postdomestication selection for centromere-linked genes affecting key domestication or agricultural traits, drives replacement of the tandem centromere repeats in maize and other crop plants. Similar forces may act during speciation in natural systems.

Urinary fumonisin B1 and estimated fumonisin intake in women from high- and low-exposure communities in Guatemala.

PubMed

Torres, Olga; Matute, Jorge; Gelineau-van Waes, Janee; Maddox, Joyce R; Gregory, Simon G; Ashley-Koch, Allison E; Showker, Jency L; Zitomer, Nicholas C; Voss, Kenneth A; Riley, Ronald T

2014-05-01

Fumonisin (FB) intake can be high when maize is a dietary staple. We determined (i) urinary FB (UFB) in women consuming maize in high- and low-exposure communities in Guatemala, (ii) the FB levels in maize, (iii) the relationship between UFB and FB intake, and (iv) the relative excretion of UFB1 , UFB2 , and UFB3 . Urine and maize were analyzed for FB for 1 year in three departments. Maize consumption was estimated by an interview questionnaire. Fumonisin B1 , B2 , and B3 (FB1 , FB2 and FB3 ), were detected in 100% of maize samples. FB1 in maize and urine was significantly higher in Jutiapa compared to Chimaltenango or Escuintla. The FB intake paralleled UFB1 in a dose-dependent manner but UFB1 was present in much higher levels than UFB2 or UFB3 compared to maize. In Jutiapa, agroecological conditions favored FB production. UFB1 mirrored the estimated FB intake. UFB1 > 0.1 ng/mL resulted in a dose-dependent increase in the risk of exceeding FB intake of 2 μg/kg b.w./day compared to women with no detectable UFB1 . More than 50% exceeded 2 μg/kg b.w./day when UFB1 was >0.5 ng/mL. UFB2 and UFB3 were rarely detected confirming that FB1 is either absorbed better or preferentially excreted in urine. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A gene regulatory network model for floral transition of the shoot apex in maize and its dynamic modeling.

PubMed

Dong, Zhanshan; Danilevskaya, Olga; Abadie, Tabare; Messina, Carlos; Coles, Nathan; Cooper, Mark

2012-01-01

The transition from the vegetative to reproductive development is a critical event in the plant life cycle. The accurate prediction of flowering time in elite germplasm is important for decisions in maize breeding programs and best agronomic practices. The understanding of the genetic control of flowering time in maize has significantly advanced in the past decade. Through comparative genomics, mutant analysis, genetic analysis and QTL cloning, and transgenic approaches, more than 30 flowering time candidate genes in maize have been revealed and the relationships among these genes have been partially uncovered. Based on the knowledge of the flowering time candidate genes, a conceptual gene regulatory network model for the genetic control of flowering time in maize is proposed. To demonstrate the potential of the proposed gene regulatory network model, a first attempt was made to develop a dynamic gene network model to predict flowering time of maize genotypes varying for specific genes. The dynamic gene network model is composed of four genes and was built on the basis of gene expression dynamics of the two late flowering id1 and dlf1 mutants, the early flowering landrace Gaspe Flint and the temperate inbred B73. The model was evaluated against the phenotypic data of the id1 dlf1 double mutant and the ZMM4 overexpressed transgenic lines. The model provides a working example that leverages knowledge from model organisms for the utilization of maize genomic information to predict a whole plant trait phenotype, flowering time, of maize genotypes.

Downregulation of transcription factor aflR in Aspergillus flavus confers reduction to aflatoxin accumulation in transgenic maize with alteration of host plant architecture.

PubMed

Masanga, Joel Okoyo; Matheka, Jonathan Mutie; Omer, Rasha Adam; Ommeh, Sheila Cecily; Monda, Ethel Oranga; Alakonya, Amos Emitati

2015-08-01

We report success of host-induced gene silencing in downregulation of aflatoxin biosynthesis in Aspergillus flavus infecting maize transformed with a hairpin construct targeting transcription factor aflR. Infestation of crops by aflatoxin-producing fungi results in economic losses as well as negative human and animal health effects. Currently, the control strategies against aflatoxin accumulation are not effective to the small holder farming systems in Africa and this has led to widespread aflatoxin exposure especially in rural populations of sub-Saharan Africa that rely on maize as a staple food crop. A recent strategy called host-induced gene silencing holds great potential for developing aflatoxin-resistant plant germplasm for the African context where farmers are unable to make further investments other than access to the germplasm. We transformed maize with a hairpin construct targeting the aflatoxin biosynthesis transcription factor aflR. The developed transgenic maize were challenged with an aflatoxigenic Aspergillus flavus strain from Eastern Kenya, a region endemic to aflatoxin outbreaks. Our results indicated that aflR was downregulated in A. flavus colonizing transgenic maize. Further, maize kernels from transgenic plants accumulated significantly lower levels of aflatoxins (14-fold) than those from wild type plants. Interestingly, we observed that our silencing cassette caused stunting and reduced kernel placement in the transgenic maize. This could have been due to "off-target" silencing of unintended genes in transformed plants by aflR siRNAs. Overall, this work indicates that host-induced gene silencing has potential in developing aflatoxin-resistant germplasm.

In Situ Nitrogen Mineralization, Nitrification, and Ammonia Volatilization in Maize Field Fertilized with Urea in Huanghuaihai Region of Northern China

PubMed Central

Zhang, Xuelin; Wang, Qun; Xu, Jun; Gilliam, Frank S.; Tremblay, Nicolas; Li, Chaohai

2015-01-01

Nitrogen (N) fertilization potentially affects soil N mineralization and leaching, and can enhance NH3 volatilization, thus impacting crop production. A fertilizer experiment with five levels of N addition (0, 79, 147, 215 and 375 kg N ha-1) was performed in 2009 and 2010 in a maize field in Huanghuaihai region, China, where > 300 kg N ha-1 has been routinely applied to soil during maize growth period of 120 days. Responses of net N mineralization, inorganic N flux (0–10cm), NH3 volatilization, and maize yield to N fertilization were measured. During the growth period, net N mineralization and nitrification varied seasonally, with higher rates occurring in August and coinciding with the R1 stage of maize growth. Soil NO3 −-N contributed to more than 60% of inorganic N flux during maize growth. Cumulative NH3 volatilization increased with N additions, with total NH3 volatilization during maize growth accounting for about 4% of added N. Relative to the control, mean maize yield in the fertilizer treatments increased by 17% and 20% in 2009 and 2010, respectively. However, grain yield, aboveground biomass, and plant N accumulation did not increase with added N at levels > 215 kg N ha-1. These results suggest that the current N rate of 300 kg N ha-1 is not only excessive, but also reduces fertilizer efficacy and may contribute to environmental problems such as global warming and eutrophication of ground water and streams. PMID:25635864

Assessment of real-time PCR based methods for quantification of pollen-mediated gene flow from GM to conventional maize in a field study.

PubMed

Pla, Maria; La Paz, José-Luis; Peñas, Gisela; García, Nora; Palaudelmàs, Montserrat; Esteve, Teresa; Messeguer, Joaquima; Melé, Enric

2006-04-01

Maize is one of the main crops worldwide and an increasing number of genetically modified (GM) maize varieties are cultivated and commercialized in many countries in parallel to conventional crops. Given the labeling rules established e.g. in the European Union and the necessary coexistence between GM and non-GM crops, it is important to determine the extent of pollen dissemination from transgenic maize to other cultivars under field conditions. The most widely used methods for quantitative detection of GMO are based on real-time PCR, which implies the results are expressed in genome percentages (in contrast to seed or grain percentages). Our objective was to assess the accuracy of real-time PCR based assays to accurately quantify the contents of transgenic grains in non-GM fields in comparison with the real cross-fertilization rate as determined by phenotypical analysis. We performed this study in a region where both GM and conventional maize are normally cultivated and used the predominant transgenic maize Mon810 in combination with a conventional maize variety which displays the characteristic of white grains (therefore allowing cross-pollination quantification as percentage of yellow grains). Our results indicated an excellent correlation between real-time PCR results and number of cross-fertilized grains at Mon810 levels of 0.1-10%. In contrast, Mon810 percentage estimated by weight of grains produced less accurate results. Finally, we present and discuss the pattern of pollen-mediated gene flow from GM to conventional maize in an example case under field conditions.

Genomic estimation of complex traits reveals ancient maize adaptation to temperate North America

USDA-ARS?s Scientific Manuscript database

By 4000 years ago, people had introduced maize to the southwestern United States; full agriculture was established quickly in the lowland deserts but delayed in the temperate highlands for 2000 years. We test if the earliest upland maize was adapted for early flowering, a characteristic of modern te...

The maize methylome influences mRNA splice sites and reveals widespread paramutation-like switches guided by small RNA

USDA-ARS?s Scientific Manuscript database

Background Maize exhibits a wealth of epigenetic phenomena, from transposon silencing, cycling and presetting, to gene imprinting and paramutation. Furthermore, despite the complexity and sophistication of maize breeding, there is a large degree of “hidden” variation for many traits that is difficul...

Efficient inoculation of rice black-streaked dwarf virus to maize using Laodelphax striatellus Fallen

USDA-ARS?s Scientific Manuscript database

Maize rough dwarf disease (MRDD) caused by Rice black-streaked dwarf virus (RBSDV) is the most important viral disease of maize in China. Although deploying disease resistant hybrids would be the most effective way to control the disease, development of resistant hybrids has been limited by virus t...

Charles W. Stuber: Maize geneticist and pioneer of marker-assisted selection

USDA-ARS?s Scientific Manuscript database

Charles W. Stuber is considered a pioneer of quantitative genetic mapping and marker-assisted selection in maize. The achievements of his four decade career in research include the development of genetic marker systems used in maize and adapted in many other crops, the first methods and studies to i...

Diallel analysis for aflatoxin accumulation and fall armyworm leaf feeding damage in maize

USDA-ARS?s Scientific Manuscript database

Two of the major impediments to profitable maize, Zea mays L., production in the southern United States are losses from feeding by fall armyworm, Spodoptera frugiperda (J.E. Smith), and losses from the production and accumulation of aflatoxin in maize grain. The fall armyworm feeds on all above-grou...

Entering the second century of maize quantitative genetics

USDA-ARS?s Scientific Manuscript database

Maize is the most widely grown cereal in the world. In addition to its role in global agriculture, it has also long served as a model organism for genetic research. Maize stands at a genetic crossroads, as it has access to all the tools available for plant genetics but exhibits a genetic architectur...

Stolbur Phytoplasma Transmission to Maize by Reptalus panzeri and the Disease Cycle of Maize Redness in Serbia

USDA-ARS?s Scientific Manuscript database

Maize redness (MR), induced by stolbur phytoplasma (Candidatus Phytoplasma solani, subgroup 16SrXII-A), is characterized by midrib, leaf and stalk reddening and abnormal ear development. MR has been reported from Serbia, Romania and Bulgaria for 50 years, and recent epiphytotics reduced yields by 4...

Prevalance of aflatoxin contamination in maize and groundnut in Ghana: Population structure, distribution, and toxigenicity of the causal agents

USDA-ARS?s Scientific Manuscript database

Aflatoxin contamination in maize and groundnut is perennial in Ghana with substantial health and economic burden on the population. The present study examined for the first time the prevalence of aflatoxin contamination in maize and groundnut in major producing regions across three agroecological zo...

Production of mycotoxins by members of the Aspergillus section Nigri isolated from peanuts and maize in the United States

USDA-ARS?s Scientific Manuscript database

Fungi of the Aspergillus section Nigri (black aspergilli) are pathogenic to maize, grapes, onions, garlic, apples, mangoes, and peanuts. Although some black aspergilli are reported as opportunistic pathogens, other species are able to colonize maize seedlings as symptomless endophytes, which under ...

DNA fingerprinting of maize seed lots to establish genetic purity using SSR markers.

USDA-ARS?s Scientific Manuscript database

Most countries in sub-Saharan Africa (SSA) grow open pollinated maize varieties (OPVs) because seed of maize OPVs can be recycled for several seasons with minimal yield reduction due to inbreeding as compared to hybrids. However, OPVs are heterogeneous, and some local seed suppliers attempt to take ...

Susceptibility to aflatoxin contamination among maize landraces from Mexico

USDA-ARS?s Scientific Manuscript database

Maize, the critical staple food for billions of people, was domesticated in Mexico about 9,000 YBP. Today, a great array of maize land races (MLRs) across rural Mexico is harbored in a living library that has been passed among generations since before establishment of the modern state. MLRs have bee...

Pathogenicity of fumonisin-producing and nonproducing strains of Aspergillus species in section Nigri to maize ears and seedlings

USDA-ARS?s Scientific Manuscript database

Species of Aspergillus section Nigri are commonly associated with maize kernels, and some strains can produce fumonisin mycotoxins. However, there is little information about the extent to which these fungi contribute to fumonisin contamination in grain, the damage they cause to maize ears, or their...

Functional and molecular characterization of genes involved in antagonisms between two maize endophytes, Fusarium verticillioides and Sarocladium zeae

USDA-ARS?s Scientific Manuscript database

Fusarium verticillioides (Fv) is a prevalent seed-borne maize endophyte capable of causing severe kernel rot and fumonisin mycotoxin contamination. Within maize kernels, Fv is primarily confined to the pedicel, while another seed-borne fungal endophyte, Sarocladium zeae (Sz), is observed in embryos....

A Battle in a Kernel: Molecular Exploration of Antagonisms between Two Maize Endophytes, Fusarium verticillioides and Acremonium zeae

USDA-ARS?s Scientific Manuscript database

Fusarium verticillioides (Fv) is a prevalent seed-borne maize endophyte capable of causing severe kernel rot and fumonisin mycotoxin contamination. Within maize kernels, Fv is primarily confined to the pedicel, while another seed-borne fungal endophyte, Acremonium zeae (Az), is observed in embryos. ...

Soil water extraction, water use, and grain yield by drought tolerant maize on the Texas High Plains

USDA-ARS?s Scientific Manuscript database

Anticipated water shortages pose a challenge to the sustainability of maize (Zea mays L.) production on the Texas High Plains. Adoption of drought tolerant (DT) hybrids is a critical management strategy for maize production under water limited conditions. However, limited information is available co...

ZmCCT and the genetic basis of day-length adaptation underlying the postdomestication spread of maize

USDA-ARS?s Scientific Manuscript database

Teosinte, the progenitor of maize, is restricted to tropical environments in Mexico and Central America. The pre-Columbian spread of maize from its center of origin in tropical Southern Mexico to the higher latitudes of the Americas required post-domestication selection for adaptation to longer dayl...

Using Association Mapping in Teosinte (Zea Mays ssp Parviglumis) to Investigate the Function of Selection-Candidate Genes

USDA-ARS?s Scientific Manuscript database

Large-scale screens of the maize genome identified 48 genes that show the putative signature of artificial selection during maize domestication or improvement. These selection-candidate genes may act as quantitative trait loci (QTL) that control the phenotypic differences between maize and its proge...

A cellular study of teosinte Zea mays ssp. parviglumis (Poaceae) caryopsis development showing several processes conserved in maize

USDA-ARS?s Scientific Manuscript database

Although recent molecular studies elucidate the genetic background leading to changed morphology of maize female inflorescence and the structure of the caryopsis during the domestication of maize (Zea mays ssp. mays) from its wild progenitor teosinte (Zea mays ssp. parviglumis), the mechanisms under...

Influence of genetic background on anthocyanin and copigment composition and behavior during thermoalkaline processing of maize

USDA-ARS?s Scientific Manuscript database

Visual color is a primary factor for foods purchase; identifying factors that influence in-situ color quality of pigmented maize during processing is important. We used 24 genetically distinct pigmented maize hybrids (red/blue, blue, red, and purple) to investigate the effect of pigment and copigme...

Susceptibility and aversion of Spodoptera frugiperda to Cry1F Bt maize and considerations for insect resistance management

USDA-ARS?s Scientific Manuscript database

Bacillus thuringiensis (Bt) maize was developed primarily for North American pests such as European corn borer (Ostrinia nubilalis Hubner). However, most Bt maize products also are cultivated outside of North America, where the primary pests are different and often have lower susceptibility to Bt to...

Joint-linkage mapping and GWAS reveal extensive genetic loci that regulate male inflorescence size in maize

USDA-ARS?s Scientific Manuscript database

Both insufficient and excessive male inflorescence size leads to a reduction in maize yield. Knowledge of the genetic architecture of male inflorescence is essential to achieve the optimum inflorescence size for maize breeding. In this study, we used approximately eight thousand inbreds, including b...

Quality protein maize germplasm characterized for amino acid profiles and endosperm opacity

USDA-ARS?s Scientific Manuscript database

Quality protein maize (QPM) is improved over normal maize in grain concentrations of the essential amino acids lysine and tryptophan. QPM has a long history as tropical adapted germplasm but little effort has been made in temperate and sub-tropical adaptation and it is unknown if different modifier ...

First report of Maize chlorotic mottle virus and maize (corn) lethal necrosis in Kenya

USDA-ARS?s Scientific Manuscript database

In September 2011, high incidence of a new maize (Zea mays L.) disease was reported at lower elevations (1900 masl) in the Longisa division of Bomet County, Southern Rift Valley of Kenya. Later the disease was noted in Bomet Central division, spreading into the neighboring Chepalungu and Narok South...

The Germplasm Enhancement of Maize (GEM) project: A Public-Private Partnership (PPP) to increase genetic diversity in US maize

USDA-ARS?s Scientific Manuscript database

The Germplasm Enhancement of Maize (GEM) Project is a mission-oriented, cooperative research effort of the United States Department of Agriculture – Agricultural Research Service (USDA-ARS), land grant universities, private industry, and international agricultural research centers to broaden the ger...

Systems genetics reveals a transcriptional network associated with susceptibility in the maize-grey leaf spot pathosystem

USDA-ARS?s Scientific Manuscript database

We have applied a systems genetics approach to elucidate molecular mechanisms of maize responses to gray leaf spot (GLS) disease, caused by Cercospora zeina, a major threat to maize production globally. We conducted expression QTL (eQTL) analysis of gene expression variation measured in earleaf samp...

The genetics of leaf flecking in maize and its relationship to plant defense and disease resistance

USDA-ARS?s Scientific Manuscript database

Physiological/genetic leaf spotting, or flecking, is a mild lesion phenotype observed on the leaves of several commonly used maize inbred lines and has been anecdotally linked to enhanced broad-spectrum disease resistance. Flecking was assessed in the maize nested association mapping (NAM) populati...

Discovery of a novel aquaporin ZmPIP2-8 from southern corn rootworm infested maize

USDA-ARS?s Scientific Manuscript database

A common paradigm of infestation by chewing insects is a jasmonic acid (JA) cascade that results in the induction of JA responsive genes. However examination of several maize genes induced by Southern corn rootworm (SCR) infestation, an insect that chews into and significantly damages maize roots, ...

Effects of fungicide seed treatments on germination, population, and yield of maize grown from seed infected with fungal pathogens

USDA-ARS?s Scientific Manuscript database

Seedborne fungi can reduce survival, growth, and yield of maize (Zea mays L.). Laboratory, field, and growth chamber experiments were conducted to determine the effects of the seed treatment fungicides fludioxonil, mefenoxam, and azoxystrobin on germination, plant population, and grain yield of maiz...

Use of benzimidazole agar plates to assess fall armyworm (Lepidoptera: Noctuidae) feeding on excised maize and sorghum leaves

USDA-ARS?s Scientific Manuscript database

The fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) is an economically significant pest of sorghum and maize. To screen sorghum and maize germplasm for resistance to fall armyworm feeding, field, greenhouse, or lab bioassays are often utilized individually or in combinatio...

Evaluation of the expression of genes associated with resistance to Aspergillus flavus colonization and aflatoxin production in different maize lines

USDA-ARS?s Scientific Manuscript database

Aflatoxins are carcinogenic toxic compounds produced by Aspergillus flavus during infection of crops including maize (Zea mays L.). Contamination of maize with aflatoxin is exacerbated by late season drought stress. Previous studies have implicated numerous resistance-associated proteins (RAPs) that...

Bioactive metabolites from Stenocarpella maydis, a stalk and ear rot pathogen of maize

USDA-ARS?s Scientific Manuscript database

Stenocarpella maydis is a fungal pathogen of major importance that causes a dry-rot of maize ears and is associated with a neuromycotoxicosis in cattle grazing harvested maize fields in southern Africa and Argentina. In an effort to investigate the potential roles of S. maydis metabolites in the fun...

Weeds and their effect on the performance of maize and fingermillet in the mid-hills of Nepal

USDA-ARS?s Scientific Manuscript database

Relay cropping of maize with fingermillet (maize/fingermillet) is the predominant cropping system for sustaining food security in the hilly regions of Nepal. In this region weed pressure severely reduces crop yields, yet basic information on weed species composition, biomass production and their eff...

A population of deletion mutants and an integrated mapping and Exome-seq pipeline for gene discovery in maize

USDA-ARS?s Scientific Manuscript database

To better understand maize endosperm filling and maturation, we developed a novel functional genomics platform that combined Bulked Segregant RNA and Exome sequencing (BSREx-seq) to map causative mutations and identify candidate genes within mapping intervals. Using gamma-irradiation of B73 maize to...

The role of photosynthesis in improving maize tolerance to ozone pollution

USDA-ARS?s Scientific Manuscript database

Ground-level ozone pollution has more than doubled since pre-industrial times, and is currently estimated to cause up to 10% reductions in U.S. maize yields annually. Maize productivity is reduced by exposure to ozone as it diffuses through stomatal pores and reacts to form damaging reactive oxygen ...

Composition and toxigenic potential of the Fusarium graminearum species complex from maize ears, stalks and stubble in Brazil

USDA-ARS?s Scientific Manuscript database

Detailed knowledge of the composition and toxigenic potential of the Fusarium graminearum species complex affecting maize crops in Brazil is lacking. A multilocus genotype approach was used to identify 539 isolates from three sub-collections: 1) maize kernels (n= 110) from five states spanning sout...

PR10 expression in maize and its effect on host resistance against Aspergillus flavus infection and aflatoxin production

USDA-ARS?s Scientific Manuscript database

Maize (Zea mays L.) is a major crop susceptible to Aspergillus flavus infection and subsequent contamination with aflatoxins, the potent carcinogenic secondary metabolites of the fungus. Protein profiles of maize genotypes resistant and susceptible to A. flavus infection and/or aflatoxin contaminati...

Contrasting insect attraction and herbivore-induced plant volatile production in maize

USDA-ARS?s Scientific Manuscript database

Maize inbred line W22 is an important resource for genetic studies due to the availability of the UniformMu mutant population and a complete genome sequence. In this study, we assessed the suitability of W22 as a model for tritrophic interactions between maize, Spodoptera frugiperda (fall armyworm) ...

Semi field trials to evaluate undersowings in maize for management of western corn rootworm larvae

USDA-ARS?s Scientific Manuscript database

Western corn rootworm larvae (Diabrotica virgifera virgifera) need to feed on maize roots after hatching from overwintering eggs. It was hypothesized that the roots of undersown plants mixed with maize roots disrupt the host finding of the larvae, lowering their survival and subsequently reducing la...

Genetic relationships and structure among open pollinated maize varieties adapted to eastern and southern Africa using microsatellite markers

USDA-ARS?s Scientific Manuscript database

The International Maize and Wheat Improvement Center (CIMMYT), in collaboration with the national agricultural systems (NARS) in sub-Saharan Africa (SSA), have developed various stress-tolerant and more nutritious open-pollinated varieties (OPVs) of maize that are suitable for smallholder farmers’ g...

Future climate impacts on maize farming and food security in Malawi

NASA Astrophysics Data System (ADS)

Stevens, Tilele; Madani, Kaveh

2016-11-01

Agriculture is the mainstay of Malawi’s economy and maize is the most important crop for food security. As a Least Developed Country (LDC), adverse effects of climate change (CC) on agriculture in Malawi are expected to be significant. We examined the impacts of CC on maize production and food security in Malawi’s dominant cereal producing region, Lilongwe District. We used five Global Circulation Models (GCMs) to make future (2011 to 2100) rainfall and temperature projections and simulated maize yields under these projections. Our future rainfall projections did not reveal a strong increasing or decreasing trend, but temperatures are expected to increase. Our crop modelling results, for the short-term future, suggest that maize farming might benefit from CC. However, faster crop growth could worsen Malawi’s soil fertility problem. Increasing temperature could drive lower maize yields in the medium to long-term future. Consequently, up to 12% of the population in Lilongwe District might be vulnerable to food insecurity by the end of the century. Measures to increase soil fertility and moisture must be developed to build resilience into Malawi’s agriculture sector.

Genetic diversity and population structure of native maize populations in Latin America and the Caribbean.

PubMed

Bedoya, Claudia A; Dreisigacker, Susanne; Hearne, Sarah; Franco, Jorge; Mir, Celine; Prasanna, Boddupalli M; Taba, Suketoshi; Charcosset, Alain; Warburton, Marilyn L

2017-01-01

This study describes the genetic diversity and population structure of 194 native maize populations from 23 countries of Latin America and the Caribbean. The germplasm, representing 131 distinct landraces, was genetically characterized as population bulks using 28 SSR markers. Three main groups of maize germplasm were identified. The first, the Mexico and Southern Andes group, highlights the Pre-Columbian and modern exchange of germplasm between North and South America. The second group, Mesoamerica lowland, supports the hypothesis that two separate human migration events could have contributed to Caribbean maize germplasm. The third, the Andean group, displayed early introduction of maize into the Andes, with little mixing since then, other than a regional interchange zone active in the past. Events and activities in the pre- and post-Columbian Americas including the development and expansion of pre-Columbian cultures and the arrival of Europeans to the Americas are discussed in relation to the history of maize migration from its point of domestication in Mesoamerica to South America and the Caribbean through sea and land routes.

Complete genome sequence of maize yellow striate virus, a new cytorhabdovirus infecting maize and wheat crops in Argentina.

PubMed

Maurino, Fernanda; Dumón, Analía D; Llauger, Gabriela; Alemandri, Vanina; de Haro, Luis A; Mattio, M Fernanda; Del Vas, Mariana; Laguna, Irma Graciela; Giménez Pecci, María de la Paz

2018-01-01

A rhabdovirus infecting maize and wheat crops in Argentina was molecularly characterized. Through next-generation sequencing (NGS) of symptomatic leaf samples, the complete genome was obtained of two isolates of maize yellow striate virus (MYSV), a putative new rhabdovirus, differing by only 0.4% at the nucleotide level. The MYSV genome consists of 12,654 nucleotides for maize and wheat virus isolates, and shares 71% nucleotide sequence identity with the complete genome of barley yellow striate mosaic virus (BYSMV, NC028244). Ten open reading frames (ORFs) were predicted in the MYSV genome from the antigenomic strand and were compared with their BYSMV counterparts. The highest amino acid sequence identity of the MYSV and BYSMV proteins was 80% between the L proteins, and the lowest was 37% between the proteins 4. Phylogenetic analysis suggested that the MYSV isolates are new members of the genus Cytorhabdovirus, family Rhabdoviridae. Yellow striate, affecting maize and wheat crops in Argentina, is an emergent disease that presents a potential economic risk for these widely distributed crops.

The molecular properties of biochar carbon released in dilute acidic solution and its effects on maize seed germination.

PubMed

Sun, Jingling; Drosos, Marios; Mazzei, Pierluigi; Savy, Davide; Todisco, Daniele; Vinci, Giovanni; Pan, Genxing; Piccolo, Alessandro

2017-01-15

It is not yet clear whether the carbon released from biochar in the soil solution stimulates biological activities. Soluble fractions (AQU) from wheat and maize biochars, whose molecular content was thoroughly characterized by FTIR, 13 C and 1 H NMR, and high-resolution ESI-IT-TOF-MS, were separated in dilute acidic solution to simulate soil rhizospheric conditions and their effects evaluated on maize seeds germination activity. Elongation of maize-seeds coleoptile was significantly promoted by maize biochar AQU, whereas it was inhibited by wheat biochar AQU. Both AQU fractions contained relatively small heterocyclic nitrogen compounds, whose structures were accounted by their spectroscopic properties. Point-of-Zero-Charge (PZC) values and van Krevelen plots of identified masses of soluble components suggested that the dissolved carbon from maize biochar behaved as humic-like supramolecular material capable to adhere to seedlings and deliver bioactive molecules. These findings contribute to understand the biostimulation potential of biochars from crop biomasses when applied in agricultural production. Copyright © 2016 Elsevier B.V. All rights reserved.

Economic viability of phytoremediation of a cadmium contaminated agricultural area using energy maize. Part I: effect on the farmer's income.

PubMed

Thewys, T; Witters, N; Van Slycken, S; Ruttens, A; Meers, E; Tack, F M G; Vangronsveld, J

2010-09-01

This paper deals with the economic viability of using energy maize as a phytoremediation crop in a vast agricultural area moderately contaminated with metals. The acceptance of phytoremediation as a remediation technology is, besides the extraction rate, determined by its profitability, being the effects it has on the income of the farmer whose land is contaminated. This income can be supported by producing renewable energy through anaerobic digestion of energy maize, a crop that takes up only relatively low amounts of metals, but that can be valorised as a feedstock for energy production. The effect on the income per hectare of growing energy maize instead of fodder maize seems positive, given the most likely values of variables and while keeping the basic income stable, originating from dairy cattle farming activities. We propose growing energy maize aiming at risk-reduction, and generating an alternative income for farmers, yet in the long run also generating a gradual reduction of the pollution levels. In this way, remediation is demoted to a secondary objective with sustainable risk-based land use as primary objective.

Indirect selection for resistance to ear rot and leaf diseases in maize lines using biplots.

PubMed

Pereira, G S; Camargos, R B; Balestre, M; Von Pinho, R G; C Melo, W M

2015-09-21

Leaf disease and ear rot have caused reductions in maize yield in Brazil and other producer countries. Therefore, the aims of this study were to analyze the association between husked ear yield and the severity of maize white spot, gray leaf spot, helminthosporium, and ear rot caused by Fusarium verticillioides and Diplodia maydis using biplots in a mixed-model approach. The responses of 238 lines introduced to Brazil and four controls were evaluated using an incomplete block design with three replicates in two locations: Lavras and Uberlândia, Minas Gerais, Brazil. Two experiments were conducted in each location, one with F. verticillioides and the other with D. maydis. The mixed models elucidated the relationship between yield, leaf disease, and ear disease. Significant genotype x environment and genotype x pathogen interactions were observed. In conclusion, husked ear yield is more associated with ear rot than with the leaf diseases evaluated, justifying the indirect selection for resistance to kernel rot in maize-F. verticillioides and maize-D. maydis pathosystems by yield evaluation.

Induction of glutathione synthesis and glutathione reductase activity by abiotic stresses in maize and wheat.

PubMed

Kocsy, Gábor; Szalai, Gabriella; Galiba, Gábor

2002-06-21

The effect of different abiotic stresses (extreme temperatures and osmotic stress) on the synthesis of glutathione and hydroxymethylglutathione, on the ratio of the reduced to oxidised forms of these thiols (GSH/GSSG, hmGSH/hmGSSG), and on the glutathione reductase (GR) activity was studied in maize and wheat genotypes having different sensitivity to low temperature stress. Cold treatment induced a greater increase in total glutathione (TG) content and in GR activity in tolerant genotypes of both species than in sensitive ones. The GSH/GSSG and hmGSH/hmGSSG ratios were increased by this treatment only in the frost-tolerant wheat variety. High-temperature stress increased the TG content and the GSH/GSSG ratio only in the chilling-sensitive maize genotype, but GR activity was greater after this treatment in both maize genotypes. Osmotic stress resulted in a great increase in the TG content in wheat and the GR activity in maize. The amount of total hydroxymethylglutathione increased following all stress treatments. These results indicate the involvement of these antioxidants in the stress responses of wheat and maize.

Low temperature caused modifications in the arrangement of cell wall pectins due to changes of osmotic potential of cells of maize leaves (Zea mays L.).

PubMed

Bilska-Kos, Anna; Solecka, Danuta; Dziewulska, Aleksandra; Ochodzki, Piotr; Jończyk, Maciej; Bilski, Henryk; Sowiński, Paweł

2017-03-01

The cell wall emerged as one of the important structures in plant stress responses. To investigate the effect of cold on the cell wall properties, the content and localization of pectins and pectin methylesterase (PME) activity, were studied in two maize inbred lines characterized by different sensitivity to cold. Low temperature (14/12 °C) caused a reduction of pectin content and PME activity in leaves of chilling-sensitive maize line, especially after prolonged treatment (28 h and 7 days). Furthermore, immunocytohistological studies, using JIM5 and JIM7 antibodies, revealed a decrease of labeling of both low- and high-methylesterified pectins in this maize line. The osmotic potential, quantified by means of incipient plasmolysis was lower in several types of cells of chilling-sensitive maize line which was correlated with the accumulation of sucrose. These studies present new finding on the effect of cold stress on the cell wall properties in conjunction with changes in the osmotic potential of maize leaf cells.

Effect of surfactant amendment to PAHs-contaminated soil for phytoremediation by maize (Zea mays L.).

PubMed

Liao, Changjun; Liang, Xujun; Lu, Guining; Thai, Truonggiang; Xu, Wending; Dang, Zhi

2015-02-01

Understanding the uptake of organic pollutants by plants is an important part of the assessment of risks from crops grown on contaminated soils. This study was an investigation of the effects of surfactants added to PAHs-contaminated soil on the uptake and accumulation of PAHs in maize tissues during phytoremediation. The accumulation of phenanthrene (PHE) and pyrene (PYR) by maize plant was not influenced significantly by the surfactant amendment to the soil. The distribution of PHE and PYR in maize tissues was not positively correlated with the corresponding lipid contents. Remarkably, the concentrations of PHE (20.9 ng g(-1)) and PYR (0.9 ng g(-1)) in maize grain were similar to or even much lower than those in some foods. Moreover, surfactants could enhance the removal of pollutants from contaminated soil during phytoremediation, which might be due to surfactant desorption ability and microbial activity in soil. The study suggests that use of maize plant with surfactant is an alternative technology for remediation of PAHs-contaminated soils. Copyright © 2014 Elsevier Inc. All rights reserved.

Xylem- and phloem-based transport of CuO nanoparticles in maize (Zea mays L.).

PubMed

Wang, Zhenyu; Xie, Xiaoyan; Zhao, Jian; Liu, Xiaoyun; Feng, Wenqiang; White, Jason C; Xing, Baoshan

2012-04-17

This work reports on the toxicity of CuO nanoparticles (NPs) to maize (Zea mays L.) and their transport and redistribution in the plant. CuO NPs (100 mg L(-1)) had no effect on germination, but inhibited the growth of maize seedlings; in comparison the dissolved Cu(2+) ions and CuO bulk particles had no obvious effect on maize growth. CuO NPs were present in xylem sap as examined by transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS), showing that CuO NPs were transported from roots to shoots via xylem. Split-root experiments and high-resolution TEM observation further showed that CuO NPs could translocate from shoots back to roots via phloem. During this translocation, CuO NPs could be reduced from Cu (II) to Cu (I). To our knowledge, this is the first report of root-shoot-root redistribution of CuO NPs within maize. The current study provides direct evidence for the bioaccumulation and biotransformation of CuO NPs (20-40 nm) in maize, which has significant implications on the potential risk of NPs and food safety.

Genetic diversity and population structure of native maize populations in Latin America and the Caribbean

PubMed Central

Bedoya, Claudia A.; Dreisigacker, Susanne; Hearne, Sarah; Franco, Jorge; Mir, Celine; Prasanna, Boddupalli M.; Taba, Suketoshi; Charcosset, Alain; Warburton, Marilyn L.

2017-01-01

This study describes the genetic diversity and population structure of 194 native maize populations from 23 countries of Latin America and the Caribbean. The germplasm, representing 131 distinct landraces, was genetically characterized as population bulks using 28 SSR markers. Three main groups of maize germplasm were identified. The first, the Mexico and Southern Andes group, highlights the Pre-Columbian and modern exchange of germplasm between North and South America. The second group, Mesoamerica lowland, supports the hypothesis that two separate human migration events could have contributed to Caribbean maize germplasm. The third, the Andean group, displayed early introduction of maize into the Andes, with little mixing since then, other than a regional interchange zone active in the past. Events and activities in the pre- and post-Columbian Americas including the development and expansion of pre-Columbian cultures and the arrival of Europeans to the Americas are discussed in relation to the history of maize migration from its point of domestication in Mesoamerica to South America and the Caribbean through sea and land routes. PMID:28403177

POPcorn: An Online Resource Providing Access to Distributed and Diverse Maize Project Data.

PubMed

Cannon, Ethalinda K S; Birkett, Scott M; Braun, Bremen L; Kodavali, Sateesh; Jennewein, Douglas M; Yilmaz, Alper; Antonescu, Valentin; Antonescu, Corina; Harper, Lisa C; Gardiner, Jack M; Schaeffer, Mary L; Campbell, Darwin A; Andorf, Carson M; Andorf, Destri; Lisch, Damon; Koch, Karen E; McCarty, Donald R; Quackenbush, John; Grotewold, Erich; Lushbough, Carol M; Sen, Taner Z; Lawrence, Carolyn J

2011-01-01

The purpose of the online resource presented here, POPcorn (Project Portal for corn), is to enhance accessibility of maize genetic and genomic resources for plant biologists. Currently, many online locations are difficult to find, some are best searched independently, and individual project websites often degrade over time-sometimes disappearing entirely. The POPcorn site makes available (1) a centralized, web-accessible resource to search and browse descriptions of ongoing maize genomics projects, (2) a single, stand-alone tool that uses web Services and minimal data warehousing to search for sequence matches in online resources of diverse offsite projects, and (3) a set of tools that enables researchers to migrate their data to the long-term model organism database for maize genetic and genomic information: MaizeGDB. Examples demonstrating POPcorn's utility are provided herein.

POPcorn: An Online Resource Providing Access to Distributed and Diverse Maize Project Data

PubMed Central

Cannon, Ethalinda K. S.; Birkett, Scott M.; Braun, Bremen L.; Kodavali, Sateesh; Jennewein, Douglas M.; Yilmaz, Alper; Antonescu, Valentin; Antonescu, Corina; Harper, Lisa C.; Gardiner, Jack M.; Schaeffer, Mary L.; Campbell, Darwin A.; Andorf, Carson M.; Andorf, Destri; Lisch, Damon; Koch, Karen E.; McCarty, Donald R.; Quackenbush, John; Grotewold, Erich; Lushbough, Carol M.; Sen, Taner Z.; Lawrence, Carolyn J.

2011-01-01

The purpose of the online resource presented here, POPcorn (Project Portal for corn), is to enhance accessibility of maize genetic and genomic resources for plant biologists. Currently, many online locations are difficult to find, some are best searched independently, and individual project websites often degrade over time—sometimes disappearing entirely. The POPcorn site makes available (1) a centralized, web-accessible resource to search and browse descriptions of ongoing maize genomics projects, (2) a single, stand-alone tool that uses web Services and minimal data warehousing to search for sequence matches in online resources of diverse offsite projects, and (3) a set of tools that enables researchers to migrate their data to the long-term model organism database for maize genetic and genomic information: MaizeGDB. Examples demonstrating POPcorn's utility are provided herein. PMID:22253616

Construction of the third-generation Zea mays haplotype map

PubMed Central

Bukowski, Robert; Guo, Xiaosen; Lu, Yanli; Zou, Cheng; He, Bing; Rong, Zhengqin; Wang, Bo; Xu, Dawen; Yang, Bicheng; Xie, Chuanxiao; Fan, Longjiang; Gao, Shibin; Xu, Xun; Zhang, Gengyun; Li, Yingrui; Jiao, Yinping; Doebley, John F; Ross-Ibarra, Jeffrey; Lorant, Anne; Buffalo, Vince; Romay, M Cinta; Buckler, Edward S; Ware, Doreen; Lai, Jinsheng; Sun, Qi

2017-01-01

Abstract Background Characterization of genetic variations in maize has been challenging, mainly due to deterioration of collinearity between individual genomes in the species. An international consortium of maize research groups combined resources to develop the maize haplotype version 3 (HapMap 3), built from whole-genome sequencing data from 1218 maize lines, covering predomestication and domesticated Zea mays varieties across the world. Results A new computational pipeline was set up to process more than 12 trillion bp of sequencing data, and a set of population genetics filters was applied to identify more than 83 million variant sites. Conclusions We identified polymorphisms in regions where collinearity is largely preserved in the maize species. However, the fact that the B73 genome used as the reference only represents a fraction of all haplotypes is still an important limiting factor. PMID:29300887

Pleiotropic effects of ZmLAZY1 on the auxin-mediated responses to gravity and light in maize shoot and inflorescences.

PubMed

Dong, Zhaobin; Jin, Weiwei

2013-01-01

Auxin has been found to control both gravitropism and inflorescence development in plant. Auxin transport has also been demonstrated to be responsible for tropism. Maize, a key agricultural crop, has distinct male (tassel) and female (ear) inflorescence, and this morphogenesis depends on auxin maximum and gradient. The classic maize mutant lazy plant1 (la1) has defective gravitropic response. The mechanism underlining maize gravitropism remains unclear. Recently, we isolated the ZmLA1 gene by map-based cloning, and our findings suggest that ZmLA1 might mediate the crosstalk between shoot gravitropism and inflorescence development by regulating auxin transport, auxin signaling, and auxin-mediated light response in maize. Here, we propose a model describing the ZmLA1-mediated complex interactions among auxin, gravity, light, and inflorescent development.

Influences of coal mining water irrigation on the maize losses in the Xingdong Mine area, China.

PubMed

Sun, Yuzhuang; Ling, Pei; Li, Yanheng; Li, Qingxue; Sun, Quande; Wang, Jinxi

2014-02-01

In 2008, a maize underproduction disaster occurred in the Xianyu village after irrigation using the coal mining water from the Xingdong Mine, China. This disaster resulted in about 40 hectare maize underproduction and 20 hectare total loss of the maize yields. In order to study the reason, a total of 25 soil, water and plant samples were taken from the study area. These samples were analysed by inductively coupled plasma mass spectrometry and ion chromatography. The results indicate that the contents of both water-soluble fluorine and total fluorine are very high and resulting of maize underproduction and total loss of production. The possible pollution sources of fluorine in the study area could be from the coal mine water used for irrigation and glass chemical factory near the study area.

Cloning and function analysis of a drought-inducible gene associated with resistance to Curvularia leaf spot in maize.

PubMed

Zhu, Jiewei; Huang, Xiuli; Liu, Tong; Gao, Shigang; Chen, Jie

2012-08-01

ZmDIP was cloned and its function against Curvularia lunata was analyzed, according to a previous finding on a drought-inducible protein in resistant maize identified through MALDI-TOF-MS/MS. The ZmDIP expression varied in roots, leaf sheaths, and young, as well as old, leaves of different maize inbred lines. The ZmDIP transcript level changed in leaves over the course of time after inoculation with C. lunata. A prokaryotic expression analysis demonstrated that the gene can regulate the salt stress tolerance of Escherichia coli. The ZmDIP transient expression in the maize leaf showed that the gene was also linked to leaf resistance against the C. lunata infection. ZmDIP-mediated ROS and ABA signaling pathways were inferred to be closely associated with maize leaf resistance to the pathogen infection.

The role of biotechnology for agricultural sustainability in Africa.

PubMed

Thomson, Jennifer A

2008-02-27

Sub-Saharan Africa could have a shortfall of nearly 90Mt of cereals by the year 2025 if current agricultural practices are maintained. Biotechnology is one of the ways to improve agricultural production. Insect-resistant varieties of maize and cotton suitable for the subcontinent have been identified as already having a significant impact. Virus-resistant crops are under development. These include maize resistant to the African endemic maize streak virus and cassava resistant to African cassava mosaic virus. Parasitic weeds such as Striga attack the roots of crops such as maize, millet, sorghum and upland rice. Field trials in Kenya using a variety of maize resistant to a herbicide have proven very successful. Drought-tolerant crops are also under development as are improved varieties of local African crops such as bananas, cassava, sorghum and sweet potatoes.

Arbuscular mycorrhizal fungi and rhizobium facilitate nitrogen uptake and transfer in soybean/maize intercropping system

PubMed Central

Meng, Lingbo; Zhang, Aiyuan; Wang, Fei; Han, Xiaoguang; Wang, Dejiang; Li, Shumin

2015-01-01

The tripartite symbiosis between legumes, rhizobia and mycorrhizal fungi are generally considered to be beneficial for the nitrogen (N) uptake of legumes, but the facilitation of symbiosis in legume/non-legume intercropping systems is not clear. Therefore, the aims of the research are as follows: (1) to verify if the dual inoculation can facilitate the N uptake and N transfer in maize/soybean intercropping systems and (2) to calculate how much N will be transferred from soybean to maize. A pot experiment with different root separations [solid barrier, mesh (30 μm) barrier and no barrier] was conducted, and the 15N isotopic tracing method was used to calculate how much N transferred from soybean to maize inoculated with arbuscular mycorrhizal fungi (AMF) and rhizobium in a soybean (Glycine max L.cv. Dongnong No. 42)/maize (Zea mays L.cv. Dongnong No. 48) intercropping system. Compared with the Glomus mosseae inoculation (G.m.), Rhizobium SH212 inoculation (SH212), no inoculation (NI), the dual inoculation (SH212+G.m.) increased the N uptake of soybean by 28.69, 39.58, and 93.07% in a solid barrier system. N uptake of maize inoculated with both G. mosseae and rhizobium was 1.20, 1.28, and 1.68 times more than that of G.m., SH212 and NI, respectively, in solid barrier treatments. In addition, the amount of N transferred from soybean to maize in a dual inoculation system with a mesh barrier was 7.25, 7.01, and 11.45 mg more than that of G.m., SH212 and NI and similarly, 6.40, 7.58, and 12.46 mg increased in no barrier treatments. Inoculating with both AMF and rhizobium in the soybean/maize intercropping system improved the N fixation efficiency of soybean and promoted N transfer from soybean to maize, resulting in the improvement of yield advantages of legume/non-legume intercropping. PMID:26029236

Intercropping Enhances Productivity and Maintains the Most Soil Fertility Properties Relative to Sole Cropping

PubMed Central

Wang, Zhi-Gang; Jin, Xin; Bao, Xing-Guo; Li, Xiao-Fei; Zhao, Jian-Hua; Sun, Jian-Hao; Christie, Peter; Li, Long

2014-01-01

Yield and nutrient acquisition advantages are frequently found in intercropping systems. However, there are few published reports on soil fertility in intercropping relative to monocultures. A field experiment was therefore established in 2009 in Gansu province, northwest China. The treatments comprised maize/faba bean, maize/soybean, maize/chickpea and maize/turnip intercropping, and their correspoding monocropping. In 2011 (the 3rd year) and 2012 (the 4th year) the yields and some soil chemical properties and enzyme activities were examined after all crop species were harvested or at later growth stages. Both grain yields and nutrient acquisition were significantly greater in all four intercropping systems than corresponding monocropping over two years. Generally, soil organic matter (OM) did not differ significantly from monocropping but did increase in maize/chickpea in 2012 and maize/turnip in both years. Soil total N (TN) did not differ between intercropping and monocropping in either year with the sole exception of maize/faba bean intercropping receiving 80 kg P ha−1 in 2011. Intercropping significantly reduced soil Olsen-P only in 2012, soil exchangeable K in both years, soil cation exchangeable capacity (CEC) in 2012, and soil pH in 2012. In the majority of cases soil enzyme activities did not differ across all the cropping systems at different P application rates compared to monocrops, with the exception of soil acid phosphatase activity which was higher in maize/legume intercropping than in the corresponding monocrops at 40 kg ha−1 P in 2011. P fertilization can alleviate the decline in soil Olsen-P and in soil CEC to some extent. In summary, intercropping enhanced productivity and maintained the majority of soil fertility properties for at least three to four years, especially at suitable P application rates. The results indicate that maize-based intercropping may be an efficient cropping system for sustainable agriculture with carefully managed fertilizer inputs. PMID:25486249

Arbuscular mycorrhizal fungi and rhizobium facilitate nitrogen uptake and transfer in soybean/maize intercropping system.

PubMed

Meng, Lingbo; Zhang, Aiyuan; Wang, Fei; Han, Xiaoguang; Wang, Dejiang; Li, Shumin

2015-01-01

The tripartite symbiosis between legumes, rhizobia and mycorrhizal fungi are generally considered to be beneficial for the nitrogen (N) uptake of legumes, but the facilitation of symbiosis in legume/non-legume intercropping systems is not clear. Therefore, the aims of the research are as follows: (1) to verify if the dual inoculation can facilitate the N uptake and N transfer in maize/soybean intercropping systems and (2) to calculate how much N will be transferred from soybean to maize. A pot experiment with different root separations [solid barrier, mesh (30 μm) barrier and no barrier] was conducted, and the (15)N isotopic tracing method was used to calculate how much N transferred from soybean to maize inoculated with arbuscular mycorrhizal fungi (AMF) and rhizobium in a soybean (Glycine max L.cv. Dongnong No. 42)/maize (Zea mays L.cv. Dongnong No. 48) intercropping system. Compared with the Glomus mosseae inoculation (G.m.), Rhizobium SH212 inoculation (SH212), no inoculation (NI), the dual inoculation (SH212+G.m.) increased the N uptake of soybean by 28.69, 39.58, and 93.07% in a solid barrier system. N uptake of maize inoculated with both G. mosseae and rhizobium was 1.20, 1.28, and 1.68 times more than that of G.m., SH212 and NI, respectively, in solid barrier treatments. In addition, the amount of N transferred from soybean to maize in a dual inoculation system with a mesh barrier was 7.25, 7.01, and 11.45 mg more than that of G.m., SH212 and NI and similarly, 6.40, 7.58, and 12.46 mg increased in no barrier treatments. Inoculating with both AMF and rhizobium in the soybean/maize intercropping system improved the N fixation efficiency of soybean and promoted N transfer from soybean to maize, resulting in the improvement of yield advantages of legume/non-legume intercropping.

Changes in Phenolic Acid Content in Maize during Food Product Processing.

PubMed

Butts-Wilmsmeyer, Carrie J; Mumm, Rita H; Rausch, Kent D; Kandhola, Gurshagan; Yana, Nicole A; Happ, Mary M; Ostezan, Alexandra; Wasmund, Matthew; Bohn, Martin O

2018-04-04

The notion that many nutrients and beneficial phytochemicals in maize are lost due to food product processing is common, but this has not been studied in detail for the phenolic acids. Information regarding changes in phenolic acid content throughout processing is highly valuable because some phenolic acids are chemopreventive agents of aging-related diseases. It is unknown when and why these changes in phenolic acid content might occur during processing, whether some maize genotypes might be more resistant to processing induced changes in phenolic acid content than other genotypes, or if processing affects the bioavailability of phenolic acids in maize-based food products. For this study, a laboratory-scale processing protocol was developed and used to process whole maize kernels into toasted cornflakes. High-throughput microscale wet-lab analyses were applied to determine the concentrations of soluble and insoluble-bound phenolic acids in samples of grain, three intermediate processing stages, and toasted cornflakes obtained from 12 ex-PVP maize inbreds and seven hybrids. In the grain, insoluble-bound ferulic acid was the most common phenolic acid, followed by insoluble-bound p-coumaric acid and soluble cinnamic acid, a precursor to the phenolic acids. Notably, the ferulic acid content was approximately 1950 μg/g, more than ten-times the concentration of many fruits and vegetables. Processing reduced the content of the phenolic acids regardless of the genotype. Most changes occurred during dry milling due to the removal of the bran. The concentration of bioavailable soluble ferulic and p-coumaric acid increased negligibly due to thermal stresses. Therefore, the current dry milling based processing techniques used to manufacture many maize-based foods, including breakfast cereals, are not conducive for increasing the content of bioavailable phenolics in processed maize food products. This suggests that while maize is an excellent source of phenolics, alternative or complementary processing methods must be developed before this nutritional resource can be utilized.

A Comprehensive Analysis of Alternative Splicing in Paleopolyploid Maize.

PubMed

Mei, Wenbin; Liu, Sanzhen; Schnable, James C; Yeh, Cheng-Ting; Springer, Nathan M; Schnable, Patrick S; Barbazuk, William B

2017-01-01

Identifying and characterizing alternative splicing (AS) enables our understanding of the biological role of transcript isoform diversity. This study describes the use of publicly available RNA-Seq data to identify and characterize the global diversity of AS isoforms in maize using the inbred lines B73 and Mo17, and a related species, sorghum. Identification and characterization of AS within maize tissues revealed that genes expressed in seed exhibit the largest differential AS relative to other tissues examined. Additionally, differences in AS between the two genotypes B73 and Mo17 are greatest within genes expressed in seed. We demonstrate that changes in the level of alternatively spliced transcripts (intron retention and exon skipping) do not solely reflect differences in total transcript abundance, and we present evidence that intron retention may act to fine-tune gene expression across seed development stages. Furthermore, we have identified temperature sensitive AS in maize and demonstrate that drought-induced changes in AS involve distinct sets of genes in reproductive and vegetative tissues. Examining our identified AS isoforms within B73 × Mo17 recombinant inbred lines (RILs) identified splicing QTL (sQTL). The 43.3% of cis- sQTL regulated junctions are actually identified as alternatively spliced junctions in our analysis, while 10 Mb windows on each side of 48.2% of trans -sQTLs overlap with splicing related genes. Using sorghum as an out-group enabled direct examination of loss or conservation of AS between homeologous genes representing the two subgenomes of maize. We identify several instances where AS isoforms that are conserved between one maize homeolog and its sorghum ortholog are absent from the second maize homeolog, suggesting that these AS isoforms may have been lost after the maize whole genome duplication event. This comprehensive analysis provides new insights into the complexity of AS in maize.

Identification and expression profiling analysis of TCP family genes involved in growth and development in maize.

PubMed

Chai, Wenbo; Jiang, Pengfei; Huang, Guoyu; Jiang, Haiyang; Li, Xiaoyu

2017-10-01

The TCP family is a group of plant-specific transcription factors. TCP genes encode proteins harboring bHLH structure, which is implicated in DNA binding and protein-protein interactions and known as the TCP domain. TCP genes play important roles in plant development and have been evolutionarily and functionally elaborated in various plants, however, no overall phylogenetic analysis or expression profiling of TCP genes in Zea mays has been reported. In the present study, a systematic analysis of molecular evolution and functional prediction of TCP family genes in maize ( Z . mays L.) has been conducted. We performed a genome-wide survey of TCP genes in maize, revealing the gene structure, chromosomal location and phylogenetic relationship of family members. Microsynteny between grass species and tissue-specific expression profiles were also investigated. In total, 29 TCP genes were identified in the maize genome, unevenly distributed on the 10 maize chromosomes. Additionally, ZmTCP genes were categorized into nine classes based on phylogeny and purifying selection may largely be responsible for maintaining the functions of maize TCP genes. What's more, microsynteny analysis suggested that TCP genes have been conserved during evolution. Finally, expression analysis revealed that most TCP genes are expressed in the stem and ear, which suggests that ZmTCP genes influence stem and ear growth. This result is consistent with the previous finding that maize TCP genes represses the growth of axillary organs and enables the formation of female inflorescences. Altogether, this study presents a thorough overview of TCP family in maize and provides a new perspective on the evolution of this gene family. The results also indicate that TCP family genes may be involved in development stage in plant growing conditions. Additionally, our results will be useful for further functional analysis of the TCP gene family in maize.

Greenhouse gas emissions and energy efficiencies for soybeans and maize cultivated in different agronomic zones: A case study of Argentina.

PubMed

Arrieta, E M; Cuchietti, A; Cabrol, D; González, A D

2018-06-01

Of all human activities, agriculture has one of the highest environmental impacts, particularly related to Greenhouse Gas (GHG) emissions, energy use and land use change. Soybean and maize are two of the most commercialized agricultural commodities worldwide. Argentina contributes significantly to this trade, being the third major producer of soybeans, the first exporter of soymeal and soybean oil, and the third exporter of maize. Despite the economic importance of these crops and the products derived, there are very few studies regarding GHG emissions, energy use and efficiencies associated to Argentinean soybean and maize production. Therefore, the aim of this work is to determine the carbon and energy footprint, as well as the carbon and energy efficiencies, of soybeans and maize produced in Argentina, by analyzing 18 agronomic zones covering an agricultural area of 1.53millionkm 2 . Our results show that, for both crops, the GHG and energy efficiencies at the Pampean region were significantly higher than those at the extra-Pampean region. The national average for production of soybeans in Argentina results in 6.06ton/ton CO 2 -eq emitted to the atmosphere, while 0.887ton of soybean were produced per GJ of energy used; and for maize 5.01ton/ton CO 2 -eq emitted to the atmosphere and 0.740ton of maize were produced per each GJ of energy used. We found that the large differences on yields, GHGs and energy efficiencies between agronomic regions for soybean and maize crop production are mainly driven by climate, particularly mean annual precipitation. This study contributes for the first time to understand the carbon and energy footprint of soybean and maize production throughout several agronomic zones in Argentina. The significant differences found in the productive efficiencies questions on the environmental viability of expanding the agricultural frontier to less suitable lands for crop production. Copyright © 2017 Elsevier B.V. All rights reserved.

Incidence of Fusarium spp. and Levels of Fumonisin B1 in Maize in Western Kenya

PubMed Central

Kedera, C. J.; Plattner, R. D.; Desjardins, A. E.

1999-01-01

Maize kernel samples were collected in 1996 from smallholder farm storages in the districts of Bomet, Bungoma, Kakamega, Kericho, Kisii, Nandi, Siaya, Trans Nzoia, and Vihiga in the tropical highlands of western Kenya. Two-thirds of the samples were good-quality maize, and one-third were poor-quality maize with a high incidence of visibly diseased kernels. One hundred fifty-three maize samples were assessed for Fusarium infection by culturing kernels on a selective medium. The isolates obtained were identified to the species level based on morphology and on formation of the sexual stage in Gibberella fujikuroi mating population tests. Fusarium moniliforme (G. fujikuroi mating population A) was isolated most frequently, but F. subglutinans (G. fujikuroi mating population E), F. graminearum, F. oxysporum, F. solani, and other Fusarium species were also isolated. The high incidence of kernel infection with the fumonisin-producing species F. moniliforme indicated a potential for fumonisin contamination of Kenyan maize. However, analysis of 197 maize kernel samples by high-performance liquid chromatography found little fumonisin B1 in most of the samples. Forty-seven percent of the samples contained fumonisin B1 at levels above the detection limit (100 ng/g), but only 5% were above 1,000 ng/g, a proposed level of concern for human consumption. The four most-contaminated samples, with fumonisin B1 levels ranging from 3,600 to 11,600 ng/g, were from poor-quality maize collected in the Kisii district. Many samples with a high incidence of visibly diseased kernels contained little or no fumonisin B1, despite the presence of F. moniliforme. This result may be attributable to the inability of F. moniliforme isolates present in Kenyan maize to produce fumonisins, to the presence of other ear rot fungi, and/or to environmental conditions unfavorable for fumonisin production. PMID:9872757

Effect on transcriptome and metabolome of stacked transgenic maize containing insecticidal cry and glyphosate tolerance epsps genes.

PubMed

Wang, Xu-Jing; Zhang, Xin; Yang, Jiang-Tao; Wang, Zhi-Xing

2018-03-01

Gene stacking is a developing trend in agricultural biotechnology. Unintended effects in stacked transgenic plants are safety issues considered by the public and researchers. Omics techniques provide useful tools to assess unintended effects. In this paper, stacked transgenic maize 12-5×IE034 that contained insecticidal cry and glyphosate tolerance G10-epsps genes was obtained by crossing of transgenic maize varieties 12-5 and IE034. Transcriptome and metabolome analyses were performed for different maize varieties, including 12-5×IE034, 12-5, IE034, and conventional varieties collected from different provinces in China. The transcriptome results were as follows. The nine maize varieties had obvious differences in gene expression. There were 3561-5538 differentially expressed genes between 12-5×IE034 and its parents and transgenic receptor, which were far fewer than the number of differentially expressed genes in different traditional maize varieties. Cluster analysis indicated that there were close relationships between 12-5×IE034 and its parents. The metabolome results were as follows. For the nine detected maize varieties, the number of different metabolites ranged from 0 to 240. Compared with its parents, 12-5 and IE034, the hybrid variety 12-5×IE034 had 15 and 112 different metabolites, respectively. Hierarchical cluster analysis with Pearson's correlation analysis showed that the differences between 12-5×IE034 and its parents were fewer than those between other maize varieties. Shikimate pathway-related genes and metabolites analysis results showed that the effects of hybrid stacking are less than those from transformation and differing genotypes. Thus, the differences due to breeding stack were fewer than those due to natural variation among maize varieties. This paper provides scientific data for assessing unintended effects in stacked transgenic plants. © 2018 The Authors The Plant Journal © 2018 John Wiley & Sons Ltd.

Reduced irrigation increases the water use efficiency and productivity of winter wheat-summer maize rotation on the North China Plain.

PubMed

Wang, Yunqi; Zhang, Yinghua; Zhang, Rui; Li, Jinpeng; Zhang, Meng; Zhou, Shunli; Wang, Zhimin

2018-03-15

The groundwater table has fallen sharply over the last 30years on the North China Plain, resulting in a shortage of water for winter wheat irrigation. Reducing irrigation may be an important strategy to maintain agricultural sustainability in the region; however, few studies have evaluated the transition from conventional irrigation management practices to reduced irrigation management practices in the winter wheat-summer maize rotation system. Here, we compare the yield, water consumption, and water use efficiency of winter wheat-summer maize rotation under conventional irrigation and reduced irrigation on the North China Plain from 2012 to 2015. Reducing irrigation decreased the yield but increased the water use efficiency and significantly advanced the harvest date of winter wheat. As a result, the summer maize sowing date advanced significantly, and the flowering date subsequently advanced 2-8days, thus extending the summer maize grain-filling stage. Therefore, the yield and water use efficiency of summer maize were higher under reduced irrigation than conventional irrigation, which compensated for the winter wheat yield loss under reduced irrigation. In addition, under reduced irrigation from 2012 to 2015, the yield and water use efficiency advantage of the winter wheat-summer maize rotation ranged from 0.0 to 9.7% and from 4.1 to 14.7%, respectively, and water consumption and irrigated water decreased by 20-61mm and 150mm, respectively, compared to conventional irrigation. Overall, the reduced irrigation management practice involving no irrigation after sowing winter wheat, and sowing summer maize on June 7 produced the most favorable grain yield with superb water use efficiency in the winter wheat-summer maize rotation. This study indicates that reducing irrigation could be an efficient means to cope with water resource shortages while maintaining crop production sustainability on the North China Plain. Copyright © 2017. Published by Elsevier B.V.

Nutrient and nontraditional food intakes by Zambian children in a controlled feeding trial.

PubMed

Schmaelzle, Samantha; Kaliwile, Chisela; Arscott, Sara A; Gannon, Bryan; Masi, Cassim; Tanumihardjo, Sherry A

2014-03-01

Many programs aim to alleviate vitamin A deficiency. Biofortification is an approach to improve provitamin A carotenoid concentrations of staple crops in some developing countries. In rural Zambia, maize accounts for the majority of energy intake. Provitamin A-biofortified (orange) maize has been released in Zambia. This study quantified food intake of Zambian children from records collected in a feeding trial in 2012 in order to compare adoption of orange maize and a new vegetable (green beans) with white maize and traditional foods. One hundred thirty-six children with a mean age of 71.5 +/- 6.9 months were fed three meals a day for 6 days a week for 15 weeks at four feeding centers. Breakfast consisted of maize porridge, and lunch and dinner were stiff porridge (nshima) with various side dishes (relishes). There were three treatment groups, which received orange maize and placebo oil, white maize and placebo oil, or white maize and a daily vitamin A supplement. Food was weighed before and after consumption. Nutritionists were trained to interview the children's caregivers about the previous day's intake using dietary recalls. Nine dietary recalls for each child were recorded and analyzed. Total food intake did not differ among the groups (p = .31) and energy intakes on Sundays (< or = 880 kcal) were below recommendations. Nshima intake was lower in the orange-maize group (p = .008), largely due to a genotype effect. Intakes of relish, green bean, and porridge did not differ among the groups (p > .19). Dietary recalls revealed that children living in sites closer to the main road consumed more on Sundays than children living about 8 km from the main road, but less in the evenings when children were off site. The intakes of energy of these Zambian children were low. Implementation and adoption of new and biofortified foods is possible with promotion.

Genome-Wide Association Study Identifies Candidate Genes That Affect Plant Height in Chinese Elite Maize (Zea mays L.) Inbred Lines

PubMed Central

Wang, Jianjun; Liu, Changlin; Li, Mingshun; Zhang, Degui; Bai, Li; Zhang, Shihuang; Li, Xinhai

2011-01-01

Background The harvest index for many crops can be improved through introduction of dwarf stature to increase lodging resistance, combined with early maturity. The inbred line Shen5003 has been widely used in maize breeding in China as a key donor line for the dwarf trait. Also, one major quantitative trait locus (QTL) controlling plant height has been identified in bin 5.05–5.06, across several maize bi-parental populations. With the progress of publicly available maize genome sequence, the objective of this work was to identify the candidate genes that affect plant height among Chinese maize inbred lines with genome wide association studies (GWAS). Methods and Findings A total of 284 maize inbred lines were genotyped using over 55,000 evenly spaced SNPs, from which a set of 41,101 SNPs were filtered with stringent quality control for further data analysis. With the population structure controlled in a mixed linear model (MLM) implemented with the software TASSEL, we carried out a genome-wide association study (GWAS) for plant height. A total of 204 SNPs (P≤0.0001) and 105 genomic loci harboring coding regions were identified. Four loci containing genes associated with gibberellin (GA), auxin, and epigenetic pathways may be involved in natural variation that led to a dwarf phenotype in elite maize inbred lines. Among them, a favorable allele for dwarfing on chromosome 5 (SNP PZE-105115518) was also identified in six Shen5003 derivatives. Conclusions The fact that a large number of previously identified dwarf genes are missing from our study highlights the discovery of the consistently significant association of the gene harboring the SNP PZE-105115518 with plant height (P = 8.91e-10) and its confirmation in the Shen5003 introgression lines. Results from this study suggest that, in the maize breeding schema in China, specific alleles were selected, that have played important roles in maize production. PMID:22216221

Maize Domestication and Anti-Herbivore Defences: Leaf-Specific Dynamics during Early Ontogeny of Maize and Its Wild Ancestors

PubMed Central

Maag, Daniel; Erb, Matthias; Bernal, Julio S.; Wolfender, Jean-Luc; Turlings, Ted C. J.; Glauser, Gaétan

2015-01-01

As a consequence of artificial selection for specific traits, crop plants underwent considerable genotypic and phenotypic changes during the process of domestication. These changes may have led to reduced resistance in the cultivated plant due to shifts in resource allocation from defensive traits to increased growth rates and yield. Modern maize (Zea mays ssp. mays) was domesticated from its ancestor Balsas teosinte (Z. mays ssp. parviglumis) approximately 9000 years ago. Although maize displays a high genetic overlap with its direct ancestor and other annual teosintes, several studies show that maize and its ancestors differ in their resistance phenotypes with teosintes being less susceptible to herbivore damage. However, the underlying mechanisms are poorly understood. Here we addressed the question to what extent maize domestication has affected two crucial chemical and one physical defence traits and whether differences in their expression may explain the differences in herbivore resistance levels. The ontogenetic trajectories of 1,4-benzoxazin-3-ones, maysin and leaf toughness were monitored for different leaf types across several maize cultivars and teosinte accessions during early vegetative growth stages. We found significant quantitative and qualitative differences in 1,4-benzoxazin-3-one accumulation in an initial pairwise comparison, but we did not find consistent differences between wild and cultivated genotypes during a more thorough examination employing several cultivars/accessions. Yet, 1,4-benzoxazin-3-one levels tended to decline more rapidly with plant age in the modern maize cultivars. Foliar maysin levels and leaf toughness increased with plant age in a leaf-specific manner, but were also unaffected by domestication. Based on our findings we suggest that defence traits other than the ones that were investigated are responsible for the observed differences in herbivore resistance between teosinte and maize. Furthermore, our results indicate that single pairwise comparisons may lead to false conclusions regarding the effects of domestication on defensive and possibly other traits. PMID:26267478

Genome-Wide Analysis of ZmDREB Genes and Their Association with Natural Variation in Drought Tolerance at Seedling Stage of Zea mays L

PubMed Central

Wang, Hongwei; Xin, Haibo; Yang, Xiaohong; Yan, Jianbing; Li, Jiansheng; Tran, Lam-Son Phan; Shinozaki, Kazuo; Yamaguchi-Shinozaki, Kazuko; Qin, Feng

2013-01-01

The worldwide production of maize (Zea mays L.) is frequently impacted by water scarcity and as a result, increased drought tolerance is a priority target in maize breeding programs. While DREB transcription factors have been demonstrated to play a central role in desiccation tolerance, whether or not natural sequence variations in these genes are associated with the phenotypic variability of this trait is largely unknown. In the present study, eighteen ZmDREB genes present in the maize B73 genome were cloned and systematically analyzed to determine their phylogenetic relationship, synteny with rice, maize and sorghum genomes; pattern of drought-responsive gene expression, and protein transactivation activity. Importantly, the association between the nucleic acid variation of each ZmDREB gene with drought tolerance was evaluated using a diverse population of maize consisting of 368 varieties from tropical and temperate regions. A significant association between the genetic variation of ZmDREB2.7 and drought tolerance at seedling stage was identified. Further analysis found that the DNA polymorphisms in the promoter region of ZmDREB2.7, but not the protein coding region itself, was associated with different levels of drought tolerance among maize varieties, likely due to distinct patterns of gene expression in response to drought stress. In vitro, protein-DNA binding assay demonstrated that ZmDREB2.7 protein could specifically interact with the target DNA sequences. The transgenic Arabidopsis overexpressing ZmDREB2.7 displayed enhanced tolerance to drought stress. Moreover, a favorable allele of ZmDREB2.7, identified in the drought-tolerant maize varieties, was effective in imparting plant tolerance to drought stress. Based upon these findings, we conclude that natural variation in the promoter of ZmDREB2.7 contributes to maize drought tolerance, and that the gene and its favorable allele may be an important genetic resource for the genetic improvement of drought tolerance in maize. PMID:24086146

Translational Genomics for the Improvement of Switchgrass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carpita, Nicholas; McCann, Maureen

2014-05-07

Our objectives were to apply bioinformatics and high throughput sequencing technologies to identify and classify the genes involved in cell wall formation in maize and switchgrass. Targets for genetic modification were to be identified and cell wall materials isolated and assayed for enhanced performance in bioprocessing. We annotated and assembled over 750 maize genes into gene families predicted to function in cell wall biogenesis. Comparative genomics of maize, rice, and Arabidopsis sequences revealed differences in gene family structure. In addition, differences in expression between gene family members of Arabidopsis, maize and rice underscored the need for a grass-specific genetic modelmore » for functional analyses. A forward screen of mature leaves of field-grown maize lines by near-infrared spectroscopy yielded several dozen lines with heritable spectroscopic phenotypes, several of which near-infrared (nir) mutants had altered carbohydrate-lignin compositions. Our contributions to the maize genome sequencing effort built on knowledge of copy number variation showing that uneven gene losses between duplicated regions were involved in returning an ancient allotetraploid to a genetically diploid state. For example, although about 25% of all duplicated genes remain genome-wide, all of the cellulose synthase (CesA) homologs were retained. We showed that guaiacyl and syringyl lignin in lignocellulosic cell-wall materials from stems demonstrate a two-fold natural variation in content across a population of maize Intermated B73 x Mo7 (IBM) recombinant inbred lines, a maize Association Panel of 282 inbreds and landraces, and three populations of the maize Nested Association Mapping (NAM) recombinant inbred lines grown in three years. We then defined quantitative trait loci (QTL) for stem lignin content measured using pyrolysis molecular-beam mass spectrometry, and glucose and xylose yield measured using an enzymatic hydrolysis assay. Among five multi-year QTL for lignin abundance, two for 4-vinylphenol abundance, and four for glucose and/or xylose yield, not a single QTL for aromatic abundance and sugar yield was shared. A genome-wide association study (GWAS) for lignin abundance and sugar yield of the 282-member maize Association Panel provided candidate genes in the eleven QTL and showed that many other alleles impacting these traits exist in the broader pool of maize genetic diversity. The maize B73 and Mo17 genotypes exhibited surprisingly large differences in gene expression in developing stem tissues, suggesting certain regulatory elements can significantly enhance activity of biomass synthesis pathways. Candidate genes, identified by GWAS or by differential expression, include genes of cell-wall metabolism, transcription factors associated with vascularization and fiber formation, and components of cellular signaling pathways. Our work provides new insights and strategies beyond modification of lignin to enhance yields of biofuels from genetically tailored biomass.« less