title: Characterization of the Maize Chitinase Genes and Their Effect on Aspergillus flavus and Aflatoxin Accumulation Resistance.
abstract: Maize (Zea mays L.) is a crop of global importance, but prone to contamination by aflatoxins produced by fungi in the genus Aspergillus. The development of resistant germplasm and the identification of genes contributing to resistance would aid in the reduction of the problem with a minimal need for intervention by farmers. Chitinolytic enzymes respond to attack by potential pathogens and have been demonstrated to increase insect and fungal resistance in plants. Here, all chitinase genes in the maize genome were characterized via sequence diversity and expression patterns. Recent evolution within this gene family was noted. Markers from within each gene were developed and used to map the phenotypic effect on resistance of each gene in up to four QTL mapping populations and one association panel. Seven chitinase genes were identified that had alleles associated with increased resistance to aflatoxin accumulation and A. flavus infection in field grown maize. The chitinase in bin 1.05 identified a new and highly significant QTL, while chitinase genes in bins 2.04 and 5.03 fell directly beneath the peaks of previously published QTL. The expression patterns of these genes corroborate possible grain resistance mechanisms. Markers from within the gene sequences or very closely linked to them are presented to aid in the use of marker assisted selection to improve this trait.
authors.affiliation: USDA-ARS Corn Host Plant Resistance Research Unit, Mississippi State, Starkville, MS, United States of America.
authors.forename: Leigh K
authors.initials: LK
authors.lastname: Hawkins
authors.affiliation: USDA-ARS Corn Host Plant Resistance Research Unit, Mississippi State, Starkville, MS, United States of America.
authors.forename: J Erik
authors.initials: JE
authors.lastname: Mylroie
authors.affiliation: Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University, Starkville, MS, 39762, United States of America.
authors.forename: Dafne A
authors.initials: DA
authors.lastname: Oliveira
authors.affiliation: USDA-ARS Corn Host Plant Resistance Research Unit, Mississippi State, Starkville, MS, United States of America.
authors.forename: J Spencer
authors.initials: JS
authors.lastname: Smith
authors.affiliation: Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University, Starkville, MS, 39762, United States of America.
authors.forename: Seval
authors.initials: S
authors.lastname: Ozkan
authors.affiliation: USDA-ARS Corn Host Plant Resistance Research Unit, Mississippi State, Starkville, MS, United States of America.
authors.forename: Gary L
authors.initials: GL
authors.lastname: Windham
authors.affiliation: USDA-ARS Corn Host Plant Resistance Research Unit, Mississippi State, Starkville, MS, United States of America.
authors.forename: W Paul
authors.initials: WP
authors.lastname: Williams
authors.affiliation: USDA-ARS Corn Host Plant Resistance Research Unit, Mississippi State, Starkville, MS, United States of America.
authors.forename: Marilyn L
authors.initials: ML
authors.lastname: Warburton
mesh_terms: D000348:Aflatoxins / Q000378:metabolism*; D001231:Aspergillus flavus / Q000378:metabolism*; D002688:Chitinases / Q000235:genetics* / Q000378:metabolism; D002874:Chromosome Mapping; D019295:Computational Biology; D030541:Databases, Genetic; D017343:Genes, Plant; D014644:Genetic Variation; D054884:Host-Pathogen Interactions / Q000235:genetics*; D010641:Phenotype; D010802:Phylogeny; D003313:Zea mays / Q000235:genetics* / Q000378:metabolism* / Q000382:microbiology
chemical_list: D000348:Aflatoxins; D002688:Chitinases