title: Susceptibility to aflatoxin contamination among maize landraces from Mexico.
abstract: Maize, the critical staple food for billions of people, was domesticated in Mexico about 9,000 YBP. Today, a great array of maize landraces (MLRs) across rural Mexico is harbored in a living library that has been passed among generations since before the establishment of the modern state. MLRs have been selected over hundreds of generations by ethnic groups for adaptation to diverse environmental settings. The genetic diversity of MLRs in Mexico is an outstanding resource for development of maize cultivars with beneficial traits. Maize is frequently contaminated with aflatoxins by Aspergillus flavus, and resistance to accumulation of these potent carcinogens has been sought for over three decades. However, MLRs from Mexico have not been evaluated as potential sources of resistance. Variation in susceptibility to both A. flavus reproduction and aflatoxin contamination was evaluated on viable maize kernels in laboratory experiments that included 74 MLR accessions collected from 2006 to 2008 in the central west and northwest regions of Mexico. Resistant and susceptible MLR accessions were detected in both regions. The most resistant accessions accumulated over 99 % less aflatoxin B1 than did the commercial hybrid control Pioneer P33B50. Accessions supporting lower aflatoxin accumulation also supported reduced A. flavus sporulation. Sporulation on the MLRs was positively correlated with aflatoxin accumulation (R = 0.5336, P < 0.0001), suggesting that resistance to fungal reproduction is associated with MLR aflatoxin resistance. Results of the current study indicate that MLRs from Mexico are potentially important sources of aflatoxin resistance that may contribute to the breeding of commercially acceptable and safe maize hybrids and/or open pollinated cultivars for human and animal consumption.
authors.affiliation: School of Plant Sciences, University of Arizona, Tucson, Arizona 85721, USA; Department of Plant Pathology, University of California, Davis, Kearney Agricultural Research and Extension Center, Parlier, CA 93648, USA.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Ortega-Beltran
authors.affiliation: Secretaría de Agricultura, Ganadería, Desarrollo Rural, Pesca y Alimentación (SAGARPA), Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias (INIFAP), Campo Experimental Norman E. Borlaug (CENEB), Ciudad Obregón, Sonora 85000, México.
authors.forename: Manuel D J
authors.initials: MD
authors.lastname: Guerrero-Herrera
authors.affiliation: Secretaría de Agricultura, Ganadería, Desarrollo Rural, Pesca y Alimentación (SAGARPA), Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias (INIFAP), Campo Experimental Norman E. Borlaug (CENEB), Ciudad Obregón, Sonora 85000, México.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Ortega-Corona
authors.affiliation: SAGARPA, INIFAP, El Centro de Investigación Regional del Noroeste (CIRNO), Santiago Ixcuintla, Nayarit 63300, México.
authors.forename: Victor A
authors.initials: VA
authors.lastname: Vidal-Martinez
authors.affiliation: U.S. Department of Agriculture, Agricultural Research Service, School of Plant Sciences, University of Arizona, Tucson, Arizona 85721, USA. pjcotty@email.arizona.edu.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Cotty
mesh_terms: D000348:Aflatoxins / Q000032:analysis* / Q000378:metabolism; D000818:Animals; D001231:Aspergillus flavus / Q000254:growth & development / Q000378:metabolism; D005260:Female; D005506:Food Contamination / Q000032:analysis*; D006801:Humans; D008800:Mexico; D003313:Zea mays / Q000737:chemistry* / Q000382:microbiology
chemical_list: D000348:Aflatoxins