Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/25/2004
Publication Date: 2/1/2005
Citation: Luthe, D.S., Pechanova, O., Peethambaran, B., Liu, G.Y., Magbanua, Z.V., Pechan, T., Bridges, S., Hawkins, L.K., Windham, G.L., Williams, W.P. 2005. Taking the cob out: genetic and proteomic approaches for investigating induced and constitutive resistance to Aspergillus flavus during maize (Zea mays L.) ear development [abstract]. Proceedings 2004 4th Annual Fungal Genomics, 5th Annual Multi-Crop Fumonisin Elimination and 17th Annual Multi-Crop Aflatoxin Elimination Workshops. p. 48.
Technical Abstract: Maize (Zea mays L.), one of the world's most important food crops, is susceptible to infection by Aspergillus species that produce the very potent mycotoxin, aflatoxin. Aflatoxin contamination of maize kernels is a serious human and animal health threat worldwide and knowledge gained in maize can be applied to crops with less tractable genetics. In maize, resistance against Aspergillus flavus infection and aflatoxin accumulation is a complex trait that is influenced by genotype and environmental conditions. We are using multiple approaches, including proteomics, to understand how maize inbred lines with varying levels of resistance and susceptibility to Aspergillus flavus resond to fungal infection. Because most aflatoxin accumulation occurs in the field during ear development, we are examining the proteomes of cob tissues from inoculatd and control ears from several different genotypes. Genetic analysis suggests that the maternally derived tissues contribute to resistance, therefore, we are examining the proteomes of the rachis, silks and pericarp. Because studies wth GFP-tagged A. flavus indicated that fungal movement is retarded in the rachis and rachilla of resistant lines, the proteome of rachis tissue collected 21 days after silk emergence has been investigated and approximately 75% of 480 proteins have been identified. Differential-in-gel-electrophoresis (DIGE) is being used to analyze differences among rachis proteins from resistant and susceptible inbreds and inoculated and control ears. Differences in the proteomes of silks from resistant and susceptible inbreds have been examined and the induction of a suite of resistance proteins in response to inoculation has been demonstrated. Protein extracts from resistant silks retard the growth of A. flavus on filter paper disks. Because drought stress is associated with aflatoxin accumulation in maize, we also are examining the proteome of ears from resistant and susceptible genotypes in response to water stress and inoculation with A. flavus. By combining quantitative trait loci mapping, microarray analyses, proteomic studies, bioinformatics and molecular biology, we hope to develop a comprehensive understanding of this complex plant-fungal interaction.