Multivariate analysis of maize disease resistances suggests a pleiotropic genetic basis and implicates a GST gene

• Published in: Proceedings of the National Academy of Sciences - PNAS 2011-05, Vol.108 (18), p.7339-7344
• Main Authors: Wisser, Randall J., Kolkman, Judith M., Patzoldt, Megan E., Holland, James B., Yu, Jianming, Krakowsky, Matthew, Nelson, Rebecca J., Balint-Kurti, Peter J., Goodman, Major M.
• Format: Article
• Language: English
• Subjects: Amino acid substitution; Amino acids; Analysis of Variance; Aspartic acid; Base Sequence; Biological resistance; Biological Sciences; Corn; Correlation analysis; Detoxification; Disease resistance; DNA Primers - genetics; Gene mapping; Genes; Genetic Association Studies; Genetic Pleiotropy - genetics; Genetic Variation; Glutathione transferase; Glutathione Transferase - genetics; Goods and services tax; Histidine; Immunity, Innate - genetics; Inbred strains; Inbreeding; Linkage Disequilibrium; Medical genetics; Models, Biological; Molecular Sequence Data; Multivariate Analysis; Nonnative species; Pathogens; Phenotypic traits; Plant diseases; Plant Diseases - genetics; Plant Diseases - microbiology; Plants; Positive selection; Proteins; Sequence Analysis, DNA; Studies; Substrate specificity; Taxonomy; Zea mays
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.1011739108

Plants are attacked by pathogens representing diverse taxonomic groups, such that genes providing multiple disease resistance (MDR) are expected to be under positive selection pressure. To address the hypothesis that naturally occurring allelic variation conditions MDR, we extended the framework of structured association mapping to allow for the analysis of correlated complex traits and the identification of pleiotropic genes. The multivariate analytical approach used here is directly applicable to any species and set of traits exhibiting correlation. From our analysis of a diverse panel of maize inbred lines, we discovered high positive genetic correlations between resistances to three globally threatening fungal diseases. The maize panel studied exhibits rapidly decaying linkage disequilibrium that generally occurs within 1 or 2 kb, which is less than the average length of a maize gene. The positive correlations therefore suggested that functional allelic variation at specific genes for MDR exists in maize. Using a multivariate test statistic, a glutathione S-transferase (GST) gene was found to be associated with modest levels of resistance to all three diseases. Resequencing analysis pinpointed the association to a histidine (basic amino acid) for aspartic acid (acidic amino acid) substitution in the encoded protein domain that defines GST substrate specificity and biochemical activity. The known functions of GSTs suggested that variability in detoxification pathways underlie natural variation in maize MDR.