Performing Department
(N/A)
Non Technical Summary
Identifying resistant germplasm is critical for reducing yield losses due to crop diseases. I propose to investigate disease resistance in populations of maize landraces and teosinte, the wild relative of maize. Maize landrace and teosinte populations have adapted to a wide range of environmental conditions and display remarkable genetic and phenotypic diversity. In this project, I will describe genetic variation for disease resistance in populations from across the native range of maize/teosinte and perform genome wide association analysis to identify alleles associated with resistance. To understand mechanisms underlying disease resistance I will measure multiple components of disease resistance in these populations and correlations between these traits and overall disease resistance. As landraces and wild relatives have experienced historical selection from their local environments, they provide an opportunity to understand how agronomically important traits have evolved. I will test selection on these traits and whether they have been shaped by adaptation to environmental features. Finally, I will investigate the transcriptomic basis of the defense response in a subset of these populations to identify genes that are differentially expressed in infected and uninfected plants. I will ask whether environmentally distinct populations have different responses to pathogens. This project supports the USDA AFRI program area Plant Health and Production and Plant Products and priority area Plant Breeding for Agricultural Production by identifying alleles and mechanisms underlying disease resistance in maize and associations between adaptive traits and growing environments.
Animal Health Component
(N/A)
Research Effort Categories
Basic
80%
Applied
(N/A)
Developmental
20%
Goals / Objectives
Goal:I propose to investigate the genetic basis of QDR in maize landraces and wild relatives, identify genetic variants associated with resistance and hypothesized underlying traits, characterize the distribution of QDR across populations sourced from along environmental gradients, and use multi-trait analyses and transcriptomic data to elucidate the mechanisms of QDR in these populations. The results of this project will inform strategies for breeding disease resistant crops and uncovering genetic variation.Objective 1:Characterize variation in disease resistance to SLB and NLB and in hypothesized associated traits in landrace and teosinte accessionsObjective 2:Analyze selection on disease resistance and hypothesized QDR associated traitsObjective 3:Characterize transcriptomic responses to disease in diverse lines.?
Project Methods
Objective 1:Characterize variation in disease resistance to SLB and NLB and in hypothesized associated traits in landrace and teosinte accessions. Methods: Evaluate disease resistance in the field as well as associated traits in growth chambers. Use multi-trait GWAS to identify markers associated with these traits.Objective 2:Analyze selection on disease resistance and hypothesized QDR associated traits. Methods: Use random forest regression to estimate associations between disease resistance and source populationenvironmental variables. Measureenvironmentally variable selection on disease resistance and associated traits.Objective 3:Characterize transcriptomic responses to disease in diverse lines. Methods: Sequence the transcriptomes of resistant and susceptible genotypes from highland and lowland populations in both inoculated and uninoculated conditions. Align reads to the B73 reference genome and identify differentially expressed genes and pathways.