Genetical Microscopy: Linking the Genic Basis of Maize Disease Resistance to Effects on Pathogenesis

Unraveling the bases of complex traits and capitalizing on the knowledge gleaned from this for population improvement continues to challenge a broad community of researchers. Quantitative disease resistance is one such trait for which the level of complexity is even greater because it involves microscopic interactions between organisms. The DR Maize (Disease Resistance of Maize) project is working toward the discovery and validation of genomic variants for resistance to quantitative defense against fungal foliar pathogens. This is being pursued using a combination of resequencing, GWAS, breakpoint analysis, mutant screens, transcriptomics, and transformational validation. Simultaneously, pathogenesis is being characterized by 3D microscopy of infected host isogenic lines that contrast for natural and induced allele effects, thereby elucidating how quantitative resistance genes function to limit disease development. An experimentally validated imaging platform and computer vision tools have been developed for this. This talk will highlight multiple aspects of the project related to gene discovery and validation, while focusing on recent developments for imaging microscopic plant-pathogen interactions across a macroscopic area of host tissue and placing those observations into the context of disease development and gene function. Working with two fungal pathogens along with other evidence suggests the imaging platform is extensible to studying other plant/pathogen systems, but differences in pathogenesis introduce the need for some tailored approaches.