High-throughput phenomics platform for interactions of barley with fungal pathogens

The plant immune system shows similarities with the innate immunity system of insects and mammals, yet keeping many plant-specific characteristics. Nonhost- and race-nonspecific host (basal-) resistance are two types of plant durable resistance hence of high importance to plant breeders. However, they are usually controlled by multiple quantitative trait loci (QTL) and therefore, difficult to approach by conventional or marker-assisted breeding. Understanding the genes underlying durable disease resistance will allow us to utilize it in a more targeted manner. Transient-induced gene silencing (TIGS) is one way to discover candidate genes underlying resistance QTL. We have developed and exploited a TIGS-based phenomics platform, which takes advantage of the well established model pathosystem of barley and the powdery mildew fungus together with efficient cloning and transformation protocols, and automated microscopic systems. The screening pipeline can be fed with candidates genes selected by different approaches such as transcript profiling, gene functional catalogs, co-localization with QTLs, etc. Until present we have tested approximately 1500 genes, which revealed 70 candidate genes significantly increasing resistance or susceptibility upon TIGS, as reflected by increased or decreased number of fungal haustoria inside transformed epidermal cells. We are working on further development of the phenomics platform towards quantification of hyphal growth rates, higher level of automation, and expanding the host and pathogen range.