Puccinia striiformis vs Triticum aestivum: Molecular Aspects of Stripe Rust Interaction With Resistant and Susceptible Wheat Host

Analysis of historical and contemporary occurrence of disease and crop loss magnitude in major wheat-producing regions estimated that stripe rust caused by P. striiformis f. sp. Tritici is the most significant biotic threat to sustainable wheat production worldwide. It can reduce wheat grain yield up to 100% in susceptible cultivars. Despite this agricultural importance and long history of study, still little is known about molecular interaction between stripe rust and the wheat host. To mitigate disease impact and improve breeding strategies for durable resistance, it is important to understand stripe rust pathogenicity on the gene expression level. Here we present analysis of the molecular interaction between P. striiformis f. sp. Tritici (Pst-100) versus resistant and susceptible lines of Triticum aestivum using next generation transcriptomics. Variable host background allowed us to indicate how gene expression patterns shift in compatible versus incompatible interactions. Resistant wheat lines induced significantly greater number of overexpressed, putative genes along with higher upregulation fold change. Oxidation-reduction, MAPK cascade, stress granule formation, osmotic stress, and other stress-related pathways were, almost exclusively, upregulated in resistant host background, suggesting broad activation of the resistance-coping mechanisms by stripe rust. In contrast, susceptible host background facilitated broad overrepresentation of the nutrient uptake pathways in the pathogen, allowing it to downregulate the expression of metabolically costly stress-related genes. The present study provides the first whole transcriptome assessment of stripe rust - wheat interaction from the fungal side and contributes to further elucidation of plant-pathogen molecular interplay on the systemic level.