Discovering disease resistance responses of field pea to major root rot pathogens using RNA-seq and comparative genomics

Abstract

Pea root rot complex (PRRC) is caused by a assemblage of soil-borne fungal and oomycete pathogens, including Aphanomyces euteiches, Fusarium spp., Rhizoctonia solani, and Pythium spp., which collectively cause severe yield losses in pea production worldwide. Studies have confirmed Aphanomyces euteiches and Fusarium avenaceum as major and highly destructive contributors to the complex. Research on the pea root rot complex and its associated pathogens has improved understanding of pathogen diversity, host resistance mechanisms, and disease management strategies. However, the lack of fully resistant cultivars and the complexity of PRRC continue to pose challenges. With the ultimate aim to develop effective solutions for controlling this economically devastating disease through resistant breeding strategies and sustainable management practices, I studied pea defense responses involved in partial resistance to two major pathogens of PRRC, A. euteiches and F. avenaceum, using integrated genomic tools. I performed both field experiments and greenhouse experiments to validate multiple genotypes for their susceptibility and partial resistance to the respective pathogens. I also performed preliminary experiments to determine the pattern and timing of pathogen colonization. Finally, by performing RNAseq on roots inoculated with both A. euteiches and F. avenaceum, I found pathways and candidate defense genes related to both pathogens that may help develop resistant pea cultivars.