Transcriptome Profile in a Susceptible Pear 'Zaosu' (Pyrus bretschneideri Rehd.)-Valsa pyri Interaction

Pear production was seriously threatened by Valsa canker, a notorious disease caused by the necrotrophic fungus Valsa pyri (Vp), but the molecular mechanism is elusive. Currently, the dynamic gene expression profiles of main susceptible variety 'Zaosu' (Pyrus bretschneideri Rehd.) in response to Vp were investigated using RNA sequencing (RNA-seq). In total, 286, 1912, and 6321 differentially expressed genes (DEGs) were detected from the infected phloem tissues at 1, 2, and 4 days after infection, respectively. Functional terms Stress biotic, Signaling. receptor kinase, and Plant hormone signal transduction were significantly enriched. DEGs associated with Ethylene, Chitinase, Glycosyl hydrolase, and receptor-like kinase (RLK) subfamilies LysM and WAK_LRK10L-1 were mainly up-regulated and contributed to induction of the immune responses in 'Zaosu'. On the contrary, DEGs involved in auxin and brassinosteroid signals, receptor-like protein, nucleotide-binding leucine-rich repeat (NB-LRR), and RLK subfamilies CrRLK1L-1, LRR-III, LRR-VII, and LRR-XII are mainly down-regulated, which are the reasons why 'Zaosu' fails to prevent Vp invasion. Our results highlight new insights into pear responses against Vp and perhaps other necrotrophs.

Automated summary

This study investigated the gene expression profiles of 'Zaosu' pear trees infected with Valsa canker using RNA sequencing. The study identified differentially expressed genes associated with immune responses and the reasons for Valsa canker invasion in 'Zaosu' pears.