Cellobiose elicits immunity in lettuce conferring resistance against.

Cellobiose is the primary product of cellulose hydrolysis and is expected to be served as pathogen/damage-associated molecular patterns (PAMPs/DAMPs) in evoking plant innate immunity. In the study, cellobiose was demonstrated to be a positive regulator in immune response, but devote to halt autoimmunity when lettuce was exposed to cellobiose higher than 60 mg·L -1. When infected by Botrytis cinerea, cellobiose endowed plants with enhanced pre-invasion resistance by activating high levels of β-1,3-glucanase and anti-oxidative enzyme activities at the initial stage of pathogenic infection. Meanwhile, cellobiose-activated core regulatory factors such as EDS1, PTI6, and WRKY70 as well as SA signaling played an indispensable role in modulating plant growth-defense tradeoffs. Transcriptomics data further suggested that the cellobiose-activated plant-pathogen pathways are involved in MAMPs / PAMPs-triggered immune responses (PTI). Genes encoding receptor-like kinases, redox homeostasis, phytohormone signal transduction, transcription factors, and pathogenesis-related proteins were also detected to be up- or down-regulated by cellobiose. Taken together, this study demonstrated that cellobiose serves as an elicitor can directly activate disease resistance-related cellular functions. Besides, multiple genes have been identified as potential modulators of the cellobiose-induced immune response, which could inform efforts to understand underlying molecular events.