Two polysaccharide elicitors trigger systemic acquired resistance to resist Sclerotium rolfsii and its transcriptional characteristic in Atractylodes macrocephala

The elicitors can trigger plants systemic acquired resistance. In contrast to the well-characterized exogenous elicitor-induced common response, little is known about how the plants have activated SAR response to pathogen challenge. Here, early transcriptional reprogramming and downstream immune outputs in SAR-activated plants against the Sclerotium rolfsii Sacc stress were investigated by comparative biochemical and transcriptomics in Atractylodes that sprayed by two polysaccharide elicitors (designated as CIP and SR). It was evident that the SAR-activated plants exhibit unique expression characteristics in response to pathogens stress, depending on the discrepancies between CIP and SR, the CIP-induced response depend on some antimicrobial proteins, but the SR depend on phytohormone genes family, in spite of both elicitors instigate common downstream immune output. Notably, some overlap genes not only occurred in SAR-activated plants but also in SAR-activated challenge plants, indicating invisible immune memory in plant. Otherwise, the SAR-activated plants share a reversed genes pattern with the SAR-activated challenge group, and they all tended to resist the susceptible plants' transcriptional reprogramming process (most positive defense genes were suppressed) via reversed genes pattern, which these up- and down-regulated in plant is analogous to "immuno-correct action" of animals' vaccines.