Extracellular self-DNA as a DAMP signal for induced systemic resistance to anthracnose rot in postharvest loquat fruit via EjRAV2-EjERF39 module

The study explored the impact of fragmented sDNA on anthracnose rot in postharvest loquat fruit and the underlying mechanisms. The findings revealed that the perception of fragmented sDNA triggered pattern-triggered immunity (PTI) defense, effectively inhibiting Colletotrichum gloeosporioide infection in postharvest loquat fruit. Transcriptome sequencing showed that fragmented sDNA activated ethylene-mediated induced systemic resistance (ISR), linked to increased transcription of genes in phenylpropanoid metabolism. Y2H and Co-IP experiments demonstrated a significant interaction between EjERF39 and EjRAV2. Furthermore, DLR and EMSA assays showed that EjRAV2 enhanced the activation of EjERF39-mediated transcription of genes related to phenylpropanoid metabolism (EjPAL1, Ej4CH, EjC4L1, EjCAD1, and EjCCR1), leading to increased accumulation of phenolics and lignin. Accordingly, overexpression of EjRAV2 in Arabidopsis thaliana increased the expression of genes related to phenylpropanoid metabolism and enhanced resistance to C. gloeosporioides compared to the wild type. Therefore, DAMP signals from fragmented sDNA activate PTI-driven ISR, with the EjRAV2-EjERF39 module regulating phenylpropanoid metabolism in loquat fruit. [Display omitted] •sDNA effectively inhibits anthracnose rot in postharvest loquat fruit.•sDNA acts as a DAMP that induces PTI defense in loquat fruit.•sDNA activates the ET-mediated induced systemic resistance.•EjRAV2-EjERF39 module upregulates phenylpropanoid metabolism through ISR.