Harpin Ea protein confers top rot resistance in <scp> <i>Rosa roxburghii</i> </scp> Tratt. through synergistic activation of structural defenses and the phenylpropanoid–flavonoid pathway

Harpin Ea-induced resistance in R. roxburghii is mediated by a synergistic enhancement of physical barriers and systemic activation of phenylpropanoid-flavonoid metabolism. This work provides the first mechanistic evidence linking this dual-layer defense to Harpin Ea-induced disease resistance and establishes a molecular basis for the sustainable application of protein elicitors in fruit crop protection. © 2026 Society of Chemical Industry.