Induction of disease resistance against Botrytis cinerea by heat shock treatment in melon (Cucumis melo L.)

The present study investigated resistance against Botrytis cinerea after heat shock treatment in melon plants. Heat shock at 50 °C for 20 s 0–24 h before inoculation resulted in maximal B. cinerea symptom reduction and peroxidase gene expression, which peaked 12 and 72 h post-treatment and decreased 24–48 h post-treatment, suggesting pathogenesis-related protein expression priming. Hot water dipping did not directly inhibit mycelia growth. Plants treated with 2-benzisothiazol-3(2H)-one 1,1-dioxide, which induces systemic acquired resistance, demonstrated higher peroxidase gene expression but no B. cinerea resistance, indicating possible involvement of additional novel mechanisms in heat shock-activated resistance of melon against B. cinerea.

► BIT did not reduce gray mold disease symptoms.
► SAR mediate partly the protective effect of heat shock treatment.
► Mechanism may be involved in the disease resistance induced by heat shock against B. cinerea.