Updated project metadata. Botrytis cinerea causes grey mold disease in leading crop plants. The disease develops only at cool temperatures, but the fungus remains viable in warm climates and can survive periods of extreme heat. We discovered a strong heat priming effect in which the exposure of B. cinerea to moderately high temperatures greatly improves its ability to cope with subsequent, potentially lethal temperature conditions. We showed that priming promotes protein solubility during heat stress and discovered a group of priming-induced serine-type peptidases. Several lines of evidence, including transcriptomics, proteomics, pharmacology and mutagenesis data, link these peptidases to the B. cinerea priming response, highlighting their important roles in regulating priming-mediated heat adaptation.