The heat shock protein 70 gene is involved for colony morphology, sporulation and mycoparasitism of Clonostachys rosea.

Heat shock protein 70 (HSP70) is an evolutionarily conserved chaperone protein. However, the role of HSP70 in mycoparasitism is unclear. Clonostachys rosea shows great potential against plant fungal pathogens. An HSP70 encoding gene, crhsp, from C. rosea 67-1 was significantly upregulated during C. rosea parasitization of the sclerotia of Sclerotinia sclerotiorum. In the present study, we investigated the role of crhsp in mycoparasitism using gene knockout experiments. The results showed that disruption of crhsp had remarkabe effects on the morphological characteristics of C. rosea. In addition, the ability of C. rosea to parasitize sclerotia and control soybean Sclerotinia stem rot in the greenhouse was significantly reduced in the Δcrhsp mutant. The results indicated that crhsp is involved in C. rosea mycoparasitism and provide the basis for further study of the molecular mechanism of C. rosea mycoparasitism. This is the first report to demonstrate the involvement of the HSP70 gene in C. rosea mycoparasitism.