Clonostachys rosea is a promising biocontrol fungus active against various plant fungal pathogens. In this study, the endochitinase-encoding gene Chi67-1, the expression of which is sharply upregulated in C. rosea 67-1 when induced by sclerotia, was transformed into the original isolate by protoplast transformation, and transformants were screened against Sclerotinia rot of soybean. The transformation efficiency was approximately 50 transformants per 1 × 107 protoplasts, and 68 stably heritable recombinants were assayed. The parasitic rates of 32.4% of the tested strains increased by more than 50% compared to 43.3% of the wild type strain in 16 h, and the Rc4-4 transformant showed a parasitic rate of 100% in 16 h. The control efficiencies of the selected efficient transformants to soybean Sclerotinia stem rot were evaluated in pots in the greenhouse, and the results revealed that Rc4-4 achieved the highest efficiency of 81.4%, which was 31.7% and 28.7% higher than the control achieved by the wide type and the pesticide carbendazim, respectively. Furthermore, the expression level of Chi67-1 was 107-fold higher in Rc4-4 than in the wild type, and accordingly, the chitinase activity of the recombinant increased by 140%. The results lay a foundation for the development of efficient genetically engineered strains of C. rosea.

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Clonostachys rosea is a promising saprophytic filamentous fungus that belongs to phylum Ascomycota. Clonostachys rosea is widespread around the world and exists in many kinds of habitats, with the highest frequency in soil. As an excellent mycoparasite, C. rosea exhibits strong biological control ability against numerous fungal plant pathogens, nematodes and insects. These behaviours are based on the activation of multiple mechanisms such as secreted cell-walldegrading enzymes, production of antifungal secondary metabolites and induction of plant defence systems. Besides having significant biocontrol activity, C. rosea also functions in the biodegradation of plastic waste, biotransformation of bioactive compounds, as a bioenergy sources and in fermentation. This mini review summarizes information about the biology and various applications of C. rosea and expands on its possible uses.