Abstact: In this study, electron beam and γ-ray were used to mutagenize Lecanicillium attenuatum 3166, and the absorbed dose suitable for mutation breeding of Lecanicillium attenuatum and the biological characteristics of the mutagenized strain were studied. The results showed that the optimal dose for electron beam and γ-ray mutagenesis of Lecanicillium attenuatum was 200 Gy, the electron beam D10 value of Lecanicillium attenuatum was 191 Gy, and the γ-ray D10 value was 366 Gy; eight mutant strains were screened and obtained with spore production rate as the index. Among them, the hypha growth and spore production rate of five strains significantly increased compared with the parent strain, which were all obtained by electron beam mutagenesis. The spore production rate increased by 30.45%, 31.55%, 23.66%, 64.83% and 68.77% respectively compared with the parent strain. The extracellular chitinase activity of the mutant strain reached the peak after five days of culture, and the chitinase activities of mutant strains Ⅱ111, Ⅱ164 and Ⅱ181 increased by 29.29%, 54.45% and 19.18% respectively, compared with that of the parent strain. The chitinase activity of mutant strain Ⅱ164 reached 1 707.41 U/mg prot; the extracellular protease activity reached its peak after 7-day culture, and the protease activities of Ⅱ111, Ⅱ164 and Ⅱ181 were significantly increased by 17.98%, 13.17% and 16.50% respectively as compared with those of the parent strain, wherein the enzyme activity of Ⅱ111 could reach 30.71 U/mg prot, and the growth rate of the mutant strain had a strong correlation with the extracellular enzyme activity. This study provides a theoretical basis for the follow-up pest control, development and utilization of Lecanicillium attenuatum.
Key words: Lecanicillium attenuatum; radiation mutagenesis; mutagenized strain; biological property; extracellular enzyme specific activity
（Acta Laser Biology Sinica, 2023, 32(5): 431-440）