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Chinese Journal Of Biological Control ›› 2020, Vol. 36 ›› Issue (5): 729-736.

• RESEARCH REPORTS •

### Effect of Serine Protease Inhibitor Serpin1 from Locusta Migratoria on the Infection of Metarhizium anisopliae

LI Beibei1,2, TIAN Ye1,3, DU Guiling4, YUE Fangzheng5, NONG Xiangqun1,2, LIU Tinghui3, ZHANG Zehua1,2, WANG Guangjun1,2

1. 1. State Key Laboratory for Biology of Plant Diseases and Insect Pests/Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China;
2. Xilingol Grassland Pest Science Observation and Experiment Station, Ministry of Agriculture and Rural Affairs, Xilinhot 026000, China;
3. College of Plant Protection, Hebei Agricultural University, Baoding 071001, China;
4. National Animal Husbandry Service, Beijing 100125, China;
5. Forest and Grassland Control Station of State Forestry and Grassland Administration, Shenyang 110034, China
• Received:2019-11-28 Online:2020-10-08 Published:2020-11-20

Abstract: Serpins are a particularly important class of protease inhibitors in insects and have the function of regulating insect immune responses. Effect of Serpin1on the infection of Metarhizium anisopliae was investigated. The serpin1 gene was cloned from Locust amigratoria and expressed in Escherichia coli BL21, and then Serpin1 protein was tested for its effect on virulence of M. anisopliae IMI330189 to the locust by feeding method. The activities of protective enzymes SOD and POD were measured in the locusts treated with M. anisopliae IMI330189, Serpin1, or M. anisopliae IMI330189 plus Serpin1. The results showed that combined treatment of M. anisopliae IMI330189 and Serpin1 decreased the mortality of locust as compared to treatment of M. anisopliae alone at 3rd day post treatment (DPT). The treatment of M. anisopliae alone caused 100% mortality of locust at the 8th DPT while the combined treatment of M. anisopliae and Serpin1 resulted in a mortality of 84.31%, the difference was significant. Activity of POD in the treatment of M. anisopliae alone increased and was significantly higher than that in the control at the 2nd and 3rd DPT, and then decreased on the 5th DPT and was significantly lower than that in the control. POD activity in the combined treatment of M. anisopliae IMI330189 and Serpin1 was significantly higher than the control group and the treatment of M. anisopliae IMI330189 alone at the 3rd and 5th DPT, while was significantly lower at the 1st DPT. Activities of SOD in the treatment of M. anisopliae IMI330189 alone and the combined treatment of M. anisopliae IMI330189 and Serpin1 were significantly higher than that in the control group at the 1st, 3rd and 5th DPT while significantly lower at the 2nd DPT. SOD activity in the combined treatment of M. anisopliae IMI330189 and Serpin1 was significantly higher than that in the M. anisopliae IMI330189 treatment at the 2nd and 3rd DPT. Our results confirmed that the serpin1 could effectively inhibit the fungal infection by decreasing the activity of proteases in locust and laid a foundation for further study of the physiological functions of serpins.

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