Expressions of the trypsin-like-enzyme, AlSP4 and total trypsin-like-enzyme in Apolygus lucorum (Meyer-Dür) (Hemiptera: Miridae) feeding on different cotton varieties

Abstract

Apolygus lucorum is currently a main pest of cotton in China. In this study, the expression of trypsin-like enzyme AlSP4 gene and corresponding protein in A. lucorum was confirmed to be significantly higher when it fed on Bt cotton than on conventional cotton and Sauteed green beans (control). Compared with Bt cotton, when A. lucorum fed on conventional cotton, the total trypsin-like enzyme activity and female fertility were reduced overtly. And, when it fed on non-hybrid cotton (Gk19 and Sim3), A. lucorum showed a higher expression of total trypsin-like protease, per female fecundity, hatching rate of eggs and life span than on hybrid cotton (Ezm10 and Sum9). This indicated that the hybrid cotton inhibited the growth and development of A. lucorum better than the non-hybrid cotton. Furthermore, data analysis showed that there were significant positive linear associations between female trypsin-like enzyme activity and key factors of population proliferation, such as female adult life span and per female fecundity. These findings indicated that the total trypsin-like enzyme was a potential target to control A. lucorum, especially the female adults.