Functional Analysis Of Hexamerin Gene Family In Locusta Migratoria Manilensis

Insect storage proteins(hexamerins)is a kind of specific haemolymph protein,widely exist as nutrients(such as amino acids)repository in insects.Hexamerins provide an important buffer link between the storage of amino acid and normal metabolic demandon(such as molting,metamorphosis,adult diapause and the formation of egg).In addition,hexamerins may be involved in the insect cuticular hardening,hormone transport,energy metabolism,immune defense and other life activities.In this study,we used molecular biology methods to study the function of hexamerins of Locusta migratoria.The main results are as follows:(1)The fragment c DNAs of hexamerin gene family from Locusta migratoria were gained.The first-strand c DNAs were synthesized using total RNA isolated from larvae,TA cloning was carried out to obtaine the fragment c DNAs of hexamerin gene family from Locusta migratoria.The Lm Hx1 gene fragment was 660 bp,Lm Hx3 gene fragment was 787 bp,Lm Hx4 gene fragment was 789 bp,Lm Hx5 gene fragment was 373 bp;The cloning results show that Lm Hx1 has alternative splicing.(2)The differences of expression levels were analyzed in different tissues.The relative expression levels of hexamerin gene family show consistency in different tissues,all members were highly expressed in epidermis and fat body,partly expressed in gonads(ovaries and testes),and hardly expressed in midgut and hemolymph.(3)Research on the immune function of the hexamerin gene family of Locusta migratoria.Epidermis and fat body highly expressed hexamerins after E.coli challenged were choosed in this study.The relative expression levels of Lm Hx1 and Lm Hx3 show a trend from declining to rising,while the relative expression levels of Lm Hx4 and Lm Hx5 show a trend from rising to declining.(4)Research on the biological function of the hexamerin gene family of Locusta migratoria.The biological functions of Lm Hx5 were studied by RNA interference,the results showed that the relative expression levels of Lm Hx5 were reduced in the nymphs and hardlyexpressed after 96 hours,and RNAi efficiency was significant.When Lm Hx5 was knocked out,Locusta migratoria displayed slowly development,some appeared malformation or death for failing to molt successfully.The relative expression levels of other members of hexamerin genes family showed varying degrees of increase when Lm Hx5 was silenced.In conclusion,Lm Hx4 and Lm Hx5 participate in the immune regulation of Locusta migratoria,hexamerin gene family members manifest functional compensation,and Lm Hx5 shows positive regulation of epidermal formation degenerate of Locusta migratoria.