Study On The Regulation Of Insulin-like Peptide On The Trade-offs Between And Reproduction Immunity In The Locusta Migratoria Manilensis

Insulin is a class of evolutionarily very conservative peptide hormones,known for its ability to lower Blood glucose,and regulates reproduction,metabolism,and development in organisms.Peptide hormones with similar structures and functions in insects are called "insulin-like peptides"(ILPs).Locusta migratoria manilensis is one of the main agricultural pests in China,and it has caused huge losses to agriculture in Chinese history.In this paper,the ILP gene sequence of the Locusta migratoria manilensis was obtained by cloning and biological information analysis was carried out.In order to further explore the regulation of LmILP on the reproduction and immunity of the Locusta migratoria,mainly through the injection of exogenous insulin,RNAi technology and mixed injection treatment methods,real-time quantitative PCR was used to detect the genes related to reproduction and immunity of female adults,as well as the expression of related genes such as insulin signaling pathway and juvenile hormone signaling pathway,and to detect the enzyme activities of phenoloxidase and lysozyme.The ovary weight to judge the effects on reproduction.The main results are as follows:(1)The biological information analysis of the known ILP sequence of the Locusta migratoria manilensis was carried out,and the protein secondary structure of the ILP and the tertiary structure of the conserved region protein were found.The open reading frame of ILP is 438 bp,encoding 145 amino acids,the predicted protein molecular weight is 15.8 kD,and the predicted protein isoelectric point is 8.99.(2)The relative expression levels of different signaling pathway-related genes in different adult female adults were determined by real-time quantitative PCR.The results showed that after injection of exogenous insulin,the genes of IIS and JH signaling pathways in Locusta migratoria manilensis were significantly down-regulated,the expression of some immune receptor genes was significantly down-regulated,the expression of antimicrobial peptide gene was significantly up-regulated,and the expression of Vg was significantly down-regulated.VgR expression was significantly upregulated.After interfering with ILP gene,LOCMI07679 and LOCMI16380 were not significantly different in IIS signaling pathway.The relative expression levels of other genes were significantly down-regulated,FOXO expression was up-regulated,indicating that IIS was inhibited;JH signal pathway,JH relative expression was extremely Significantly down-regulated,Tai A and MCM7 were not significantly different,and the relative expression of the remaining genes was significantly down-regulated,indicating that the JH signaling pathway was inhibited;the expression levels of the immune pathway-related genes LOCM09346,LOCM10748,and LmDEF3 were significantly down-regulated,and the remaining genes were not significantly different;The relative expression levels of VgA,VgB,VgR1 and VgR2 in the gene were all significantly down-regulated,indicating that the reproduction of the Locusta migratoria manilensis was affected.After mixed injection of dsILP and insulin,the expression of FOXO gene in IIS was significantly up-regulated,and the expression of LmILP gene was significantly down-regulated,indicating that IIS was inhibited in the case of mixed injection,but the expression of PI3K92 E gene was significantly up-regulated,indicating that IIS may be Not completely inhibited,the inhibited part may be the regulatory pathway gene downstream of IIS;under mixed injection,the expression of MET and 20 E in the JH signaling pathway of Locusta migratoria manilensis was extremely significantly down-regulated,and the expression level of MCM4 was significantly up-regulated.The Toll receptor9 gene was significantly up-regulated in the immunization-related genes of the Locusta migratoria manilensis under mixed injection.The Toll intreacting protein gene was significantly up-regulated,but the relative expression levels of Toll-like receptor6 and LmDEF3,LmDEF4 and LmDEF5 were significantly down-regulated,probably due to the activation of PI3 K.The expression of Toll-like receptor6 and antibacterial peptide genes was inhibited.Under the mixed injection,the expression levels of Vg and VgR in the growth of the Locusta migratoria manilensis showed a decrease,indicating that the Locusta migratoria manilensis breeding gene was regulated by the downstream genes of IIS.After the downstream genes of IIS were inhibited,the growth of the Locusta migratoria manilensis was inhibited.(3)For the ovary development of the Locusta migratoria,the weight of the ovary increased although it was not significant when the exogenous insulin was injected.After injection of dsILP,the ovary weight decreased but was not significant.However,when the exogenous insulin and dsILP were mixed,the ovary weight of the Locusta migratoria manilensis decreased significantly.The possible reason was that the synthesis and absorption of Vg and VgR were inhibited after the mixed injection of exogenous insulin and dsILP.In terms of enzyme activity,the activity of mites lysozyme was significantly decreased when only exogenous insulin was injected,but the activity of phenoloxidase increased,but there was no significant difference,indicating that the immunity of Locusta migratoria manilensis was inhibited after injection of exogenous insulin;When only dsRNA was injected,the lysozyme activity and phenoloxidase activity of Locusta migratoria manilensis decreased,indicating that the interference of ILP will affect Locusta migratoria manilensis immunity from the enzyme activity level;the lysozyme and phenoloxidase activity of Locusta migratoria manilensis were extremely significant under the mixed injection of exogenous insulin and dsILP.The decrease indicates that the inhibitory effect of the lysozyme and phenoloxidase activity of Locusta migratoria manilensis is enhanced under mixed injection.