Identification And Expression Analysis Of Putative Chemoreception Genes From Nezara Viridula And Leptocorisa Acuta

Nezara viridula and Leptocorisa acuta are notorious rice pests in Asia.Due to various drawbacks of chemical prevention,it is necessary to seek environmentally friendly control measures.OBPs and CSPs in insect antennae are the main olfactory proteins that recognize various odor compounds,and have also been proved to be the important target molecμles for insect olfactory-driven behavior regμlators.Due to the functional diversity of insects OBPs and CSPs,their gene expression patterns need to accurately judge.Antennae and mouthparts belong to insect olfactory and non-olfactory organs,respectively,and are rich in these two types of OBP and CSP.In this study,Next-generation sequencingmethod was used to sequence the antennae and mouthparts of two bugs,and bioinformatics methods was used to identify the OBPs and CSPs genes.Then the evolutionary relationship between these proteins and other hemiptera insects were analyzed.In order to further explore the potential functions of Nezara viridμla and Leptocorisa acuta,differential expression analysis of OBPs and CSPs genes between antennae and mouthparts were analyzed as well as Real-time quantitative PCR(RT-q PCR)method.The research resuts were as follows:(1)In N.viridula,42 unigenes were identified coding for OBPs(34 Classic OBPs and eight Plus-C OBPs),and 13 unigenes coding for CSPs.In L.acuta,26 unigenes were identified coding for OBPs(22 Classic OBPs and 4 Plus-C OBPs),and 17 unigenes coding for CSPs.(2)Phylogenetic analysis revealed that the OBPs of Nezara viridula and Leptocorisa acuta are highly conserved,and can be divided into Classic OBPs and Plus-C OBPs.In N.viridula,there was an OBP expansion(Nvir OBP29/30/32/36),and two sister pairs(Nvir OBP12/18 and Nvir OBP21/34).N.viridula CSPs were not found gene expansion and sister pairs,and other OBPs were clustered with OBPs from the Halyomorpha halys and Tessaratoma papillosa,respectively.In L.acuta,there was only one OBP expansion(Lacu OBP21/24/26),and two sister pairs in CSPs(Lacu CSP4/8 and Lacu CSP5/9).(3)Differential expression analysis of OBP and CSP showed that 29 OBPs(Nvir OBP1,3-14,16-18,20-25,27-30,33,35,37)and 4 CSPs(Nvir CSP3,4,6 and 9)were mainly expressed in antennae,whereas five OBPs(Nvir OBP36,38,39,41 and 42)and 3 CSPs(Nvir CSP8,11 and12)are predominantly expressed mouthparts.12 OBPs(Lacu OBP1,3,5,6,7,9,11,13,15,16,18 and 23)and 2 CSPs(Lacu CSP6 and 13)were mainly expressed in antennae,whereas seven OBPs(Lacu OBP4,8,12,19,24,25 and 26)and eight CSPs(Lacu CSP3,4,6,8,9,10,12 and13)are predominantly expressed mouthparts.(4)Real-time quantitative PCR(RT-q PCR)method was further analyzed the expression levels of OBP and CSP in the male and female antennae and mouthparts in Nezara viridula and Leptocorisa acuta.In N.viridula,except for two OBPs(Nvir OBP29 and 37),the results of differential expression analysis were consistent with the RT-q PCR analysis.In addition,the expression level of female antennae in three OBPs(Nvir OBP16/25/27)was significantly higher than that of males,and the expression level of one OBP(Nvir OBP20)in male antennae was significantly higher than that of females.In L.acuta,9 OBPs(Lacu OBP1,5,7,11,13,14,17,20,and 23)are highly expressed in antennae,and 2 OBPs(Nvir OBP11 and 13)are significantly highly expressed in the male antennae.However,there was no significant difference in the expression levels of the male and female antennae in two bugs CSPs.