Cloning And Expression Of SmHSP23 In Response To Diapause And Cold Stress In Sitodiplosis Mosellana (Gehin)(Diptera: Cecidomyiidae)

Small heat shock proteins(s HSPs)are closely related to insect tolerance to the environment stress and its diapause.Sitodiplosis mosellana(Géhin)(Diptera: Cecidomyiidae)is a typical obligatory diapause pest,which diapause in summer and winter.In order to explore the roles of sHSPs in S.mosellana,we cloned cDNA sequence of SmHSP23 by RACE technology,and detected the mRNA transcription level of SmHSP23 in response to diapause and cold stress.Here are the main results:1.We got the cDNA sequence of SmHSP23,which full-length was 1087 bp(GenBank accession number: KT749988).The predicted open reading frame(ORF)of SmHSP23 sequence was 582 bp in length,encoding 193 amino aid residues.The relative molecular weight of Sm HSP23 protein was 21.98 kDa,and the theoretical pI was 5.67.The SmHSP23 had the highest identity with Chironomus riparius,which was 59%.2.The relative expression level of SmHSP23 at pre-diapause,diapause and post-diapause had significant differences.The expression of SmHSP23 was high in pre-diapause;then,it falled significantly when entering the diapause,which was 0.12 fold of pre-diapause;the expression remained low before September,then gradually increased after October,and had a maxium in the January the following year,which was 3.43 fold of pre-diapause;and it significantly decreased in post-diapause.3.SmHSP23 in overwinter diapause larvae was highly induced by short cold shock,and it had the maximum at-5 ?,which was 6.20 fold of untreated larvae.The expression of-10 ? was higher than 0 ?,-15 ?,and untreated larvae.4.The expression of SmHSP23 was influenced by duration time of cold shock and it reached the peak in about 30-60 min at-5 ?;and it had a maxium in 60 min at-10 ?,with no significant differences among other duration time.The results will contribute to the understanding of the molecular regulation mechanism in the diapause of S.mosellana,and provide new ideas to further explore the stress tolerance mechanisms in diapause.