第44卷第10期2008年10月林业科学SCIE NTI A SI LVAE SI NIC AE V ol 144,N o 110Oct.,20081个油茶Y 2SK 2型脱水素的全长cDNA克隆及生理功能的预测3胡孝义　谭晓风　张党权　曾艳铃　陈鸿鹏　田晓明　刘　巧(中南林业科技大学经济林育种与栽培国家林业局重点实验室　长沙410004)摘　要:　以构建的油茶EST 文库为基础,采用电子克隆技术,分离克隆一个脱水素基因的全长cDNA 序列,该基因的cDNA 全长1406bp ,含一个600bp 的C DS ,编码200aa 的小分子蛋白。推测该基因编码蛋白的分子质量为21ku ,等电点7,暂命名为C oDH NI 。同源性分析发现该基因的编码蛋白具有2个Y -片段(DEYG NP ),1个S -片段(SG SSSSSS ),2个K-片段(KIKEK LPG ),属于典型的Y 2SK 2型脱水素。经Blast 比对,发现富含苏氨酸的Thr -区在各物种间变异显著,推测该区为油茶所特有,有利于在被保护的大分子表面形成水合层;同时还发现一个十分保守的基序:E DDG QGG RRKK,可能有利于脱水素的磷酸化和亚细胞定位。通过与柑桔和拟南芥的脱水素比较,提出C oDH NI 有可能缓冲种子脱水胁迫响应时钙离子的瞬时增高,并可结合重金属离子,以减轻活性氧的危害。关键词:　油茶;脱水素基因;cDNA 文库;RACE;生理功能;生物信息学中图分类号:S718146;Q94312　　　文献标识码:A 　　　文章编号:1001-7488(2008)10-0055-08收稿日期:2007-11-15。基金项目:国家“十一五”科技支撑项目(2006BAD18B0204,2006BAD01A1706),国家自然科学基金项目(30371184),湖南省科学技术厅科技计划项目(06F J4111)。3谭晓风为通讯作者。A Full 2Length cDNA Clone of Typical Y 2SK 2Dehydrin and Its SpeculatedPhysiological R ole in the Seeds of Camellia oleiferaHu X iaoyi 　T an X iaofeng 　Zhang Dangquan 　Z eng Y anling 　Chen H ongpeng 　T ian X iaom ing 　Liu Qiao(K ey Laboratory o f Non 2Wood Forest Products o f State Forestry Administratrion 　Central South Univer sity o f Forestry and Technology 　Changsha 410004)Abstract :　Based on a constructed EST library of Camellia oleifera ,a full 2length cDNA encoding a dehydrin was cloned from its seed by the electronic PCR technique.The cDNA ,tentatively designated as C oDH N1,was 1406bp long containing an open reading frame of 600bp.The deduced C oDH N1protein had 200am ino acid residues ,which formed a 21ku polypeptide w ith a predicted isoelectric point (pI )of 71The C oDH N1protein had tw o Y 2segments ,an S 2segment and tw o K 2segments.H om ology analysis indicated that the Y 2segment ,S 2segment and K 2segment of C oDH N1shared identity w ith those of other reported dehydrins ,indicating that C oDH N belonged to dehydrin superfam ily.There was a w ide range of variation for Thr 2region existed am ong dehydrins from various species ,and the C oDH N1Thr 2region was Camellia oleifera specific ,protecting some macrom olecules by form ing hydrated layer outside of them.A very conserved m otif of E DDG QGG RRKK was found in C oDH N1,and it m ight contribute to dehydrin ’s phosphorylation and subcellular localization.By com parison w ith dehydrins from citrus and Arabidopsis respectively ,it was proposed that C oDH N1m ight serve as a bu ffer for transiently increased Ca 2+when the matured seeds was under the condition of desiccation stress to some extent ,and that C oDH N1m ight bind heavy metal ions such as Cu 2+,Ni 2+,Zn 2+,C o 2+,Fe 3+and hence scavenge reactive oxygen species to alleviate toxin caused by them.K ey w ords :　Camellia oleifera ;dehydrin ;cDNA library ;RACE;physiological role ;bioin formatics晚期胚胎发育丰富蛋白(late embry ogenesis abundant ,LE A )是在植物种子发育过程中形成的一类低分子质量蛋白,受发育阶段、ABA 和脱水信号等调节(Bray ,1997;Shinozaki et al .,1996)。LE A 蛋白含有大量的极性氨基酸和无规则结构,具有很高的亲水性和热稳定性(Close et al .,1993)。根据氨基酸序列的同源性和基序,把LE A 蛋白分为6组(张木清等,2005),其中第2组的脱水素不仅存在于高等植物,也存在于藻类、酵母和盐细菌中(Svenss on et al .,2002),分子质量为9～200ku (Sarhan et al .,1997),在C 端或其附近具有一个或多个富含赖氨酸的基序,约15个氨基酸残基(EKKGI MDKIKEK LPG )组成,其中KIKEK LPG 在不同物种间极为

1个油茶Y - 2SK - 2型脱水素的全长cDNA克隆及生理功能的预测