向日葵查尔酮合酶HaCHS基因的克隆与逆境应答

Cloning and stress response of chalcone synthase gene in sunflower(Helianthus annuus)

为探讨查尔酮合成酶(CHS)基因在向日葵抗逆机制中的作用,在核盘菌诱导向日葵转录组文库的基础上,从向日葵耐病品种龙食葵2号中克隆了1个CHS的c DNA序列,该基因开放阅读框为1 197bp,编码398个氨基酸残基,分子量为43.54k D,等电点为6.17,命名为Ha CHS(Gen Bank登录号为KR921882)。氨基酸序列分析显示,Ha CHS具有CHS家族蛋白3个保守的功能活性位点(C^(167),H^(306)和N^(339))和特征多肽标签序列GVLFGFGPGL。系统进化分析表明,Ha CHS与菊科植物的大丽菊、紫茎泽兰和黑心菊等的CHS蛋白有很高的同源性,氨基酸序列相似性在93%~94%。实时荧光定量PCR结果表明,该基因在向日葵花中表达量最高为19.96,其次是盘、叶、茎和种,在根中的表达量最低为0.02。Ha CHS基因表达受核盘菌、创伤、4℃低温和茉莉酸(JA)等因素调控,但对脱落酸(ABA)和水杨酸(SA)处理的应答差异不显著。

To explore the role of chalcone synthase（ CHS） gene in stress tolerance mechanism of sunflower,a full- length c DNA of CHS（ LSK- 2） was cloned based on Helianthus annuus transcriptome induced by Sclerotinia sclerotiorum. Sequence analysis showed that Ha CHS（ Gen Bank No. KR921882） c DNA contained 1 197 bp ORF encoding a protein of 398 amino acids residues with molecular mass of 43. 54 k Da and theoretical p I of 6. 17.Ha CHS protein contained 3 conserved active sites（ C^167,H^306 and N^339） and a family signature sequence of GVLFGFGPGL. Phylogenetic analysis revealed that Ha CHS shared 93%- 94% identities with CHS proteins of Dahlia pinnata,Rudbeckia hirta and Ageratina adenophora in Asteraceae. Q RT- PCR results showed that Ha CHS was highly expressed in flower,much more than in sunflower root. Its expression was significantly regulated by S. sclerotiorum,wounding,4℃ chilling and jasmonic acid（ JA）,but not by salicylic acid（ SA） and abscisic acid（ ABA）.