参薯赤霉素途径基因的克隆与表达分析

Cloning and Expression Analysis of Genes Related to Gibberellin Pathway in Dios core a alala

参薯是薯蓣科植物,其块茎有较高的营养价值和经济效益。为探究赤霉素对参薯生长及结块影响,本研究对参薯组培苗进行赤霉素处理,统计与对照组相比结薯时间差异;并检测了赤霉素合成及降解相关基因GA20ox、KO、KAO、GA3ox、GA20ox,赤霉素受体GID1基因(4个)和信号传导的DELLA基因(4个)、SPY、SLY1等24个赤霉素途径基因的表达变化。RT-PCR结果显示赤霉素相关基因在叶、茎中都有表达,仅LSH基因在块茎中特异性表达。统计赤霉素处理参薯的结薯时间表明,赤霉素处理的参薯苗结块时间明显提前。RT-qPCR结果显示赤霉素处理后,4个GID1、GA20ox、DELLA2、SNE等基因表达在所有组织或部分组织显著下降,DELLA1和KAO1表达变化不明显,GRF2在块茎中表达上升。试验结果显示外源赤霉素添加对参薯结薯有诱导作用,且对内源赤霉素合成有一定的抑制,可能通过改变参薯赤霉素含量的平衡而提前进入结薯过程,为将来人工控制结薯时间提供科学数据。

Greater yam(Dioscorea alata 2 n=40)belongs to the Dioscorea family and has high nutritional value and economic benefits.To explore the effect of gibberellin on the growth and tuber development of greater yam,in the study,tissue-cultured yam seedings were treated by gibberellin(GA)and compared of the tuberization time with the control group.Further,we characterized the gene expression profiles of 24 gibberellin related genes:GA synthesis and degradation-GA20ox,KO,KAO,GA3ox,GA20ox,GA receptors(GID1,4),GA signal transduction-DELLA(4),SPY,SLY1,and so on.The RT-PCR assay showed that these genes were highly expressed in leaf and stem tissues,and LSH genes expressed specifically in tubers.The greater yam seedlings treated with GA had significant shorter growth time before tuberization than that of the control seedlings.RT-qPCR assays showed that the expression levels of GA receptors(GID1,4),GA20ox,DELLA2,and SNE were significantly decreased after GA treatment in all tissues or part tissues,while DELLA1 and KAO1 showed no significant changes in gene expression and the expression of GRF2 increased in tuber tissues.Therefore,our results suggested that the exogenous gibberellin could induce greater yam tuberization process and suppress endogenous GA biosynthesis,which changed the intrinsic GA balance.This research will provide molecular scientific data for artifical manipulation of tuberization time in the furture.