烟草DELLA基因家族的克隆与表达模式分析

Cloning and expression pattern analyses of tobacco DELLA gene family

为明确烟草受逆境胁迫时DELLA基因家族的转录调节功能,通过烟草EST序列比对分析克隆了3个DELLA基因家族基因(NtDELLA1,NtDELLA2,NtDELLA3),并对3个基因的结构和表达模式进行了分析。生物信息学分析结果表明,烟草DELLA基因全长1700 bp左右,其编码蛋白包含DELLA蛋白的特征结构域DELLA基序和VHYNP基序,与拟南芥DELLA蛋白家族的GAI蛋白高度同源,推测烟草DELLA蛋白与拟南芥DELLA蛋白具有类似的功能;荧光定量PCR分析结果表明,这3个基因在烟草不同组织和关键生长发育时期表达模式类似,尤以茎中表达量最高;胁迫应答分析结果表明,烟草DELLA基因的转录对干旱、低温、烟草花叶病毒(Tobacco mosaic virus,TMV)侵染和外源激素均表现出不同程度的响应,其中干旱、赤霉素(GA)和脱落酸(ABA)可抑制烟草DELLA基因的表达,而低温胁迫可诱导NtDELLA1上调表达,TMV侵染可诱导NtDELLA1和NtDELLA2的大量表达。

In order to clarify the transcription regulation function of DELLA gene family in tobacco under adversity stress,three members(NtDELLA1,NtDELLA2,NtDELLA3)of DELLA gene family were cloned by tobacco EST sequence alignment,and their gene structures and expression patterns were analyzed.The results of bioinformatics analysis showed that the full length of tobacco DELLA genes were around 1700 bp,and the proteins encoded by those genes contained DELLA protein feature structures,DELLA motif and VHYNP motif,and were highly homologous to GAI protein of Arabidopsis DELLA protein family.Thus,it was assumed that the functions of tobacco DELLA proteins were similar to those of Arabidopsis.qRT-PCR analysis further confirmed that the three genes had similar expression patterns in different tissues at key development stages,and their expression levels in tobacco stalk were the highest.The results of analysis on stress responses indicated that tobacco responded to drought,low temperature,TMV infection and exogenous hormones at varying degrees,and drought,GA and ABA inhibited the expression of tobacco DELLA gene family,while low temperature induced up-regulated expression of NtDELLA1,TMV induced the abundant expression of NtDELLA1 and NtDELLA2.