苜蓿全基因组WRKY转录因子基因的分析

Genome-wide analysis of the WRKY transcription factor family in Medicago truncatula

蒺藜苜蓿的基因组较小,遗传转化相对容易,是国际上广泛用于研究豆科植物的模式植物,其全基因组测序已经完成。WRKY转录因子是近年来在植物中发现的N-端含有WRKYGQK高度保守氨基酸序列的新型转录调控因子,调节启动子中含W-box元件的调节基因和(/或)功能基因的表达,从而参与植物的各种防卫反应。本研究以苜蓿基因组序列(Mt2.0)为材料,利用生物信息学方法分析苜蓿全基因组WRKY转录因子基因的数目、种类、系统发生学、保守基序,结果表明,苜蓿中共有28个WRKY基因,其中5个基因含有2个WRKY结构域,共含有33个WRKY结构域,根据其结构域特点可以分为3个大类,同时与水稻WRKY基因进行了比较研究,发现基因数目远少于拟南芥和水稻,同时研究证实苜蓿与水稻WRKY基因的起源和进化关系存在较大差异,显示出苜蓿WRKY进化有其独特的特点,此外分析苜蓿WRKY基因的保守motif共有46个,筛选得到WRKY结构域的5个保守motif。该研究对苜蓿WRKY基因功能的研究及进化具有重要的意义。

Medicago truncatula is a model Leguminosae plant because it has a small genome,is easily transformed,and its genome has been completely sequenced.WRKY transcription factor is a new protein family containing conserved WRKYGQK amino acid sequences.Regulator genes and（/or） functional genes containing a W-box in the promoter are regulated.WRKY proteins correlate to plant defense response.M.truncatula genome sequence（Mt2.0） was employed in this research.The gene number,class,phylogenetic relation and conserved motif of WRKY transcription factor genes were analysed in M.truncatula.Twenty-eight WRKY genes were found in M.truncatula,two domains were confirmed in five WRKY genes and 33 WRKY domains were found in all WRKY genes.The number of genes is less than those of Arabidopsis and rice.Phylogenetic trees show different evolution patterns of Arabidopsis,rice and M.truncatula.WRKY genes have a unique evolutionary mechanism in Medicago.WRKY proteins were found to contain 33 conserved motifs by using MEME analysis,and five motifs were affirmed in WRKY domains.The study provides a foundation for function and evolution of WRKY genes in M.truncatula.