谷子WAK基因家族全基因组鉴定及表达分析

Whole Genome Identification and Expression Analysis of WAK Gene Family in Foxtail Millet

细胞壁关联蛋白激酶(Wall-associated kinases,WAKs)是一类独特的类受体蛋白激酶(Receptor like ki?nases,RLKs),在寄主植物抗病反应中起着关键作用。为分析谷子WAK基因家族的特征及潜在功能,基于已研究发表的拟南芥、水稻WAK蛋白序列,通过同源序列比对的方法对xiaomi全基因组进行WAK基因家族鉴定,借助TBtools、MEGA等软件对谷子WAK基因理化性质、基因定位、系统进化、保守结构域、顺式作用元件进行分析。结果表明,共鉴定到谷子WAK家族成员41个,在谷子1~9号染色体上均有分布,编码590~1131个氨基酸;蛋白质分子质量为65.62~123.36 ku,等电点为5.18~8.49;Si3g36660、Si7g23280、Si8g19780的蛋白表现为疏水性,其他蛋白均为亲水性;亚细胞定位预测结果显示,28个基因定位于质膜,6个基因定位于叶绿体,其他基因分别定位于高尔基体、液泡、内质网、细胞外基质。系统发育分析结果显示,谷子、拟南芥和水稻的WAK基因家族可分为5类,其中,Si1g24650与Os01g26174、Si1g12300与Os02g02120的同源关系最近。谷子WAK基因家族的8个基序中,Motif 3、Motif 1、Motif 6、Motif 4、Motif 5基序为保守基序。Si1g25040、Si3g10590、Si3g32650、Si4g01670、Si4g02770、Si4g02780、Si5g09950、Si7g06570、Si7g08090都含有防御和胁迫响应相关元件,推测这9个谷子WAK基因在发挥寄主抗病性方面具有重要作用。基于禾生指梗霉早期侵染互作转录组数据分析表明,谷子Si6g20040、Si7g08090、Si8g19780等3个基因在禾生指梗霉早期侵染阶段,在抗病品种晋谷20号中的表达量均高于感病品种晋谷21号,且于48 h在晋谷20号与晋谷21号中的相对表达量差异显著,差异倍率分别为4.99、10.46、2.04。表明所筛选的3个基因可能在响应禾生指梗霉侵染过程中发挥重要作用。

Wall-associated kinases(WAKs)are a unique class of receptor like kinases(RLKs),they play a key role in disease resistance response of host plant.In order to analyze the characteristics and potential functions of WAK gene family in foxtail millet,in this study,WAK gene family was identified in the whole genome of xiaomi by homologous sequence alignment based on the published WAK protein sequences of arabidopsis and rice.The physicochemical properties,gene localization,phylogenetic evolution,conserved domain,and cis-acting elements of WAK genes in foxtail millet were analyzed by TBtools and MEGA.The results showed that a total of 41 WAK family members were identified,they were distributed on chromosomes 1-9 of foxtail millet and encoded 590-1131 amino acids.The molecular weight of the protein ranged from 65.62 ku to 123.36 ku,and the isoelectric point ranged from 5.18 to 8.49.The proteins of Si3g36660,Si7g23280,and Si8g19780 were hydrophobic,while the others were hydrophilic.Subcellular localization prediction showed that 28 genes were located in the plasma membrane,6 genes were located in chloroplasts,and the rest of the genes were located in Golgi apparatus,vacuoles,endoplasmic reticulum,and extracellular matrix,respectively.The phylogenetic analysis showed that WAK gene family in foxtail millet,arabidopsis,and rice could be divided into 5 categories,among which Si1g24650 and Os01g26174,Si1g12300 and Os02g02120 had the closest homologous relationship.Among the 8 motifs of foxtail millet WAK gene family,Motif 3,Motif 1,Motif 6,Motif 4,and Motif 5 were conserved.Si1g25040,Si3g10590,Si3g32650,Si4g01670,Si4g02770,Si4g02780,Si5g09950,Si7g06570 and Si7g08090 contained defense and stress response elements.It was suggested that these 9 WAK genes in foxtail millet played an important role in host disease resistance.Based on the analysis of transcriptome data of early infection interaction of Sclerospora graminicola,the expression levels of three genes,Si6g20040,Si7g08090 and Si8g19780,were higher in the resistant variety Jingu 20 than that in the susceptible variety Jingu 21 at the early infection stage of Sclerospora graminicola.At 48 h,the relative expression levels in Jingu 20 and Jingu 21 were significantly different,and the difference ratios were 4.99,10.46 and 2.04,respectively.The study above indicated that the three genes might play an important role in response to the infection of Sclerospora graminicola.