甘蓝型油菜BnKNOX基因家族的鉴定与分析

Identification and analysis of BnKNOX gene family in Brassica napus

植物特异的KNOTTED-LIKE HOMEOBOX(KNOX)蛋白属于转录调控因子家族,该家族在植物生长发育过程和各种胁迫应答中发挥着重要的作用。KNOX蛋白中存在4个保守的结构域:TALE(three amino acid loop extension)类型的HD(homeodomain)、ELK结构域,以及2个亚结构域KNOX1和KNOX2。目前,甘蓝型油菜的BnKNOX基因家族还未有系统的研究报道。本研究通过生物信息学分析鉴定获得甘蓝型油菜的36个BnKNOX家族成员。通过序列比对和系统发育树分析,将其分为3个亚家族(Ⅰ、Ⅱ和M类)。进化分析表明,全基因组复制(whole genome duplication,WGD)和片段复制(segmental duplication)是BnKNOX基因家族扩张的主要动力。基于甘蓝型油菜不同发育时期组织/器官的RNA-seq分析发现,该基因家族的BnKNAT25/26/29/30在胚乳和种子发育过程中特异表达,而BnKNAT31/32/34在成熟种子中高表达。通过BnKNOX家族的顺式作用元件分析和非生物胁迫条件下的表达模式分析,本文鉴定获得17个响应干旱和渗透胁迫的BnKNOX成员。

The plant specific KNOTTED-LIKE HOMEOBOX(KNOX)protein is a transcription factor family that plays an im-portant role in plant growth and development,as well as responses to various stresses.KNOX proteins contain four conserved domains[a three amino acid loop extension(TALE)type homeodomain(HD),ELK domain,and two subdomains(KNOX1 and KNOX2)].At present,the comprehensive study of BnKNOX genes in Brassica napus has not been reported yet.In this study,36 BnKNOX family members were identified in B.napus genome via bioinformatic analyses,which were classified into three sub-families(I,II,and M-type)based on sequence alignment and phylogenetic analyses.Evolutionary analysis showed that the whole genome duplication(WGD)and segmental duplication were the main driving forces for the expansion of BnKNOX gene family.Based on the RNA-seq data of developing tissues and organs of B.napus,BnKNAT25/26/29/30 were specifically expressed in endosperm and developing seeds,while BnKNAT31/32/34 were highly expressed in mature seeds.We analyzed the cis-acting elements and expression pattern of BnKNOXs under various abiotic stresses,and identified 17 BnKNOX members that might be involved in drought and osmotic stress responses.