甘蓝型油菜BnAPs基因家族成员全基因组鉴定及分析

Genome wide analysis of BnAPs gene family in Brassica napus

天冬氨酸蛋白酶(AP)属于四大蛋白水解酶之一,在蛋白质加工、信号转导和胁迫反应中发挥着重要作用。甘蓝型油菜是我国重要的油料作物,利用蛋白质同源性分析,在甘蓝型油菜中鉴定出154个APs编码基因,分别编码典型、非典型和珠心类天冬氨酸蛋白酶。基因结构分析结果表明,多数BnAPs基因包含1~4个外显子,同一类型的天冬氨酸蛋白酶成员之间蛋白质基序(Motif)分布相似。共线性分析表明,甘蓝型油菜与白菜、甘蓝和拟南芥存在大量的同源基因,约89%的BnAPs基因来自于全基因组复制事件。转录水平检测结果表明,BnAPs基因家族成员在各个组织中均有表达,其中BnAP30.A05.1/A05.2/C05.1/C05.2、BnAP36.A04/C08、BnAP39.A06/C03在授粉后的柱头显著提高。BnAPs基因启动子区域顺式元件分析结果表明,逆境相关的顺式调控元件被显著富集;进一步利用RT-qPCR验证了这些富含逆境相关顺式调控元件的基因在逆境(ABA、NaCl或4℃)处理后的表达水平显著变化,推测这些BnAPs基因可能参与甘蓝型油菜对逆境的响应。进一步和拟南芥同源基因组织表达模式进行比较后发现,大约有24%的BnAPs与其同源AtAPs具有相同的表达模式。本研究为进一步解析天冬氨酸蛋白酶家族在甘蓝型油菜中的生物学功能奠定了基础。

Aspartate protease(AP) is one of the four major proteolytic enzymes and plays an important role in protein processing,signal transduction, and stress response. Brassica napus is an important oil crop in China. We identified 154 APs coding genes in Brassica napu by protein homology analysis, which encoded typical, atypical, and nucellar aspartate proteases, respectively. Gene structure analysis showed that most BnAPs genes contained 1–4 exons and the motif distribution of the same type of aspartic protease was similar. Collinearity analysis revealed that there was a large number of homologous genes between Brassica napus and Brassica rape, Brassica oleracea and Arabidopsis thaliana, and about 89% of BnAPs genes came from genome-wide replication events. Transcriptional analysis demonstrated that BnAPs gene family was expressed in all tissues. The stigma of BnAP30.A05.1/A05.2/C05.1/C05.2, BnAP36.A04/C08, and BnAP39.A06/C03 increased significantly after pollination. Cis-element analysis in the promoter region of BnAPs gene presented that stress-related cis regulatory elements were significantly enriched. We further verify that the relative expression levels of these genes rich in stress-related cis regulatory elements changed significantly after stress(ABA, NaCl, or 4℃), suggesting that these BnAPs genes may be involved in response to stress in Brassica napus. Compared with Arabidopsis homologous genes, about 24% of Bn APs had the same expression pattern as their homologous AtAPs. This study laid a foundation for further understanding the biological function of aspartic protease family in Brassica napus.