芥菜MAPK基因家族成员鉴定及其响应根肿菌侵染的表达分析

Genome-wide identification, characterization, and expression analysis of MAPK genes in response to Plasmodiophora brassicae infection in Brassica juncea

摘要:

芸薹属根肿菌(Plasmodiophora brassica)侵染引起的根肿病蔓延会严重影响芥菜[Brassica juncea(L.) Czern.]的产量和品质。丝裂原活化蛋白激酶(mitogen-activated protein kinases,MAPK)级联作为一种高度保守的信号通路，在植物的生物和非生物胁迫中发挥重要作用。为了挖掘芥菜抗根肿病相关的MAPK基因，本研究对芥菜进行全基因组鉴定，并对芥菜MAPK基因家族的系统进化以及基因结构等进行生物信息学分析。筛选鉴定的66个BjuMAPK基因不均匀分布在17条染色体上。在基因组尺度上，发现基因的串联重复导致了芥菜MAPK基因数目增多。同一亚族成员之间具有相似的基因结构，不同亚族间差异较大。预测的顺式作用元件与植物激素、抗逆性以及植物的生长发育相关，表达分析显示BjuMAPK02、BjuMAPK15、BjuMAPK17和BjuMAPK19等基因在根肿菌侵染芥菜后具有不同的响应模式。以上结果为进一步研究BjuMAPK基因在芥菜应对根肿病生物胁迫中的功能奠定了理论基础。

Abstract:

In recent years, the spread of clubroot disease caused by Plasmodiophora brassicae infection has seriously affected the yield and quality of Brassica juncea (L.) Czern.. The cascade of mitogen-activated protein kinases (MAPKs), a highly conserved signaling pathway, plays an important role in plant responses to both biotic and abiotic stress conditions. To mine the MAPK genes related to clubroot disease resistance in B. juncea, we conducted a genome-wide analysis on this vegetable, and we analyzed the phylogenetic evolution and gene structure of the MAPK gene family in mustard. The 66 BjuMAPK genes identified by screening the whole genome sequence of B. juncea were unevenly distributed on 17 chromosomes. At the genomic scale, tandem repeats led to an increase in the number of MAPK genes in B. juncea. It was found that members of the same subfamily had similar gene structures, and there were great differences among different subfamilies. These predicted cis-acting elements were related to plant hormones, stress resistance, and plant growth and development. The expression of BjuMAPK02, BjuMAPK15, BjuMAPK17, and BjuMAPK19 were down-regulated or up-regulated in response to P. brassicae infection. The above results lay a theoretical foundation for further studying the functions of BjuMAPK genes in B. juncea in response to the biotic stress caused by clubroot disease.