茎瘤芥β-半乳糖苷酶家族基因鉴定及表达分析

Genome-wide Identification and Expression Analysis ofβ-galactosidase Family Members in Brassica juncea var.tumida

植物β-半乳糖苷酶(β-D-galactosidases,BGAL,EC 3.2.1.23)是糖苷水解酶家族35(GH35),在植物细胞壁生成和组分修饰中具有重要作用。为探索BGAL家族基因在茎瘤芥的茎发育中的功能,本研究从茎瘤芥基因组中鉴定到39个BjuBGAL家族成员,并运用生物信息学对其进化关系、蛋白理化性质、基因结构及保守序列、染色体定位和在茎膨大过程中的表达等进行系统分析。结果表明,39个BjuBGAL家族成员,分为8个亚族,相同亚族具有类似基因结构和保守序列;有35个BjuBGAL分别定位于A和B亚基因组中的9和7条染色体上;BjuBGAL启动子具有光、植物激素和胁迫响应的顺式作用元件;转录组数据表明10个BjuBGAL在茎膨大过程中明显上调,进一步利用荧光定量PCR分析发现BjuBGAL4-2随着茎的膨大呈显著上调,且在茎的内髓区表达水平显著高于外髓区,可能参与茎内髓区的发育。本研究为进一步揭示茎瘤芥BGAL家族的功能提供参考。

β-galactosidases(BGAL,EC 3.2.1.23)of plant are belonged to glycoside hydrolases 35 family,which are play a vital role in cell wall development and modification.In order to understand the function of BGAL in stem development of Brassica juncea var.tumida,in present study,39 BGAL genes from Brassica juncea genome were identified,and a comprehensive genome-wide analysis of BjuBGAL genes is presented using bioinformatics,including their phylogeny,protein physicochemical properties,gene structure and conserved motifs,chromosomal distribution,and gene expression pattern during stem swelling.The results showed that 39 BjuBGAL genes clustered into 8 subfamilies,such that genes within the same subfamily had similar exon-intro structures and conserved motif.35 BjuBGAL genes were located in 9 chromosomes of A subgenomes and 7 chromosomes of B subgenomes.The promotor region of BjuBGAL genes contained a group of putative cis-acting elements response to light,plant hormone and stress.The expression of 10 BjuBGAL genes were up-regulated during stem swelling.Furthermore,quantitative real-time PCR analysis demonstrated that the BjuBGAL4-2 expressed significantly increasing during stem swelling,and significantly higher e xpressed in the inner pith region than outer pith,indicating it may be required for the inner pith development of stem.These results will be useful for further functional analyses of the BGAL gene family in Brassica juncea var.tumida.