蒺藜苜蓿中1个聚半乳糖醛酸酶基因突变体的筛选及共生固氮表型的初步鉴定  

Screening and identifying polygalacturonase gene mutant in Medicago truncatula

作　　者：杨倩倩 刘元 陈大松[1] 李友国[1] 

机构地区：[1]农业微生物学国家重点实验室/华中农业大学生命科学技术学院,武汉430070

出　　处：《华中农业大学学报》2017年第4期62-70,共9页Journal of Huazhong Agricultural University

基　　金：国家重点研发计划项目(2016YFD0100702);国家自然科学基金项目(31670243;31371549)

摘　　要：以模式豆科植物蒺藜苜蓿中1个聚半乳糖醛酸酶(polygalacturonase,PG)基因为对象,对其进行生物信息学分析,结果显示:该基因全长4 150bp,其编码区1 278bp,编码425个氨基酸;其编码蛋白包括2个与细胞壁主要成分果胶降解有关的保守结构域PL-6superfamily和Glyco_hydro_28;该酶蛋白与鹰嘴豆、赤豆等豆科植物中的PG蛋白同源关系更近。苜蓿基因表达谱数据库分析和RT-PCR检测结果表明,MtPG在根瘤中呈显著增强表达,在非共生组织如根、叶中表达量很低。此外,基于该基因3个Tnt1转座子插入的目标候选突变体(NF0999、NF5561和NF4746)插入位点分析,得到1个纯合突变体材料NF4746,共生表型观察表明,MtPG基因在豆科植物共生固氮的早期侵染过程中发挥重要作用。The polygalacturonase （PG） gene in Medicago truncatulawas analyzed with bioinformat- ics.Results showed that the length of the gene was 4 150 bp with 1 278 bp coding region encoding 425 amino acids.The protein encoded contains two conserved domains, PL-6 superfamily and G lyco hydro_ 28, which are related to degradation of cell wall pectin. The homology between PG in Medicago truncatula and PG insome other leguminous plants including chickpeas and red bean was close.Results of gene expression profile and RT-PCR detection showed that MtPG expression was significantly enhanced in the root nodules but very low in non-symbiotic tissues including roots and leaves.Three Tntl transposons insertion mutants （NF0999, NF5561 and NF4746） were screened by PCR and one homozygous mutant NF4746 was obtained.It is indicated that the MtPG gene may play an important role in the early infection of symbiotic nitrogen fixation in legumes.

关 键 词：蒺藜苜蓿 聚半乳糖醛酸酶基因 RT-PCR 转座子插入突变 共生表型 

分 类 号：Q939.9[生物学—微生物学]