蒺藜苜蓿多聚半乳糖醛酸酶基因家族的全基因组分析

多聚半乳糖醛酸酶(Polygalacturonases,PGs)是一种果胶水解酶,参与果实成熟、器官脱落、花粉成熟等多个植物发育过程。采用相似性比对和结构域搜索方法,从蒺藜苜蓿基因组中共鉴定出74个MtPG基因。根据系统进化关系将其分为6个亚家族,分别包含9、7、4、11,18和25个MtPG基因家族成员。染色体定位分析发现,MtPG基因在蒺藜苜蓿的8条染色体上呈现不均匀分布,每条染色体上分布有2-16个MtPG基因;同时,基因组复制分析结果显示,蒺藜苜蓿的PG基因家族成员之间存在大量的基因复制。最后,通过蒺藜苜蓿的高通量测序数据分析发现,MtPG基因家族广泛地在根部、结瘤、叶片、芽,心皮和花等组织中表达。根据它们在不同组织中表达水平,将31个MtPG基因聚类为4组,分别探讨了四组基因在蒺藜苜蓿组织器官分化中表达模式,重点解析了它们在花器官发育以及根部组织分化中可能的调控机制,这将为进一步研究蒺藜苜蓿MtPG基因家族成员的基因功能提供了理论基础。

Genome-wide analysis of polygalacturonasegene family in Medicago truncatula

Polygalacturonases(PGs) are pectin degrading enzymes, which are involved in various plant developmental processes, such as fruit ripening, organ abscission, and pollen ripening. Through using homolog searching and protein domain identifying method, 74 MtPGgenes were distinguished from the Medicago truncatulagenome. According to multiple alignments and phylogenetic analysis results, the genes were classified into six subfamilies, including 9,7, 4,1, 18, and 25 MtPGgene members. Besides, chromosomal location analysis shows that the MtPGgenes in M. truncatulawere unevenly distributed among the eight chromosomes, varying from two to sixteen members on every chromosome. Meanwhile, numerous duplication events were identified in the PGgene family, which indicates that MtPGgenes expanded through gene duplication events in M. truncatula.Finally, their expressional profiles were assessed using public RNA-Seq data, and results show that MtPGgenes were expressed in the root, nodule, blade, bud, seedpod, and flower. The 31 MtPGgenes were clustered into four groups (Cluster Group I to VI) based on their expression levels, and most of the PGgene family members showed the highest expression levels in nodule and/or flower, which suggests their significant roles in tissues development process, especially for flower and root. In summary, these findings will be valuable for determining detailed MtPGgenes functions in M. truncatula.