白菜型油菜IGT基因家族的鉴定与表达分析

Identification and expression analysis of the IGT gene family in Brassica rapa

IGT是调控植物分枝角度的关键基因家族,且对植物的产量、生物量以及观赏效果都有着重要作用。本研究基于白菜型油菜(Brassica rapa)、拟南芥(Arabidopsis thaliana)等基因组序列信息,在全基因组水平上,对IGT基因家族进行理化性质分析、染色体定位、亚细胞定位预测、进化关系、顺式元件预测、共线性及表达模式分析。结果表明,在白菜型油菜中共鉴定到11个IGT基因;系统进化关系将其分为7个分枝,每个分枝均由相似的保守基序组成;染色体定位和共线性分析表明,在杂交和多倍化的过程中,该家族成员的染色体并未发生明显的变化,且片段复制和同源拷贝可能是其扩张的主要方式。在多数IGT启动子中发现光响应元件占主导地位,脱落酸、茉莉酸甲酯响应元件次之,表明IGT启动子可能为诱导型启动子。转录组分析发现,白菜型油菜的IGT基因在不同组织(愈伤组织、花、叶、根、角果、茎)中有着不同的表达模式,尤其是TAC1基因(BraIGT-11)在花中有着较高的表达水平,叶和茎则次之,表明TAC1在调控分枝角度和花发育等方面可能发挥着重要的功能。综上所述,本研究为后续BraIGT基因功能的研究提供了理论依据,同时也为白菜型油菜理想株型的选育以及分子育种提供了参考。

The IGT gene family regulates the branching angle of plants and is important for plant yield,biomass,and ornamental effects.In this study,we analyzed the physicochemical properties,chromosomal localization,subcellular localization prediction,evolutionary relationship,cis-element prediction,covariance,and expression pattern of the IGT gene family at the genome-wide level based on the genome sequence information of Brassica rapa and Arabidopsis thaliana.A total of 11 IGT genes were identified in B.rapa,which were classified into seven branches,each of which comprised similar conserved motifs.Chromosomal localization and covariance analyses indicated that the chromosomes of the family members did not experience any significant changes during hybridization and polyploidization and that fragment duplication and homologous copying might be the primary modes of their expansion.Light-responsive elements predominated in most IGT promoters,followed by abscisic acid-and methyl jasmonate-responsive elements,indicating that the IGT promoter may be inducible.Transcriptome analysis revealed that the IGT genes of B.rapa had different expression patterns in different tissues(callus,flowers,leaves,roots,siliques,and stems);in particular,the TAC1 gene(BraIGT-11)had a higher expression level in flowers,followed by leaves and stems,suggesting that TAC1 may be important in regulating other aspects such as branching angle and flower development.In summary,this study provides a theoretical basis for the subsequent study of BraIGT gene function and provides a reference for breeding ideal plant types and the molecular breeding of B.rapa.