番茄C3H基因家族的全基因组鉴定及表达分析

Genome-wide identification and expression analysis of C3H gene family in tomato

C3H基因编码含有3个半胱氨酸和1个组氨酸残基的锌指蛋白,在植物生长和胁迫反应中具有重要作用,但目前相关研究主要集中在拟南芥(Arabidopsis thaliana)和水稻(Oryza sativa)中。为探究番茄(Solanum lycopersicum)C3H基因家族的进化关系与相关功能,本研究从番茄全基因组中鉴定出47个C3H成员,并通过生物信息学手段和荧光定量PCR技术(qRT-PCR)对其展开分析。结果表明,番茄C3H基因家族含有7个亚家族,各亚家族基因结构差异较大;该基因家族成员不均匀分布在除第8号染色体外的11条染色体上,并存在3个串联重复的基因簇;番茄C3H蛋白序列中均含有C3H基序,其中C-X_(7-8)-C-X_(5)-C-X_(3)-H最为丰富;亚细胞定位分析显示,番茄C3H蛋白绝大多数位于细胞核中;组织表达分析表明,该家族成员的组织表达模式具有一定相似性,多数C3H基因在番茄的营养分生组织、根和花蕾中相对高表达,但各亚族间也存在一定差异;qRT-PCR结果显示,脱落酸(ABA)、聚乙二醇6000(PEG6000)、NaCl胁迫可使大多数C3H转录因子表达水平上调,同时抑制少数成员的表达。特别是SlC3H-21和SlC3H-26在PEG6000胁迫下能够分别上调表达16.17倍和7.05倍,SlC3H-41基因则被抑制显著下调表达,暗示这些基因可能在番茄胁迫应答过程中发挥重要作用。该研究结果为培育耐旱性番茄品种提供了良好的候选基因,可为深入研究该家族成员在番茄生长和胁迫反应中的功能机制提供一定参考。

C3H gene encodes zinc finger protein with three cysteines and one histidine residue,which plays an important role in plant growth,development as well as stress response.However,the current studies on the C3H gene family are mainly focused on the model plants Arabidopsis thaliana and rice(Oryza sativa).In order to explore the evolutionary relationship and function of the tomato(Solanum lycopersicum)C3H gene family,47 C3H members were identified by genome-wide analysis and analyzed by bioinformatic methods and quantitative real-time PCR(qRT-PCR).The results indicate that tomato C3H genes can be divided into seven subfamilies,and the gene structures of different subfamilies are quite different.The members of this gene family are unevenly distributed on 11 chromosomes except chromosome 8,and there are three tandem repeat gene clusters.Tomato C3H protein sequences all contain C3H motifs,of which C-X_(7-8)-C-X_(5)-CX_(3)-H is the most abundant.Subcellular localization analysis shows that most of tomato C3H proteins are located in the nucleus.Tissue expression analysis shows that the tissue expression patterns of members of this family are similar,and most of C3H genes are relatively highly expressed in vegetative meristems,roots and buds of tomato,but there are some differences among subfamilies.The results of qRT-PCR show that most C3H transcription factor members can be induced by abscisic acid(ABA),polyethylene glycol 6000(PEG6000)and NaCl stress,while a few members can be inhibited.In particular,SlC3H-21 and SlC3H-26 can be up-regulated by 16.17 and 7.05 times by PEG6000 stress,while SlC3H-41 gene can be inhibited and down-regulated significantly,suggesting that these genes may play an important role in tomato stress response.The results of this study can provide some good candidate genes for the breeding of drought-tolerant tomato varieties and a reference for the further study of the functional mechanism of the family members in the process of tomato growth and development and stress response.