茉莉酸在植物的生长发育、应激反应和次生代谢过程中起着重要的调控作用。转录抑制因子JAZ(Jasmonate ZIM-domain)蛋白则是茉莉酸信号从SCFCOI1受体复合物向下游茉莉酸应答基因转导的纽带。采用比较基因组学的方法, 从多谱系的角度对植物JAZ蛋白家族进行分子进化分析并取得以下研究结果。(1) 在藻类植物、苔藓植物、蕨类植物、裸子植物及单、双子叶植物6个不同谱系的15种代表植物基因组中, 鉴定了82个JAZ同源基因, 其中在低等藻类植物基因组中没有鉴定到JAZ同源基因, 提示JAZ家族基因可能起源于陆生植物。(2) 系统发育分析表明, 在植物基因组中JAZ蛋白家族可分为10个保守的亚家族, 而谱系特异扩增尤其是串联重复和区段重复可能是陆生植物JAZ家族基因扩增与进化的主要机制, 并导致多个谱系特异的JAZ亚家族产生。(3) 基因结构分析表明, JAZ家族基因含有0–7个数目不等、62–4 222 bp长度不等的内含子, 提示在植物基因组进化过程中, JAZ家族基因可能发生内含子丢失或内含子插入缺失, 进而导致基因外显子-内含子结构的多样性。该研究结果将为植物JAZ蛋白家族的深入研究提供参考。
Jasmonic acid (JA) plays a significant role in the regulation of developmental processes, stress responses and secondary metabolisms in plants. Jasmonate ZIM-domain (JAZ) proteins are transcriptional repressors that regulate the process of JA signal transduction from the SCFCOI1 complex to JA response genes in the JA signaling pathway. Comparative genomic analysis was performed to investigate the original and evolutionary relationship among JAZ paralogs in plants. The main results are as follows: (1) 82 JAZ genes and their homologs were identified from 15 representative species, including the 6 major plant lineages of chlorophytes, bryophytes, pteridophytes, gymnosperms, monocots and eudicots; moreover, green algae contained no JAZ homologs, which suggests that JAZ genes probably originated from land plants. (2) Phylogenetic analysis revealed 10 well-conserved subfamilies in plants; lineage- specific expansion, especially by tandem duplication and segmental duplication among species, were the major mechanisms in the evolution of the JAZ protein family and generated several lineage-specific JAZ subfamilies in land plants. (3) Exon-intron structure analysis revealed that the gene structures of JAZ paralogs contained a variable number of introns, from 0 to 7, and variable length of introns, from 62 to 4 222 bp, which suggests the events of intron loss as well as indels within introns that contributed to the structural diversity of current JAZ homologs. We provide valuable information on research into the JAZ protein family in plants.
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