水稻ECT基因家族的全基因组研究

A Genome-wide Study of the Rice ECT Gene Family

真核生物mRNA转录后修饰可调控许多基因的遗传信息,植物m^(6)A甲基化研究正成为关注的新热点。m^(6)A结合蛋白(m^(6)A readers)调节m^(6)A修饰的特异性,通常具有YTH(YT521-B homology)结构域,在拟南芥中被命名为ECT结构域(evolutionarily conserved C-terminal region ECT domain)。目前ECT基因已在拟南芥和水稻等植物中检测到,但该基因家族在水稻中的成员及生物学功能还缺乏研究。本研究通过水稻ECT基因家族的全基因组分析,鉴定出12个OsECT基因,具有1个保守的基序,多位于蛋白质氨基酸序列C-端。共线性分析表明,在水稻基因组内OsECT-c与OsECT-e发生了重复事件,在物种间ECT同源基因对可能是在双子叶和单子叶植物分化后形成。同源基因对OsECT的Ka/Ks<1,表明OsECT基因家族在进化过程中可能经历了较强的纯化选择压力。表达模式分析显示,OsECT-b、OsECT-c、OsECT-e和OsECT-j在水稻生长初期各个组织均保持较高的表达水平,OsECT-g在干旱处理后表达量显著下调。因此,OsECT基因在水稻生长发育和逆境胁迫中可能发挥着重要作用。本研究为今后OsECT基因在水稻的节水抗旱机制研究和相关抗逆育种提供了重要的理论基础。

Post-transcriptional modifications of eukaryotic mRNA can regulate the genetic information of many genes,and the study of m^(6)A methylation in plants is becoming a new focus of attention.m^(6)A“reader”proteins regulate the specificity of m^(6)A modification,usually with a YTH domain,named ECT(evolutionarily conserved C-terminal region domain)domain in Arabidopsis thaliana.At present,the ECT gene has been detected in Arabidopsis and rice,but the members and biological functions of the ECT gene family in rice are still lacking.In this study,12 OsECT genes were identified through genome-wide analysis of the rice ECT gene family,with a conserved motif located at the C-terminus of the protein.The synteny analysis showed that OsECT-c and OsECT-e were duplicated in the rice genome;ECT homologous gene pairs between species may be formed after the differentiation of dicotyledonous and monocotyledonous plants.The Ka/Ks of homologous OsECT gene pairs were less than 1,indicating that the OsECT gene family may have experienced strong selection pressures during evolution.Expression pattern analysis showed that OsECT-b,OsECT-c,OsECT-e and OsECT-j maintained high expression levels in various tissues at the early stage of rice growth,while OsECT-g was significantly down-regulated after drought treatment.In conclusion,our results suggest that OsECT genes may play an important role in rice growth,development and stress.This study provides an important theoretical basis for the future research on the water-saving and drought-resistance mechanism of OsECT genes in rice and related stress-resistance breeding.