OsSAMS1在水稻稻瘟病抗性中的功能研究

Functional studies of rice blast resistance related gene OsSAMS1

稻瘟病是水稻最重要的病害之一,对农业生产造成巨大的经济损失。研究表明,水稻中S-腺苷-L-甲硫氨酸合成酶OsSAMS1参与了水稻衰老相关的进程,我们实验室前期利用转录组测序分析发现,OsSAMS1基因的表达水平受稻瘟病菌诱导后明显提高。然而,OsSAMS1是否参与水稻的免疫反应,尚未明确。基于此,本研究选取野生型ZH11为背景材料,通过构建OsSAMS1基因敲除突变体来探究该基因在水稻抗病中的功能。结果表明,OsSAMS1主要在水稻叶片中表达;且其表达明显受稻瘟病菌侵染所诱导。亚细胞定位结果显示,OsSAMS1在细胞膜、细胞质和细胞核内均有表达。通过接种稻瘟病菌发现,与对照相比,2个等位敲除突变体ossams1-1和ossams1-2均表现为更加感病,且体内病程相关基因的表达也明显更低,同时突变体中乙烯合成相关基因的表达也受到明显抑制。综上所述,Os-SAMS1参与了水稻的免疫反应,且正调控水稻稻瘟病的抗性。本研究为深入揭示OsSAMS1在稻瘟病免疫反应的分子机理奠定了基础,并为稻瘟病抗病育种研究提供了基因资源。

Rice blast is one of the most devastating diseases in rice,which causes great economic losses to agricultural production.It has been reported that S-Adenosyl-l-Mmethionine Synthetase 1(OsSAMS1)is involved in the process of senescence in rice.Transcriptome sequencing analysis showed that the relative expression level of OsSAMS1 was significantly increased after inocu-lation with Magnaporthe oryzae(M.oryzae).However,it remains unclear whether OsSAMS1 is involved in rice immunity.To verify this,we constructed the knock-out mutants of OsSAMS1 in the wild type variety ZH11.The results showed that OsSAMS1 was mainly expressed in rice leaves,and its expression was significantly induced by M.oryzae inoculation.Subcellular localiza-tion revealed that OsSAMS1 was distributed in the plasma membrane,cytoplasm,and nucleus.Compared to the wild type,the two knockout mutants,ossams1-1 and ossams1-2,displayed enhanced susceptibility upon M.oryzae infection,and the expression of pathogenesis-related(PR)genes was significantly inhibited.In addition,ethylene synthesis-related genes were also dramati-cally decreased in both two mutants.These results suggested that OsSAMS1 was involved in rice immune response and positively regulated rice blast resistance,which lays a foundation for further revealing the molecular mechanism of OsSAMS1 in plant im-munity and provides genetic resources for rice breeding of blast resistance.