水稻抗纹枯病基因OsSeh1的克隆及功能鉴定

Cloning and Identification of Os Seh1 Gene With Function in Rice Resistance to Sheath Blight

为了挖掘抗水稻纹枯病的相关功能基因,本研究从日本晴（Oryza sativa L.spp.japonica,var nippobare）水稻品种中克隆了1个编码核孔蛋白的基因,命名为Os Seh1。该基因与拟南芥中的At Seh1同源,且不同植物物种的Seh1具有相同的保守结构域。Os Seh1蛋白定位于烟草叶片细胞核内。水杨酸和纹枯病病原菌均能诱导水稻Os Seh1的表达,水杨酸诱导48h时Os Seh1表达量达到最高值,约为诱导0h的2倍;而立枯丝核菌（Rhizoctonia solani）诱导24h时Os Seh1表达量达到最高,为诱导0h的3.5倍。接种纹枯病病原菌15d后,转基因过表达水稻植株比野生型抗性高,而RNA干扰（RNAi）植株比野生型更感病。抗病性显著的T1过表达植株中Os Seh1的相对表达量为6～11,比野生型相对表达量高3～4倍,而感病性显著的RNAi植株中Os Seh1的相对表达量为0.2～0.6,表明Os Seh1的表达水平与水稻对纹枯病病菌的抗性正相关。本研究初步证明了Os Seh1在水稻抗纹枯病中的重要功能,为利用水稻自身基因资源提高纹枯病抗性提供了新思路。

To screen functional genes related to resist rice sheath blight disease,,a gene encoding a nucleoporin（ nup）,named as Os Seh1,was cloned from rice Nipponbare（ Oryza sativa L. spp. japonica,var nippobare） in this study. Os Seh1 shared identity with At Seh1 of Arabidopsis thaliana,and Seh1 proteins from different plant species contained the same conservative domains. Protein Os Seh1 was observed exclusively in the nucleus of tobacco leaves. In rice plant,the expression of Os Seh1 gene was induced by salicylic acid or sheath blight agent Rhizoctonia solani. The expression of Os Seh1 at 48 hours point reached the peak under the induction of salicylic acid and the quantity was 2 times higher than that at 0 hour point. The highest expression quantity of Os Seh1 at 24 hours was as 3. 5 times as that at 0 hour point,with treated with Rhizoctonia solani. 15 days after inoculation with Rhizoctonia solani,the disease degree results overall showed that T1 rice plants over-expression of Os Seh1 were more resistant to Rhizoctonia solani. On the contrast,RNA interference（ RNAi） rice lines were more susceptible to Rhizoctonia solani. In T1over-expression rice plants with significant resistance,relative expression quantity of Os Seh1 is 6 to 11,which higher than 2. 47 in wild type rice Nipponbare. Otherwise, relative expression quantity of Os Seh1 is 0. 2 to 0. 6 in RNAi rice plants with obvious susceptibility. These results showed that rice resistance to Rhizoctonia solani was positively correlated with Os Seh1 expression levels. Os Seh1 was preliminarily proved to be an important gene in rice resistance to sheath blight,and this work will give a new thinking of improving sheath blight resistance by using rice genes resource.