OsCYP 96B4等位突变体的抗病性分析

Resistance Analysis of OsCYP 96B4 Allele Mutants

优良抗病性是水稻绿色生产的重要需求,在当前水稻育种中有着举足轻重的地位.矮秆水稻具有耐倒伏、适合密植等优良特性,但其存在较高秆水稻生物产量低、密植易发生严重病害等问题,多年来困扰着水稻育种的研究,因此挖掘矮秆抗病资源成了育种家们一直研究的热点.从EMS诱变处理的西农1B突变体库中鉴定到4个水稻矮化易感纹枯病突变体(Dwarf and susceptibility to sheath blight 1 mutants,dssb1s),遗传分析发现:这4个突变体均是在LOC_Os03g04680编码框中的不同位置发生突变,LOC_Os03g04680编码一个细胞色素酶OsCYP 96B4,接种水稻白叶枯病菌和纹枯病菌后发现这4个突变体均感病,qRT-PCR发现突变体中病程相关基因(NPR1,PR10,PR1a和WRKY45)表达量降低.组织切片和扫描电镜分析发现:突变体的叶片发育异常,叶表面硅化细胞的数量明显增多,分布密集、杂乱.对叶片和叶鞘的细胞壁成分测定发现:突变体中的木质素和纤维素质量分数均显著或极显著低于野生型.实验结果表明:OsCYP 96B4是通过调控植物的叶片等发育和细胞壁的组分,进而增强了对水稻病害的耐受性.

Excellent disease resistance is an important requirement for rice green production and it plays an important role in rice breeding.Dwarf rice has good characteristics such as strong lodging resistance and suitable for dense planting.However,there are many problems with dwarf rice,such as low productivity and the occurrence of serious diseases in dense planting.Therefore,it has been a hot topic for breeders to explore the resources of disease resistance in dwarf rice.In this study,we identified four dwarf and susceptibility to sheath blight mutants(dssb 1 s)in rice from the library of Xinong 1B mutants treated by EMS.Genetic analysis showed that all the four mutants were mutated at different positions of LOC_Os03g04680 coding frame.These four mutants may be the new allelic mutants of OsCYP 96B4.All the four mutants were found to be susceptible to bacterial blight and sheath blight after inoculation.qRT-PCR showed that the expression of disease related genes(NPR1,PR10,PR1a and WRKY45)were decreased in the mutants.Tissue section and scanning electron microscopy analysis showed that the leaves of the mutants were abnormal.The number of silicified cells on the leaf surface was significantly increased,and the silicified cells densely and disorderly distributed.The lignin and cellulose contents of the leaf in the mutant plants were significantly lower than those in the wild type.We found that OsCYP 96B4 enhanced the disease resistance of rice by affecting development of leaf and cell wall components.