水稻类病斑突变体spl41的表型鉴定及生理分析

大多数水稻类病斑突变体会提高病程基因的表达从而抑制病原菌的生长,为进一步探索类病斑突变体抗病抗逆的机制,本研究对突变体spl41的形态性状、生理、抗病性等方面进行了研究。spl41是通过甲基磺酸乙酯(EMS)诱变籼稻品种‘黄华占’,获得的一个稳定遗传的水稻类病斑突变体。结果表明,该突变体从三叶期开始出现红褐色坏死斑,斑点数目随植株生长增多并导致枯黄衰老;突变体spl41类病斑的产生使株高、穗长、分蘖数、千粒重及结实率显著下降,并导致叶片的光合色素含量低于野生型;台盼蓝、NBT和DAB染色结果显示突变体spl41病斑部位有大量的死亡细胞并伴随着H_2O_2及O_2^-的积累,表明spl41植株病斑部位正在发生细胞程序性死亡。抗病性鉴定表明,突变体spl41相比于野生型对7个水稻白叶枯病菌生理小种的抗性增强;qRT-PCR分析表明PR1b、PR3、PR4、PR5、PBZ1和Cht1病程相关基因在突变体spl41中表达量上调。这些结果为探索植物抗病机制及选育植物抗病新材料提供了分子依据。

Phenotypic and Physiological Analysis of a Rice Lesion Mimic Mutant spl41

Rice lesion mimic mutants often show resistance to pathogens coupled with increased expression of pathogenesis-related genes.In order to explore the mechanism of disease resistance,we analyzed the morphology physiology,and disease resistance traits of mutant spl41.Mutant spl41 was obtained by using ethyl methylsulfonate(EMS)to mutagenize indica rice cultivar’Huanghuazhan’.The results showed that this mutant displayed reddish brown necrotic spots from three-leaf stage,and then leaves start to wilt and become yellowish.The plant height,panicle length,tiller number,1000-grain weight and seed setting rate of the mutant spl41 were significantly lower than those of wild type.Additionally,we found that the photosynthetic pigment content of spl41 was lower than that of wild type.Trypan blue staining showed that there were a large number of dead cells in spl41.NBT and DAB staining revealed that spl41 was accompanied with the accumulation of H2O2 and O2-around necrotic spots,indicating that programmed cell death was occurring.Furthermore,the resistance score of spl41 to seven races of Xanthomonas oryzae pv.oryzae(Xoo)was higher than wild type.The expression levels of PR1 b,PR3,PR4,PR5,PBZ1 and Cht1 were much higher in mutant spl41 than wild type by qRT-PCR analysis.These results provide help on explaining the mechanism of plant disease resistance and on selecting new plant disease resistant materials.