Lesion mimic mutants are important genetic materials for studying molecular mechanisms of plant cell death and dis-ease resistance.Through radiation mutagenesis of a japonica rice cultivar'Wuyunjing 7',a rare lesion mimic and dis-ease-susceptible mutant lms1 was obtained.Compared to the wild type,the leaves of this mutant spontaneously appeared red-dish-brown spots,and its plant height,panicle length,number of grains per panicle,and yield per plant decreased,but the weight of 1000-grain increased.In addition,the resistance of lms1 to rice bacterial blight decreased significantly,and tissue staining showed significant cell death and excessive accumulation of reactive oxygen species in the mutant leaves.Genetic analysis showed that the phenotype of the lms1 mutant was controlled by a single recessive nuclear gene,and the lms1 gene was finely located between two molecular markers,Indel7 and Indel8,on chromosome 9 of rice with a physical distance of 62 kb.PCR am-plification and sequencing of candidate genes in the localization interval showed that a 654 bp sequence was inserted into the first exon of the OsLMP1(Lesion Mimic Phenotype 1)gene,which encodes a ubiquitin carboxyl-terminal hydrolase,resulting in pre-mature termination of protein translation.The protein compositions of lms1 mutants and WT controls were analyzed by a pro-teomics technology,which identified a total of 19 differentially accumulated proteins(7 upregulated and 12 down-regulated),mainly involved in redox,chlorophyll synthesis,photosynthesis,and other metabolic pathways.The above results provide a ref-erence for further research on the function of the OsLMP1 gene and its molecular mechanism of regulating programmed cell death and disease resistance.
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