Proteome analysis and phenotypic characterization of the lesion mimic mutant bspl in barley

Abstract

Characterization and molecular mechanism dissection for lesion-mimic mutation can help to gain an in-depth insight into regulatory mechanisms of programmed cell death in plants. In present study, the barley lesion mimic mutant bspl (barley spotted 1eaf) was used to investigate the formation of the bspl lesion mimic phenotype in barley using proteomics and quantitative real-time (qRT)-PCR techniques. The experiment showed that the formation of the bspl phenotype was directly related to light. Cell necrosis spontaneously formed in multiple parts of the leaf, and H2O2 accumulated continuously along with the formation of lesions. A total of 31 differentially expressed protein spots were identified using two-dimensional electrophoresis and mass spectrometry analysis of the expressed proteins between the bspl and the wild-type. These differentially expressed proteins are involved in different biological processes, mainly related to defense, photosynthesis, nitrogen acid metabolism, and carbohydrate metabolism. The expression of 15 genes was analyzed by qRT-PCR, and the results showed that the transcription level was basically consistent with the change in the protein level. The decreased expression of ATPase β subunit, cytochrome B6-F complex, photosystem I reaction center subunit VI, and other proteins may lead to the blockage of electron transport during photosynthesis, leading to cell death. Moreover, the overexpression of chitinase, thaumatin-like protein, PR-1a and other proteins, and the increased expression of NADPH-thioredoxin reductase and dehydroascorbate reductase may increase the disease resistance and stress resistance of bspl. This study will provide a new insight into the molecular mechanism underlying bspl-induced cell death in plants.