The soil-borne necrotrophic fungus Rhizoctonia solani is one of destructive fungi causing severe yield losses in various important crops.  However, the host defense mechanisms against the invasion of this pathogen are poorly understood.  In this study, we employed an iTRAQ-based quantitative proteomic approach to investigate host proteins responsive to R. solani using the resistant rice cultivar YSBR1.  As a whole, we identified 319 differentially accumulated proteins (DAPs) after inoculation of rice plants with R. solani.  Functional categorization analysis indicates that these DAPs cover a broad range of functions.  Notably, a substantial portion of the DAPs are involved in cell redox homeostasis, carbohydrate metabolism, and phenylpropanoid biosynthesis, or belong to pathogenesis-related proteins, indicating that these processes/proteins play important roles in host defense against R. solani.  Interestingly, all of the DAPs involved in photosynthesis and chlorophyll biosynthetic processes, and part of the DAPs involved in phenylpropanoid biosynthesis, show reduced accumulation after R. solani infection, suggesting that R. solani probably inhibits host photosynthetic system and phenylpropanoid biosynthesis to facilitate infection and colonization.  In conclusion, our results provide both valuable resources and new insights into the molecular mechanisms underlying rice and R. solani interaction.

Cuticular wax plays an important role in protecting plants against water loss and pathogen infection and in the adaptations to environmental stresses.  The genetic mechanism of the biosynthesis and accumulation of epicuticular wax in rice remains largely unknown.  Here, we show a spontaneous mutant displaying wax crystal-sparse leaves and decreased content of epicuticular wax that was derived from the cytoplasmic male sterility (CMS) restorer line Zhenhui 714.  Compared with the wild type Zhenhui 714, the mutant exhibited hydrophilic features on leaf surface and more sensitivity to drought stress.  The mutation also caused lower grain number per panicle and thousand grain weight, leading to the decline of yield.  Genetic analysis indicates that the mutation is controlled by a single recessive gene, named wax crystal-sparse leaf3 (wsl3).  Using segregation populations derived from crosses of mutant/Zhendao 88 and mutant/Wuyujing 3, respectively, the wsl3 gene was fine-mapped to a 110-kb region between markers c3-16 and c3-22 on chromosome 3.  According to the rice reference genome and gene analysis, we conclude that a novel gene/mechanism involved in regulation of rice cuticular wax formation.