Rhizoctonia solani is a major fungal pathogen of rice (Oryza sativa L.) that causes great yield losses in all rice-growing regions of the world. Here we report the draft genome sequence of the rice sheath blight disease pathogen, R. solani AG1 IA, assembled using next-generation Illumina Genome Analyser sequencing technologies. The genome encodes a large and diverse set of secreted proteins, enzymes of primary and secondary metabolism, carbohydrate-active enzymes, and transporters, which probably reflect an exclusive necrotrophic lifestyle. We find few repetitive elements, a closer relationship to Agaricomycotina among Basidiomycetes, and expand protein domains and families. Among the 25 candidate pathogen effectors identified according to their functionality and evolution, we validate 3 that trigger crop defence responses; hence we reveal the exclusive expression patterns of the pathogenic determinants during host infection.

SummaryGrain weight is the most important component of rice yield and is mainly determined by grain size, which is generally controlled by quantitative trait loci (QTLs). Although numerous QTLs that regulate grain weight have been identified, the genetic network that controls grain size remains unclear. Herein, we report the cloning and functional analysis of a dominant QTL, grain length and width 2 (GLW2), which positively regulates grain weight by simultaneously increasing grain length and width. The GLW2 locus encodes OsGRF4 (growth‐regulating factor 4) and is regulated by the microRNA miR396c in vivo. The mutation in OsGRF4 perturbs the OsmiR396 target regulation of OsGRF4, generating a larger grain size and enhanced grain yield. We also demonstrate that OsGIF1 (GRF‐interacting factors 1) directly interacts with OsGRF4, and increasing its expression improves grain size. Our results suggest that the miR396c‐OsGRF4‐OsGIF1 regulatory module plays an important role in grain size determination and holds implications for rice yield improvement.

Kandelia candel is being established as a model xylophyte for ecoadaptation due to its salt tolerance. To adapt to high salinity, the photosynthesis apparatus must function efficiently under these conditions. Proteomic analysis of chloroplasts isolated from plants under different degrees of salt stress was performed to quantify the changes of individual proteins and to gain a global view of the total chloroplast protein dynamics. Among the 1030 proteins quantified (unique peptide ≥ 1), 76 showed a more than 1.5-fold change in abundance, of which 36 are involved in the light-dependent reactions and 12 in the Calvin cycle. The dynamic change of these proteins indicates that light-dependent reactions are maintained by up-regulating the levels of component proteins at both moderate and high salinity, and the Calvin cycle remained functional at moderate salinity but showed a decline at high salinity. In addition to proteins related to photosynthesis, some known abiotic-stress proteins and plastoglobuli were up-regulated in salt-stressed plants. Plastoglobuli might contribute to maintaining membrane integrity and fluidity. In conclusion, this extensive proteomic investigation on intact chloroplasts of the salt-tolerant xylophyte under salt stress provides some important novel information on adaptative mechanisms involving photosynthesis in responses to salt stress in K. candel.

No abstract