Rice最新文献

Inclination of leaf and plant height are important agronomic traits that are closely related to grain yields. Proteins involved in regulating free auxin (IAA) levels have a central role in modulating rice leaf angle and plant height. In this study, a rice mutant (named lc4) was found to have enlarged leaf angles and exhibit dwarfism compared to wild-type (WT) plants. Flanking analysis revealed that the mutation was caused by a T-DNA insertion at 270 bp upstream of the oxalate oxidase 2 (OsOxO2) ATG start codon. The insertion significantly increased the transcript levels of indole-3-acetic acid glucosyltransferase (OsIAAGLU), OsOxO1, OsOxO2 and OsOxO3 and OxO activity in lc4. Mutation of OsIAAGLU in lc4 led to partial restoration of the WT leaf angle and plant height phenotypes in iaaglu/lc4 which, however, still exhibited OxO activity comparable with that in lc4. On the other hand, mutation of OsOxO2 in lc4 also resulted in restoration of the WT leaf angle and plant height phenotypes, accompanied by reduced OxO activity and transcripts of OsIAAGLU, OsOxO1, OsOxO2 and OsOxO3. Nevertheless, overexpression of OsIAAGLU, but not OsOxO2 in the WT background, resulted in the transgenic plants showing leaf angle and plant height similar to lc4. Overexpression of OsOxO2 had no effect on the transcripts of OsIAAGLU, OsOxO1 and OsOxO3. These results suggest that activation of OsOxO2 and OsIAAGLU together resulted in altered plant architecture of lc4, while OsIAAGLU played a more direct role, OsOxO2 might be involved in regulating OsIAAGLU, OsOxO1 and OsOxO3 in a chromosome position-dependent manner.

Rice serves as the primary food source for over half the world's population, making its stable production is critical for global food security. The brown planthopper (BPH, Nilaparvata lugens Stål.) ranks among the most devastating rice pests in Asia. Developing BPH-resistant varieties through resistance gene discovery represents the most sustainable control strategy. Our study identified two novel resistance loci, Bph50 and Bph51, through analysis of the resistant wild rice germplasm GXU184 (Oryza rufipogon) using BSA-seq and QTL mapping. Interestingly, neither locus of Bph50 or Bph51 alone conferred resistance; rather, their combined presence in lines restored the high resistance observed in GXU184. Fine mapping localized Bph50 to a 177 kb region (6.732-6.909 Mb) on chromosome 4S and Bph51 to a 700 kb interval (15.035-15.735 Mb) on chromosome 4L. We developed a near-isogenic line (NIL) 9311^Bph50/Bph51 carrying both loci through marker-assisted selection (MAS), which exhibited strong BPH resistance without compromising agronomic performance. Integrated transcriptomic and histological analyses indicate that this resistance mechanism involves the coordinated upregulation of cellulose biosynthesis-related genes and the accumulation of polysaccharides such as cellulose in leaf sheaths. This enhancement of cell wall components likely increases tissue rigidity, forming a physical barrier that impedes stylet penetration during BPH feeding. Our findings unveil a novel resistance mechanism in which Bph50 and Bph51 genetically interact to confer BPH resistance, providing valuable insights for breeding durable pest-resistant rice varieties.

Rice blast, caused by the fungus Magnaporthe oryzae, is one of the most devastating diseases that affects rice production globally. Identifying new QTLs or R genes for blast resistance is crucial for developing rice varieties with enhanced resistance. In this study, a genome-wide association study (GWAS) to identify QTLs associated with blast resistance was conducted using phenotypic and genotypic data from 236 rice accessions. A total seven important QTLs linked to rice blast resistance were identified on chromosomes 1, 5, 6, 7, 10, and 12. Four main QTLs (qMZ6.1, qMZ7.1, qMZ10.1, and qMZ12.1) were key contributors to the blast resistance. Through combined analysis of differential expression and annotations of the predicted genes within qMZ12.1 based on haplotype and disease phenotype, we identified OsCBP606, which encodes a calmodulin protein, as the candidate gene for qMZ12.1. Compared with the wild-type plants, OsCBP606 knockout plants exhibited enhanced resistance to M. oryzae, while OsCBP606 overexpressing plants showed increased susceptibility. These findings highlight the critical role of OsCBP606 in modulating the rice immune response, making it a promising target for breeding programs aimed at improving rice blast resistance.

Rice serves as a fundamental staple crop, supporting the dietary needs of nearly one-third of the global population. This critical role necessitates immediate and strategic efforts to develop multi-attribute genotypes to ensure sustainable food and nutritional security for the burgeoning population. The augmentation of rice production is not only vital for addressing immediate food demands but also crucial for fostering long-term sustainability, thereby supporting livelihoods and driving economic development. Achieving this transformation necessitates a holistic and systems-level understanding of the molecular and regulatory networks that govern phenotypic plasticity and agronomic performance. While coding regions are pivotal for expression, non-coding elements play an even more prominent role in regulating transcriptional activity and orchestrating essential biological processes. Natural allelic variation within these non-coding elements serves as an evolutionary substrate for regulatory rewiring, contributing to adaptive plasticity, domestication traits, and intraspecific diversification. Therefore, the precise modulation of desirable agronomic traits could be facilitated by targeted engineering of such elements, which often allows for the fine-tuning of allelic effects in terms of the attenuation and partial restoration of alleles to impact desirable traits over coding components, which often results in complete exclusion or lethality. Therefore, we attempted to provide a comprehensive synthesis of functionally characterized non-coding elements exclusively for rice, highlight their functional roles, and emphasize how natural variation within these elements is critical for selecting traits associated with domestication and the breeding of elite genotypes. Notably, the potential of engineered non-coding RNA elements for the enhancement of agronomically advantageous traits is critically discussed. The future roadmap of non-coding element editing in rice is expected to be significantly shaped by continuous technological innovations in the editing toolbox, coupled with breakthrough discoveries for non-coding elements influencing agronomical traits. These advances have the potential to revolutionize the development of superior rice genotypes, ultimately contributing to the global effort to ensure food and nutritional security.

The intersubspecific rice hybrid Xieyou9308 exhibits striking hybrid vigor and serves as a valuable resource for dissecting the genetic basis of yield heterosis in indica-japonica crosses. However, the molecular mechanisms underlying this hybrid vigor remain poorly understood. Leveraging a set of recombinant inbred lines (RILs) and an immortalized F2 (IMF₂) population derived from Xieyou9308, 1,300,425 genomic variants were identified, which were consolidated into 3818 BIN markers. Genomic regions inherited from Zhonghui9308 were positively associated with traits including plant height, heading date, panicle length, and grain number per panicle. In contrast, regions derived from XieqingzaoB, particularly those located on chromosome 3, positively associated with grain length and 1000-grain weight. In the RIL population, 43 additive QTLs and 3 pairs of epistatic QTLs were identified for 10 agronomic traits, with the majority mapped to chromosomes 3 and 10, which harbor candidate genes including Ehd1, GS3, and OsTB1. In the IMF₂ population, 118 significant QTLs exhibiting partial dominance and 11 epistatic interactions were identified, underscoring the contributions of both partial dominance and epistasis to trait expression. Transcriptomic analysis further corroborated these findings, showing that alleles predominantly from Zhonghui9308 contributed to a prolonged growth duration, while those from XieqingzaoB shortened the growth duration. Collectively, these findings indicate that the hybrid vigor exhibited in Xieyou9308 is attributable to the synergistic effects of superior parental alleles and their epistatic interactions. These insights offer a valuable foundation for molecular breeding strategies aimed at improving yield in indica-japonica hybrid rice.

Soil salinization seriously impacts the growth and development, yield, and grain quality of crops. Elucidating the molecular underlying of salt tolerance is crucial for advancing stress-resistant molecular breeding research in crops. Here, we identified a salt stress-responsive gene, SQUAMOSA-promoter binding protein like 10 (OsSPL10), and characterized its molecular function in conferring salt tolerance to rice. Firstly, we generated and characterized three distinct types of spl10 mutants using CRISPR/Cas9 mutagenesis. In spl10 mutant, the leaf withered rate was lower than that in wild type (WT), the plant height and fresh weight per plant of spl10 were higher than WT under salt stress, indicating that spl10 exhibits tolerance to salt stress. Based on biochemical and physiological assays, the OsSPL10/14 complex was identified as a key regulator of salt stress response in rice by modulating the homeostasis of reactive oxygen species (ROS). Besides, the RNA-Seq assay confirmed that OsSPL10 may be involved in plant hormone signal transduction and phenylpropanoid biosynthesis pathways under salt stress, providing valuable insights for exploring the downstream target genes of OsSPL10. These findings offer novel insights into the molecular mechanisms underlying salt tolerance mediated by the SPL transcription factor in plants.