Rice最新文献

The Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-CRISPR-associated protein (Cas)9 genome-editing technology has become a cornerstone for generating knockout mutations in plant functional genomics. To obtain genetically stable CRISPR-edited plants, the removal of exogenous CRISPR constructs through genetic segregation is imperative. However, current transgene-free strategies lack universality and operational simplicity. Here, we developed a modular CRISPR toolkit integrated with the widely applicable visual RUBY marker. This system achieved 100% editing efficiency in three independent CRISPR-Cas9 editing events in rice (cv. Zhonghua 11), enabled rapid visual identification of transgene-free progeny, and may provide a framework for future adaptation of CRISPR vectors to other plant species. Our design significantly accelerates the identification of edited lines while bypassing laborious molecular validation steps.

The plant cell wall serves as the primary structural barrier against herbivorous insect damage. Calcium ions (Ca²⁺) play a crucial role as a second messenger in plants. Exogenous calcium application has been demonstrated to enhance plant resistance to both biotic and abiotic stresses, thereby promoting sustainable crop production. This study investigates the mechanisms by which exogenous calcium induces resistance in rice. Our results show that calcium chloride (CaCl₂) promotes the biosynthesis of cellulose, pectin, and callose within the rice cell wall. It also up-regulates the expression of genes associated with cell wall component synthesis (OsCESA8, OsPME15, and OsGRP0.9) and callose synthesis (OsGSL1, OsGSL10, and OsGSL12). These biochemical modifications strengthen the cell wall structure, resulting in reduced nutrient availability for the female brown planthopper (BPH), Nilaparvata lugens. Consequently, the growth and development of BPH are hindered, ovarian development is delayed, and the expression levels of NlVg and NlVgR genes are reduced. These physiological alterations lead to a shortened oviposition period, reduced longevity, and decreased fecundity in female BPH. Our findings indicate that CaCl₂ strengthens the cell wall structure and promotes callose deposition as a critical defense mechanism in rice. This research provides a foundation for further exploration of the molecular mechanisms and cellular processes underlying exogenous calcium-induced resistance in rice and offers a promising strategy for environmentally friendly BPH management.

Rising food demand has led to heavy use of chemical fertilizers, which are costly and pose serious threats to soil health and the environment. This two-year field study evaluated whether integrating beneficial bacteria with reduced nitrogen (N) fertilizer could improve soil health, wheat productivity, and N use efficiency (NUE), thereby reducing dependence on chemical N inputs. Nine treatments were tested, including combinations of no N (CK), 50% (N50) and 100% (N100) recommended N rates, with or without soil application and seed inoculation using beneficial bacteria (SAB and SIB). Results demonstrated that seed inoculation with beneficial bacteria (particularly N50 + SIB and N100 + SIB) significantly enhanced soil ammonium and nitrate contents, microbial biomass carbon (MBC), dissolved organic carbon (DOC), and soil enzyme activities at critical growth stages compared to uninoculated controls. These improvements in soil health translated into better plant physiological functioning, evidenced by increased chlorophyll content, higher antioxidant enzyme activities (CAT, POD, SOD, GSH), and reduced membrane injury. Consequently, beneficial bacteria inoculated treatments improved N accumulation and translocation efficiencies, with N100 + SIB showing the highest N accumulation at maturity and its contribution to grain. Grain N content and 1000-grain weight were substantially improved with bacterial treatments, with N100 + SIB achieving a 15-20% increase in protein content and the highest grain yield (5705-5760 kg/ha). Notably, N50 + SIB achieved comparable grain yield and quality improvements as N100 alone, highlighting a promising reduction in chemical N dependency. Moreover, bacterial treatments enhanced PFPN, NUPE, and NIE by 16-34% over conventional N treatments, and the N harvest index (NHI) exceeded 67% in N100 + SIB, indicating efficient N partitioning into grain. In summary, seed inoculation with beneficial bacteria significantly improved soil health, plant growth, and N utilization, allowing for reduced application of synthetic N fertilizers without compromising wheat yield or grain quality. This suggests a sustainable and eco-friendly strategy for enhancing N use efficiency in wheat production.

The 14-3-3 proteins are highly conserved and widely distributed across eukaryotes. Some 14-3-3 proteins have been identified as regulators of phosphorus (Pi) deficiency tolerance in rice, but their diverse functions remain largely unexplored. In this study, we characterized the role of rice plant-specific non-ε group 14-3-3 proteins (OsGF14a-f) in response to Pi starvation by mutating these genes. We found that the expression of OsGF14a decreased in response to Pi starvation, while the expression of other non-ε group genes was induced. Subcellular localization studies transiently expressing them in tobacco leaves showed that OsGF14a was present in both the cytoplasm and nucleus, whereas the other proteins were predominantly localized in the cytoplasm. By developing single and multiple mutants, we demonstrated that OsGF14a plays a negative role in Pi homeostasis and root growth, while OsGF14b, OsGF14c and OsGF14f may act as positive regulators of Pi homeostasis and root growth in rice. However, all non-ε group 14-3-3 genes positively regulated rhizosphere acidification. Furthermore, the mutation of OsGF14a enhanced Pi accumulation and plant growth under various Pi supply conditions, likely due to the induction of OsPHR3, OsPT2 and OsPHO1;2 in the roots. Overall, this study highlights the diverse functions of plant-specific non-ε group 14-3-3 proteins in response to Pi starvation in rice and identifies the mutation of OsGF14a as a potential strategy to improve rice tolerance to Pi deficiency.

Rho GTPase-activating proteins (RhoGAPs) play crucial roles in regulating various biological processes. However, the functions of RhoGAP family genes in rice (Oryza sativa) remain largely unexplored. Here, we identified 19 RhoGAP genes in rice, and preliminarily analyzed the genes information, expression patterns, and evolutionary relationship with AtRhoGAPs in Arabidopsis. Using CRISPR/Cas9-mediated gene editing, we generated loss-of-function mutants of OsRhoGAP2 (rhogap2) and found that seed germination was significantly delayed compared to the wild type (WT). Further analysis revealed that α-amylase activity was reduced in rhogap2 germinating seeds. RNA-seq profiling identified 291 upregulated and 130 downregulated genes in the mutant, with differentially expressed genes (DEGs) primarily enriched in phenylpropanoid biosynthesis and other metabolic pathways. Notably, most phenylpropanoid biosynthesis-related genes exhibited increased expression in rhogap2 germinating seeds. These findings establish a foundational framework for future functional studies of RhoGAP genes in rice and provide novel insights into the molecular mechanisms by which RhoGAPs regulate seed germination in plants.

Alternative polyadenylation (APA) is a widespread post-transcriptional regulatory mechanism in eukaryotes that modulates gene expression by generating transcript variants. The development of young panicles in rice is a critical stage that determines grain number and weight. However, the regulatory mechanisms and inheritance patterns of APA during this process remain poorly understood. In this study, full-length isoform sequencing (Iso-seq) and metabolome were employed to investigate APA dynamics in the young panicle of hybrid rice variety Wufengyou T025 and in parent lines, Wufeng B and Changhui T025. This analysis revealed that approximately 80% of genes possessed two or more polyadenylation (pA) sites. These APA genes were predominantly enriched in the pathways associated with rice spikelet development, including response to external photoperiod changes, energy production and transportation, protein signal exchange, and amino acid metabolism. Notably, transcripts with a shortened 3'-untranslated region (3'UTR) exhibited elevated expression levels of their corresponding genes, suggesting that APA plays an important role in modulating gene expression. Furthermore, the variable 3'UTR of the 25% differentially expressed APA genes contained numerous miRNA binding sites, including osa-miR1848 and osa-miR5075, which are known to influence spikelet development. In the offspring, the expression levels of core APA factors during young panicle development were generally downregulated compared to the parental lines. Additionally, metabolomic analysis identified 209 and 164 differentially abundant metabolites in the offspring relative to Wufeng B and Changhui T025, respectively. Intriguingly, some of the enriched metabolic pathways overlapped with those of differentially expressed APA genes, implying that APA may influence small-molecule metabolites in pathways related to spike development. Collectively, these findings are valuable for understanding the regulation of APA and its genetic basis in young panicle development, offering new insights into the molecular mechanisms underlying this critical development stage.

Chilling stress can severely damage rice and lead to yield losses. The genetic mechanisms underlying responses of rice to chilling stress are complex and can vary depending on the genetic background, developmental stage, and experimental conditions. In this study, we used the chilling stress-tolerant japonica variety Taiken 9 (TK9) and the chilling stress-sensitive indica variety Taichung Sen 17 (TCS17) to investigate the genetic basis of chilling tolerance in rice seedlings. A BC₃-derived backcross inbred line, NSY1051070, which inherited high chilling tolerance from TK9 within the genetic background of TCS17, was developed through recurrent backcross breeding. A major quantitative trait locus (QTL), qCTS11-TK9, was identified in the distal region of the long arm of chromosome 11 by using F₂ and F₃ populations derived from the cross between TCS17 and NSY1051070. High-resolution linkage analysis delimited qCTS11-TK9 to a 191-kb genomic region containing 16 annotated putative genes in the rice reference genome. Expression and sequence analyses revealed three candidate genes responsible for chilling tolerance in NSY1051070: LOC_Os11g42790, LOC_Os11g42800, and LOC_Os11g42850. Our findings unveiled a novel major QTL associated with chilling tolerance in rice seedlings. The discovery of qCTS11-TK9 highlights a new source of seedling-stage chilling tolerance, and the markers developed in this study may aid future breeding programs.

The main purpose of the present study was to study the degeneration of the high-quality japonica rice varieties during long-term cultivation, with a focus on changes in yield, rice quality and indices related to 2-acetyl-1-pyrroline (2-AP) biosynthesis, to provide a scientific basis for the comprehensive purification and improvement of high-quality rice varieties. By selecting the lines from the populations of Nanjing 9108 and Nanjing 46 at Liyang, it was found that the mutant lines showed significant differences in the yield and yield components, processing and appearance quality, cooking and flavor quality, rapid viscosity analyser profile characteristics and 2-AP content. Molecular marker detection can be used as a primary method for seed purity identification. The results revealed that the 2-AP content was positively correlated with proline activity, ProDH activity and δ-OAT activity but negatively correlated with BADH2 activity. Through stepwise discriminant analysis, it was determined that 1000-grain weight and trough viscosity could be used as core indicators for discriminating line variations.

Sheath rot disease, caused by Sarocladium oryzae, is a severe problem in rice cultivation and can result in significant yield loss worldwide. In this study, we analyzed the function of LOC_Os09G23084, encoding an endoglucanase-1 precursor, through gene overexpression. Two single T-DNA insertion homozygous overexpression lines, 1-16 S and 4-10 S, derived from Oryza sativa cv. TNG67, were used for functional characterization. In field conditions, overexpression of LOC_Os09g23084 resulted in a decrease in rice development and an increase in susceptibility to sheath rot disease at the harvest stage. The overexpression lines showed delayed maturation, reduced internode and panicle neck length, deformed and less protruded vascular bundles, lower lignin content, and decreased yield. To verify the susceptibility of the overexpression lines to sheath rot disease, we set up a leaf-cutting inoculation method on seedlings. Lesion length was used to assess disease severity and was confirmed by fungal colonization using a GFP-tagged S. oryzae transgenic strain. The data confirmed that the overexpression lines were more susceptible to S. oryzae than wild-type lines. The reduced internode length and panicle neck length, less protruded peripheral vascular bundles, and low lignin content might contribute to the susceptibility to sheath rot. In this study, we provide insights into the potential function and mechanism of the endoglucanase gene LOC_Os09g23084 in rice susceptibility to sheath rot disease. Additionally, we demonstrated that LOC_Os09G23084 plays a crucial role in rice growth and development.