Rice最新文献

Interspecific and intersubspecific hybrid rice have demonstrated substantial heterosis and increased yield potential, yet they are frequently restricted by complex hybrid sterility (HS). Gene regulation has primarily been used to explain the genetic mechanism of HS; however, it is still unclear how cryptic chromosomal structural hybridity results in heterozygote semi-sterility at the molecular level. This study identified a T-DNA-mediated heterozygous mutant mfss (male and female semi-sterility) in rice, of which the self-pollinated progeny would produce heterozygous semi-sterile mutant plants and homozygous fertile mutant plants, mm, with homozygous in inserted T-DNA. The hybrids derived from mm plants crossing with other rice varieties exhibited conservative semi-sterility. Genomic analyses and fluorescence in situ hybridization (FISH) observation revealed that the end of chromosome 6 (170 genes) translocated with the end of chromosome 2 (566 genes) in mm plants. Among these 736 translocated genes, 102 reproduction-concerned genes, including a new gene, MCM5, were detected, which may result in half of gametes lacking many reproduction-concerned genes to display sterility and caused semi-sterility of mfss-heterozygotes. Hybrids derived from an autotetraploid rice line created from mm plants by genome duplication crossed with a neo-tetraploid rice displayed high fertility, implying that the mfss-heterozygote semi-sterility might be overcome by producing polyploid hybrid rice. These findings elucidate the genetic process of reciprocal translocation causing the heterozygote semi-sterility in rice and offer valuable insights for the production of fertile polyploid hybrid rice.

Precise regulation of floral primordia initiation is essential for normal flower development. However, the mechanisms regulating floral primordia initiation (PI) are complex and poorly understood. Herein, we identified a natural mutant in rice, stamen less (sl), which develops florets with reduced stamen number and no carpel due to defects in stamen and carpel PI. STAMENLESS (SL) encodes the CC-type glutaredoxin OsROXY2 and is involved in the regulation of stamen PI. OsROXY1, the closest homolog of OsROXY2, showed no function in stamen PI regulation. The osroxy1 single mutant showed normal reproductive development, while the floret phenotypes of osroxy1/2 double mutant were comparable to those of osroxy2 mutant. The TGA transcription factor OsbZIP47 showed a strong interaction with OsROXY2, and the two genes exhibited overlapping subcellular localizations and expression patterns during flower development. The number of stamens in the osbzip47 mutant was increased to seven (around 35%), indicating that OsbZIP47 is a negative regulator of stamen PI, in contrast to OsROXY2. Taken together, our results reveal that OsROXY2 regulates stamen number via interaction with OsbZIP47, indicating GRX-TGA-mediated floral organ number regulation mechanism is conserved in monocots and eudicots.

Phase separation (PS) of BARENTSZ (BTZ), a core member of the exon-junction complex (EJC), is involved in various physiological and developmental processes in animals. However, less is known about plant equivalents. Here, we demonstrated that the loss of function of Oryza sativa BTZ genes (OsBTZs) reduced rice tolerance to salinity stress. Moreover, OsBTZ proteins underwent PS independent of other core members of EJC, forming condensates under salt stress. OsBTZs may recruit proteins that play roles in the salt tolerance response to form cytoplasmic condensates, which act as stress granules. The predicted prion-like domain (PrLD), that originated ancestrally and is functionally conserved, was demonstrated to be key to the PS of OsBTZs upon NaCl treatment. This work revealed a new role for plant BTZs through an evolutionarily conserved mechanism-PS-in the formation of condensates in response to salinity stress, thus providing new insights into the adaptive evolution of plant BTZs under abiotic stress.

Brassinosteroids (BRs) and gibberellins (GAs) are two important phytohormones that regulate plant growth and development. Crosstalk between BR and GA has been unveiled in Arabidopsis but the molecular mechanism by which the concurrence of these two signaling pathways regulates plant growth and development in rice remains elusive. The14-3-3 proteins are a family of conserved molecules that interact with a number of protein clients to regulate fundamental cellular processes including different aspects of plant hormone physiology. Here, we report that the rice 14-3-3 protein OsGF14h (G-box factor 14-3-3 homolog h) negatively modulates BR response and positively regulates GA signaling in rice. Overexpressing OsGF14h in rice increased plant height and grain yield, whereas knocking out OsGF14h increased lamina joint angle and reduced plant height and grain yield. OsGF14h interacted with both OsOFP8, a positive regulator in BR signaling, and SLR1, a negative key regulator in GA signaling. Interaction with OsGF14h led to nuclear export and cytoplasmic retention of OsOFP8, whereas OsGF14h interaction resulted in SLR1 shuttling from the nucleus to the cytoplasm and consequently inducing degradation of SLR1. Our results indicate that OsGF14h functions in both BR and GA signaling pathways and acts as a crosstalk point for BR and GA signaling, which offers new insights into the role of 14-3-3 proteins in regulating plant growth and development by modulating BR and GA signaling crosstalk.

This review synthesizes how amino acid (AA) metabolism regulates rice stress tolerance, growth and quality through stress protection and growth-modulating pathways, bridging mechanisms to field applications. Under abiotic stresses, rice accumulates specific AAs-notably proline (Pro), γ-aminobutyric acid (GABA), and branched-chain AAs (BCAAs)-as osmoprotectants and antioxidants, correlating strongly with stress tolerance. Genetic evidence establishes causality: overexpression of biosynthetic genes (e.g., OsOAT for Pro, OsDIAT for BCAAs), while suppressing catabolism (e.g., OsProDH knockout) or engineering AA transporters (AATs) (e.g., ABA-induced OsANT1 for amino acids redistribution) enhances tolerance. Integrated AA biosynthetic, catabolic, and transport pathways collectively maintain cellular function under stress. These insights enable practical strategies: exogenous AA treatments (e.g., Pro, GABA) mitigate stress damage, while breeding/engineering (e.g., OsAAP3, OsAAP11, and OsProDH knockout) develops high-yield, high-quality, and stress-tolerant rice. Future work should translate molecular insights into field applications, addressing trade-offs between growth, nutrition, and tolerance to enhance climate-resilient rice production.

Nitrogen (N) dynamics critically regulate rice productivity through root-mediated absorption and assimilation processes. This study investigates the differential responses of japonica (Suxiu 867) and indica (Yangxianyou 918) rice to N deficiency and subsequent high-efficiency compensation, integrating metagenomic analysis with physiological assessments of N metabolism. Building on an established high-efficiency N compensation period (18 days after tillering for japonica and 12 days for indica), we demonstrate that optimized N compensation significantly enhances dry matter accumulation and yield in both subspecies through distinct biological mechanisms. Compensation treatment elevated key metabolic indicators including soluble protein content (Cpr), glutamine synthetase (GDH) activity, soil urease (S-UE) activity, glutamate synthase (GOGAT) activity, and glutamine synthetase (GS) activity, collectively enhancing N assimilation efficiency. Rhizosphere microbiome restructuring showed subspecies-specific patterns, with Chloroflexi and Betaproteobacteria abundance positively correlating with N metabolic enzymes in indica, versus Actinomycetia, Deltaproteobacteria associations in japonica. Functional microbial analysis revealed divergent keystone taxa, with Noviherbaspirillum (indica) and Bacillus (japonica) driving N conversion efficiencies through niche-specific community synergies. Notably, indica rice presented a relatively high N absorption capacity and conversion efficiency, while japonica rice presented relatively stable N absorption and distribution mechanisms, and relatively high N fertilizer application significantly increased the abundance of specific microbial communities in japonica rice. These findings elucidate how subspecies-specific root physiology coordinates with rhizosphere microbial ecology to optimize N utilization, providing actionable insights for precision N management strategies tailored to rice genetic types.

Melatonin (Mel), a multifunctional molecule, has emerged as a pivotal regulator of plant stress responses, enhancing antioxidant defenses, and modulating metabolic pathways. This meta-analysis evaluated the role of Mel in mitigating various abiotic stresses, including salinity, drought, heavy metals, light intensity, and humidity, across diverse experimental conditions in rice crop. The findings reveal significant improvements in enzymatic antioxidant activities such as superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX), with notable increases in POD (77%) and CAT (61%) activities under hydroponic application. Mel application reduced oxidative stress markers, such as hydrogen peroxide (H₂O₂) and malondialdehyde (MDA), by up to 45% and 54%, respectively, highlighting its capacity to alleviate cellular damage under stress conditions. Additionally, Mel enhanced osmotic regulator such as proline, soluble sugar, and protein accumulation, contributing to osmotic adjustment, with an exceptional increase of 987% proline contents in Thailand. Experimental type and application methods significantly influenced the efficacy of Mel. Hydroponic treatments and seed soaking methods consistently showed the highest improvement in stress tolerance, while field experiments exhibited variability. The effects were also modulated by light intensity and humidity. Under light intensity of 150 µmol m⁻² s⁻¹, Mel enhanced antioxidant activities and reduced oxidative damage, while humidity at 70-75% showed the highest stress alleviation effects. These findings highlight Mel's complex contribution to increasing plant resilience by control of antioxidant enzymes, reduction of oxidative damage, and enhancement of osmotic adaptations under abiotic pressures. The present study offers a thorough knowledge of Mel's potential as a plant growth regulator, therefore guiding sustainable development under demanding environmental conditions.

This study presents a detailed analysis of the molecular mechanisms involved in heat stress tolerance in rice, focusing on the endoplasmic reticulum (ER) protein processing pathway. Through RNA sequencing (RNA-seq), we identified differentially expressed genes in two rice varieties, BNP162 and BNP206, emphasizing the importance of ER quality control mechanisms in maintaining cellular balance during heat stress. We identified three novel genes, Os11g0244200, Os01g0135800, and Os04g0445100, belonging to the Hsp20/alpha crystallin family, which are upregulated in response to heat stress. These genes play essential roles in protein stabilization, folding, and preventing aggregation, critical functions for maintaining protein balance under stress conditions. The upregulation of these genes highlights their potential in enhancing thermotolerance, a key trait for rice cultivation in the face of global climate change challenges. Our findings suggest that these novel genes could be promising targets for genetic manipulation to enhance heat tolerance in rice, contributing to the development of heat-resistant rice varieties. This research provides new insights into the molecular mechanisms of heat stress adaptation and lays a solid foundation for future studies aimed at improving crop resilience to environmental stress.

Biopesticides are promising alternatives to chemical pesticides because of their low residual effects, high selectivity, and capacity for long-term disease control. Melatonin (N-acetyl-5-methoxytryptamine) may be an ideal candidate for biopesticide because it is widely present in the plant kingdom, involved in growth, development, and stress-induced responses in plants, and can inhibit the growth and propagation of some microbial pathogens. However, it remains largely unclear whether melatonin influences rice and the blast fungus Magnaporthe oryzae. Here, we demonstrate that melatonin enhances rice immunity and inhibits the growth of M. oryzae, resulting in resistance to rice blast disease. Melatonin acts in rice response to M. oryzae because biosynthesis-related genes are induced upon M. oryzae infection. Melatonin treatment remarkably reduces blast disease severity in a susceptible rice accession. Mechanistically, melatonin treatment activates the mitogen-activated protein kinase cascades and up-regulates the expression of defense-related genes. Melatonin treatment also significantly inhibits the growth, sporulation, and spore germination of M. oryzae. Notably, melatonin treatment results in the death of M. oryzae hyphal cells. Altogether, our findings indicate that melatonin plays dual roles in the rice-M. oryzae interactions, activating rice immunity and inhibiting fungal growth. Thus, this study offers insights into the potential development of novel melatonin-based biopesticides for controlling rice blast disease.

Calcineurin B-like interacting protein kinases (CIPKs) are central regulators of plant development and stress adaptation. However, the specific roles of individual CIPK family members remain largely unexplored in major crops like wheat and rice. In this study, we characterized the function of TaCIPK19-3D through overexpression in transgenic rice and CRISPR-Cas9-mediated oscipk19 knockout lines. Expression profiling and subcellular localization analyses revealed that TaCIPK19-3D is associated with chloroplast development and metabolic activity. Overexpression lines exhibited enhanced chloroplast structure, increased chlorophyll biosynthesis, stomatal conductance, net photosynthetic rate, transpiration, and elevated levels of K⁺/Na⁺, Ca²⁺, and Mg²⁺, resulting in improved growth and yield compared to wild-type and mutant lines. Notably, TaCIPK19-3D overexpression conferred increased salt tolerance by upregulating ABA signaling, antioxidant responses, and proline biosynthesis. Key genes involved in chlorophyll synthesis (OsCAO, OsCHLH) and salt stress responses (OsAPX2, OsP5CS, OsABA2) were significantly upregulated in transgenic plants. Protein interaction studies using yeast two-hybrid and bimolecular fluorescence complementation (BiFC) assays demonstrated that TaCIPK19-3D interacts with TaFBA-4D and four CBL proteins (TaCBL1, TaCBL3, TaCBL4, and TaCBL7). Collectively, our findings reveal that TaCIPK19-3D positively regulates photosynthesis, ion homeostasis, and stress-responsive signaling pathways, highlighting its potential for improving crop productivity and stress resilience in wheat and rice.