Rice最新文献

Rice serves as the staple food for over half of the world's population, yet its propensity to accumulate cadmium (Cd), a toxic heavy metal and potential human carcinogen, poses significant food safety concerns. OsNRAMP5, the primary transporter responsible for Cd and manganese (Mn) uptake in rice, has emerged as a key target for developing low-Cd rice varieties through breeding programs. However, the broader physiological roles of OsNRAMP5 beyond metal transport remain poorly understood. Here, we demonstrate that OsNRAMP5 mutations, while effectively reducing Cd accumulation, significantly compromise rice blast resistance by disrupting Mn homeostasis. Our mechanistic analysis reveals that Mn deficiency in osnramp5 mutants leads to reduced activities of critical defense enzymes, including manganese-dependent superoxide dismutase (Mn-SOD) and phenylalanine ammonia-lyase (PAL), resulting in decreased accumulation of hydrogen peroxide (H₂O₂) and lignin, which are essential components of plant defense responses. Furthermore, pathogen-induced expression of pathogenesis-related (PR) genes is markedly suppressed in osnramp5 mutants, indicating impaired immune signaling pathways. Importantly, our study also demonstrated that utilizing rice variety carrying major blast-resistance genes as a background can effectively eliminate the reduced rice blast resistance caused by OsNRAMP5 mutation. This study reveals an important trade-off between cadmium safety and disease resistance in rice breeding and provides a promising approach for developing rice varieties that balance low Cd accumulation with maintained blast resistance, informing breeding strategies that reconcile food safety and agronomic performance.

Grain weight and panicle architecture are pivotal determinants of rice yield, yet the regulatory mechanisms coordinating these traits remain elusive. Here, we functionally characterized a phytochrome-interacting factor, OsPIL11, serving as a negative regulator of grain weight and grain number per panicle. Knocking out OsPIL11 resulted in increased grain weight and grain number per panicle. OsPIL11 regulates grain weight by affecting cell expansion and division in the spikelet hulls, and controls grain number per panicle by regulating the number of primary branches. We further identified MicroRNA530, and cytokinin oxidase/dehydrogenase 2 as the target genes of OsPIL11 to regulate grain size and grain number in rice. Analysis of genetic variations suggested that there are two main haplotypes (Hap1 and Hap2) of OsPIL11. Hap1 confers the increased grain width and grain weight compared to Hap2, implying Hap1 as a superior haplotype for yield improvement. These findings provide novel insights into the molecular mechanisms underlying the regulation of rice yield, offering valuable genetic resources for the development of high-yield rice varieties through molecular breeding approaches.

Magnesium (Mg) and calcium (Ca) are the most abundant divalent cations in plants. Cause their antagonistic interaction in plant cell, maintaining Ca-Mg balance is critical for optimal plant growth and development. However, the molecular mechanisms underlying the regulation of Ca-Mg balance remain poorly understood. In this study, we found that the expression of OsCAX1a was highly induced under high Ca:Mg ratio conditions in rice. Heterologous expression of OsCAX1a in yeast demonstrated that it enhances cytosolic Mg efficiency by mediating Ca efflux. Genetic knockout or overexpression of OsCAX1a in rice altered the Ca:Mg ratio and impaired growth performance. Collectively, our results indicate that OsCAX1a-mediated Ca efflux plays an important role in Mg homeostasis, providing a new insight for Ca-Mg balance in plant.

Submergence stress is a major abiotic factor that reduces the seedling establishment of rice. Gibberellic acid (GA) acts as a signal regulating anaerobic tolerance in rice, while seed priming is a pre-sowing treatment widely used to improve stress tolerance. However, whether and how GA seed priming affects rice seedling establishment under submergence stress remains unknown. In the present study, seeds of Oryza sativa L. cv. Xiangzaoxian45 were subjected to three treatments: no priming (NP), hydro-priming with distilled water (HP), and GA₃ priming (0.1 mM GA₃; GAP). Subsequent germination test was conducted under submergence (5 cm of water) in growth chambers (25 °C, 12-h photoperiod). Seedling establishment attributes, α-amylase activity, soluble sugar content, respiration rate, ATP content, respiratory enzyme activities, hormone levels, and gene expression in starch degradation, energy metabolism, and hormone biosynthesis pathways were measured. Results showed that GAP significantly promoted seed germination and seedling growth under submergence compared to NP and HP treatments. This improvement was attributed to higher GA₃ levels in rice seeds, resulting from both exogenous application during priming and the upregulation of GA biosynthesis genes (OsGA3ox1 and OsGA20ox1). Elevated GA₃ subsequently induced the expression of GA-responsive α-amylase genes (OsRamy1A, OsRamy3B, and OsRamy3E), thereby enhancing starch degradation, as evidenced by significantly increased α-amylase activity and total soluble sugar content. Furthermore, GAP enhanced the energy status of rice seedlings under submergence by increasing the oxygen consumption rate and ATP content and improved anaerobic respiration by elevating lactate dehydrogenase (LDH) activity and up-regulating OsLDH expression. However, GAP and HP did not differ significantly in regulating aerobic and anaerobic respiration under submergence. Moreover, principal component analysis, correlation analysis, and hierarchical partitioning analysis suggested a higher contribution of starch degradation than energy metabolism to seedling establishment under submergence stress. In summary, these findings indicate that GA priming enhances rice seedling establishment under submergence, and this improvement is predominantly attributed to GA-activated starch degradation.

The persistent challenge of weed management in agriculture has been profoundly influenced by the development and adoption of herbicide-resistant (HR) crops. This review examines the historical evolution, current dynamics, and future directions of HR crop development and integrated weed management (IWM) strategies, providing an in-depth analysis of the field. We trace the advent of herbicide resistance in crops, highlighting the genetic and biotechnological advancements that have facilitated the development of crops resistant to various herbicidal modes of action. Concurrently, we explore the biological mechanisms of herbicide resistance in weeds and their implications for agricultural practices and herbicide effectiveness. A significant focus is placed on the renewed efforts in herbicide discovery, highlighting the challenges faced and the innovative approaches being explored, including natural product research and advanced molecular techniques. As the agronomic landscape evolves, the review emphasizes the escalating importance of IWM, presenting it as a multifaceted approach that integrates chemical, cultural, and mechanical strategies to sustainably manage weed populations. Moreover, the review highlights the emergence of non-chemical control measures, such as harvest weed seed control (HWSC) and breeding weed-competitive cultivars, underscoring their role in a comprehensive weed management strategy. The advent of site-specific weed management (SSWM) and its potential to revolutionize weed control practices are critically analysed, discussing the integration of cutting-edge technologies in precision agriculture. Looking forward, we contemplate the challenges and policy implications associated with the widespread adoption of HR crops and IWM practices, emphasizing the necessity for well-informed regulatory frameworks to ensure agricultural sustainability.

The signal peptidase complex (SPC) is a crucial membrane enzyme complex involved in the process of protein secretion and maturation in both prokaryotic and eukaryotic cells. SPC is responsible for the cleavage of N-terminal signal sequences from nascent proteins, a sequence of amino acids that directs the newly synthesized protein to the secretory pathway. The yeast SPC is composed of four subunits: Spc1, Spc2, Spc3, and Sec11. To understand how SPC functions in the fungal plant pathogen, we identified the SPC component gene MoSPC2 and characterized its functions in M. oryzae. Through measuring the colony diameter of the ΔMospc2 mutant and control strains on culture medium plates, quantifying conidia production, observing conidial morphology, and assessing pathogenicity on rice and barley plants, we found that MoSpc2 contributes to fungal growth, asexual development, and pathogenicity. Since host-derived reactive oxygen species (ROS) are crucial for rice to defend against M. oryzae, we further investigated the role of MoSpc2 in ROS modulation. Our results indicate that MoSpc2 plays a pivotal role in suppressing the accumulation of ROS and regulating the activities of extracellular peroxidases and laccases. Notably, MoSpc2 mediates the accumulation and secretion of the effector protein MoSlp1. Furthermore, using affinity purification, we discovered MoSpc2-interacting proteins and identified potential SPC interactors. These candidates provide a foundation for future mechanistic studies aimed at elucidating their functional roles in SPC complex assembly and pathogenic regulation. Our results highlight the significance of the SPC component gene MoSPC2 involvement in fungal development and pathogenicity and widen our understanding of the connections between the SPC and fungal pathogenesis.

Tetraspanins (TETs) are evolutionarily conserved transmembrane scaffolding proteins that play crucial roles in plant development, reproduction, and stress responses. However, their functions in rice root development remain poorly understood. Here, we characterized OsTET8, a rice TET family member, which displays root-specific expression in rice and predominantly localizes to the root elongation zone. Subcellular localization revealed that OsTET8 is dual-targeted to the endoplasmic reticulum (ER) and plasma membrane. OsTET8 knockout mutants exhibited significantly elongated primary roots, increased lateral root density, and enhanced adventitious root formation, whereas root-specific overexpression suppressed these characteristics. Furthermore, cytological analyses showed reduced root cross-sectional area and cortical cell layers in both knockout mutants and overexpression lines, indicating impaired cell proliferation. Transcriptomic profiling identified differentially expressed genes (DEGs) involved in intracellular redox homeostasis and jasmonic acid (JA) biosynthesis/signaling, which were further validated by qRT-PCR. Together, our findings demonstrate that OsTET8 negatively regulates rice root development, potentially through its coordination of redox homeostasis and JA signaling pathways. This study provides new insights into the molecular mechanisms underlying TET-mediated root development and highlights OsTET8 as a potential target for rice improvement.

Ratoon rice (RR), recognized as an efficient method of rice cultivation, plays a crucial role in the food production system. By enabling two harvests-during the main season rice (MSR) and the ratoon season rice (RSR)-from a single planting, this cropping system significantly enhances the utilization of land and temperature-solar radiation resources, thereby providing essential support for food security. However, the yield formation of RSR is constrained by several factors, including the adaptability of the rice variety, nitrogen fertilizer management strategies, and the uneven distribution of temperature and solar radiation resources, which collectively hinder the actual realization of its yield potential. This research first employed a meta-analysis approach to identify the optimal nitrogen management practices for ratoon rice. Through multi-location field experiments, high-yielding ratoon rice varieties with strong ecological adaptability were selected. Then, the selected high-yielding and adaptable varieties were cultivated under field conditions by using the optimal nitrogen management practices to compare the yield formation differences and underlying mechanisms among the MSR, RSR, and late-season rice (LSR) with synchronous heading. The research findings indicated that the yield of RSR was significantly lower compared to both MSR and LSR with delayed panicle emergence. Nevertheless, considering that its growth period constituted only 53.52% and 55.47% of the growth periods of MSR and LSR with delayed panicle emergence, respectively. Its daily grain yield (DGY) was 28.33% and 13.56% higher than that of MSR and LSR with delayed panicle emergence. Furthermore, RSR exhibited significant advantages in terms of effective panicle (EP) and seed setting percentage (SSP), although its number of grains per panicle (NP) and 1000-grain weight (TGW) were notably lower than those of MSR and LSR. Subsequent analysis demonstrated that enhancing the utilization efficiency of temperature and solar radiation resources can significantly increase the EP and SSP in RSR. By extending the days before flowering and augmenting accumulated temperature and radiation before flowering, there is a significant notable increase in NP and TGW, thereby overcoming the yield limitations. This study offers a theoretical foundation and technical support for the high-yield and efficient cultivation of RSR.