MicroRNAs (miRNAs) are a class of small, non-coding RNAs that regulate gene expression in eukaryotes. Among them, miR396 targets GROWTH-REGULATING FACTOR (GRF) transcription factors and forms one of the most highly conserved regulatory modules in plants. Recent studies have greatly expanded the functional landscape of the miR396-GRF module, showing that, beyond its canonical role in leaf morphogenesis, it also participates in root meristem regulation, reproductive development, yield formation, tissue regeneration, and responses to diverse abiotic and biotic stresses. In crop plants, this module further controls agronomically important traits. Here, we summarize current knowledge of the evolutionary conservation and diversification of the MIR396 loci, the upstream pathways that control miR396 expression, and the developmental and stress-related outputs mediated by the miR396-GRF module. We also discuss evidence that miR396 functions as a context-dependent regulator rather than a simple growth suppressor, and highlight how precise manipulation of the miR396-GRF module may provide new opportunities for crop improvement by optimizing growth, regeneration, and stress resilience.

Waxy rice is an important raw material in food processing, particularly for traditional Asian products such as rice balls. High-quality waxy rice powder, characterized by low levels of damaged starch and small particle size, is typically produced via wet grinding. However, this method generates substantial wastewater and consumes lots of energy, raising environmental concerns. In non-waxy rice, floury endosperm mutants have enabled high-quality rice powder through dry grinding, but this approach has not been extended to waxy rice. Here, a waxy rice mutant with floury-core endosperm was developed by an insertion mutation of the soluble starch synthase IIIa ( ssIIIa ) gene. Compared with the ssIIIa mutant of non-waxy rice, the waxy rice mutant exhibited distinct agronomic characteristics, including reduced yield-related traits. Nevertheless, the floury-core endosperm reduced starch damage and particle size in dry-ground flour, enhancing its suitability for waxy rice ball production. The mutant also contained more short chains and smaller molecules in amylopectin, associated with the upregulation of multiple ssIIIa -related genes. Those changes further resulted in decreased crystallinity and altered pasting and thermal properties. Waxy rice powder of the mutant was obtained via dry grinding and exhibited favorable processing and eating qualities. Dough was harder and easier to handle, while boiled balls were softer, less sticky, and easier to chew and swallow. Collectively, the floury-core endosperm modified agronomic traits, physicochemical properties, and gene expression in waxy rice, ultimately improving product quality. The dry grinding method using the mutant offers an environmentally friendly alternative to conventional wet grinding for high-quality waxy rice powder.

BACKGROUND:Early indica rice frequently encounters high temperature damage during grain-filling period in the Yangtze River basin, China induced by later sowing date, decreasing grain yield and qualities. Nitrogen panicle fertilizer application (NPF) positively mitigates the adverse effects; however, the specific details remain unclear. A field experiment using poor or high-quality early indica rice cultivars was conducted over 2 years to investigate rice yield, grain qualities and starch related traits subjected to slightly natural warming (W) under different NPF levels (Low NPF, LN; Middle NPF, MN; High NPF, HN) through delaying sowing date, with normal sowing date as the control. RESULTS:The result showed that under W, compared to LN, elevated NPF (HN and MN) significantly increased the grain yield of the rice cultivars by 11.7-21.0%, which was mainly attributed to the high effective panicle and spikelets. Elevated NPF increased the protein and amino acid contents, especially for the HN treatment, resulting in the high nutritional qualities of rice grain, at the same time as demonstrating increased hardness and stickiness, as well as decreased breakdown and amylose content, negatively affecting the eating and textural qualituies of cooking rice. Notably, compared with HN and LN, MN treatment totally enhanced the processing qualities under W in 2 years. However, HN significantly deteriorated the rice appearance qualities in the temperature treatments. These results might be a result of the unordered arrangement and irregular surface of starch granules, particular high-quality rice cultivar. CONCLUSION:The results suggest that optimizing NPF under slightly warming at grain-filling stage synergistically improve grain yield and processing qualities of early indica rice. © 2026 Society of Chemical Industry.

Boro II (BT), the first cytoplasmic male sterility (CMS) system in rice, is widely used in three-line japonica hybrid rice production. Accurate detection of maintainer-seed contamination in BT-type CMS seed lots is critical for ensuring genetic purity and hybrid seed quality. In this study, we developed a SYBR Green-based quantitative real-time PCR (qPCR) assay for the detection and quantification of maintainer-seed contamination in BT-type CMS seed lots. Maintainer-specific primers targeting a mitochondrial sequence unique to the maintainer line, together with an endogenous reference targeting a conserved mitochondrial sequence present in both maintainer and CMS lines, were validated for specificity. A standard curve was constructed using defined CMS-maintainer seed mixtures (0.1-5% contamination), and ΔCt values were converted to relative abundance (2-ΔCt). The assay exhibited high specificity, reproducibility, and sensitivity, with a strong linear relationship between 2-ΔCt values and actual contamination levels (R2 > 0.99). Performance testing using simulated contamination samples (0.2-3.13%) demonstrated accurate quantification with acceptable recovery rates. This method provides a rapid, robust, and reliable tool for routine genetic purity testing and quality control in BT-type CMS hybrid rice seed production.

Lodging is a major constraint on the stable production of high-quality japonica rice in the Yangtze River Delta. This study evaluated whether different concentrations of prohexadione calcium (Pro-Ca) could improve lodging resistance while maintaining grain yield in high-quality japonica rice. Field experiments were conducted in the 2024 and 2025 growing seasons, with TA 1 cultivated in 2024 and TA 1, SY 28, and HR 1212 cultivated in 2025. Pro-Ca was applied at the jointing stage at four concentrations: CK (water spray), P1 (15 mg L-1), P2 (30 mg L-1) and P3 (45 mg L-1). Rice yield and its components, lodging parameters, culm morphological traits, and non-targeted metabolomic profiles were analyzed. Compared with CK, the P1 treatment significantly reduced the lodging index without a significant reduction in grain yield. In contrast, the P2 and P3 treatments further decreased the lodging index by 14.0-48.1% but decreased grain yield by 6.7-17.9%, mainly due to reductions in effective panicle number and spikelets per panicle. Pro-Ca treatment significantly increased internode diameter and culm wall thickness by 4.9-29.3% and 11.7-76.5%, respectively, and promoted the accumulation of lignin by 5.4-17.7% and cellulose by 3.0-8.6%, thereby enhancing the structural reinforcement of the rice stem. A metabolomic analysis showed that Pro-Ca treatment was associated with changes in carbon- and nitrogen-related metabolites, including metabolites linked to the tricarboxylic acid (TCA) cycle and amino acid biosynthesis. These changes were accompanied by increased accumulation of phenylpropanoid pathway intermediates and lignin-related precursors, including sinapyl alcohol and coniferyl aldehyde. Therefore, in our study, 15 mg L-1 Pro-Ca showed the most favorable balance between lodging resistance and yield, indicating its potential for further evaluation; however, its agronomic and economic feasibility requires additional investigation before practical recommendation.

IntroductionDirect-seeding rice faces the prominent challenge of low seedling emergence vigor, particularly under deep-sowing mechanical resistance and hypoxic conditions. Although some physiological traits are known, the systemic molecular networks determining superior emergence remain elusive. MethodsHere, we integrated metabolomic and transcriptomic analyses to compare the elite direct-seeding variety ChongShang2022 (CS2022) with the control Huxiangruan450 (HXR450). Results and discussionWeighted gene co-expression network analysis (WGCNA) identified germination-associated metabolic modules. Hub metabolite analysis revealed that the accelerated germination of CS2022 correlates with a higher accumulation of cytokinins (zeatin and cis-zeatin-9-N-glucoside), known for antagonizing abscisic acid (ABA)-induced dormancy, alongside key amino acids (e.g., L-lysine) and structural sphingolipids. Physiological validation confirmed the functional significance of these hubs, demonstrating that exogenous trans-zeatin and L-lysine significantly promoted seed germination in a dose-dependent manner. Notably, CS2022 exhibited heightened sensitivity, achieving maximal promotion at concentrations approximately 10-fold lower than HXR450. Targeted LC-MS/MS assays further demonstrated that CS2022 maintains a significantly higher GA20/ABA ratio during germination by accumulating the key precursor GA20 and deactivating free ABA into ABA-glucosyl ester. This hormonal homeostasis couples with elevated α-amylase activity, accelerating energy mobilization. At the seedling stage, multi-omics integration suggests an optimized growth-defense trade-off in CS2022. Auxin signaling supports rapid elongation, while the upregulation of jasmonic acid (JA) precursor transcripts contrasts with restricted accumulation of bioactive signals (e.g., JA-Ile). This potential signal buffering mechanism likely mitigates growth arrest. Additionally, lipid remodeling involving sphingolipids and waxes may contribute to hypoxia tolerance. Altogether, this study delineates a correlative regulatory network where dynamic hormone buffering, redirected metabolic flux, and adaptive lipid remodeling synergistically maximize direct-seeding rice emergence vigor, providing mechanistic insights and candidate modules for breeding.

Japonica soft rice varieties possess excellent eating quality, and their cultivation area has been steadily expanding in recent years. This study aimed to analyze japonica soft rice varieties cultivated in the Yangtze River Delta region of China at the genome level and to provide a theoretical basis for optimizing disease resistance and other important traits. Genotypic characterization and evaluation of ten major japonica soft rice varieties from the Yangtze River Delta region were conducted using a genome-wide single nucleotide polymorphism (SNP) chip. The experimental results indicated that the soft rice varieties in the Yangtze River Delta region had a relatively high japonica component and were all classified as typical japonica rice varieties. Specifically, the highest (95.6%) and lowest (91.5%) proportions of japonica genomic segments were detected in Tai’an 1 and Zhehexiang 2, respectively. Japonica soft rice varieties from Shanghai exhibited a closer genetic distance to those from Jiangsu Province than to those from Zhejiang Province. Genomic identity was highest between Tai’an 1 and Nanjing 46 (87.9%) and lowest between Tai’an 1 and Jia 67 (74.4%). Based on the results of the chip assay, a total of twenty-six functional genes controlling key traits, such as yield, quality, and resistance to biotic and abiotic stresses, were identified in the ten analyzed varieties. Among them, Zhehexiang 2 carried the broad-spectrum blast resistance genes Pi2 and Pita, which is useful for improving the blast resistance of japonica soft rice varieties. The findings of this study provide genetic resources and carrier materials for the efficient molecular improvement of japonica soft rice varieties.

IntroductionLodging is a critical limiting factor affecting stable rice production in the lower reaches of the Yangtze River in China.MethodsThis study aims to clarify the optimal spraying period and concentration of paclobutrazol for high-quality japonica rice by examining its effects on the mechanical, morphological, and metabolic characteristics of the stem. A clean water treatment (CK) was established alongside five spraying periods (S1: July 19; S2: July 26; S3: August 2; S4: August 9; S5: August 16) with three spraying concentrations (LP: 100 mg L-1; MP: 200 mg L-1; HP: 300 mg L-1).Results and discussionThe results indicate that the MP treatment during the S4 period resulted in a yield increase of 2.3–11.8% while reducing the lodging index by 15.8-25.5%. In the early stages of spraying (S1, S2 and S3), the lodging resistance of rice was primarily enhanced by reducing plant height, but led to a significant decrease in the spikelets per panicle and grain filling, ultimately resulting in reduced yield. In the later stages of spraying (S4 and S5), lodging resistance was mainly improved by increasing internode diameter and culm wall thickness, which concurrently resulted in a significant increase in the grain filling. Although high concentrations of paclobutrazol in each period can reduce the lodging index, they are not conducive to yield formation. Correlation analysis revealed a significant negative correlation between the lodging index and both the internode diameter and the culm wall thickness. Non-target metabolism indicated that the significant increase in mandelonitrile and sarcosine content within cyanoamino acids metabolism, and glycine, serine, and threonine metabolism during S4, might be the primary metabolic factors promoting the development and thickness of stem walls. Additionally, the increase in pheophytin-a in porphyrin and chlorophyll metabolism, along with leucine in valine, leucine, and isoleucine degradation, may be the key contributors to the enhancement of rice lodging resistance and stable yield when treated with an appropriate concentration of paclobutrazol.

Improving plant architecture and increasing yields are the main goals of rice breeders. However, yield is a complex trait influenced by many yield-related traits. Identifying and characterizing important genes in the coordinated network regulating complex rice traits and their interactions is conducive to cultivating high-yielding rice varieties. In this study, we determined that the interaction between mitogen-activated protein kinase kinase kinase5 (OsMAPKKK5) and brassinosteroid-signalling kinase1-1 (OsBSK1-1) regulates yield-related traits in rice. Specifically, OsMAPKKK5 phosphorylates OsBSK1-1, which enhances the interaction between these two proteins, but adversely affects the OsBSK1-1-OsBRI1 (BR insensitive1) and OsBSK1-1-OsPPKL1 (protein phosphatase with two Kelch-like domains) interactions. Additionally, OsMAPKKK5 disrupts brassinosteroid signal transduction, which prevents OsBZR1 (brassinazole-resistant1) from efficiently entering the nucleus, thereby negatively modulating its function as a transcription factor regulating downstream effector genes, ultimately adversely affecting plant architecture and yield. This study revealed the relationship between the MAPK cascade and the regulatory effects of brassinosteroid on the rice grain yield involves OsMAPKKK5 and OsBSK1-1. The study data may be important for future investigations on the rice yield-regulating molecular network.

Conventional rice breeding predominantly relies on hybridization techniques, with hybrid progenies typically requiring 8 to 10 generations of selfing to achieve genetically stable homozygous lines. In contrast, haploid breeding enables the derivation of stable doubled haploid (DH) lines from hybrid progeny in just one generation, substantially shortening the breeding cycle. Haploid breeding comprises two core steps: haploid induction and chromosome doubling, with efficient haploid induction being pivotal to the success of this technology. Currently, anther culture, due to its relatively mature and stable protocol, has become the primary method for obtaining haploids in rice haploid breeding. This review systematically summarizes the research progress in rice anther culture, focusing on the fundamental steps and applications of haploid breeding, the developmental history of anther culture, factors influencing anther culture efficiency and their underlying genetic mechanisms, current challenges and potential countermeasures, and future prospects for rice anther culture technology.

Understanding the genetic basis of elite rice varieties is conducive to the strategic utilization of genetic resources in modern breeding programs. To elucidate the genetic component and transmission across pedigrees, we investigated two elite inbred japonica varieties, Huruan1212 (HR1212) and Hugeng137 (HG137), through whole-genome sequencing with an average depth of 38.2× and pedigree analysis. We identified specific SNPs and enriched pathways underlying HR1212's excellent eating and cooking quality and HG137's stress resistance. Genomic scans traced the contributions of founder parents Xiushui04 and Wuyugeng3, revealing transmission patterns of favorable alleles across generations. Notably, the shared identity-by-descent (sIBD) segments of the two pedigrees overlapped by 74 Mb, total formed 118.42 Mb of conserved genetic segments, with validation in other founder-derived lines. This research provides valuable insights for utilizing founder parents and elite varieties and highlights the critical need to implement genome-informed breeding strategies in future breeding practice.

Fusarium fujikuroi is the primary causal agent of rice bakanae disease, which can lead to substantial yield losses. Developing a rapid, highly specific, and accurate method for detecting F. fujikuroi is crucial for effective surveillance, prevention, and control of rice bakanae disease. In this study, a novel detection assay, RPA-Cas12a-F, was developed by integrating recombinase polymerase amplification (RPA) and Cas12a for the detection of F. fujikuroi. This assay demonstrated a limit of detection (LOD) of 1 copy/μL of reference plasmid or 0.1 fg/μL of F. fujikuroi genomic DNA (gDNA). Furthermore, to enable on-site detection, the RPA-Cas12a technique was combined with a lateral flow strip (LFS) for visual readout, thereby developing the RPA-Cas12a-LFS assay. The LOD of the RPA-Cas12a-LFS assay was 1000 copies/μL of plasmid or 10 fg/μL of F. fujikuroi gDNA. The RPA-Cas12a-based assays developed in this study enable rapid, highly accurate, sensitive, and specific detection of F. fujikuroi, making them a promising tool for on-site detection without the need for expensive equipment and time-consuming methodologies.

In recent years, there has been widespread cultivation of high-quality rice along the southeast coast of China, particularly in Shanghai. However, the specific changes in the yield and quality performance of rice in the Shanghai region have not been well understood. A study conducted on 194 rice varieties in the Shanghai region from 1994 to 2023 focused on yield, growth characteristics, and quality. The findings revealed significant increases in rice yield (+16.8%) and spikelets per panicle (+45.4%) in the Shanghai region over the past 30 years, along with a decrease in amylose content (−27.9%). However, parameters such as grain filling, 1000-grain weight, plant height, panicle length, chalkiness, and gel consistency showed no significant changes over the same period. Additionally, the study found that the yield, nitrogen application amount, growth period, and head rice rate of japonica rice and indica-japonica hybrid rice were higher than those of indica rice, although the panicle length was lower in comparison. Japonica inbred rice exhibited the lowest amylose content and superior taste. Correlation analyses suggested that the breeding of japonica rice varieties in the Shanghai region should focus on balancing nitrogen absorption and high chalkiness, plant biomass, and amylose content, and yield and the appearance and taste quality of rice. In addition, the potential rice yield per unit area in the Shanghai region in the future depends on the promotion of hybrid japonica rice planting and developing best management practices.

Auxin plays critical roles in plant development and stress response. However, the roles of auxin and the immune signaling factor, reactive oxygen species (ROS), in resistance to the brown planthopper (BPH), a notorious rice-specific piercing-sucking insect that causes severe yield losses, remain unclear. We revealed that moderate naphthalene acetic acid treatment activates rice resistance to BPH, BPH infestation induces ROS accumulation, and increase in ROS content promotes BPH resistance. Underlying these phenomena, the auxin receptors OsTIR1 and OsAFB2 positively, whereas the posttranscriptional regulator OsmiR393 negatively, regulate BPH resistance. Downstream of the OsmiR393/OsTIR1 module, through successive genetic function analysis of each gene, solid genetic relationship analysis, and various biochemical assays, we established an OsmiR393/OsTIR1-OsIAA10-OsARF12-OsRbohB genetic pathway that mediates BPH resistance, in which ROS are integral. Such cross-talk between auxin and ROS reveals the intricate signaling network underlying BPH resistance, which might assist with BPH resistance breeding.

Plant height is a key agronomic trait influencing both seed production and yield in hybrid rice. In the elite japonica hybrid ‘Shenyou 26’, optimal plant height differences between the restorer line (‘Shenhui 26’) and the male sterile line (‘Shen 9A’) are critical for efficient pollination. In this study, we dissected the genetic basis of plant height variation using a doubled haploid (DH) population derived from ‘Shenyou 26’. Multi-environment phenotyping and QTL mapping identified seven QTLs associated with plant height, among which qPH1.1 and qPH9.1 were validated. qPH1.1 co-localized with the semi-dwarf gene SD1, and ‘Shen 9A’ carries a rare SD1-EQH allele that potentially confers reduced height relative to the SD1-EQ allele in ‘Shenhui 26’. qPH9.1 also contributed significantly to plant height variation, with the Shenhui26 allele increasing plant height in backcross validation. These findings indicate that plant height variation in ‘Shenyou 26’ is controlled by multiple loci, including SD1 allelic variants and other complementary QTLs, providing valuable resources for fine-tuning plant architecture in rice breeding.

IntroductionHuruan1212 (HR1212) is well-regarded for its superior eating and cooking quality in the lower reaches of the Yangtze River in China. Still, its high susceptibility to rice panicle blast and lack of fragrance have limited its further spread and utilization. Pigm and Pi-ta are two dominant genes known for their stable broad-spectrum resistance against rice blast fungus Magnaporthe oryzae, while badh2 is the crucial gene that regulates rice aroma.MethodsIn this study, we utilized a molecular marker-assisted selection backcrossing strategy to introduce Pigm, Pi-ta, and badh2 into introgressed lines employing re-sequencing for precise genetic background selection.ResultsFinally, we selected three introgressed lines, including two that carry Pigm with the highest background recovery rates, showing eating and cooking qualities similar to those of HR1212, and one line that pyramids Pigm, Pi-ta, and badh2, which features a strong aroma. They all displayed significantly enhanced resistance to panicle blast and improved yield compared to HR1212.DiscussionIn conclusion, this study expanded the germplasm resources of japonica, providing a material foundation for enhancing breeding programs aimed at developing rice blast-resistant and high-quality fragrant japonica varieties. Additionally, the study demonstrated that integrating molecular markers and re-sequencing can inform breeders’ decision-making more precisely and efficiently.

The advancement of hybrid japonica rice is pivotal for securing japonica rice supplies and bolstering food security. To address prevalent issues such as inconsistent yields, subpar rice quality, and inadequate seed production in existing cultivars, Shenyou R3 was developed using advanced high-density rice gene chip technology, which is characterized by the expression of specific genes. This late-season, premium aromatic variety, characterized by a popcorn-like aroma, was bred by the Crop Breeding and Cultivation Research Institute of the Shanghai Academy of Agricultural Sciences. Shenyou R3 incorporates superior genes such as badh2-E7, Pi2, Xa21, Sdt97, and Hd17, among which, badh2-E7 and Hd17 are inherited from the maternal line, while Pi2, Xa21, and Sdt97 are inherited from both the maternal and paternal lines. Shenyou R3 offers high-quality rice that adheres to national premium grade 2 standards, with level 1 resistance to blast disease, and yields surpassing the control variety Huayou 14 by over 5% in 2022 Shanghai trials. The new hybrid japonica rice Shenyou R3 has high yield potential and nitrogen utilization efficiency. This paper elaborates on the molecular marker-assisted selection process, key traits, quality metrics, and yield performance of Shenyou R3, while also outlining essential cultivation practices.

Leaf morphology significantly impacts rice (Oryza sativa L.) plant architecture and yield. Here, we identified and characterized a novel narrow-leaf mutant, nal25, derived from indica rice cultivar ‘Huazhan’ using EMS mutagenesis. Phenotypic analyses revealed that nal25 exhibited significantly narrower leaves, reduced plant height, increased tiller number, and notably decreased grain size, seed setting rate, and thousand-grain weight compared to the wild type. Genetic analyses demonstrated that the narrow-leaf phenotype is controlled by a single recessive nuclear gene. Through precise localization analysis, the NAL25 gene was located within a region of approximately 103 kb on the long arm of rice chromosome 7. The sequencing results showed that the mutant nal25 had a T to C mutation at position 173 of the heat-shock protein gene LOC_Os07g09450 encoding the DnaJ domain in this interval, resulting in a change in amino acid 58 from leucine to proline. The qRT-PCR results showed that the expression level of NAL25 gene decreased in the mutant. The nal25 mutant obtained in this study exhibits stable mutant phenotypes, including dwarfism and excessive tillering, traits typically unfavorable for rice production. Nevertheless, it serves as valuable genetic material for forward genetics approaches to identify yield-related genes regulating leaf morphology and culm height. Thus, research on the nal25 mutant advances the development of rice varieties with ideal plant architecture, thereby stabilizing yield increases and safeguarding global food security.

The development of a new salt–alkaline-tolerant hybrid japonica rice is crucial for enhancing japonica rice supply and ensuring national food security. Utilizing molecular marker-assisted selection (MAS) technology combining Kompetitive Allele-Specific PCR (KASP) markers and a gene breeding chip, the salt-tolerant gene SKC1 was introgressed into a rice genotype Fan 14. This led to the development of Shenyanhui 1, a new high-quality, strongly heterotic, and salt-tolerant japonica restorer line. Subsequently, the high-quality, salt-tolerant japonica three-line hybrid rice variety Shenyanyou 1 was developed by crossing the BT-type japonica cytoplasmic male sterile (CMS) line Shen 21A with the restorer line Shenyanhui 1. Shenyanyou 1 carries the major salt tolerance gene SKC1, exhibiting excellent salt tolerance with seedling stage salt tolerance reaching level 5. Under precise salt tolerance evaluation throughout its growth cycle, Shenyanyou 1 achieved a yield of 3640.5 kg/hm2, representing an extremely significant increase of 20.7% over the control variety Yandao 21. Shenyanyou 1 exhibits superior grain quality, meeting the Grade 3 high-quality rice standards issued by the Ministry of Agriculture. Shenyanyou 1 has good comprehensive resistance, aggregating rice blast resistance genes such as Pi2, Pita, Pizt and LHCB5, bacterial blight resistance genes Xa26/Xa3, stripe blast resistance gene STV11, semi-dwarf gene Sdt97, nitrogen-efficient utilization gene NRT1.1B, the light repair activity enhancement gene qUVR-10, the cold resistance gene qLTG3-1, and the iron tolerance gene OsFRO1. It has good resistance to biotic and abiotic stresses. This paper details the breeding process, key agronomic traits, salt tolerance, yield performance, and grain quality characteristics of Shenyanyou 1.

BACKGROUND:Yield and quality are the two most important traits in crop breeding. Exploring the regulatory mechanisms that affect both yield and quality traits is of great significance for understanding the molecular genetic networks controlling these key crop attributes. Expansins are cell wall loosening proteins that play important roles in regulating rice grain size.RESULTS:We investigated the effect of OsEXPA7, encoding an expansin, on rice grain size and quality. OsEXPA7 overexpression resulted in increased plant height, panicle length, grain length, and thousand-grain weight in rice. OsEXPA7 overexpression also affected gel consistency and amylose content in rice grains, thus affecting rice quality. Subcellular localization and tissue expression analyses showed that OsEXPA7 is localized on the cell wall and is highly expressed in the panicle. Hormone treatment experiments revealed that OsEXPA7 expression mainly responds to methyl jasmonate, brassinolide, and gibberellin. Transcriptome analysis and RT-qPCR experiments showed that overexpression of OsEXPA7 affects the expression of OsJAZs in the jasmonic acid pathway and BZR1 and GE in the brassinosteroid pathway. In addition, OsEXPA7 regulates the expression of key quantitative trait loci related to yield traits, as well as regulates the expression levels of BIP1 and bZIP50 involved in the seed storage protein biosynthesis pathway.CONCLUSIONS:These results reveal that OsEXPA7 positively regulates rice yield traits and negatively regulates grain quality traits by involving plant hormone pathways and other trait-related pathway genes. These findings increase our understanding of the potential mechanism of expansins in regulating rice yield and quality traits and will be useful for breeding high-yielding and high-quality rice cultivars.