Panicle size is an important agronomic trait in rice, greatly influences the grain yield of rice (Oryza sativa L.). Although many panicle size genes have been reported, new panicle size controlling genes still need to be discovered. Here, we isolated two rice mutants, named Oryza sativa short panicle gene 3 (Osspg3), which displayed a semi-dwarf phenotype, shorter panicle, and smaller grain, thus, the number of grains per spike decreased. Inhibition of cell expansion of the Osspg3 mutants resulted in smaller grain size. We cloned Osspg3 by using map-based cloning combined with resequencing technique. OsSPG3 is highly expressed in the leaf sheath and panicle, and OsSPG3 protein is localized in the nucleus. Transcriptional analysis revealed antenna proteins photosynthesis, plant hormone signal transduction, plant mitogen-activated protein kinase (MAPK) signaling pathway, glycosaminoglycan degradation, glycosphingolipid biosynthesis and starch and sucrose metabolism were affected in the Osspg3 mutant. Moreover, the content of endogenous IAAs is significant decrease, but the content of endogenous cytokinin is significant increase. Our results indicating OsSPG3 is a key crosstalk factor of auxin and cytokinin pathway and providing a new potential gene resource for the improvement of rice panicle size.

Gamma irradiation-based mutant creation is one of the most important methods for rice plant mutagenesis breeding and molecular biology research. Although median lethal dose irradiation severely damages rice seedlings, applying brassinolide (BR) can increase the survival rate of irradiated seedlings. In this study, we investigated the effects of soaking seeds in solutions containing different BR concentrations (0.001, 0.01, 0.1, 1.0, and 5.0 μmol/L) and then spraying the resulting seedlings twice with 0.1 μmol/L BR. The combined BR treatments markedly decreased the superoxide anion (O2•−), hydrogen peroxide (H2O2), and malondialdehyde contents but increased the chlorophyll content. An appropriate BR treatment of gamma-irradiated samples substantially increased the activities of the antioxidant enzymes superoxide dismutase, peroxidase, and ascorbate peroxidase as well as the proline, ascorbic acid, and glutathione contents in rice seedling shoots. The BR treatment also promoted the growth of seedlings derived from irradiated seeds and increased the shoot and root fresh and dry weights. Most notably, soaking seeds in 0.01 or 0.1 μmol/L BR solutions and then spraying seedlings twice with 0.1 μmol/L BR significantly increased the final seedling survival rate and decreased mutant loss. The study results suggest that exogenous BR treatments can protect rice seedlings from gamma irradiation stress by enhancing antioxidant metabolism.

Seed aging is a complex process that involves various physiological and biochemical changes leading to a decline in seed viability during storage. However, the specific biomarkers for assessing the degree of seed aging in rice remain elusive. In this study, we isolated a golden hull mutant, gh15, from the indica rice Z15 by employing a radiation mutagenesis technique. Compared with the wild type (WT) Z15, the mutant gh15 displayed a golden hue in the hull, stem, and internodes, while no significant differences were observed in the key agronomic traits. A genetic analysis showed that the gh15 phenotype is regulated by a single recessive gene, which possibly encodes cinnamyl alcohol dehydrogenase OsCAD2. Significant differences of seed aging tolerance were observed between gh15 and WT after six months of natural storage and artificial aging treatment, with gh15 exhibiting a markedly lower aging tolerance compared to the WT. Haplotype assays indicated that the Hap2 of OsCAD2 was significantly associated with the dark coloration of the hull and lower seed aging tolerance. The molecular marker of OsCAD2 associated with seed color was explored in rice. These findings demonstrate that the golden hull serves as a potential biomarker for the rapid assessment of seed aging tolerance in rice.

Rice (Oryza sativa L.) is a major food crop in China, and its high and stable yield is crucial for ensuring food security in the country. However, over the past few years, extreme weather events induced by global climate change have impacted rice growth. For example, the effects of heat stress on rice quality and yield have been significant. Therefore, it is fundamental to conduct in-depth research on the heat-tolerance mechanisms of rice and to cultivate superior new thermotolerant rice varieties. This review summarizes the adverse effects of high temperatures on rice growth at various stages, the heat-tolerance mechanisms in rice, and the heat-tolerance genes and QTLs that have been identified in recent years. We also discuss strategies to enhance the heat tolerance of rice, offering new insights for rice breeding research.

With the development and improvement of indica–japonica hybrid rice breeding technologies, it has become possible to directly utilize the heterosis between indica and japonica subspecies to cultivate high-yielding rice varieties. Precisely analyzing the attributes and heterosis levels of indica–japonica varieties is crucial for successfully breeding indica–japonica hybrid rice and utilizing heterosis. This study employed 34 insertion–deletion (InDel) molecular markers to identify the indica–japonica attributes in 122 rice varieties and validated the results using cluster analyses and principal component analyses (PCAs). Additionally, the yield-related traits of the hybrids and parents were assessed, heterosis was analyzed, and the feasibility of predicting heterosis using parental genetic distance (GD) was explored. InDel molecular markers showed that all the hybrids were indica–japonica crosses with varying genetic components, confirmed by the cluster analyses and the PCAs. A heterosis analysis revealed that an increase in the effective panicle number per plant (EP) was the main factor in increasing the yield. Different GD intervals showed varying correlations with trait heterosis. These results indicate the effectiveness of InDel molecular markers in accurately distinguishing indica–japonica attributes and that hybrid combinations demonstrate significant heterosis. This study provides a reference for parent selection and utilizing heterosis in indica–japonica hybrid rice.

Salinity stress has a great impact on crop growth and productivity and is one of the major factors responsible for crop yield losses. The K-homologous (KH) family proteins play vital roles in regulating plant development and responding to abiotic stress in plants. However, the systematic characterization of the KH family in rice is still lacking. In this study, we performed genome-wide identification and functional analysis of KH family genes and identified a total of 31 KH genes in rice. According to the homologs of KH genes in Arabidopsis thaliana, we constructed a phylogenetic tree with 61 KH genes containing 31 KH genes in Oryza sativa and 30 KH genes in Arabidopsis thaliana and separated them into three major groups. In silico tissue expression analysis showed that the OsKH genes are constitutively expressed. The qRT-PCR results revealed that eight OsKH genes responded strongly to salt stresses, and OsKH12 exhibited the strongest decrease in expression level, which was selected for further study. We generated the Oskh12-knockout mutant via the CRISPR/Cas9 genome-editing method. Further stress treatment and biochemical assays confirmed that Oskh12 mutant was more salt-sensitive than Nip and the expression of several key salt-tolerant genes in Oskh12 was significantly reduced. Taken together, our results shed light on the understanding of the KH family and provide a theoretical basis for future abiotic stress studies in rice.

Rice (Oryza sativa L.) is the world’s most important food crop. Rice cultivars with high yield are good objects to further explore yield potential for feeding tremendous world populations. In this study, a γ-irradiation-induced mutant rl99 obtained from Zhejing 99 demonstrated serious rolling leaves and shortened adventitious roots. Exogenously applying low concentration of BR has no promotion on any root growth of either the wild type or the mutant, whereas high concentrations of BR repressed the length of the adventitious roots of the rl99 mutant. This is the first report about exogenous BR inhibition on the adventitious roots in rice. The gene RL99 (LOC_Os07g03450) was map-based cloned and allelic to the reported gene NAAL1/CRL6/CHR729/OsCHR4. This was the first report about the leaf-rolling trait performed by the gene. As a chromatin remodeling factor, the CHD protein RL99 was not detected using the yeast two-hybrid experiment to interact with AS1/AS2 homologous in rice, as a protein related to the KNOX family in Arabidopsis. In all, the low yield of the mutant owed to serious leaf rolling with decreased bulliform cells and abnormal chloroplast structure with increased osmiophilic granules, decreased starch grains, and shortened adventitious roots with unclear BR homeostasis mechanism. Therefore, this research gives a clue to exploring high yield in rice and to better ensure the food security of the world.

Crop yield is largely determined by the solar energy utilization efficiency of photosynthesis; plants with long stay-green periods have greater total photosynthetic production levels and crop yields. Here, a novel seedling chlorosis and lethality ( scl ) mutant exhibiting a yellow leaf and seedling-lethal phenotype was identified in rice ( Oryza sativa L.). The mutant had deformed chloroplasts and almost no protein complexes in thylakoid membranes. The expression levels of photosynthesis-associated genes were significantly down-regulated in scl compared with the wild-type (WT). Positive transgenic lines generated by Agrobacterium tumefaciens -mediated transformation of the scl mutant with a complementation vector harboring SCL cDNA exhibited the normal green leaf phenotype, whereas the scl seedling harboring the empty vector displayed the yellow leaf phenotype, indicating that SCL is LOC_Os01g72800. A fusion protein expressing SCL with green fluorescent protein revealed the fluorescence signal localized to chloroplasts. The expression patterns of chloroplast development and chlorophyll biosynthesis and degradation-related genes were disordered in scl mutant, possibly resulting in the yellow leaf phenotype. These results indicated that the SCL loss of function impaired chloroplast development, chlorophyll biosynthesis, and light-harvesting chlorophyll-binding protein transportation in rice.

Rice kernel quality has vital commercial value. Grain chalkiness deteriorates rice's appearance and palatability. However, the molecular mechanisms that govern grain chalkiness remain unclear and may be regulated by many factors. In this study, we identified a stable hereditary mutant, white belly grain 1 (wbg1), which has a white belly in its mature grains. The grain filling rate of wbg1 was lower than that of the wild type across the whole filling period, and the starch granules in the chalky part were oval or round and loosely arranged. Map-based cloning showed that wbg1 was an allelic mutant of FLO10, which encodes a mitochondrion-targeted P-type pentatricopeptide repeat protein. Amino acid sequence analysis found that two PPR motifs present in the C-terminal of WBG1 were lost in wbg1. This deletion reduced the splicing efficiency of nad1 intron 1 to approximately 50% in wbg1, thereby partially reducing the activity of complex I and affecting ATP production in wbg1 grains. Furthermore, haplotype analysis showed that WBG1 was associated with grain width between indica and japonica rice varieties. These results suggested that WBG1 influences rice grain chalkiness and grain width by regulating the splicing efficiency of nad1 intron 1. This deepens understanding of the molecular mechanisms governing rice grain quality and provides theoretical support for molecular breeding to improve rice quality.

Soil salinity is one of the major abiotic stresses limiting rice growth. Hybrids outperform their parents in salt tolerance in rice, while its mechanism is not completely understood. In this study, a higher seedling survival was observed after salt treatment in an inter-subspecific hybrid rice, Zhegengyou1578 (ZGY1578), compared with its maternal japonica Zhegeng7A (ZG7A) and paternal indica Zhehui1578 (ZH1578). A total of 2584 and 3061 differentially expressed genes (DEGs) with at least twofold changes were identified between ZGY1578 and ZG7A and between ZGY1578 and ZH1578, respectively, in roots under salt stress using the RNA sequencing (RNA-Seq) approach. The expressions of a larger number of DEGs in hybrid were lower or higher than those of both parents. The DEGs associated with transcription factors, hormones, and reactive oxygen species (ROS)–related genes might be involved in the heterosis of salt tolerance. The expressions of the majority of transcription factors and ethylene-, auxin-, and gibberellin-related genes, as well as peroxidase genes, were significantly higher in the hybrid ZGY1578 compared with those of both parents. The identified genes provide valuable clues to elucidate the heterosis of salt tolerance in inter-subspecific hybrid rice.

浙1831系浙江省农业科学院作物与核技术利用研究所选育的常规早籼稻新品种,2022年通过浙江省主要农作物品种审定委员会审定,具有熟期早、株高中等、株型紧凑、丰产性好、中抗稻瘟病、稻谷适宜加工等特点,适宜在浙江省及同类型生态地区作早稻种植.2022年在浙江省多地开展了生产示范,介绍了浙1831的选育经过、品种特性、生产示范情况与栽培技术要点.

Rice (Oryza sativa L.) is a staple food for more than half of the global population. Various abiotic and biotic stresses lead to accumulation of reactive oxygen species in rice, which damage macromolecules and signaling pathways. Rice has evolved a variety of antioxidant systems, including glutaredoxin (GRX), that protect against various stressors. A total of 48 GRX gene loci have been identified on 11 of the 12 chromosomes of the rice genome; none were found on chromosome 9. GRX proteins were classified into four categories according to their active sites: CPYC, CGFS, CC, and GRL. In this paper, we summarized the recent research advances regarding the roles of GRX in rice development regulation and response to stresses, and discussed future research perspectives related to rice production. This review could provide information for rice researchers on the current status of the GRX and serve as guidance for breeding superior varieties.

常规育种是水稻育种的基础,常规晚粳稻新品种的培育为浙江特色的籼粳杂交稻新品种选育提供了重要亲本来源.本文综述"十三五"审定的浙江省常规晚粳稻品种的产量、 米质、 抗性和推广情况:1)浙江晚粳稻品种产量优势明显,不断突破高产记录;2)整体抗性水平有待进一步提高,特别是在白叶枯病、 褐飞虱抗性方面,双抗品种也亟须提升;3)育成新品种推广面积逐年提高,2020年在常规晚粳稻推广面积中占比达59.04％.常规晚粳稻品种产量有所突破,品种类型多样性方面也有较大进展,但抗性品种培育还需进一步加强.

以杂交水稻浙粳优1578为材料,进行不同种植密度试验,研究行株距分别为30 cm×30 cm、27 cm×27 cm、30 cm×20 cm、27 cm×20 cm、23 cm×20 cm和20 cm×20 cm 6个处理对其产量及经济性状的影响.结果表明,不同种植密度对杂交水稻浙粳优1578的产量有显著影响;种植行距20 cm的产量高于27和30 cm行距,株距则以23～27 cm为佳.

Chloroplast signal recognition particle (cpSRP) is composed of cpSRP54 and cpSRP43, which form a soluble transit complex with light-harvesting chlorophyll a/b-binding protein in the chloroplast stroma. cpSRP participates in the transport of chloroplast proteins to the thylakoid membranes. Rice (Oryza sativa L.) has two copies of cpSRP54s, OscpSRP54a and OscpSRP54b. In this study, we obtained knockout mutants by editing OsYGL54 (OscpSRP54b) and overexpressed plants (OEYGL54). Compared with the wild type, OsYGL54 knockout mutants had a higher degree of yellow and a lower chlorophyll content in their leaves (P < 0.05). OsYGL54 was expressed constitutively and preferentially in the leaves, and the OsYGL54 protein was localized to the chloroplasts. Abnormal and irregular chloroplasts were observed in the leaves of the OsYGL54 knockout mutants. Furthermore, the expression levels of genes related to pigment metabolism, chloroplast development, and photosynthesis, such as HEMA1, CAO1, psbO, atpA, petA, petE, Lhca1, Lhcb2.1, and Lhcb4.1 were significantly affected by OsYGL54. High chlorophyll content was detected, and the transcriptional level of OsYGL54 was elevated in the OEYGL54. Interestingly, the expression of CHLM, PSY2, atpG and chl a/b were increased in OEYGL54, but were decreased in ygl54-1. These results suggested further studies will be needed to examine cpSRP54s and to elucidate the mechanisms of this protein in rice chloroplast development. Furthermore, this study provided a theoretical basis for breeding rice varieties with high light efficiency.

产加销农文旅一体化发展模式在乡村振兴战略实施中具有重要作用.本文以绍兴良根生态农业开发有限公司为例,剖析了基于糯稻产业的产加销农文旅一体化发展模式与途径,包括糯稻种植、黄酒酿制、黄酒销售和酒文化传播的农文旅一体化的全过程,通过品种筛选、施用有机肥、绿色防控等提升黄酒专用糯米品质,以产加销融合发展提升公司整体经济效益,开展农文旅一体化实现提质增效,实现稻米产业的复合型全产业链发展,值得示范推广.

Soil salinity is a key source of abiotic stress in the cultivation of rice. In this study, two currently cultivated japonica rice species—Zhegeng 78 (salt-tolerant) and Zhegeng 99 (salt-sensitive)—with similar backgrounds were identified and used to investigate their differential responses to salt stress at the post-germination and seedling stages. Quantitative RT-PCR analysis demonstrated that the expression of OsSOS1, OsHAK1, and OsHAK5 at the post-germination stage, and the expression of OsHKT1,1, OsHTK2,1, and OsHAK1 at the seedling stage, were significantly higher in the salt-tolerant Zhegeng 78 compared with those of the salt-sensitive Zhegeng 99 under salt stress. The significantly lower Na+ net uptake rate at the post-germination and higher K+ net uptake rates at the post-germination and seedling stages were observed in the salt-tolerant Zhegeng 78 compared with those of the salt-sensitive Zhegeng 99 under salt stress. Significantly higher activity of peroxidase (POD) and the lower hydrogen peroxide (H2O2) accumulation were observed in the salt-tolerant Zhegeng 78 compared with those of salt-sensitive Zhegeng 99 under salt stress at the seeding stage. The salt-tolerant Zhegeng 78 might be valuable in future cultivation in salinity soils.