Rice is the world's largest food crop, and its yield and quality are directly related to food security and human health. Grain size, as one of the important factors determining the rice yield, has been widely concerned by breeders and researchers for a long time. To decipher the regulatory mechanism of rice grain size, we obtained a multi-tiller, dwarf, and small-grain mutant htd1 by ethyl methanesulfonate (EMS) mutation from the Japonica rice cultivar 'Zhonghua 11' ('ZH11'). Genetic analysis indicated that the phenotype of htd1 was controlled by a single recessive gene. Using the mutation site map (Mutmap) method, we identified the candidate gene OsHTD1, which encoded a carotenoid cleavage dioxygenase involved in the biosynthesis of strigolactone (SL). The SL content in htd1 was significantly lower than that in 'ZH11'. Cytological analysis showed that the grain size of the mutant decreased due to the reductions in the length and width of glume cells. The function of htd1 was further verified by the CRISPR/cas9 gene editing technology. The plants with the gene knockout exhibited similar grain size to the mutant. In addition, gene expression analysis showed that the expression levels of multiple grain size-related genes in the mutant changed significantly, suggesting that HTD1 may interact with other genes regulating grain size. This study provides a new theoretical basis for research on the regulatory mechanism of rice grain size and potential genetic resources for breeding the rice cultivars with high yields.
Oryza/growth & development* ; Mutation ; Edible Grain/growth & development* ; Alleles ; Plant Proteins/genetics* ; Dioxygenases/genetics* ; Lactones/metabolism* ; Gene Expression Regulation, Plant ; Genes, Plant ; Gene Editing ; CRISPR-Cas Systems ; Phenotype

Rice (Oryza sativa L.) is an important food crop. The appearance of lesion mimics in rice leads to phytohormone disorders, which affects rice adaptation to environmental stresses and ultimately reduces the yield and quality. To explore whether the changes in the adaptability of rice lesion-mimic mutants to stressful environments are caused by the disorder of phytohormone metabolism in plants. In this study, we screened an ethyl methane sulfonate-treated population of the japonica cultivar 'Taipei 309' for a mutant with rust-like spots on leaves at the early tillering stage and brown-red spots at maturity and named it rsl1 (rust spotted leaf 1). Compared with the wild type, rsl1 showed decreases in plant height, panicle length, primary branch number, secondary branch number, filled grains per panicle, seed-setting rate, and 1 000-grain weight, and an increase in number of effective panicles. Genetic analysis indicated that rsl1 was controlled by a single recessive nuclear gene. RSL1 was localized between two molecular markers, B7-7 and B7-9, on rice chromosome 7 by map-based cloning. PCR sequencing of the annotated genes in this interval revealed a mutation of C1683A on the eighth exon of SPL5 (LOC_Os07g10390) in rsl1, which resulted in premature termination of protein translation. Exogenous phytohormone treatments showed that rsl1 was less sensitive to salicylic acid (SA), abscisic acid (ABA), and indo-3-acetic acid (IAA) and more sensitive to methyl jasmonate (MeJA) and gibberellin acid (GA) than the wild type. In addition, the survival rate of rsl1 was lower than that of the wild type under salt, alkali, drought, and high temperature stresses, and it was higher than that of the wild type under cold stress. Quantitative real-time polymerase chain reaction (qRT-PCR) results showed that RSL1 was involved in the regulation of ABA, SA, MeJA, IAA, and GA-related genes under abiotic stresses. The present study showed that the RSL1 mutation led to the appearance of lesion mimics and affected the growth, development, and stress resistance of rsl1 under abiotic stresses. The study of the functional mechanism of this gene can provide theoretical guidance for the research on rice stress resistance.
Oryza/microbiology* ; Stress, Physiological/genetics* ; Plant Diseases/genetics* ; Cloning, Molecular ; Chromosome Mapping ; Plant Growth Regulators/metabolism* ; Plant Proteins/genetics* ; Mutation ; Cyclopentanes ; Genes, Plant ; Plant Leaves/genetics* ; Oxylipins

Synthetic biology, recognized as one of the most revolutionary interdisciplinary fields in the 21st century, has established innovative strategies for the genetic improvement of rice through the integration of multidisciplinary technologies including genome editing, genetic circuit design, metabolic engineering, and artificial intelligence. This review systematically summarizes recent research advancements and breakthrough achievements in the application of synthetic biology in the genetic improvement of rice, focusing on three critical domains: yield improvement, nutritional quality fortification, and reinforcement of disease resistance and abiotic stress tolerance. It elucidates that synthetic biology enables precise genomic and metabolic pathway engineering through modular, standard, and systematic approaches, effectively overcoming the limitations of conventional breeding methods characterized by prolonged cycles and restricted trait modification capabilities. The implementation of synthetic biology has facilitated synergistic improvement of multi-traits, thereby providing critical technical references for developing elite rice cultivars with superior productivity and nutritional value. These technological breakthroughs hold significant implications for ensuring global food security and promoting green and sustainable development of agriculture.
Oryza/growth & development* ; Synthetic Biology/methods* ; Metabolic Engineering ; Plant Breeding/methods* ; Gene Editing ; Genetic Engineering/methods* ; Plants, Genetically Modified/genetics* ; Disease Resistance/genetics*

Rice (Oryza sativa L.), as a thermophilic crop, is highly susceptible to cold stress during its growth process. Chilling injury at the plumule stage and seedling stage often affects the morphological development and leads to yield reduction of rice. The exploration and utilization of cold tolerance genes are among the most direct and effective approaches to address cold stress in rice. To identify quantitative trait loci (QTLs) associated with cold tolerance at plumule and seedling stages, in this study, we measured the seedling rates and survived seedling rates of the indica rice cultivar 'HZ', the japonica cultivar 'Nekken2', and their 120 recombinant inbred lines (RILs) under cold stress. A previously constructed high-density genetic linkage map was used for the mapping of the QTLs conferring cold tolerance at the plumule and seedling stages. A total of 4 QTLs for plumule-stage cold tolerance and 9 QTLs for seedling-stage cold tolerance were detected, with the maximum limit of detection reaching 5.20. Notably, a genetically overlapping QTL for both plumule and seedling stages was identified on chromosome 8, spanning a physical interval of 24 432 953-25 295 129 bp. Candidate genes within the detected QTL intervals were screened, and quantitative real-time polymerase chain reaction (qRT-PCR) was conducted to analyze the gene expression during the plumule and seedling stages. The results revealed that LOC_Os03g06570, LOC_Os03g07100, LOC_Os06g08280, LOC_Os08g38440, LOC_Os08g39100, and LOC_Os08g39540 exhibited significantly differential expression between the parental lines. These genes were either significantly downregulated or upregulated under cold stress. Among them, the first three gene (LOC_Os03g06570, LOC_Os03g07100, and LOC_Os06g08280) were hypothesized to be key candidates regulating the cold tolerance of rice seedlings, while the latter three genes (LOC_Os08g38440, LOC_Os08g39100, and LOC_Os08g39540) were identified as comprehensive regulators of cold tolerance during both plumule and seedling stages. These findings lay a foundation for the fine mapping and cloning of cold tolerance genes at the plumule and seedling stages, providing valuable insights for breeding cold-tolerant rice varieties.
Quantitative Trait Loci/genetics* ; Oryza/growth & development* ; Seedlings/growth & development* ; Cold Temperature ; Chromosome Mapping ; Gene Expression Regulation, Plant

Excavating the quantitative trait locus (QTL) associated with rice cooking quality, analyzing candidate genes, and improving cooking quality-associated traits of rice varieties by genetic breeding can effectively improve the taste of rice. In this study, we used the indica rice HZ, the japonica rice Nekken2 and 120 recombinant inbred lines (RILs) populations constructed from them as experimental materials to measure the gelatinization temperature (GT), gel consistency (GC) and amylose content (AC) of rice at the maturity stage. We combined the high-density genetic map for QTL mapping. A total of 26 QTLs associated with rice cooking quality (1 QTL associated with GT, 13 QTLs associated with GC, and 12 QTLs associated with AC) were detected, among which the highest likelihood of odd (LOD) value reached 30.24. The expression levels of candidate genes in the localization interval were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR), and it was found that the expression levels of six genes were significantly different from that in parents. It was speculated that the high expression of LOC_Os04g20270 and LOC_Os11g40100 may greatly increase the GC of rice, while the high expression of LOC_Os01g04920 and LOC_Os02g17500 and the low expression of LOC_Os03g02650 and LOC_Os05g25840 may reduce the AC. The results lay a molecular foundation for the cultivation of new high-quality rice varieties, and provide important genetic resources for revealing the molecular regulation mechanism of rice cooking quality.
Quantitative Trait Loci ; Oryza/genetics* ; Plant Breeding ; Cooking ; Genetic Association Studies

Innovation is an important way to promote economic development and social progress. Recent years have seen rapid development of biological sciences. In response to social demands and the needs for developing an innovative country, fostering innovative talents in the field of biosciences has become a significant initiative supported by national policies and the needs from talent market. Taking the innovative talent training mode implemented by Zhejiang Normal University in the field of biological sciences as an example, this paper comprehensively introduces several key aspects of the mode. This includes establishing a mentorship system as the foundation, carrying out curriculum reform through project competitions and practical platforms, and promoting synergy among industry, academia, and research in talent training. This training mode has achieved positive results in practice, promoting the training of outstanding innovative talents in biological science majors, and may facilitate the reform of talent training in similar majors.
Humans ; Biological Science Disciplines ; Industry ; Policy ; Universities

The CRISPR-Cas9 system is composed of a clustered regularly interspaced short palindromic repeat (CRISPR) and its associated proteins, which are widely present in bacteria and archaea, serving as a specific immune protection against viral and phage secondary infections. CRISPR-Cas9 technology is the third generation of targeted genome editing technologies following zinc finger nucleases (ZFNs) and transcription activator like effector nucleases (TALENs). The CRISPR-Cas9 technology is now widely used in various fields. Firstly, this article introduces the generation, working mechanism and advantages of CRISPR-Cas9 technology; secondly, it reviews the applications of CRISPR-Cas9 technology in gene knockout, gene knock-in, gene regulation and genome in breeding and domestication of important food crops such as rice, wheat, maize, soybean and potato. Finally, the article summarizes the current problems and challenges encountered by CRISPR-Cas9 technology and prospects future development and application of CRISPR-Cas9 technology.
Gene Editing ; CRISPR-Cas Systems/genetics* ; Plant Breeding ; Crops, Agricultural/genetics* ; Technology

Objective:To explore the application of Sojump in clinical teaching assessment of nursing students in operating room and to evaluate its effect.Methods:The graduation examination results of nursing students in clinical practice in the operating room of Second Affiliated Hospital of Medical College of Shantou University from 2017 to 2019 were collected, the results of 2017-2018 as the control group, and those of 2018-2019 as the observation group. The control group took the paper handwriting test, and the observation group took the electronic Sojump test, and the two-year graduation examination results were compared. A questionnaire survey was conducted to investigate the nursing students' satisfaction with the teaching work of the teachers in 2018-2019, and the teachers' feelings of the teachers' training was investigated with the questionnaire. SPSS 22.0 was used for t test. Results:The graduation examination scores of all educational levels in the observation group were higher than those in the control group, with statistical differences between the two groups ( P<0.05). The satisfaction rate of nursing students who did not understand the contents of the questionnaire and studied again was 98.19%, and the teachers' satisfaction rate of automatic marking of Sojump test was 100%. Conclusion:Sojump is easily and efficiently operational, paperless, targeted teaching, which can promote teaching by evaluation, and reach high satisfaction of nursing students and teachers, worthy of promotion in clinical teaching.