Stigma exsertion ratio (SER) of rice male sterile line directly affects the hybrid rice F1 seed production, while SER was directly affected by the total of stigma and style length (TSSL). To improve the F1 seed production, it is necessary to identify the genes or quantitative trait loci (QTLs) controlling TSSL. In this study, we used the 7001 S with short TSSL, Zitai S with long TSSL and F2 to preliminarily map the QTL controlling TSSL to a 2.71 Mb interval using BSA-seq method. Based on the known SSR marker and newly designed InDel markers, the target region was further narrowed down to a 58.2 kb interval between TSL25 and TSL128 on chromosome 3. Gene knockout experiment was used to confirm Os03g0407400 (GS3) as a candidate gene controlling TSSL. Furthermore, according to the sequence alignment difference in the coding region of GS3 between 7001 S and Zitai S, the marker M1 was developed and revealed to be closely linked to TSSL. Combining fertility identification and molecular marker-assisted selection, a fertility-stable near-isogenic line (NIL) of C815S with long TSSL was created. It was found through small-scale F1 seed production combination trials that the outcrossing seed setting ratio of combination NIL-C815S × R919 was 39.31

Introduction:Grain volume is a key agronomic trait of rice. It is coordinately determined by grain length, width, thickness, and roundness, which influences the rice yield and quality, yet the molecular mechanism is still not fully understood. Methods:In this study, a mapping population of Ludao (weedy rice) and Guangbaixiangzhan (GBXZ) was developed in Lianyungang, Jiangsu province, China, and was employed to construct a high-density genetic map by use of the RICE 1 K mGPS chip in 2021. The mapping of QTLs was carried out with IciMapping software using the inclusive composite interval mapping (ICIM) method. Results and discussion:A total of eight QTLs for grain volume, explained 4.22-19.75% of the total phenotypic variation, were detected with LOD scores ranging from 3.33 to 13.25. Among these loci, five are known genes or loci related to grain size, and three loci, qGV4-2, qGV7-1, and qGV7-2, were newly identified. The major QTL, qGV7-2, explained the highest phenotypic variation, was validated using NIL pairs. By combining gene functional annotation, gene expression analysis and sequence comparison within the mapping interval of qGV7-2, a candidate gene (LOC_Os07g15540), encoding an ethylene receptor, OsETR4, was identified. Further haplotype-phenotype analysis revealed this gene to be significantly associated with grain length, width, and thousand-grain weight. Thus we identified LOC_Os07g15540 as the most likely candidate gene. Taken together, our findings provide a basis for functional research on qGV7-2, and broaden our understanding of role of genetic factors in regulating grain volume, thus providing an important resource for yield improvement in rice.

Main conclusion Transcriptional regulation of stress-responsive genes is a crucial step in establishing the mechanisms behind plant abiotic stress tolerance. A sensitive method of regulating transcription factors activity, stability, protein interaction, and subcellular localization is through phosphorylation. This review highlights a widespread regulation mechanism that involves phosphorylation of plant TFs in response to abiotic stress. Abstract Abiotic stress is one of the main components limiting crop yield and sustainability on a global scale. It greatly reduces the land area that is planted and lowers crop production globally. In all living organisms, transcription factors (TFs) play a crucial role in regulating gene expression. They participate in cell signaling, cell cycle, development, and plant stress response. Plant resilience to diverse abiotic stressors is largely influenced by TFs. Transcription factors modulate gene expression by binding to their target gene's cis-elements, which are impacted by genomic characteristics, DNA structure, and TF interconnections. In this review, we focus on the six major TFs implicated in abiotic stress tolerance, namely, DREB, bZIP, WRKY, ABF, MYB, and NAC , and the cruciality of phosphorylation of these transcription factors in abiotic stress signaling, as protein phosphorylation has emerged as one of the key post-translational modifications, playing a critical role in cell signaling, DNA amplification, gene expression and differentiation, and modification of other biological configurations. These TFs have been discovered after extensive study as stress-responsive transcription factors which may be major targets for crop development and important contributors to stress tolerance and crop production.

连粳6188(参试名称连粳18302)是连云港市农业科学院采用系谱法杂交育种,结合分子标记辅助选择选育而成的早熟、优质、高产、中熟中粳稻新品种.该品种全生育期142.8d,中感稻瘟病,抗条纹叶枯病,米质达部标一级.该品种具有优质早熟、高产稳产、适宜轻简化栽培等特点.2022年通过江苏省农作物品种审定委员会审定(审定编号:苏审稻20220034),适宜在江苏省淮北地区种植.介绍了该品种的选育过程、特征特性及高产栽培技术要点.

[目的]对水稻类病斑突变体的研究有助于解析其与植物生长和防御反应的关系.[方法]本研究在粳稻品系FI135胚培养过程中获得了1个类病斑突变体lmm7(lesion mimic mutant 7).通过对其进行系统的表型鉴定、农艺性状考查、超微结构观察、生理学特性分析,阐明LMM7基因对植物生长的调控.通过病原菌抗性鉴定,明确lmm7对植物防御反应的影响.利用9311B与突变体lmm7杂交所得F2群体对该突变体进行了遗传分析和基因精细定位.[结果]该突变体苗期表型正常,分蘖初期,植株基部叶片从叶尖开始不断出现褐色斑点,并向整株扩散,且斑点数目随植株生长不断增加.与野生型相比,突变体的株高、穗长、有效穗数、每穗粒数、结实率及剑叶长宽都显著降低,但籽粒性状和抽穗期没有显著性差异.遮光处理表明,突变体lmm7的表型受到光照诱导,抽穗期突变体lmm7叶肉细胞严重失绿,光合色素含量显著降低.组织化学分析表明,突变体病斑处的H2O2含量显著升高.透射电镜观察结果表明,突变体lmm7叶肉细胞的叶绿体数目减少,叶绿体类囊体片层结构严重受损,细胞器肿胀解体,并出现大量嗜锇小体,同时病斑内部和周围区域积累了大量的ROS.抗性鉴定结果显示突变体lmm7稻瘟病抗性水平显著高于野生型.遗传分析表明lmm7的突变表型受单个隐性基因控制.利用图位克隆的方法,目的基因被定位于水稻第7染色体短臂两InDel标记7B35和7B43之间,区间范围约260 kb.测序结果表明该区间内候选基因LOC_Os07g0203700第2891位碱基T发生了单碱基缺失,导致后续移码突变及翻译提前终止.[结论]lmm7与spl5互为等位基因,其突变抑制了植株的生长,同时增强了对稻瘟病的抗性.

水稻是我国最主要的粮食作物之一.水稻的安全生产越来越依赖分子生物学功能基础研究.PPR(Pentatricopeptide repeat)蛋白是水稻中较大的蛋白家族之一,研究证明PPR蛋白由核基因编码并参与细胞器前体RNA加工,如RNA起始翻译、RNA稳定、RNA剪接、RNA编辑,调控水稻叶绿体和线粒体等的发育,进而影响水稻的花粉、胚、胚乳、叶片及其他组织的生长发育.该类蛋白表达受抑制将严重影响水稻正常生长发育.对近年报道的水稻PPR蛋白结构、分类、定位、RNA作用靶位点、作用方式及其对水稻生长发育的影响进行综述.对已报道水稻PPR蛋白功能作出总结并对今后PPR蛋白对水稻种质资源的创新应用等可能的研究方向进行了展望.

旨在分析橹稻与栽培稻间的遗传多样性,为橹稻的保护和开发利用提供分子依据.以包括橹稻在内的48份水稻种质资源为试验材料,利用1K mGPS SNP芯片进行基因分型,使用PowerMaker 3.25软件进行UPGMA聚类分析.结果表明,4785对多态性SNP标记共检测出9570个等位基因,平均每对标记检测出2个等位变异;多态性信息含量(PIC)变化范围为0.0400～0.5957,平均值为0.3123,基因多样性指数(GD)变化范围为0.0408～0.6667,平均值为0.3839.UPGMA聚类分析将48份参试种质划分为2个亚群,即籼稻亚群和粳稻亚群,其中橹稻分属于粳稻亚群.厌氧萌发耐受性评价表明,橹稻具有很强的耐低氧萌发能力,可为适宜直播水稻的培育提供重要的种质基础,同时本研究为橹稻优异基因的挖掘和利用提供理论基础.

The bzip transcription factors can modulate the transcriptional expressions of target genes by binding specifically to cis-regulatory elements in the promoter region of stress-related genes, hence regulating plant stress resistance. Here, we investigated a stress-responsive transcription factor Osbzip20 under abiotic stresses. The OsbZIP20-GFP fusion protein predominantly aggregated in the nucleus, in accordance with our subcellular localization. Osb-ZIP20 transcript was observed in all vegetative tissues with highest levels being detected in the seed. Tran-scription of Osbzip20 was induced by salinity, exsiccation, and abscisic acid. Overexpression of OsbZIP20 in transgenic rice considerably improved tolerance to salt and drought stresses, as well as increased sensitivity to ABA. Furthermore, abiotic stress responsive genes transcript were found to be remarkably elevated in transgenic rice overexpressing OsbZIP20 than in wild-type plants. SAPK10 was discovered to directly interact with and phosphorylate OsbZIP20. Yeast one-hybrid and luciferase assay revealed that OsbZIP20 acted as a transcriptional stimulator. Interestingly, gel shift assay showed that phosphorylated bZIP20 augmented its DNA-binding affinity to the ABRE element of the NHX1 promoter and induced its transcription. In sum, our findings establish a novel signaling pathway associated with the SAPK10-bZIP20-NHX1 synergistic interaction, as well as a new strategy for enhancing rice drought and salt tolerance.

连5041S系连云港市农业科学院以广占63-4S为母本、天丰B为父本,进行杂交、回交选育而成的两系光温敏核不育系.该不育系米质优,农艺性状优良,不育性稳定,开花习性好,异交结实率高,配合力强,2019年通过江苏省品种审定委员会鉴定.

WRKY transcription factors play a role in a variety of biological processes. Several studies have revealed that abiotic stress regulates the transcription of a large number of WRKY genes. In this study, we report the identification of a novel ‘SAPK10-WRKY87-ABF1’ biological pathway, through which they harmoniously enhance drought and salinity tolerance. We generated OsWRKY87-overexpressing transgenic rice and found that the transgenic seedlings exhibited significantly improved drought and salinity stress tolerance. Subcellular localization in rice seedling protoplast revealed that OsWRKY87-GFP fusion protein mostly accumulated in the nucleus, suggesting that OsWRKY87 is a nucleus-localized protein, in line with the predicted function of OsWRKY87 as a transcription factor. In vivo interaction between SAPK10 and WRKY87 was demonstrated by Yeast two-hybrid-assay. In addition, phosphorylation assays showed that SAPK10 exhibits autophosphorylation activity on the 177th serine, enabling it to phosphorylate WRKY87. OsWRKY87 functioned as a transcriptional initiator, according to a yeast one-hybrid assay and a luciferase assay. Remarkably, gel mobility shift assay showed that phosphorylated WRKY87 enhances its DNA-binding ability to the W-box cis-element of ABF1 promoter and activated its transcription, thereby elevating the ABF1 transcription and improving drought and salinity tolerance. Overall, our findings revealed a novel ‘SAPK10- WRKY87-ABF1’ module, which synergistically interacts to improve drought and salt tolerance in rice (Oryza sativa).

采用国际水稻所标准营养液培养63份水稻种质资源,在水稻幼苗长至3叶期对种质资源进行0.5％盐胁迫处理.盐胁迫7d后,根据盐害症状评价水稻耐盐级别,并测量和计算苗期苗高、根长、地上部和根部的干(鲜)质量的相对值,分析各项生长指标与盐害等级的相关性.结果表明,茎叶鲜质量和幼苗整体鲜质量这2个指标与盐害等级呈极显著负相关,幼苗的根干(鲜)质量、茎叶干质量、整体干质量和苗长与盐害等级呈负相关,相对根长与盐害等级无相关性.运用统计学方法,将与盐害等级有显著相关性的生长指标对63份种质资源苗期的耐盐性进行综合评价及分类,以幼苗的整体干质量和整体鲜质量2个综合评价指标较为合理,并作为分类依据.供试品种分为强耐盐、耐盐、轻度感盐和感盐4个类群,且类群间呈显著性差异.利用本方法筛选出的7个耐盐品种资源在青口盐场盐碱地实地种植,均表现出良好的耐盐性.本鉴定方法利用了生长指标评价和主成分分析等统计学方法相结合,有效避免了盐害等级评价中主观因素的影响,可以作为一种快速有效的水稻品种资源苗期耐盐性鉴定方法.

Screening of germplasm resources, exploiting and utilization of genes conferring tolerance to hypoxia are the key to breeding new cultivars adapted to direct seeding. In order to evaluate the germinability of germplasm resources under submerged condition in a simple and efficient way, 191 japonica germplasm resources released from different years and regions were screened, 12 japonica varieties with high germinability under submerged condition were found. Among them, Lianjing 15, a japonica variety, showed stable and high tolerance to hypoxia. Using a F2:3 population derived from Lianjing 15 and Huanglizhan (HLZ, a highly susceptible indica rice variety), four quantitative trait loci (QTL) conferring tolerance to hypoxia, namely qGS1, qGS3, qGS9, and qGS10 were identified under simulated field environment, and they explained 70.9% of the total phenotypic variation. Among them, qGS1, qGS3, and qGS10, were repeatedly detected in different years, accounting for 19.2%–24.0%, 12.6%–14.7%, and 19.1%–20.5% of the total phenotypic variation, respectively. The germplasm resources and QTL found in our study would provide innovative resources for breeding rice cultivars with high germinability under submerged condition, and would also provide a theoretical basis for breeding varieties adapted to direct seeding.

We created CRISPR-Cas9 knock-out and overexpressing OsbZIP72 transgenic rice plants to gain a better understanding of the role and molecular mechanism of OsbZIP72 gene in stress tolerance, which has remained largely elusive. OsbZIP72 was expressed and integrated into rice transgenic plant genomes, and the OsbZIP72 transcript in overexpression lines was elicited by salinity, abscisic acid (ABA) and drought stresses. OsbZIP72 overexpressing plants showed higher tolerance to drought and salinity stresses, while knock-out transgenic lines showed higher sensitivity to these stresses. The differentially expressed genes (DEGs) from RNA-sequencing data encompassed several abiotic stress genes, and the functional classification of these DEGs demonstrated the robust transcriptome diversity in OsbZIP72. Yeast one-hybrid, along with luciferase assay, indicated that OsbZIP72 acted as a transcriptional initiator. Remarkably, electrophoresis mobility assay revealed that OsbZIP72 bound directly to the ABA- responsive element in the OsHKT1;1 promoter region and activated its transcription. Overall, our findings revealed that OsbZIP72 can act as a transcriptional modulator with the ability to induce the expression of OsHKT1;1 in response to environmental stress through an ABA-dependent regulatory pathway, indicating that OsbZIP72 can play a crucial role in the ABA-mediated salt and drought tolerance pathway in rice.

The plastidial 3-phosphoglycerate (3-PGA) pathway plays an important role in supplying serine in non-photosynthetic tissues in plants under environmental stresses. Synthesis of serine in rice (Oryza sativa L.) is intangible, but little kinetic and structural information for enzymes is available. In this study, a comprehensive characterization and analysis of phylogenetic variable was carried out on three 3-phosphoglycerate dehydrogenase (PGDH) members in rice, in addition to an analysis of their whole-life expression patterns. All of the Oryza sativa phosphoglycerate dehydrogenases (OsPGDHs) have three highly conserved motifs. The three genes were detected in all tissues and development stages in (Oryza sativa, ssp. japonica Nipponbare) by quatitative real-time polymerase chain reaction (qRT-PCR). Under abiotic stresses, such as salt, drought, oxidative and low temperature, the expressions of all these OsPGDHs were significantly altered. These results highlighted the importance of the OsPGDH family in phosphorylated serine biosynthesis pathway in rice.

The seed tolerance to anoxia were analyzed in vitro germination tolerance in tubes and under soil-media in order to simulate the field environment .Coleoptile length of seedlings under anoxia situation for 7 days as survey indicator among 95 rice varieties with 4 ecological types. Results show that: (1) the coleoptile length among different rice varieties had rich variatio. (2) the germination of rice seeds in the two kinds of flooding methods in vitro and soil medium is very different. The most significant inhibition of seed scabbard growth under soil-media is the low temperature environment of soil medium after flooding to seed germination. (3) Tthe rice varieties of Lianjing 9, Yanjing 7, Lianjing 7, Lianjing 15 had high tolerance to low temperature and anoxia through two methods,which provide the direct seedling cultivars for the local rice area.

晚直播条件下,以中熟中粳超级稻品种连粳7号及早熟优质灌浆快的直立穗型品种连粳15号为试验材料,设置4种氮肥水平,通过水稻籽粒灌浆过程中的动态取样,应用Richard方程对籽粒灌浆过程进行拟合,研究淮北主推品种不同粒位籽粒灌浆特性及其品质对氮肥施用量的响应.结果 表明:随施氮量的增加,产量先显著增加后降低,强、弱势粒粒重、灌浆速率、最大和平均灌浆速率减小;与强势粒相比,弱势粒粒重较轻,最大灌浆速率和平均灌浆速率较小,到达最大灌浆速率时间较迟,活跃灌浆期较长.连粳15号二次枝梗籽粒灌浆启动早,灌浆速率较连粳7号快,进入灌浆盛期早,籽粒充实紧密.连粳7号一次枝梗籽粒灌浆速率下降后,二次枝梗籽粒灌浆速率才有较大上升;二次枝梗籽粒较多导致其充实度较低、结实率下降、出米率不高.随施氮量的增加,整精米率显著下降且相同氮水平下品种间差异显著;连粳7号垩白粒率、垩白度呈增长趋势,差异显著;连粳15号垩白粒率降低,垩白度先升后降.

[目的]为明确黄淮海稻区育成水稻品种的稻瘟病抗性及其基因型,[方法]收集了来自本稻区5个不同地区的水稻品种,连续两年通过稻瘟病菌接种鉴定和田间病圃自然诱发对供试品种进行了稻瘟病抗性鉴定,并利用4个抗病基因Pita,Pib,Pi54和Pikm的分子标记,对水稻品种基因型进行了统计分析,并以抗性等级为表型值对品种资源进行聚类分析.[结果]黄淮海稻区水稻品种发病率较高,分别达85.2％和65.9％.Pi54和Pib检出率分别达84％、65％.同时抗性聚类分析表明Pi54和Pib在本稻区的抗性贡献率却很低.[结论]黄淮海稻区水稻品种稻瘟病抗性弱,携带的抗瘟基因的抗性在不断减弱或丧失,需加强稻瘟病主效抗性的发掘、开发与利用.

BACKGROUNDDrought is the most serious limiting factor of rice production worldwide and is becoming more intensive with climate change in recent years. Screening and breeding drought-tolerant rice genotypes are essential to maintain yield gain and ensure food security under adverse environments. However, thus far, little attention has been given to the temporal changes of drought resistance concomitant with the year of release in rice genetic breeding. RESULTSSixteen rice genotypes bred or widely cultivated from 1934 to 2007 were grown in paddy fields (control) and upland fields (drought stress) to explore the variation of drought resistance in rice genotypes with the year of release. Grain yield and daily grain yield significantly increased with the year of release. The genetic improvements in the grain yield partially resulted from the significant increase in panicle, spikelets per panicle and filling percentage. In addition, various growth-related characteristics like biomass, harvest index, relative growth rate, grain density and growth duration increased with an increase of genetic refinement of the genotypes through the years, and they contributed to improvement of final rice yields. However, grain yield, yield components and these growth-related traits sharply declined under drought stress. Furthermore, the drought resistance coefficients of K-Yield, K-Daily grain yield, K-Panicle number, K-Spikelets per panicle, K-Biomass, K-Plant height, K-Relative growth rate and K-Filling percentage were prominently improved by genetic breeding. CONCLUSIONSDrought resistance of rice genotypes has been significantly enhanced by genetic processes during the last 73years in China, but they are still sensitive to drought conditions. Currently, there is still room for further improvement in drought resistance which is an important target in future breeding programs. (c) 2019 Society of Chemical Industry

为探明不同施氮水平对水稻品种氮肥利用率和农艺性状的影响,以适宜黄淮稻区的18个粳稻品种为材料,田间种植,设置4个施氮水平(0、225、300和375 kg/hm2),研究各品种氮肥利用率和农艺性状的变化规律.结果 表明:不同施氮水平下,各品种的氮肥农学利用率及其农艺性状差异显著;株高、有效穗数和全生育期与施氮量呈正相关关系;结实率和氮肥偏生产力与施氮量呈负相关关系;穗长、每穗粒数、千粒重、单株谷重和氮肥农学利用率随氮肥的施加出现先增加后降低的趋势.隶属度函数和K-均值聚类分析结果显示,综合评价氮肥利用效率最高的3个品种为连粳16117、连粳15号和新粮12号.

以抗倒能力存在差异的中熟中粳品种连粳7号、徐稻3号和早熟中粳品种连粳15号、连粳13ZJ61为试验材料,在稻麦两熟制下,研究了播期对直播稻根系生长动态的影响,以及水稻根系生长与根系抗倒伏能力的关系。结果表明:（1）在播期范围（6月10～30日）内,中熟中粳品种越早播其抗倒能力越强,早熟中粳在适宜的播期抗倒能力表现较好;（2）根冠比较大、根干质量大、蜡熟期根干质量在播期范围内衰减少是直播稻抗倒能力强的主要特征;（3）中下层根占全部根的比例大、蜡熟期中下层根系在播期范围内衰减少是抗倒能力强的显著特征之一;（4）在播期范围内根数多、根直径大、后期根长和根数衰减少是根部抗倒能力强的重要特征。