Heterotrimeric G protein α subunit is involved in rice brassinosteroid response

Heterotrimeric G proteins are known to function as messengers in numerous signal transduction pathways.The nullmutation of RGA(rice heterotrimeric G protein α subunit),which encodes the α subunit of heterotrimeric G proteinin rice,causes severe dwarfism and reduced responsiveness to gibberellic acid in rice.However,less is known aboutheterotrimeric G protein in brassinosteroid(BR)signaling,one of the well-understood phytohormone pathways.In thepresent study,we used root elongation inhibition assay,lamina inclination assay and coleoptile elongation analysis todemonstrated reduced sensitivity of dl mutant plants(caused by the null mutation of RGA)to 24-epibrassinolide(24-epiBL),which belongs to brassinosteroids and plays a wide variety of roles in plant growth and development.Moreover,RGA transcript level was decreased in 24-epiBL-treated seedlings in a dose-dependent manner.Our results show thatRGA is involved in rice brassinosteroid response,which may be beneficial to elucidate the molecular mechanisms of Gprotein signaling and provide a novel perspective to understand BR signaling in higher plants.

The Arabidopsis Spontaneous Cell Death1 gene, encoding a ζ-carotene desaturase essential for carotenoid biosynthesis, is involved in chloroplast development, photoprotection and retrograde signalling

Carotenoids, a class of natural pigments found in all photosynthetic organisms, are involved in a variety of physiologi-cal processes, including coloration, photoprotection, biosynthesis of abscisic acid (ABA) and chloroplast biogenesis.Although carotenoid biosynthesis has been well studied biochemically, the genetic basis of the pathway is not wellunderstood. Here, we report the characterization of two allelic Arabidopsis mutants, spontaneous cell death 1-1 (spcl-1)and spcl-2. The weak allele spcl-1 mutant showed characteristics of bleached leaves, accumulation of superoxide andmosaic cell death. The strong mutant allele spcl-2 caused a complete arrest of plant growth and development shortlyafter germination, leading to a seedling-lethal phenotype. Genetic and molecular analyses indicated that SPC1 encodesa putative ζ-carotene desaturase (ZDS) in the carotenoid biosynthesis pathway. Analysis of carotenoids revealed thatseveral major carotenoid compounds downstream of SPC1/ZDS were substantially reduced in spcl-1, suggesting thatSPC1 is a functional ZDS. Consistent with the downregulated expression of CAO and PORB, the chlorophyll contentwas decreased in spcl-1 plants. In addition, expression of Lhcb1.1, Lhcb1.4 and RbcS was absent in spcl-2, suggestingthe possible involvement of carotenoids in the plastid-to-nucleus retrograde signaling. The spcl-1 mutant also displaysan ABA-deficient phenotype that can be partially rescued by the externally supplied phytohormone. These results suggestthat SPC1/ZDS is essential for biosynthesis of carotenoids and plays a crucial role in plant growth and development.

The brassinosteroid signal transduction pathway

类固醇作为在动物和植物表明分子工作。当动物类固醇荷尔蒙被抄写因素的原子受体家庭察觉时，在植物的 brassinosteroids (BR ) 被房间表面受体 kinase 察觉， BRI1。最近的研究证明了到 BRI1 的细胞外的域的那 BR 绑定与另一受体 kinase 导致 kinase 激活和 dimerization， BAK1。激活的 BRI1 或 BAK1 然后调整，可能间接地， BIN2 kinase 的活动或 BSU1 磷酸酶，它直接调整 phosphorylation 地位和二个相应抄写因素， BZR1 和 BES1 的原子累积。BZR1 和 BES1 直接绑在 BR 应答的基因的倡导者调整他们的表示。表明小径的 BR 为在一般来说由房间表面受体发信号的植物和类固醇发信号的两受体 kinase 成为了一个范例。

Construction of a chloroplast protein interaction network and functional mining of photosynthetic proteins in Arabidopsis thaliana

叶绿体是光合作用发生的一个典型植物细胞细胞器。在这研究，在 Arabidopsis thaliana 的 1 808 叶绿体核心蛋白质的一个总数被联合以前出版的研究和我们的自己的预言的结果可靠地识别。我们然后首先基于这些核心蛋白质相互作用构造了一个叶绿体蛋白质相互作用网络。网络有 22 包含了 2 的 925 蛋白质相互作用对 214 蛋白质。160 的一个总数以前， uncharacterized 蛋白质在这个网络被注解。光合的建筑群的子单元被模块化，并且在 photosystem 之中的功能的关系我(希腊语的第二十三个字母)， photosystem II ( PSII )， photosystem 的轻收获建筑群我( LHC 我)并且 photosystem 的轻收获建筑群( LHC II )我能在这个网络从预言的蛋白质相互作用被推出。我们进一步由酵母证实了在未知蛋白质 AT1G52220 和光合的子单元 PSI-D2 之间的一个相互作用二混血儿的分析。我们的叶绿体蛋白质相互作用网络应该为光合的蛋白质的功能的采矿和在在 Arabidopsis 的系统生物学水平的叶绿体相关的函数的调查是有用的。

Genome resources for the elite bread wheat cultivar Aikang 58 and mining of elite homeologous haplotypes for accelerating wheat improvement

Despite recent progress in crop genomics studies,the genomic changes brought about by modern breeding selection are still poorly understood,thus hampering genomics-assisted breeding,especially in polyploid crops with compound genomes such as common wheat(Triticum aestivum).In this work,we constructed genome resources for the modern elite common wheat variety Aikang 58(AK58).Comparative genomics between AK58 and the landrace cultivar Chinese Spring(CS)shed light on genomic changes that occurred through recent varietal improvement.We also explored subgenome diploidization and divergence in common wheat and developed a homoeologous locus-based genome-wide association study(HGWAS)approach,which was more effective than single homoeolog-based GWAS in unraveling agronomic trait-associated loci.A total of 123 major HGWAs loci were detected using a genetic population derived from AK58 and cs.Elite homoeologous haplotypes(HHs),formed by combinations of subgenomic homoeologs of the associated loci,were found in both parents and progeny,and many could substantially improve wheat yield and related traits.We built a website where users can download genome assembly sequence and annotation data for AK58,perform blast analysis,and run JBrowse.Our work enriches genome resources for wheat,provides new insights into genomic changes during modern wheat improve-.ment,and suggests that efficientmining of elite HHs can make a substantial contribuutionto genomics-assisted breeding in common wheat and other polyploid crops.

2023年中国植物科学重要研究进展

2023年中国科学家在植物科学主流期刊发表的论文数量相比2022年大幅提高,在柱头受体调控十字花科种内和种间生殖隔离,叶绿体TOC-TIC超级复合物结构,作物高产、耐逆及抗病机制,葡萄和柑橘属植物的起源和传播,现代玉米、谷子和马铃薯种质资源演化等方面取得了重要研究进展。其中,“农作物耐盐碱机制解析及应用”和“新方法实现单碱基到超大片段DNA精准操纵”入选2023年度中国科学十大进展,“植物远缘杂交过程中‘花粉蒙导效应’的分子机制”入选2023年度中国生命科学十大进展。该文总结了2023年度我国植物科学研究取得的成果,并简要介绍了30项有代表性的重要进展,梳理了植物科学研究中所使用的实验材料,以帮助读者了解我国植物科学的发展态势,进而思考如何更好地开展下阶段研究和服务国家重大战略需求。

管形构件热处理形状系数数值模拟

针对现行热处理标准中长管形状系数准确性问题,采用ABAQUS模拟软件提供的Heat Transfer分析模块,统一采用环境辐射传热方式,建立了圆棒直径φ20~φ40 mm共21条模拟升温曲线组成的标准样库。利用模拟仿真及数据分析技术,提出了“等效圆棒直径条件厚度对比法”,经过模拟计算得到:短管形状系数为2,长管形状系数为2+2R_(内)/R_(外)。

2022年中国植物科学重要研究进展

2022年中国科学家在植物科学主流期刊发表的论文数量相比2021年显著增加,在防止“多精受精”分子机制,胞外pH感受器,叶绿体蛋白运输通道结构,作物高产、优质、耐逆、抗病及共生固氮机制,被子植物自交不亲和性的起源和演化机制,甘蔗和玉蜀黍种质资源演化等方面取得了重要研究进展。其中,“水稻抗高温基因挖掘及调控新机制”入选2022年度中国生命科学十大进展。该文总结了2022年度我国植物科学研究取得的成果,简要介绍了30项有代表性的重要进展,梳理了植物科学研究中所使用的实验材料,以帮助读者了解我国植物科学的发展态势,进而思考如何更好地开展下阶段研究和服务国家需求。

2020年中国植物科学若干领域重要研究进展

2020年中国植物科学家在国际综合性学术期刊及植物科学主流期刊发表的论文数量比上一年显著增加,在植物发育、耐逆、系统进化和作物生物学等领域取得了重要研究进展。其中,"小麦抗赤霉病基因Fhb7的克隆、机理解析及育种利用"和"提高作物品种氮肥利用效率的新机制"两项成果入选2020年度"中国生命科学十大进展"。该文总结了2020年我国植物科学研究取得的成绩,简要介绍了30项代表性的重要进展,以帮助读者了解我国植物科学发展态势,思考如何更好地开展下阶段的研究,服务国家需求。

2018年中国植物科学若干领域重要研究进展

2018年中国植物科学继续呈现快速发展的态势,我国科学家在国际植物科学主流学术刊物发表论文数量大幅增加,取得了多项具有重要影响的成果。调控植物生长-代谢平衡实现可持续农业发展入选2018年度中国科学十大进展;中国被子植物区系进化历史研究入选2018年度中国生命科学十大进展。以水稻为代表的农作物和果蔬等经济作物研究在国际上已呈现出明显的优势,若干领域已从'追赶'状态跨越到'领跑'地位。该文对2018年中国科学家在植物科学若干领域取得的重要研究成果进行了概括性评述,旨在全面追踪和报道当前中国植物科学领域的发展前沿和热点,展示中国科学家所取得的杰出成就。

2019年中国植物科学若干领域重要研究进展

2019年中国植物科学家在国际综合性学术期刊及植物科学主流期刊发表的论文数量大幅增加,在光生物学、植物抗逆和分子进化等若干领域取得了重要成果。其中,硅藻光合膜蛋白超分子结构和功能研究入选2019年度中国科学十大进展和中国生命科学十大进展;植物抗病小体的结构与功能研究入选2019年度中国生命科学十大进展。该文评述了2019年中国科学家在植物科学若干领域取得的重要研究进展,以期追踪和报道当前中国植物科学领域发展的前沿和热点及展示中国科学家所取得的辉煌成果。

2021年中国植物科学重要研究进展

2021年中国植物科学家在国际综合性学术期刊及植物科学主流期刊发表的论文数量相比2020年显著增加,在雌雄细胞识别与受精、干细胞命运决定、菌根共生、光合膜蛋白复合体、氮磷养分利用、先天免疫、作物从头驯化与基因组设计等方面取得了重要研究进展,“异源四倍体野生稻快速从头驯化”入选2021年度“中国生命科学十大进展”。该文总结了2021年度我国植物科学研究取得的成绩,简要介绍了30项重要进展,以帮助读者了解我国植物科学的发展态势,思考如何更好地将植物科学研究与国家重大需求有效衔接。

Circadian Evening Complex Represses Jasmonate-lnduced Leaf Senescence in Arabidopsis

Plants initiate leaf senescence to reallocate energy and nutrients from aging to developing tissues for optimizing growth fitness and reproduction at the end of the growing season or under stress. Jasmonate （JA）, a lipid-derived phytohormone, is known as an important endogenous signal in inducing leaf senescence. However, whether and how the circadian clock gates JA signaling to induce leaf senescence in plants remains elusive. In this study, we show that Evening Complex （EC）, a core component of the circadian oscillator, negatively regulates leaf senescence in Arabidopsis thaliana. Transcriptomic profiling analysis reveals that EC is closely involved in JA signaling and response, consistent with accelerated leaf senescence unanimously displayed by EC mutants upon JA induction. We found that EC directly binds the promoter of MYC2, which encodes a key activator of JA-induced leaf senescence, and represses its expression. Ge- netic analysis further demonstrated that the accelerated JA-induced leaf senescence in EC mutants is abrogated by myc2 myc3 myc4 triple mutation. Collectively, these results reveal a critical molecular mechanism illustrating how the core component of the circadian clock gates JA signaling to regulate leaf senescence.

Wheat genomic study for genetic improvement of traits in China

Bread wheat(Triticum aestivum L.)is a major crop that feeds 40%of the world’s population.Over the past several decades,advances in genomics have led to tremendous achievements in understanding the origin and domestication of wheat,and the genetic basis of agronomically important traits,which promote the breeding of elite varieties.In this review,we focus on progress that has been made in genomic research and genetic improvement of traits such as grain yield,end-use traits,flowering regulation,nutrient use efficiency,and biotic and abiotic stress responses,and various breeding strategies that contributed mainly by Chinese scientists.Functional genomic research in wheat is entering a new era with the availability of multiple reference wheat genome assemblies and the development of cutting-edge technologies such as precise genome editing tools,highthroughput phenotyping platforms,sequencing-based cloning strategies,high-efficiency genetic transformation systems,and speed-breeding facilities.These insights will further extend our understanding of the molecular mechanisms and regulatory networks underlying agronomic traits and facilitate the breeding process,ultimately contributing to more sustainable agriculture in China and throughout the world.

The vernalization-induced long non-coding RNA VAS functions with the transcription factor TaRF2b to promote TaVRN1 expression for flowering in hexaploid wheat

Vernalization is a physiological process in which prolonged cold exposure establishes flowering competence in winter plants. In hexaploid wheat, TaVRN1 is a cold-induced key regulator that accelerates floral transition. However, the molecular mechanism underlying the gradual activation of TaVRN1 during the vernalization process remains unknown. In this study, we identified the novel transcript VAS (TaVRN1 alternative splicing) as a non-coding RNA derived from the sense strand of the TaVRN1 gene only in winter wheat, which regulates TaVRN1 transcription for flowering. VAS was induced during the early period of vernalization, and its overexpression promoted TaVRN1 expression to accelerate flowering in winter wheat. VAS physically associates with TaRF2b and facilitates docking of the TaRF2b-TaRF2a complex at the TaVRN1 promoter during the middle period of vernalization. TaRF2b recognizes the Sp1 motif within the TaVRN1 proximal promoter region, which is gradually exposed along with the disruption of a loop structure at the TaVRN1 locus during vernalization, to activate the transcription of TaVRN1. The tarf2b mutants exhibited delayed flowering, whereas transgenic wheat lines overexpressing TaRF2b showed earlier flowering. Taken together, our data reveal a distinct regulatory mechanism by which a long non-coding RNA facilitates the transcription factor targeting to regulate wheat flowering, providing novel insights into the vernalization process and a potential target for wheat genetic improvement.

OsCIPK7 point-mutation leads to conformation and kinase-activity change for sensing cold response

Calcineurin B-like interacting protein kinases(CIPKs) play important roles via environmental stress.However, less is known how to sense the stress in molecular structure conformation level. Here, an Os CIPK7 mutant via TILLING procedure with a point mutation in the kinase domain showed increased chilling tolerance, which could be potentially used in the molecular breeding. We found that this point mutation of Os CIPK7 led to a conformationalchange in the activation loop of the kinase domain,subsequently with an increase of protein kinase activity,thus conferred an increased tolerance to chilling stress.

The RING E3 ligase CLG1 targets GS3 for degradation via the endosome pathway to determine grain size in rice

G-protein signaling and ubiquitin-dependent degradation are both involved in grain development in rice,but how these pathways are coordinated in regulating this process is unknown.Here,we show that Chang Li Geng 1(CLG1),which encodes an E3 ligase,regulates grain size by targeting the Gγprotein GS3,a negative regulator of grain length,for degradation.Overexpression of CLG1 led to increased grain length,while overexpression of mutated CLG1 with changes in three conserved amino acids decreased grain length.We found that CLG1 physically interacts with and ubiquitinats GS3which is subsequently degraded through the endosome degradation pathway,leading to increased grain size.Furthermore,we identified a critical SNP in the exon 3 of CLG1 that is significantly associated with grain size variation in a core collection of cultivated rice.This SNP results in an amino acid substitution from Arg to Ser at position 163 of CLG1 that enhances the E3 ligase activity of CLG1 and thus increases rice grain size.Both the expression level of CLG1 and the SNP CLG1163S may be useful variations for manipulating grain size in rice.

AtECB1/MRL7, a Thioredoxin-Like Fold Protein with Disulfide Reductase Activity, Regulates Chloroplast Gene Expression and Chloroplast Biogenesis in Arabidopsis thaliana

Plastid-encoded RNA polymerase （PEP） is closely associated with numerous factors to form PEP complex for plastid gene expression and chloroplast development. However, it is not clear how PEP complex are regulated in chloroplast. Here, one thioredoxin-like fold protein, Arabidopsis early chloroplast biogenesis 1 （AtECB1）, an allele of MRL7, was identified to regulate PEP function and chloroplast biogenesis. The knockout lines for AtECB1 displayed albino phenotype and impaired chloroplast development. The transcripts of PEP-dependent plastid genes were barely detected, suggesting that the PEP activity is almost lost in atecbl-1. Although AtECB1 was not identified in PEP complex, a yeast two-hybrid assay and pull-down experiments demonstrated that it can interact with Trx Z and FSD3, two intrinsic subunits of PEP complex, respectively. This indicates that AtECB1 may play a regulatory role for PEP-dependent plastid gene expression through these two subunits. AtECB1 contains a βαβαββα structure in the thioredoxin-like fold domain and lacks the typical C-X-X-C active site motif. Insulin assay demonstrated that AtECB1 harbors disulfide reductase activity in vitro using the purified recombinant AtECB1 protein. This showed that this thioredoxin-like fold protein, AtECB1 also has the thioredoxin activity. AtECB1 may play a role in thioredoxin signaling to regulate plastid gene expression and chloroplast development.

Overexpression of OsJAC1, a Lectin Gene, Suppresses the Coleoptile and Stem Elongation in Rice

Lectin plays an Important role In defense signaling In plants, but its function In plant growth and development is not well known. Previously, we cloneds rice （Oryza sativa L.） gene OsJAC1 encoding s msnnose-blndlng Jscslln-relsted lectln, and found that OsJAC1 was Jssmonlc acid （JA） Inducible. Here we cloned the promoter of OsJAC1, and GUS activity was detected In young roots, coleoptlles, sheaths, leaves, nodes of stems, stems, rschlses, pistils, stsmens and lemmss of OsJAC1：：GUS trsnsgenlc rice, suggesting that OsJAC1 Is s constitutive expression gene In rice. Moreover, OsJAC1-overexpressed （Ubi：：OsJAC1） rice showed dwarfism with shorter coleptlles resulting from the failure of cell elongation of coleoptlles. In addition, compared with coleoptlles of wild-type plants, those of OsJAC1 overexpresslon rice were more sensitive to JA treatment. These data revealed that, besides Its roles in defense response, lectin plays an Important role in rice growth and development.

Adenosine Diphosphate Ribosylation Factor-GTPase-Activating Protein Stimulates the Transport of AUX1 Endosome,Which Relies on Actin Cytoskeletal Organization in Rice Root Development

Polar auxin transport,which depends on polarized subcellular distribution of AUXIN RESISTANT 1/LIKE AUX1（AUX1/LAX） influx carriers and PIN-FORMED（PIN） efflux carriers,mediates various processes of plant growth and development.Endosomal recycling of PIN1 is mediated by an adenosine diphosphate（ADP）ribosylation factor（ARF）-GTPase exchange factor protein,GNOM.However,the mediation of auxin influx carrier recycling is poorly understood.Here,we report that overexpression of OsAGAP,an ARF-GTPase-activating protein in rice,stimulates vesicle transport from the plasma membrane to the Golgi apparatus in protoplasts and transgenic plants and induces the accumulation of early endosomes and AUX1.AUX1 endosomes could partially colocalize with FM4-64 labeled early endosome after actin disruption.Furthermore,OsAGAP is involved in actin cytoskeletal organization,and its overexpression tends to reduce the thickness and bundling of actin filaments.Fluorescence recovery after photobleaching analysis revealed exocytosis of the AUX1 recycling endosome was not affected in the OsAGAP overexpression cells,and was only slightly promoted when the actin filaments were completely disrupted by Lat B.Thus,we propose that AUX1 accumulation in the OsAGAP overexpression and actin disrupted cells may be due to the fact that endocytosis of the auxin influx carrier AUX1 early endosome was greatly promoted by actin cytoskeleton disruption.