拟南芥LRR-RLKs亚家族蛋白RLK6的亚细胞定位及RLK6的组织表达

以拟南芥(Arabidopsis thaliana)为材料,运用RT-PCR技术扩增得到了富含亮氨酸的类受体蛋白激酶(LRR-RLKs)亚家族基因RLK6,构建了RLK6与绿色荧光蛋白基因(GFP)融合表达载体并转化拟南芥,用激光共聚焦扫描显微镜观察转基因植物细胞表明:RLK6蛋白定位于细胞膜上;将RLK6-GFP在原生质体中进行瞬时表达,进一步证实了RLK6蛋白定位于细胞膜上。构建了RLK6启动子(2 063bp)融合GUS报告基因的载体并转化拟南芥,对转基因植株进行组织化学染色分析表明:RLK6在拟南芥的幼苗、根、花、角果等组织中都有表达,花中表达量较高,尤其是在雄蕊中特异高表达,而在茎、莲座叶和干种子中几乎没有表达。RT-PCR分析结果与GUS组织化学染色的结果一致。研究推测,RLK6可能在花器官生长发育或相关生理过程的信号转导中发挥作用。

基于ITS和RLKs序列的苦荞种质资源遗传多样性分析

为明确苦荞资源的遗传多样性水平及遗传关系,对45份苦荞地方品种的ITS和RLKs序列进行基因测序和序列比较分析。结果显示,苦荞ITS和RLKs扩增序列较为保守,基因多态位点数分别占10.6%和7.7%。云贵川地区苦荞材料的遗传多样性最丰富,陕西、山西及宁夏地区次之,甘肃及内蒙古地区最低。四川和贵州地区的苦荞品种均能够单独聚为一类,基于ITS序列构建的NJ树中,陕西地区以北的苦荞品种未形成明显的分支,而云南地区的苦荞穿插在不同的分支中;基于RLKs基因构建的NJ树中,同一地区的苦荞材料较为明显地形成地域聚类,但自展值均较低。

工业大麻类受体激酶基因家族生物信息学分析

工业大麻RLK基因家族在碱性盐胁迫响应过程中有重要的调控作用。为探究工业大麻RLK基因家族响应NaHCO_(3)胁迫的信号转导机制,利用生物信息学方法对工业大麻63个RLK基因家族成员进行分析,结果表明,工业大麻的RLK基因家族可分为12个亚组。分析了RLK基因家族在不同盐碱耐受性品种中的表达模式及潜在的生物学功能,此试验结果为进一步研究工业大麻RLK基因家族在逆境响应和生长发育过程中的分子功能提供重要依据。

Analysis of expressed receptor-like kinases (RLKs) in soybean

Receptor-like kinases （RLKs） play crucial roles in cellular signal perception and propagation. To study the evolutionary relationships among RLKs in soybean, a large-scale expressed sequence tags （ESTs） survey for RLKs-related sequences was conducted. By doing BLAST analysis using our database and The Gene Index Database, 605 putative RLK genes were identified. Based on the phylogeny of the kinase domain, these soybean RLKs were classified into 58 different small subfamilies. The phylogenetic analysis of RLKs in soybean, rice and Arabidopsis showed that different subfamilies of RLKs had different functions and could have experienced different selective pressures.

PIP/PIPL:一类调控植物逆境响应和发育的植物内源性多肽

植物内源性多肽由前体蛋白剪切而成,由天然氨基酸以不同组成和排列方式构成。多肽分泌至细胞外后,被其受体识别,从而调控植物生长发育和逆境响应。PIP(PAMP-induced secreted peptide)/PIP-Like(PIPL)是包含SGPS和GxGH基序的植物内源性多肽,可被受体激酶RLK7(receptor-like kinase 7)识别,在植物抵抗病原菌、病毒和盐害等逆境及调控生长发育过程中扮演重要角色。本文重点阐述了PIP/PIPL家族多肽在植物抵抗逆境胁迫和调控生长发育过程中的信号转导通路,并讨论了该领域尚待解决的一些科学问题和可能的应用方向,以期为PIP/PIPL的深入研究提供参考。

Pseudomonas Cyclic Lipopeptide Medpeptin:Biosynthesis and Modulation of Plant Immunity

The multifunctional secondary metabolites known as cyclic lipopeptides(CLPs),which are produced by a large variety of bacteria,have become a key category of plant immunity elicitors.Pseudomonas-CLPs(PsCLPs)are extremely diverse in structure and biological activity.However,an understanding of CLP-plant structure–function interactions currently remains elusive.Here,we identify medpeptin,a novel CLP from Pseudomonas mediterranea that consists of 22 amino acids.Medpeptin is synthesized by a non-ribosomal peptide synthase(NRPS)gene cluster and regulated by a quorum-sensing system.Further research indicates that medpeptin does not exhibit antimicrobial activity;instead,it induces plant cell death immunity and confers resistance to bacterial infection.Comparative transcriptome analysis and virus-induced gene silencing(VIGS)reveal a set of immune signaling candidates involved in medpeptin perception.Silencing of a cell-wall leucine-rich repeat extensin protein(NbLRX3)or a receptor-like protein kinase(NbRLK25)—but not BAK1 or SGT1—compromises medpeptin-triggered cell death and resistance to pathogen infection in Nicotiana benthamiana.Our findings point to a noncanonical mechanism of CLP sensing and suggest perspectives for the development of plant disease resistance.

蔷薇科果树类受体激酶的研究进展

类受体激酶(receptor like kinase,RLK)参与调控植物几乎所有的生命活动,是植物生长发育和环境适应的“中央处理器”。该文对近年来国内外有关蔷薇科果树RLK基因鉴定、进化特征及其在各器官生长发育、非生物和生物逆境中的作用及调控机制等方面的研究进展进行了综述。蔷薇科果树基因组中存在数目庞大的RLKs,不同树种间的RLK数目和各亚家族成员数目都存在较大差异,而且蔷薇科果树RLK存在极为普遍的部分重复和串联重复现象,是导致家族成员迅速变化的重要原因。有研究发现,一些RLKs调控蔷薇科果树器官发育和对环境的适应性。在器官发育方面,LRR-RLK亚家族成员调控根系发育,CrRLK1L、LysM-RLK和LRR-RLK亚家族部分成员参与调控果实发育,CrRLK1L亚家族成员参与调控花粉管发育,LRR-RLK、LysM-RLK、L-LEC-RLK和B-Lectin-RLK亚家族部分成员调控蔷薇科果树对生物逆境的适应。今后RLK功能研究可侧重于蔷薇科果树特色性状,通过提高目标基因的筛选和验证的效率,加速主效RLKs的筛选进程,并通过筛选主效RLKs诱导方式和加速分子育种进程等途径,将研究成果应用于实际生产。

Receptor-like kinase OsASLRK regulates methylglyoxal response and content in rice

Receptor-like kinases(RLKs) are essential for plant abiotic stress responses. Methylglyoxal(MG) is a cellular metabolite that is often considered to be a stress signal molecule. However, limited information is available about the relationship between RLKs and MG. Here, we addressed the function of a receptor-like kinase, Os ASLRK, in the MG response and content in rice. A typical MG-responsive element(AAAAAAAA) exists in the promoter region of the OsASLRK gene. RTqPCR analysis indicated that the transcript level of OsASLRK was significantly increased by exogenous MG in a time-and dosage-dependent fashion. GUS staining also confirmed that the expression of Os ASLRK in rice root was enhanced by exogenous MG treatment. Genetic analysis suggested that the Osaslrk mutant displays increased sensitivity to MG and it showed higher endogenous MG content under exogenous MG treatments, while OsASLRK-overexpressing rice plants showed the opposite phenotypes. Diaminobenzidine(DAB) staining, scavenging enzyme activities and GSH content assays indicate that OsASLRK regulates MG sensitivity and content via the elevation of antioxidative enzyme activities and alleviation of membrane damage. Therefore, our results provide new evidence illustrating the roles that receptor-like kinase Os ASLRK plays in MG regulation in rice.

对植物病害相关受体-PRR的研究

先前大量的研究表明植物与病原体博弈进化的过程中,病原体配备了一系列的进攻之“矛”,而同时植物也配备了一套复杂有效的防御之“盾”,植物的免疫系统可大致分为PTI和ETI两个层面。即PAMPs或DAMPs诱导的免疫反应PTI是植物抵御病原菌的第1层反应,由病原体释放的效应子(effectors)引发的免疫反应ETI是植物的第2层防卫反应。植物所配置的各种类型的受体在植物免疫及生长发育等过程中启着重要作用。而模式识别受体(Pattern Recognition Receptor,PRR)在PTI反应中发挥重要作用,研究就PRR的结构分类,对病原的识别,信号传导,转录表达以及调控下游免疫的方面展开讨论。

Curation,nomenclature,and topological classification of receptor-like kinases from 528 plant species for novel domain discovery and functional inference

Receptor-like kinases(RLKs)are the most numerous signal transduction components in plants and play important roles in determining how different plants adapt to their ecological environments.Research on RLKs has focused mainly on a small number of typical RLK members in a few model plants.There is an urgent need to study the composition,distribution,and evolution of RLKs at the holistic level to increase our understanding of how RLKs assist in the ecological adaptations of different plant species.In this study,we collected the genome assemblies of 528 plant species and constructed an RLK dataset.Using this dataset,we identified and characterized 524948 RLK family members.Each member underwent systematic topological classification and was assigned a gene ID based on a unified nomenclature system.Furthermore,we identified two novel extracellular domains in some RLKs,designated Xiao and Xiang.Evolutionary analysis of the RLK family revealed that the RLCK-XVII and RLCK-XII-2 classes were present exclusively in dicots,suggesting that diversification of RLKs between monocots and dicots may have led to differences in downstream cytoplasmic responses.We also used an interaction proteome to help empower data mining for inference of new RLK functions from a global perspective,with the ultimate goal of understanding how RLKs shape the adaptation of different plants to the environments/ecosystems.The assembled RLK dataset,together with annotations and analytical tools,forms an integrated foundation of multiomics data that is publicly accessible via the metaRLK web portal(http://metaRLK.biocloud.top).

玉米类受体蛋白激酶基因ZmLRRPK1的cDNA克隆与表达分析

富亮氨酸重复区的类受体蛋白激酶(LRR-RLKs)在植物对多种信号的响应中发挥作用。应用电子克隆的方法在玉米中克隆了一个LRR-RLKs类基因的全长cDNA,命名为ZmLRRPK1(GenBank接受号为EU873320)。推断的ZmLRRPK1蛋白含有594个氨基酸,分子量为66kDa,等电点pI为5.42,具有典型的LRR-RLKs结构域。半定量RT-PCR结果表明,在ABA、甘露醇和氯化钠的诱导下,ZmLRRPK1在玉米胚芽鞘中表达并在24h内保持较高的转录水平。

Protein kinases in plant responses to drought, salt,and cold stress

Protein kinases are major players in various signal transduction pathways. Understanding the molecular mechanisms behind plant responses to biotic and abiotic stresses has become critical for developing and breeding climate-resilient crops. In this review,we summarize recent progress on understanding plant drought, salt, and cold stress responses, with a focus on signal perception and transduction by different protein kinases, especially sucrose nonfermenting1(SNF1)-related protein kinases(Sn RKs),mitogen-activated protein kinase(MAPK) cascades,calcium-dependent protein kinases(CDPKs/CPKs),and receptor-like kinases(RLKs). We also discuss future challenges in these research fields.

Receptor-like kinases and receptor-like proteins： keys to pathogen recognition and defense signaling in plant innate immunity

Plants have evolved multiple layers of defense against various pathogens in the environment. Receptor-like kinases/proteins （RLKs/RLPs） are on the front lines of the battle between plants and pathogens since they are present at the plasma membrane and perceive signature molecules from either the invading pathogen or damaged plant tissue. With a few notable exceptions, most RLKs/RLPs are positive regulators of plant innate immunity. In this review, we summarize recently discovered RLKs/RLPs that are involved in plant defense responses against various classes of pathogens, We also describe what is currently known about the mechanisms of RLK-mediated initiation of signaling via protein-protein interactions and phosphorylation.

Patterning the embryo in higher plants:Emerging pathways and challenges

Embryogenesis,which establishes the basic body plan for the post-embryonic organs after stereotyped cell divisions,initiates the first step of the plant life cycle.Studies in the last two decades indicate that embryogenesis is a precisely controlled process,and any defect would result in abnormalities.Here we discuss the recent progresses,with a focus on the cellular pathways governing early embryogenesis in the model species Arabidopsis.

山荆子WAK类受体激酶基因家族鉴定与表达分析

以表皮生长因子(epidermal growth factor,EGF,Pfam PF00008.28)和激酶(pkinase,Pfam PF00069)保守域全蛋白序列为种子序列,鉴定了山荆子(Malus baccata)WAK-RLK(Wall-associated kinases-Reporter like kinase)家族成员,对其家族成员理化性质、进化关系、重复现象和表达模式等进行分析。结果表明,山荆子WAK基因家族包括27个成员,其氨基酸序列大小介于496~805,分子量介于55.45~89.61 kD,理论等电点介于5.15~8.75,主要分布于质膜;根据进化分析,将拟南芥、水稻、番茄、香蕉、苹果、山荆子6个物种的WAK-RLK分为8个亚组,山荆子WAK主要分布于亚组Ⅰ、Ⅱ、Ⅳ、Ⅴ、Ⅶ和Ⅷ。基因重复分析表明山荆子WAK成员扩增的主要原因是发生基因组范围的重复(wide-genome duplication,WGD)。启动子顺式作用元件(cis-acting regulatory element,cis-element)分析表明,该家族成员主要响应多种激素和逆境信号。PCR表达分析表明,WAK基因在山荆子不同组织中存在差异表达,且在苹果树腐烂病菌(Valsa mali)侵染后,MABA031460、MABA030455和MABA014609在前期显著上调表达。由此表明山荆子WAK家族成员发生扩增,响应逆境和腐烂病信号,MABA031460、MABA030455和MABA014609可作为抗腐烂病研究的候选基因。本研究结果为进一步抗病研究和功能分析提供了参考。

Somatic Embryogenesis Receptor Kinases Control Root Development Mainly via Brassinosteroid-Independent Actions in Arabidopsis thaliana

Brassinosteroids （BRs）, a group of plant steroidal hormones, play critical roles in many aspects of plant growth and development. Previous studies showed that BRI1-mediated BR signaling regulates cell division and differentiation during Arabidopsis root development via interplaying with auxin and other phytohormones. Arabidopsis somatic embryogenesis receptor-like kinases （SERKs）, as co-receptors of BRI1, were found to play a fundamental role in an early activation step of BR signaling pathway. Here we report a novel function of SERKs in regulating Arabidopsis root development. Genetic analyses indicated that SERKs control root growth mainly via a BR-independent pathway. Although BR signaling pathway is completely disrupted in the serkl bakl bkkl triple mutant, the root growth of the triple mutant is much severely damaged than the BR deficiency or signaling null mutants. More detailed analyses indicated that the triple mutant exhibited drastically reduced expression of a number of genes critical to polar auxin transport, cell cycle, endodermis development and root meristem differentiation, which were not observed in null BR biosynthesis mutant cpd and null BR signaling mutant bril-701.

Receptor-Like Kinases in Plant Innate Immunity

Plants employ a highly effective surveillance system to detect potential pathogens, which is critical for the success of land plants in an environment surrounded by numerous microbes. Recent efforts have led to the identification of a number of immune receptors and components of immune receptor complexes. It is now clear that receptor-like kinases （RLKs） and receptor-like proteins （RLPs） are key pattern-recognition receptors （PRRs） for microbe- and plant-derived molecular patterns that are associated with pathogen invasion. RLKs and RLPs involved in immune signaling belong to large gene families in plants and have undergone lineage specific expansion. Molecular evolution and population studies on phytopathogenic molecular signatures and their receptors have provided crucial insight into the co-evolution between plants and pathogens.

Genome-Wide Expression Pattern Analyses of the Arabidopsis Leucine-Rich Repeat Receptor-Like Kinases

Receptor-like protein kinases （RLKs） are a large group of transmembrane proteins playing critical roles in cell-cell and cell--environment communications. Based on extracellular domain structures, RLKs were classified into more than 21 subfamilies, among which leucine-rich repeat RLKs （LRR-RLKs） belong to the largest subfamily in plants such as Arabidopsis and rice. In Arabidopsis, there are approximately 223 LRR-RLKs, but only about 60 of which have been functionally described to date. To systematically investigate the roles of LRR-RLKs in regulating plant growth, development, and stress adaptations, we generated promoter：：GUS transgenic plants for all 223 LRR-RLK genes in Arabidopsis and analyzed their detailed expression patterns at various developmental stages. The results provide valuable resources for functionally elucidating this large and essential signaling protein subfamily.

水稻白叶枯病抗病机制与抗病育种展望

水稻白叶枯病抗病基因的发掘与育种利用是目前针对白叶枯病害(Xoo)最环保和有效的手段。迄今,已报道至少45个抗白叶枯病抗性基因(Xa),本文对已报道基因的发掘和定位进行了总结,并根据蛋白结构与抗病机制对其中已克隆的15个Xa基因进行了分类,包括:(1)编码蛋白激酶受体的抗性基因,如RLK(receptor-like kinase);(2)编码NLR (nucleotide-binding leucine-rich repeat)免疫受体的抗性基因;(3)糖转运蛋白SWEET编码基因;(4)抗性执行基因(executor);(5)其他类型基因。Xa21作为第一个被克隆的白叶枯抗性基因,其编码蛋白RLK所介导的抗病机制已较为清晰。研究发现,除编码RLK的Xa基因外,大部分Xa发挥功能依赖于Xoo III型分泌系统分泌的类转录激活效应因子(transcriptionalactivator-likeeffectors,TALE)。很多受白叶枯菌分泌的TALE效应因子调控表达的水稻Xa基因实际为感病基因,其隐性突变产生抗病性。目前为止,白叶枯病non-TALE效应因子与抗病蛋白互作尚无报道,因此,突破口将是对编码NLR的Xa基因的抗病机制的研究。本文结合Xa的来源、抗谱、机制的研究及当前抗病育种存在的问题,针对白叶枯病广谱抗病分子育种提出了展望。