Leaf senescence that occurs in the last stage of leaf development is a genetically programmed process. It is very significant to isolate the upstream components in the senescence signaling pathway and to elucidate the...Leaf senescence that occurs in the last stage of leaf development is a genetically programmed process. It is very significant to isolate the upstream components in the senescence signaling pathway and to elucidate the molecular mechanisms that control the initiation and progression of leaf senescence. In this study, full-length cDNAs of three receptor-like protein kinase genes, designated rlpkl, rlpk2 and rlpk3, were cloned from artificially-induced senescent soybean （Glycine max L.） primary leaves （GenBank accession AY687390, AY687391, AF338813）. The deduced amino acid sequences indicated that they belonged to a receptor-like kinase family. Each of rlpkl and rlpk2 encodes a leucine-rich repeat （LRR） receptor-like protein kinase. They both comprise a typical signal peptide, several LRR motifs, a single-pass transmembrane domain, and a cytoplasmic protein kinase domain. No typical extracellular domain of RLPK3 was predicted. Organ-specific expression pattern analysis by reverse-transcription polymerase chain reaction （RT-PCR） revealed higher expression levels of the three genes in cotyledons, roots and flowers. Phylogenetic analysis indicated that RLPK1 and RLPK2 belonged to an independent branch, whereas RLPK3 shared common nodes with several known RLKs responding to ablotic and biotic stresses. The evident alternations of expression profiles of rlpkl and rlpk2 induced by the artificial senescence-inducing treatment implied involvements of these two RLKs in regulating soybean leaf senescence.展开更多
Leucine-rich repeat （LRR） receptor-like kinases （RLKs）, evolutionarily related LRR receptor-like proteins （RLPs） and receptor-like cytoplasmic kinases （RLCKs） have important roles in plant signaling, and their...Leucine-rich repeat （LRR） receptor-like kinases （RLKs）, evolutionarily related LRR receptor-like proteins （RLPs） and receptor-like cytoplasmic kinases （RLCKs） have important roles in plant signaling, and their gene subfamilies are large with a complicated history of gene duplication and loss. In three pairs of closely related lineages, including Arabidopsis thaliana and A. lyrata （Arabidopsis）, Lotus japonicus, and Medicago truncatula （Legumes）, Oryza sativa ssp. japonica, and O. sativa ssp. indica （Rice）, we find that LRR RLKs comprise the largest group of these LRR-related subfamilies, while the related RLCKs represent the smal est group. In addition, comparison of orthologs indicates a high frequency of reciprocal gene loss of the LRR RLK/LRR RLP/RLCK subfamilies. Furthermore, pairwise comparisons show that reciprocal gene loss is often associated with lineage-specific duplication（s） in the alternative lineage. Last, analysis of genes in A. thaliana involved in development revealed that most are highly conserved orthologs without species-specific duplication in the two Arabidopsis species and originated from older Arabidopsis-specific or rosid-specific duplications. We discuss＆amp;nbsp;potential pitfal s related to functional prediction for genes that have undergone frequent turnover （duplications, losses, and domain architecture changes）, and conclude that prediction based on phylogenetic relationships wil likely outperform that based on sequence similarity alone.展开更多
Identification of immunity-associated leucine-rich repeat receptor-like protein kinases(LRR-RLK) is critical to elucidate the LRR-RLK mediated mechanism of plant immunity.Here,we reported the map-based cloning of a no...Identification of immunity-associated leucine-rich repeat receptor-like protein kinases(LRR-RLK) is critical to elucidate the LRR-RLK mediated mechanism of plant immunity.Here,we reported the map-based cloning of a novel rice SPOTTED-LEAF 41(Os SPL41) encoding a putative LRR-RLK protein(Os LRR-RLK41/Os SPL41) that regulated disease responses to the bacterial blight pathogen Xanthomonas oryzae pv.oryzae(Xoo).An 8-bp insertion at position 865 bp in a mutant spotted-leaf 41(spl41) allele led to the formation of purple-brown lesions on leaves.Functional complementation by the wild type allele(Os SPL41) can rescue the mutant phenotype,and the complementary lines showed similar performance to wild type in a number of agronomic,physiological and molecular indices.Os SPL41 was constitutively expressed in all tissues tested,and Os SPL41 contains a typical transmembrane domain critical for its localization to the cell membrane.The mutant exhibited an enhanced level of resistance to Xoo in companion of markedly up-regulated expression of pathogenesis-related genes such as Os PR10a,Os PAL1 and Os NPR1,while the level of salicylic acid was significantly increased in spl41.In contrast,the over-expression lines exhibited a reduced level of H_(2)O_(2) and were much susceptible to Xoo with down-regulated expression of pathogenesis-related genes.These results suggested that Os SPL41 might negatively regulate plant immunity through the salicylic acid signaling pathway in rice.展开更多
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 extreme...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.展开更多
Plants utilize plasma membrane-localized receptor-like kinases （RLKs） to sense extracellular signals to coordinate growth, development, and innate immune responses. BAK1 regulates multiple signaling pathways acting ...Plants utilize plasma membrane-localized receptor-like kinases （RLKs） to sense extracellular signals to coordinate growth, development, and innate immune responses. BAK1 regulates multiple signaling pathways acting as a co-receptor of several distinct ligand-binding RLKs. It has been debated whether BAK1 serves as an essential regulatory component or only a signal amplifier without pathway specificity. This issue has been clarified recently. Genetic and structural analyses indicated that BAK1 and its homologs play indispensible roles in mediating brassinosteroid （BR） signaling pathway by directly perceiving the ligand BR and activating the receptor of BR, BRII. The mechanism revealed by these studies now serves as a paradigm for how a pair of RLKs can function together in ligand binding and subsequent initiation of signaling.展开更多
Ligand-receptor signaling initiated by the CLAVATA3/ENDOSPERM SURROUNDING REGION （CLE） family peptides is critical in regulating cell division and differentiation in meristematic tissues in plants. Biologically acti...Ligand-receptor signaling initiated by the CLAVATA3/ENDOSPERM SURROUNDING REGION （CLE） family peptides is critical in regulating cell division and differentiation in meristematic tissues in plants. Biologically active CLE peptides are released from precursor proteins via proteolytic processing. The mature form of CLE ligands consists of 12-13 amino acids with several post-translational modifications. This review summarizes recent progress toward understanding the proteolytic activities that cleave precursor proteins to release CLE peptides, the molecular structure and function of mature CLE ligands, and interactions between CLE ligands and cor- responding leucine-rich repeat （LRR） receptor-like kinases （RLKs）.展开更多
基金Supported by the National Natural Science Foundation of China （30270140）.
文摘Leaf senescence that occurs in the last stage of leaf development is a genetically programmed process. It is very significant to isolate the upstream components in the senescence signaling pathway and to elucidate the molecular mechanisms that control the initiation and progression of leaf senescence. In this study, full-length cDNAs of three receptor-like protein kinase genes, designated rlpkl, rlpk2 and rlpk3, were cloned from artificially-induced senescent soybean （Glycine max L.） primary leaves （GenBank accession AY687390, AY687391, AF338813）. The deduced amino acid sequences indicated that they belonged to a receptor-like kinase family. Each of rlpkl and rlpk2 encodes a leucine-rich repeat （LRR） receptor-like protein kinase. They both comprise a typical signal peptide, several LRR motifs, a single-pass transmembrane domain, and a cytoplasmic protein kinase domain. No typical extracellular domain of RLPK3 was predicted. Organ-specific expression pattern analysis by reverse-transcription polymerase chain reaction （RT-PCR） revealed higher expression levels of the three genes in cotyledons, roots and flowers. Phylogenetic analysis indicated that RLPK1 and RLPK2 belonged to an independent branch, whereas RLPK3 shared common nodes with several known RLKs responding to ablotic and biotic stresses. The evident alternations of expression profiles of rlpkl and rlpk2 induced by the artificial senescence-inducing treatment implied involvements of these two RLKs in regulating soybean leaf senescence.
基金supported by the United States National Science Foundation(DEB 1026200 to M.J.S.and IOS 1257316 to F.E.T.)
文摘Leucine-rich repeat （LRR） receptor-like kinases （RLKs）, evolutionarily related LRR receptor-like proteins （RLPs） and receptor-like cytoplasmic kinases （RLCKs） have important roles in plant signaling, and their gene subfamilies are large with a complicated history of gene duplication and loss. In three pairs of closely related lineages, including Arabidopsis thaliana and A. lyrata （Arabidopsis）, Lotus japonicus, and Medicago truncatula （Legumes）, Oryza sativa ssp. japonica, and O. sativa ssp. indica （Rice）, we find that LRR RLKs comprise the largest group of these LRR-related subfamilies, while the related RLCKs represent the smal est group. In addition, comparison of orthologs indicates a high frequency of reciprocal gene loss of the LRR RLK/LRR RLP/RLCK subfamilies. Furthermore, pairwise comparisons show that reciprocal gene loss is often associated with lineage-specific duplication（s） in the alternative lineage. Last, analysis of genes in A. thaliana involved in development revealed that most are highly conserved orthologs without species-specific duplication in the two Arabidopsis species and originated from older Arabidopsis-specific or rosid-specific duplications. We discuss＆amp;nbsp;potential pitfal s related to functional prediction for genes that have undergone frequent turnover （duplications, losses, and domain architecture changes）, and conclude that prediction based on phylogenetic relationships wil likely outperform that based on sequence similarity alone.
基金supported by the National Natural Science Foundation of China(Grant No.32072049)the Central Public-Interest Scientific Institution Basal Research Fund, China(Grant No.CPSIBRF-CNRRI-202203)。
文摘Identification of immunity-associated leucine-rich repeat receptor-like protein kinases(LRR-RLK) is critical to elucidate the LRR-RLK mediated mechanism of plant immunity.Here,we reported the map-based cloning of a novel rice SPOTTED-LEAF 41(Os SPL41) encoding a putative LRR-RLK protein(Os LRR-RLK41/Os SPL41) that regulated disease responses to the bacterial blight pathogen Xanthomonas oryzae pv.oryzae(Xoo).An 8-bp insertion at position 865 bp in a mutant spotted-leaf 41(spl41) allele led to the formation of purple-brown lesions on leaves.Functional complementation by the wild type allele(Os SPL41) can rescue the mutant phenotype,and the complementary lines showed similar performance to wild type in a number of agronomic,physiological and molecular indices.Os SPL41 was constitutively expressed in all tissues tested,and Os SPL41 contains a typical transmembrane domain critical for its localization to the cell membrane.The mutant exhibited an enhanced level of resistance to Xoo in companion of markedly up-regulated expression of pathogenesis-related genes such as Os PR10a,Os PAL1 and Os NPR1,while the level of salicylic acid was significantly increased in spl41.In contrast,the over-expression lines exhibited a reduced level of H_(2)O_(2) and were much susceptible to Xoo with down-regulated expression of pathogenesis-related genes.These results suggested that Os SPL41 might negatively regulate plant immunity through the salicylic acid signaling pathway in rice.
基金funded by the National Key R&D Program of China(2022YFD1901300)the National Natural Science Foundation of China(31901932)+2 种基金the Agricultural Science and Technology Innovation Program of Chinese Academy of Agricultural Sciences(CAAS-ZDRW202308 and Y2022PT12)the Beijing Innovation Consortium of Agriculture Research System(BAIC04-2022)the Science and Technology Programs of the Zunyi Tobacco(2021XM03)。
文摘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.
基金supported by the grants from the National Natural Science Foundation of China to J.L.(91117008 and 90917019)National Basic Research Program of China to J.L.(2011CB915401)Fundamental Research Funds for the Central Universities to S.X.(lzujbky-2009-35)
文摘Plants utilize plasma membrane-localized receptor-like kinases （RLKs） to sense extracellular signals to coordinate growth, development, and innate immune responses. BAK1 regulates multiple signaling pathways acting as a co-receptor of several distinct ligand-binding RLKs. It has been debated whether BAK1 serves as an essential regulatory component or only a signal amplifier without pathway specificity. This issue has been clarified recently. Genetic and structural analyses indicated that BAK1 and its homologs play indispensible roles in mediating brassinosteroid （BR） signaling pathway by directly perceiving the ligand BR and activating the receptor of BR, BRII. The mechanism revealed by these studies now serves as a paradigm for how a pair of RLKs can function together in ligand binding and subsequent initiation of signaling.
基金supported by a startup fund from the Tobacco Research Institute,Chinese Academy of Agricultural Sciences
文摘Ligand-receptor signaling initiated by the CLAVATA3/ENDOSPERM SURROUNDING REGION （CLE） family peptides is critical in regulating cell division and differentiation in meristematic tissues in plants. Biologically active CLE peptides are released from precursor proteins via proteolytic processing. The mature form of CLE ligands consists of 12-13 amino acids with several post-translational modifications. This review summarizes recent progress toward understanding the proteolytic activities that cleave precursor proteins to release CLE peptides, the molecular structure and function of mature CLE ligands, and interactions between CLE ligands and cor- responding leucine-rich repeat （LRR） receptor-like kinases （RLKs）.
