Xiangzong Meng

Texas A&M University, College Station, Texas, United States

Are you Xiangzong Meng?

Claim your profile

Publications (28)113.68 Total impact


  • No preview · Article · Jan 2016
  • Xiangzong Meng · Libo Shan · Ping He
    [Show abstract] [Hide abstract]
    ABSTRACT: Heterotrimeric G proteins are molecular switches that relay intracellular signaling in eukaryotes. Recent studies in plant immunity provide a link between heterotrimeric G proteins and a MAPK cascade via the RACK1 scaffolding proteins. Research also points to a potential regulation of G proteins by cell surface receptors.
    No preview · Article · Nov 2015 · Molecular Plant
  • [Show abstract] [Hide abstract]
    ABSTRACT: Plants use cell-surface-resident receptor-like kinases (RLKs) to sense diverse extrinsic and intrinsic cues and elicit distinct biological responses. In Arabidopsis, ERECTA family RLKs recognize EPIDERMAL PATTERNING FACTORS (EPFs) to specify stomatal patterning. However, little is known about the molecular link between ERECTA activation and intracellular signaling. We report here that the SOMATIC EMBRYOGENESIS RECEPTOR KINASE (SERK) family RLKs regulate stomatal patterning downstream of EPF ligands and upstream of a MAP kinase cascade. EPF ligands induce the heteromerization of ERECTA and SERK family RLKs. SERK and ERECTA family RLKs transphosphorylate each other. In addition, SERKs associate with the receptor-like protein (RLP) TMM, a signal modulator of stomata development, in a ligand-independent manner, suggesting that ERECTA, SERKs, and TMM form a multiprotein receptorsome consisting of different RLKs and RLP perceiving peptide ligands to regulate stomatal patterning. In contrast to the differential requirement of individual SERK members in plant immunity, cell-death control, and brassinosteroid (BR) signaling, all four functional SERKs are essential but have unequal genetic contributions to stomatal patterning, with descending order of importance from SERK3/BAK1 to SERK2 to SERK1 to SERK4. Although BR signaling connects stomatal development via multiple components, the function of SERKs in stomatal patterning is uncoupled from their involvement in BR signaling. Our results reveal that the SERK family is a shared key module in diverse Arabidopsis signaling receptorsomes and that different combinatorial codes of individual SERK members regulate distinct functions. Copyright © 2015 Elsevier Ltd. All rights reserved.
    No preview · Article · Aug 2015 · Current biology: CB
  • Source
    Rongxia Guan · Jianbin Su · Xiangzong Meng · Sen Li · Yidong Li · Juan Xu · Shuqun Zhang
    [Show abstract] [Hide abstract]
    ABSTRACT: Ethylene, a key phytohormone involved in plant-pathogen interaction, plays a positive role in plant resistance against fungal pathogens. However, its function in plant bacterial resistance remains unclear. Here, we report a detailed analysis of ethylene induction in Arabidopsis in response to Pseudomonas syringae pv. tomato DC3000 (Pst). Ethylene biosynthesis is highly induced in both pathogen/microbe-associated molecular pattern (PAMP)-triggered immunity (PTI) and effector-triggered immunity (ETI), and the induction is potentiated by salicylic acid (SA) pretreatment. In addition, Pst actively suppresses PAMP-triggered ethylene induction in a Type III secretion system-dependent manner. SA potentiation of ethylene induction is dependent mostly on mitogen-activated protein kinase 6 (MPK6) and MPK3, and their downstream ACS2 and ACS6, two Type I isoforms of 1-amino-cyclopropane-1-carboxylic acid synthases (ACSs). ACS7, a Type III ACS whose expression is enhanced by SA pretreatment, is also involved. Pst-avrRpt2, which is capable of triggering ETI, induces a higher level of ethylene production, and the elevated portion is dependent on SID2 and NPR1, two key players in SA biosynthesis and signaling. High-order ACS mutants with reduced ethylene induction are more susceptible to both Pst and Pst-avrRpt2, demonstrating a positive role of ethylene in plant bacterial resistance mediated by both PTI and ETI. Copyright © 2015, Plant Physiology.
    Full-text · Article · Aug 2015 · Plant physiology
  • Source
    Dataset: mmc5

    Full-text · Dataset · Mar 2015
  • Source
    Dataset: mmc6

    Full-text · Dataset · Mar 2015
  • Source
    Dataset: mmc2

    Full-text · Dataset · Mar 2015
  • Source
    Dataset: mmc4

    Full-text · Dataset · Mar 2015
  • Source
    Dataset: mmc7

    Full-text · Dataset · Mar 2015
  • Source
    Dataset: mmc3

    Full-text · Dataset · Mar 2015
  • Source
    Dataset: mmc1

    Full-text · Dataset · Mar 2015
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Perception of microbe-associated molecular patterns (MAMPs) elicits host transcriptional reprogramming as part of the immune response. Although pathogen perception is well studied, the signaling networks orchestrating immune gene expression remain less clear. In a genetic screen for components involved in the early immune gene transcription reprogramming, we identified Arabidopsis RNA polymerase II C-terminal domain (CTD) phosphatase-like 3 (CPL3) as a negative regulator of immune gene expression. MAMP perception induced rapid and transient cyclin-dependent kinase C (CDKC)-mediated phosphorylation of Arabidopsis CTD. The CDKCs, which are in turn phosphorylated and activated by a canonical MAP kinase (MAPK) cascade, represent a point of signaling convergence downstream of multiple immune receptors. CPL3 directly dephosphorylated CTD to counteract MAPK-mediated CDKC regulation. Thus, modulation of the phosphorylation dynamics of eukaryotic RNA polymerase II transcription machinery by MAPKs, CTD kinases, and phosphatases constitutes an essential mechanism for rapid orchestration of host immune gene expression and defense upon pathogen attacks. Copyright © 2014 Elsevier Inc. All rights reserved.
    Full-text · Article · Nov 2014 · Cell host & microbe
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Author Summary Pollen development, or male gametogenesis, is a process by which a haploid uninucleate microspore undergoes cell division and specification to form a mature pollen grain containing two sperm cells. The highly defined cell linage makes pollen development an ideal model to understand the regulation of plant cellular development. Pollen development has multiple phases and involves dynamic changes in gene expression, which highlights the importance of transcription factors and their regulatory pathway(s). In this report, we demonstrate that WRKY34 and WRKY2, two closely related WRKY transcription factors in Arabidopsis, play important roles in pollen development. WRKY34 is phosphorylated by MPK3/MPK6, two functionally redundant mitogen-activated protein kinases (MAPKs or MPKs), at early stages in pollen development. Utilizing a combination of genetic, biochemical, and cytological tools, we determined that this MAPK-WRKY signaling module functions at the early stage of pollen development. Loss of function of this pathway reduces pollen viability, and the surviving pollen has poor germination and reduced pollen tube growth, all of which reduce the transmission rate of the mutant pollen. This study discovers a novel stage-specific signaling pathway in pollen development.
    Full-text · Article · May 2014 · PLoS Genetics
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The salt-tolerant green alga Dunaliella has remarkable capability to survive in some extreme environments such as nitrogen starvation, which makes Dunaliella a proper model for mining novel genes on nitrogen uptake or assimilation. In this study, a glutamine synthetase (GS) gene DvGS2 with amino acid identity of 72% to other homologous GS proteins, was isolated and characterized from Dunaliella viridis. Phylogenetic comparison with other GSs revealed that DvGS2 occupied an independent phylogenetic position. Expressional analysis in D. viridis cells under nitrogen starvation confirmed that DvGS2 increased its mRNA level in 12h. Subcellular localization study and functional analysis in a GS-deficient Escherichia coli mutant proved that DvGS2 was a chloroplastic and functional GS enzyme. In order to investigate the potential application of DvGS2 in higher plants, the transgenic studies of DvGS2 in Arabidopsis thaliana were carried out. Results showed that the transgenic lines expressed the DvGS2 gene and demonstrated obviously enhanced root length (29%), fresh weight (40%-48% at two concentrations of nitrate supplies), stem length (21%), leaf size (39%) and silique number (44%) in contrast with the wild-type Arabidopsis. Furthermore, the transgenic lines had higher total nitrogen content (35%-43%), total GS activity (39%-45%) and soluble protein concentration (23%-24%) than the wild type. These results indicated that the overexpression of DvGS2 in A. thaliana resulted in higher biomass and the improvement of the host's nitrogen use efficiency.
    Full-text · Article · Dec 2013 · Gene
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A novel glutamine synthetase (GS) gene DvGS1 showing highest amino acid sequence identity of 78 % with the other homologous GS proteins from green algae, was isolated and characterized from Dunaliella viridis. Phylogenetic analysis revealed that DvGS1 occupied an independent phylogenetic position which was different with the GSs from higher plants, animals and microbes. Functional complement in E. coli mutant confirmed that the DvGS1 encoded functional GS enzyme. Real-time PCR analysis of DvGS1 in D. viridis cells under nitrogen starvation revealed that the mRNA level of DvGS1 was positively up-regulated in 12 h. The DvGS1 levels at the points of 12 and 24 h were separately twofold and fourfold of the level before nitrogen starvation. In order to investigate the potential application of DvGS1 in higher plants, the transgenic study of DvGS1 in Arabidopsis thaliana was carried out. Phenotype identification demonstrated that all three transgenic lines of T3 generation showed obviously enhanced root length (26 %), fresh weight (22-46 % at two concentrations of nitrate supplies), stem length (26 %), leaf size (29 %) and silique number (30 %) compared with the wild-type Arabidopsis. Biochemical analysis confirmed that all three transgenic lines had higher total nitrogen content, soluble protein concentration, total amino acid content and the leaf GS activity than the wild type plants. The free NH4 (+) and NO3 (-) concentration in fresh leaves of three transgenic lines were reduced by 17-26 % and 14-15 % separately (at two concentrations of nitrate supplies) compared with those of the wild types. All the results indicated that over-expression of DvGS1 in Arabidopsis significantly results in the improvement of growth phenotype and the host's nitrogen use efficiency.
    Full-text · Article · Dec 2013 · Molecular Biology Reports
  • Xiangzong Meng · Shuqun Zhang
    [Show abstract] [Hide abstract]
    ABSTRACT: Mitogen-activated protein kinase (MAPK) cascades are highly conserved signaling modules downstream of receptors/sensors that transduce extracellular stimuli into intracellular responses in eukaryotes. Plant MAPK cascades play pivotal roles in signaling plant defense against pathogen attack. In this review, we summarize recent advances in the identification of upstream receptors/sensors and downstream MAPK substrates. These findings revealed the molecular mechanisms underlying MAPK functions in plant disease resistance. MAPK cascades have also emerged as battlegrounds of plant-pathogen interactions. Activation of MAPKs is one of the earliest signaling events after plant sensing of pathogen/microbe-associated molecular patterns (PAMPs/MAMPs) and pathogen effectors. They are involved in signaling multiple defense responses, including the biosynthesis/signaling of plant stress/defense hormones, reactive oxygen species (ROS) generation, stomatal closure, defense gene activation, phytoalexin biosynthesis, cell wall strengthening, and hypersensitive response (HR) cell death. Pathogens, however, employ effectors to suppress plant MAPK activation and downstream defense responses to promote pathogenesis. Expected final online publication date for the Annual Review of Phytopathology Volume 51 is August 04, 2013. Please see http://www.annualreviews.org/catalog/pubdates.aspx for revised estimates.
    No preview · Article · May 2013 · Annual Review of Phytopathology
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Arabidopsis thaliana MPK3 and MPK6, two mitogen-activated protein kinases (MAPKs or MPKs), play critical roles in plant disease resistance by regulating multiple defense responses. Previously, we characterized the regulation of phytoalexin biosynthesis by Arabidopsis MPK3/MPK6 cascade and its downstream WRKY33 transcription factor. Here, we report another substrate of MPK3/MPK6, ETHYLENE RESPONSE FACTOR6 (ERF6), in regulating Arabidopsis defense gene expression and resistance to the necrotrophic fungal pathogen Botrytis cinerea. Phosphorylation of ERF6 by MPK3/MPK6 in either the gain-of-function transgenic plants or in response to B. cinerea infection increases ERF6 protein stability in vivo. Phospho-mimicking ERF6 is able to constitutively activate defense-related genes, especially those related to fungal resistance, including PDF1.1 and PDF1.2, and confers enhanced resistance to B. cinerea. By contrast, expression of ERF6-EAR, in which ERF6 was fused to the ERF-associated amphiphilic repression (EAR) motif, strongly suppresses B. cinerea-induced defense gene expression, leading to hypersusceptibility of the ERF6-EAR transgenic plants to B. cinerea. Different from ERF1, the regulation and function of ERF6 in defensin gene activation is independent of ethylene. Based on these data, we conclude that ERF6, another substrate of MPK3 and MPK6, plays important roles downstream of the MPK3/MPK6 cascade in regulating plant defense against fungal pathogens.
    Full-text · Article · Mar 2013 · The Plant Cell
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Spatiotemporal-specific cell proliferation and cell differentiation are critical to the formation of normal tissues, organs, and organisms. The highly coordinated cell differentiation and proliferation events illustrate the importance of cell-cell communication during growth and development. In Arabidopsis thaliana, ERECTA (ER), a receptor-like protein kinase, plays important roles in promoting localized cell proliferation, which determines inflorescence architecture, organ shape, and size. However, the downstream signaling components remain unidentified. Here, we report a mitogen-activated protein kinase (MAPK; or MPK) cascade that functions downstream of ER in regulating localized cell proliferation. Similar to an er mutant, loss of function of MPK3/MPK6 or their upstream MAPK kinases (MAPKKs; or MKKs), MKK4/MKK5, resulted in shortened pedicels and clustered inflorescences. Epistasis analysis demonstrated that the gain of function of MKK4 and MKK5 transgenes could rescue the loss-of-function er mutant phenotype at both morphological and cellular levels, suggesting that the MPK3/MPK6 cascade functions downstream of the ER receptor. Furthermore, YODA (YDA), a MAPKK kinase, was shown to be upstream of MKK4/MKK5 and downstream of ER in regulating inflorescence architecture based on both gain- and loss-of-function data. Taken together, these results suggest that the YDA-MKK4/MKK5-MPK3/MPK6 cascade functions downstream of the ER receptor in regulating localized cell proliferation, which further shapes the morphology of plant organs.
    Preview · Article · Dec 2012 · The Plant Cell
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Plants under pathogen attack produce high levels of ethylene, which plays important roles in plant immunity. Previously, we reported the involvement of ACS2 and ACS6, two Type I ACS isoforms, in Botrytis cinerea-induced ethylene biosynthesis and their regulation at the protein stability level by MPK3 and MPK6, two Arabidopsis pathogen-responsive mitogen-activated protein kinases (MAPKs). The residual ethylene induction in the acs2/acs6 double mutant suggests the involvement of additional ACS isoforms. It is also known that a subset of ACS genes, including ACS6, is transcriptionally induced in plants under stress or pathogen attack. However, the importance of ACS gene activation and the regulatory mechanism(s) are not clear. In this report, we demonstrate using genetic analysis that ACS7 and ACS11, two Type III ACS isoforms, and ACS8, a Type II ACS isoform, also contribute to the B. cinerea-induced ethylene production. In addition to post-translational regulation, transcriptional activation of the ACS genes also plays a critical role in sustaining high levels of ethylene induction. Interestingly, MPK3 and MPK6 not only control the stability of ACS2 and ACS6 proteins via direct protein phosphorylation but also regulate the expression of ACS2 and ACS6 genes. WRKY33, another MPK3/MPK6 substrate, is involved in the MPK3/MPK6-induced ACS2/ACS6 gene expression based on genetic analyses. Furthermore, chromatin-immunoprecipitation assay reveals the direct binding of WRKY33 to the W-boxes in the promoters of ACS2 and ACS6 genes in vivo, suggesting that WRKY33 is directly involved in the activation of ACS2 and ACS6 expression downstream of MPK3/MPK6 cascade in response to pathogen invasion. Regulation of ACS activity by MPK3/MPK6 at both transcriptional and protein stability levels plays a key role in determining the kinetics and magnitude of ethylene induction.
    Full-text · Article · Jun 2012 · PLoS Genetics
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Plant sensing of invading pathogens triggers massive metabolic reprogramming, including the induction of secondary antimicrobial compounds known as phytoalexins. We recently reported that MPK3 and MPK6, two pathogen-responsive mitogen-activated protein kinases, play essential roles in the induction of camalexin, the major phytoalexin in Arabidopsis thaliana. In search of the transcription factors downstream of MPK3/MPK6, we found that WRKY33 is required for MPK3/MPK6-induced camalexin biosynthesis. In wrky33 mutants, both gain-of-function MPK3/MPK6- and pathogen-induced camalexin production are compromised, which is associated with the loss of camalexin biosynthetic gene activation. WRKY33 is a pathogen-inducible transcription factor, whose expression is regulated by the MPK3/MPK6 cascade. Chromatin immunoprecipitation assays reveal that WRKY33 binds to its own promoter in vivo, suggesting a potential positive feedback regulatory loop. Furthermore, WRKY33 is a substrate of MPK3/MPK6. Mutation of MPK3/MPK6 phosphorylation sites in WRKY33 compromises its ability to complement the camalexin induction in the wrky33 mutant. Using a phospho-protein mobility shift assay, we demonstrate that WRKY33 is phosphorylated by MPK3/MPK6 in vivo in response to Botrytis cinerea infection. Based on these data, we conclude that WRKY33 functions downstream of MPK3/MPK6 in reprogramming the expression of camalexin biosynthetic genes, which drives the metabolic flow to camalexin production in Arabidopsis challenged by pathogens.
    Full-text · Article · Apr 2011 · The Plant Cell

Publication Stats

515 Citations
113.68 Total Impact Points

Institutions

  • 2014-2015
    • Texas A&M University
      • Institute for Plant Genomics and Biotechnology
      College Station, Texas, United States
  • 2011-2015
    • University of Missouri
      • Department of Biochemistry
      Columbia, Missouri, United States
  • 2008-2013
    • Shanghai University
      • School of Life Sciences
      Shanghai, Shanghai Shi, China
  • 2009-2010
    • Shanghai Institutes for Biological Sciences
      Shanghai, Shanghai Shi, China