CaARP1/CaSGT1 Module Regulates Vegetative Growth and Defense Response of Pepper Plants against .

Pepper ( L.) suffers severe quality and yield loss from oomycete diseases caused by . CaSGT1 was previously determined to positively regulate the immune response of pepper plants against , but by which mechanism remains elusive.

Acts Positively in Pepper ( L.) Immunity against .

Bacterial wilt caused by is one of the most important diseases in solanaceous plants, including peppers. It generally tends to be more serious under warm-temperature and moist (WM) conditions than at moist room-temperature (RM) conditions. Although immunity mechanisms at room temperature have been intensively studied, the mechanisms underlying WM conditions remain poorly understood.

CaSTH2 disables CaWRKY40 from activating pepper thermotolerance and immunity against via physical interaction.

CaWRKY40 coordinately activates pepper immunity against infection (RSI) and high temperature stress (HTS), forms positive feedback loops with other positive regulators and is promoted by CaWRKY27b/CaWRKY28 through physical interactions; however, whether and how it is regulated by negative regulators to function appropriately remain unclear. Herein, we provide evidence that CaWRKY40 is repressed by a SALT TOLERANCE HOMOLOG2 in pepper (CaSTH2). Our data from gene silencing and transient overexpression in pepper and epoptic overexpression in plants showed that CaSTH2 acted as negative regulator in immunity against RSI and thermotolerance.

Identification of Family Members and Characterization of the Low-Temperature-Stress-Responsive Genes in Luffa ( L.).

The plant-specific WRKY transcription factor family members have diverse regulatory effects on the genes associated with many plant processes. Although the WRKY proteins in and other species have been thoroughly investigated, there has been relatively little research on the WRKY family in , which is one of the most widely grown vegetables in China. In this study, we performed a genome-wide analysis to identify genes, which were subsequently classified and examined in terms of their gene structures, chromosomal locations, promoter cis-acting elements, and responses to abiotic stress.

CaIAA2-CaARF9 module mediates the trade-off between pepper growth and immunity.

To challenge the invasion of various pathogens, plants re-direct their resources from plant growth to an innate immune defence system. However, the underlying mechanism that coordinates the induction of the host immune response and the suppression of plant growth remains unclear. Here we demonstrate that an auxin response factor, CaARF9, has dual roles in enhancing the immune resistance to Ralstonia solanacearum infection and in retarding plant growth by repressing the expression of its target genes as exemplified by Casmc4, CaLBD37, CaAPK1b and CaRROP1.

Transcription factor CaHDZ15 promotes pepper basal thermotolerance by activating HEAT SHOCK FACTORA6a.

High temperature stress (HTS) is a serious threat to plant growth and development and to crop production in the context of global warming, and plant response to HTS is largely regulated at the transcriptional level by the actions of various transcription factors (TFs). However, whether and how homeodomain-leucine zipper (HD-Zip) TFs are involved in thermotolerance are unclear. Herein, we functionally characterized a pepper (Capsicum annuum) HD-Zip I TF CaHDZ15.

Temperature-dependent action of pepper mildew resistance locus O 1 in inducing pathogen immunity and thermotolerance.

Plant diseases tend to be more serious under conditions of high-temperature/high-humidity (HTHH) than under moderate conditions, and hence disease resistance under HTHH is an important determinant for plant survival. However, how plants cope with diseases under HTHH remains poorly understood. In this study, we used the pathosystem consisting of pepper (Capsicum annuum) and Ralstonia solanacearum (bacterial wilt) as a model to examine the functions of the protein mildew resistance locus O 1 (CaMLO1) and U-box domain-containing protein 21 (CaPUB21) under conditions of 80% humidity and either 28 °C or 37 °C.

Ralstonia solanacearum effector RipAK suppresses homodimerization of the host transcription factor ERF098 to enhance susceptibility and the sensitivity of pepper plants to dehydration.

Plants have evolved a sophisticated immune system to defend against invasion by pathogens. In response, pathogens deploy copious effectors to evade the immune responses. However, the molecular mechanisms used by pathogen effectors to suppress plant immunity remain unclear.

Differential CaKAN3-CaHSF8 associations underlie distinct immune and heat responses under high temperature and high humidity conditions.

High temperature and high humidity (HTHH) conditions increase plant susceptibility to a variety of diseases, including bacterial wilt in solanaceous plants. Some solanaceous plant cultivars have evolved mechanisms to activate HTHH-specific immunity to cope with bacterial wilt disease. However, the underlying mechanisms remain poorly understood.

SlWRKY30 and SlWRKY81 synergistically modulate tomato immunity to by directly regulating .

Bacterial wilt is a devastating disease of tomato () caused by that severely threatens tomato production. Group III WRKY transcription factors (TFs) are implicated in the plant response to pathogen infection; however, their roles in the response of tomato to infection (RSI) remain largely unexplored. Here, we report the crucial role of SlWRKY30, a group III SlWRKY TF, in the regulation of tomato response to RSI.

MADS-box protein AGL8 interacts with chromatin-remodelling component SWC4 to activate thermotolerance and environment-dependent immunity in pepper.

Pepper (Capsicum annuum) employs distinct defence responses against Ralstonia solanacearum infection (RSI); however, the mechanisms by which pepper activates these defence responses in a context-dependent manner is unclear. Here we study pepper plants defence response to RSI under room temperature-high humidity (RSRT, 28 °C / 90%) and high temperature-high humidity (RSHT, 37 °C / 90%) conditions, and non-infected plants under high temperature-high humidity (HTHH, 42 °C / 90%) stress. Herein, we found that the MADS-box transcription factor CaAGL8 was up-regulated by HTHH stress and RSRT or RSHT, and its silencing significantly reduced pepper thermotolerance and susceptibility to infection under both room and high temperature-high humidity (RSRT and RSHT).

PMT6 Is Required for SWC4 in Positively Modulating Pepper Thermotolerance.

High temperature stress (HTS), with growth and development impairment, is one of the most important abiotic stresses frequently encountered by plants, in particular solanacaes such as pepper, that mainly distribute in tropical and subtropical regions. Plants activate thermotolerance to cope with this stress; however, the underlying mechanism is currently not fully understood. SWC4, a shared component of SWR1- and NuA4 complexes implicated in chromatin remodeling, was previously found to be involved in the regulation of pepper thermotolerance, but the underlying mechanism remains poorly understood.

N-Methyltransferase Acts as a Positive Regulator of Immunity against Bacterial Pathogens in Pepper.

Proteins with conserved SET domain play a critical role in plant immunity. However, the means of organization and functions of these proteins are unclear, particularly in non-model plants such as pepper ( L.).

The CaPti1-CaERF3 module positively regulates resistance of Capsicum annuum to bacterial wilt disease by coupling enhanced immunity and dehydration tolerance.

Bacterial wilt, a severe disease involving vascular system blockade, is caused by Ralstonia solanacearum. Although both plant immunity and dehydration tolerance might contribute to disease resistance, whether and how they are related remains unclear. Herein, we showed that immunity against R.

CabZIP23 Integrates in CabZIP63-CaWRKY40 Cascade and Turns CabZIP63 on Mounting Pepper Immunity against via Physical Interaction.

CabZIP63 and CaWRKY40 were previously found to be shared in the pepper defense response to high temperature stress (HTS) and to inoculation (RSI), forming a transcriptional cascade. However, how they activate the two distinct defense responses is not fully understood. Herein, using a revised genetic approach, we functionally characterized CabZIP23 in the CabZIP63-CaWRKY40 cascade and its context specific pepper immunity activation against RSI by interaction with CabZIP63.

CaSWC4 regulates the immunity-thermotolerance tradeoff by recruiting CabZIP63/CaWRKY40 to target genes and activating chromatin in pepper.

Pepper (Capsicum annuum) responds differently to high temperature stress (HTS) and Ralstonia solanacearum infection (RSI) but employs some shared transcription factors (TFs), such as CabZIP63 and CaWRKY40, in both cases. How the plant activates and balances these distinct responses, however, was unclear. Here, we show that the protein CaSWC4 interacts with CaRUVBL2 and CaTAF14b and they all act positively in pepper response to RSI and thermotolerance.

RNAi-Based Gene Silencing of RXLR Effectors Protects Plants Against the Oomycete Pathogen .

is a broad-host range oomycete pathogen that can cause severe phytophthora blight disease of pepper and hundreds of other plant species worldwide. Natural resistance against is inadequate, and it is very difficult to control by most of existing chemical fungicides. Therefore, it is urgent to develop alternative strategies to control this pathogen.

A CaCDPK29-CaWRKY27b module promotes CaWRKY40-mediated thermotolerance and immunity to Ralstonia solanacearum in pepper.

CaWRKY40 in pepper (Capsicum annuum) promotes immune responses to Ralstonia solanacearum infection (RSI) and to high-temperature, high-humidity (HTHH) stress, but how it interacts with upstream signalling components remains poorly understood. Here, using approaches of reverse genetics, biochemical and molecular biology we functionally characterised the relationships among the WRKYGMK-containing WRKY protein CaWRKY27b, the calcium-dependent protein kinase CaCDPK29, and CaWRKY40 during pepper response to RSI or HTHH. Our data indicate that CaWRKY27b is upregulated and translocated from the cytoplasm to the nucleus upon phosphorylation of Ser137 in the nuclear localisation signal by CaCDPK29.

Solanaceous plants switch to cytokinin-mediated immunity against Ralstonia solanacearum under high temperature and high humidity.

Plant diseases generally tend to be more serious under conditions of high temperature and high humidity (HTHH) than under ambient temperature, but plant immunity against pathogen attacks under HTHH remains elusive. Herein, we used pepper as an example to study how Solanaceae cope with Ralstonia solanacearum infection (RSI) under HTHH by performing RNA-seq combined with the reverse genetic method. The result showed that immunities mediated by salicylic acid (SA) and jasmonic acid (JA) in pepper roots were activated by RSI under ambient temperature.

CaAIL1 Acts Positively in Pepper Immunity against Ralstonia solanacearum by Repressing Negative Regulators.

APETALA2 (AP2) subfamily transcription factors participate in plant growth and development, but their roles in plant immunity remain unclear. Here, we discovered that the AP2 transcription factor CaAIL1 functions in immunity against Ralstonia solanacearum infection (RSI) in pepper (Capsicum annuum). CaAIL1 expression was upregulated by RSI, and loss- and gain-of-function assays using virus-induced gene silencing and transient overexpression, respectively, revealed that CaAIL1 plays a positive role in immunity to RSI in pepper.

A cysteine-rich receptor-like protein kinase CaCKR5 modulates immune response against Ralstonia solanacearum infection in pepper.

Background: Cysteine-rich receptor-like kinases (CRKs) represent a large subfamily of receptor-like kinases and play vital roles in diverse physiological processes in regulating plant growth and development.

Results: CaCRK5 transcripts were induced in pepper upon the infection of Ralstonia solanacearum and treatment with salicylic acid. The fusions between CaCRK5 and green fluorescence protein were targeted to the plasma membrane.

The Pepper Mitogen-Activated Protein Kinase CaMAPK7 Acts as a Positive Regulator in Response to Infection.

Mitogen-activated protein kinase (MAPK) pathways play a vital role in multiple plant processes, including growth, development, and stress signaling, but their involvement in response to is poorly understood, particularly in pepper plants. Herein, was identified from the pepper genome and functionally analyzed. The accumulations of transcripts and promoter activities were both significantly induced in response to strain FJC100301 infection, and exogenously applied phytohormones, including methyl jasmonate (MeJA), brassinolide (BR), salicylic acid (SA), and ethephon (ETN), were decreased by abscisic acid (ABA) treatment.

Pepper NAC-type transcription factor NAC2c balances the trade-off between growth and defense responses.

Plant responses to pathogen attacks and high-temperature stress (HTS) are distinct in nature but generally share several signaling components. How plants produce specific responses through these common signaling intermediates remains elusive. With the help of reverse-genetics approaches, we describe here the mechanism underlying trade-offs in pepper (Capsicum annuum) between growth, immunity, and thermotolerance.

CaWRKY28 Cys249 is Required for Interaction with CaWRKY40 in the Regulation of Pepper Immunity to .

WRKY transcription factors have been implicated in plant response to pathogens but how WRKY-mediated networks are organized and operate to produce appropriate transcriptional outputs remains largely unclear. Here, we identify a member of the WRKY family from pepper (), CaWRKY28, that physically interacts with CaWRKY40, a positive regulator of pepper immunity and thermotolerance. We confirmed CaWRKY28-CaWRKY40 interaction by coimmunoprecipitation, bimolecular fluorescence complementation, and microscale thermophoresis.