- Bacterial endophytes from Artemisia nilagirica (Clarke) Pamp., with antibacterial efficacy against human pathogens. [Journal Article]
- MPMicrob Pathog 2019 Jul 16; :103624
- A study was conducted to isolate and characterize endophytes from Artemisia nilagirica, a traditional medicinal plant. The plant was collected from Western Ghats, India. Endophytes isolated included …
A study was conducted to isolate and characterize endophytes from Artemisia nilagirica, a traditional medicinal plant. The plant was collected from Western Ghats, India. Endophytes isolated included Arthrobacter sp. WWAT1, Pseudomonas sp. WYAT2, Microbacterium sp. WYAT3, Psychrobacter sp. WBAT4, Enterobacter sp. WWAT5, Bacillus sp. WBAT6, Kosakonia cowanii WBAT7, Bacillus sp. WBAT8, Bacillus sp. WBAT9, Chromobacterium violaceum WVAT6, Serratia sp.WPAT8 and Burkholderia sp. WYAT7. Of these two bacteria, Chromobacterium violaceum strain WVAT6 and Burkholderia sp. strain WYAT exhibited antibacterial property against human pathogens. Similar to the environmental isolates, Burkholderia sp. WYAT7 showed pleomorphism and produced different enzymes, whereas like clinical strains they showed multidrug resistance, for their survival in different environmental conditions. Chromobacterium violaceum WVAT6 exhibited rod shape morphology and showed multiple drug resistance except to erythromycin, tetracycline and gentamicin antibiotics. Both produced biofilm and enzymes such as protease and lipase. The antimicrobial compounds from these endophytes may find application in the preparation of antimicrobial formulations.
- A PAMP-triggered MAPK-cascade inhibits phosphatidylinositol 4,5-bisphosphate production by PIP5K6 in Arabidopsis thaliana. [Journal Article]
- NPNew Phytol 2019 Jul 18
- •The phosphoinositide kinase PIP5K6 has recently been identified as a target for the MAP-kinase MPK6. Phosphorylation of PIP5K6 inhibited the production of phosphatidylinositol 4,5-bisphosphate (PtdI…
•The phosphoinositide kinase PIP5K6 has recently been identified as a target for the MAP-kinase MPK6. Phosphorylation of PIP5K6 inhibited the production of phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2), impacting membrane trafficking and cell expansion in pollen tubes. Here, we analyzed whether MPK6 regulated PIP5K6 in vegetative Arabidopsis cells in response to the PAMP flg22. •Promoter-GUS analyses and qPCR-data show PIP5K6 expressed throughout Arabidopsis tissues. Upon flg22-treatment of transgenic protoplasts, PIP5K6 protein was phosphorylated, and this modification was reduced for a PIP5K6 variant lacking MPK6-targeted residues, or in protoplasts from mpk6-mutants. •Upon flg22-treatment of Arabidopsis plants, phosphoinositide levels mildly decreased and a fluorescent reporter for PtdIns(4,5)P2 displayed reduced plasma membrane association, contrasting with phosphoinositide increases reported for abiotic stress responses. Flg22-treatment and chemical induction of the upstream MAPKK, MKK5, decreased PI4P 5-kinase-activity in mesophyll protoplasts, indicating that the flg22-activated MAPK-cascade limited PtdIns(4,5)P2-production. PIP5K6 expression or PIP5K6 protein abundance changed only marginally upon flg22-treatment, consistent with posttranslational control of PIP5K6 activity. PtdIns(4,5)P2-dependent endocytosis of FM 4-64, PIN2 and the NADPH-oxidase RbohD were reduced upon flg22-treatment or MKK5-induction. Reduced RbohD-endocytosis correlated with enhanced ROS-production. •We conclude that MPK6-mediated phosphorylation of PIP5K6 limits the production of a functional PtdIns(4,5)P2 pool upon PAMP-perception. This article is protected by copyright. All rights reserved.
- Platelet Inflammatory Response to Stress. [Review]
- FIFront Immunol 2019; 10:1478
- Blood platelets play a central hemostatic role, (i) as they repair vascular epithelial damage, and (ii) they play immune defense roles, as they have the capacity to produce and secrete various cytoki…
Blood platelets play a central hemostatic role, (i) as they repair vascular epithelial damage, and (ii) they play immune defense roles, as they have the capacity to produce and secrete various cytokines, chemokines, and related products. Platelets sense and respond to local dangers (infectious or not). Platelets, therefore, mediate inflammation, express and use receptors to bind infectious pathogen moieties and endogenous ligands, among other components. Platelets contribute to effective pathogen clearance. Damage-associated molecular patterns (DAMPs) are danger signals released during inflammatory stress, such as burns, trauma and infection. Each pathogen is recognized by its specific molecular signature or pathogen-associated molecular pattern (PAMP). Recent data demonstrate that platelets have the capacity to sense external danger signals (DAMPs or PAMPs) differentially through a distinct type of pathogen recognition receptor (such as Toll-like receptors). Platelets regulate the innate immune response to pathogens and/or endogenous molecules, presenting several types of "danger" signals using a complete signalosome. Platelets, therefore, use complex tools to mediate a wide range of functions from danger sensing to tissue repair. Moreover, we noted that the secretory capacity of stored platelets over time and the development of stress lesions by platelets upon collection, processing, and storage are considered stress signals. The key message of this review is the "inflammatory response to stress" function of platelets in an infectious or non-infectious context.
- A calmodulin-gated calcium channel links pathogen patterns to plant immunity. [Journal Article]
- NatNature 2019 Jul 17
- Pathogen-associated molecular patterns (PAMPs) activate innate immunity in both animals and plants. Although calcium has long been recognized as an essential signal for PAMP-triggered immunity in pla…
Pathogen-associated molecular patterns (PAMPs) activate innate immunity in both animals and plants. Although calcium has long been recognized as an essential signal for PAMP-triggered immunity in plants, the mechanism of PAMP-induced calcium signalling remains unknown1,2. Here we report that calcium nutrient status is critical for calcium-dependent PAMP-triggered immunity in plants. When calcium supply is sufficient, two genes that encode cyclic nucleotide-gated channel (CNGC) proteins, CNGC2 and CNGC4, are essential for PAMP-induced calcium signalling in Arabidopsis3-7. In a reconstitution system, we find that the CNGC2 and CNGC4 proteins together-but neither alone-assemble into a functional calcium channel that is blocked by calmodulin in the resting state. Upon pathogen attack, the channel is phosphorylated and activated by the effector kinase BOTRYTIS-INDUCED KINASE1 (BIK1) of the pattern-recognition receptor complex, and this triggers an increase in the concentration of cytosolic calcium8-10. The CNGC-mediated calcium entry thus provides a critical link between the pattern-recognition receptor complex and calcium-dependent immunity programs in the PAMP-triggered immunity signalling pathway in plants.
- Chitin synthase is involved in vegetative growth, asexual reproduction, and pathogenesis of Phytophthora capsici and P. sojae. [Journal Article]
- EMEnviron Microbiol 2019 Jul 17
- Chitin is a structural and functional component of the fungal cell wall, and also serves as a pathogen-associated molecular pattern (PAMP) that triggers the innate immune responses of host plants. Ho…
Chitin is a structural and functional component of the fungal cell wall, and also serves as a pathogen-associated molecular pattern (PAMP) that triggers the innate immune responses of host plants. However, no or very little chitin is found in the fungus-like oomycetes. In Phytophthora spp., the presence of chitin has not been demonstrated so far, although putative chitin synthase (CHS) genes, which encode the enzymes that synthesize chitin, are present in their genomes. Here, we revealed that chitin is present in the zoospores and released sporangia of Phytophthora, and this is most consistent with the transcriptional pattern of PcCHS in P. capsici and PsCHS1 in P. sojae. Disruption of the CHS genes indicated that PcCHS and PsCHS1, but not PsCHS2 (which exhibited very weak transcription), have similar functions involved in mycelial growth, sporangial production, zoospore release, and the pathogenesis of P. capsici and P. sojae. We also suggest that chitin in the zoospores of P. capsici can act as a PAMP that is recognized by the chitin receptors AtLYK5 or AtCERK1 of Arabidopsis. These results provide new insights into the biological significance of chitin and CHSs in Phytophthora and help with the identification of potential targets for disease control. This article is protected by copyright. All rights reserved.
- Overexpression a "fruit-weight 2.2-like" gene OsFWL5 improves rice resistance. [Journal Article]
- RRice (N Y) 2019 Jul 16; 12(1):51
- CONCLUSIONS: Putting our finds and previous work together, OsFWL5 could be a candiate gene for breeders to genetically improve rice resistance and grain quality.
- Ameliorative effects of ginseng and ginsenosides on rheumatic diseases. [Review]
- JGJ Ginseng Res 2019; 43(3):335-341
- CONCLUSIONS: Ginseng and ginsenosides play an ameliorative role on rheumatic diseases, and this review provides new insights into ginseng and ginsenosides as promising agents to prevent and treat rheumatic diseases.
- The OsMPK15 Negatively Regulates Magnaporthe oryza and Xoo Disease Resistance via SA and JA Signaling Pathway in Rice. [Journal Article]
- FPFront Plant Sci 2019; 10:752
- Mitogen-activated protein kinase (MAPK) cascades play central roles in response to biotic and abiotic stresses. However, the mechanisms by which various MAPK members regulate the plant immune respons…
Mitogen-activated protein kinase (MAPK) cascades play central roles in response to biotic and abiotic stresses. However, the mechanisms by which various MAPK members regulate the plant immune response in rice remain elusive. In this article, to characterize the mechanisms, the knock-out and overexpression mutants of OsMPK15 were constructed and the disease resistance was investigated under the various fungal and bacterial inoculations. The knock-out mutant of OsMPK15 resulted in the constitutive expression of pathogenesis-related (PR) genes, increased accumulation of reactive oxygen species (ROS) triggered by the pathogen-associated molecular pattern (PAMP) elicitor chitin, and significantly enhanced the disease resistance to different races of Magnaporthe oryzae and Xanthomonas oryzae pv. oryzae (Xoo), which cause the rice blast and bacterial blight diseases, respectively. On contrary, the expression of PR genes and ROS were down-regulated in the OsMPK15-overexpressing (OsMPK15-OE) lines. Meanwhile, phytohormones such as salicylic acid (SA) and jasmonic acid (JA) were accumulated in the mpk15 mutant lines but decreased in the OsMPK15-OE lines. The expression of SA- and JA-pathway associated genes were significantly upregulated in the mpk15 mutant, whereas it was down regulated in the OsMPK15-OE lines. We conclude that OsMPK15 may negatively regulate the disease resistance through modulating SA- and JA-mediated signaling pathway.
- Molecular regulation of pepper innate immunity and stress tolerance: An overview of WRKY TFs. [Review]
- MPMicrob Pathog 2019 Jul 06; :103610
- The WRKY transcription factors (TFs) family constitutes a major group of TFs in spermatophytes. Different studies have endorsed the considerable biological roles performed by WRKY TFs in plant growth…
The WRKY transcription factors (TFs) family constitutes a major group of TFs in spermatophytes. Different studies have endorsed the considerable biological roles performed by WRKY TFs in plant growth, biotic and abiotic stress responses. Genomic and transcriptomic profiling facilitate us in understanding the WRKY genes in various plants and reveal how WRKY TFs perform their action in response to different plant stresses. WRKY TFs actively take part in metabolism including carbohydrate synthesis, senescence, and secondary metabolites production. Molecular organization of WRKY TFs in plants highlight most predicted outcome of multiple responses simultaneously. Repression and activation related to W-box and other such elements is controlled at transcriptional, translational and domain level. WRKY TFs are becoming more important in crop improvement because of their binding with downstream elements. Additionally, WRKY proteins intermingle with various other TFs for modulating plant immunity. However, WRKY TFs self-regulation and crosstalk between different signaling pathways using WRKY TFs still need extensive investigations. In this review, we focused characteristics of WRKY TFs in Capsicum annum and related research advancement on their functional involvement in plant responses to the challenges of high temperature stress and pathogens infection. We summarized information about Capsicum annum WRKY TFs on the basis of their functions, their target genes and signaling pathways. Moreover, the mechanisms for synergistic responses to various biotic and abiotic stresses, WRKY target genes and other TFs as well will be of more interest with increments in existing information.
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- Nucleic acid sensing activates the innate cytosolic surveillance pathway and promotes parasite survival in visceral leishmaniasis. [Journal Article]
- SRSci Rep 2019 Jul 08; 9(1):9825
- Microbial pattern recognition critically contributes to innate response, both at extracellular and intracellular cytosolic surveillance pathway (CSP) interface. However, the role of pattern recogniti…
Microbial pattern recognition critically contributes to innate response, both at extracellular and intracellular cytosolic surveillance pathway (CSP) interface. However, the role of pattern recognition by host innate receptors in CSP is poorly understood in Leishmania donovani infection. Here, we have demonstrated that cytosolic targeting of L.donovani DNA (Ld-DNA) inhibits macrophage responsiveness to IFNɣ, through decreased MHC-II expression and lowered pSTAT1 (Y701) levels, involving host three-prime repair exonuclease-1 (TREX-1). The Ld-DNA potently induced type-1 IFNs, i.e. significant over-production of IFNβ through activation of the IRF pathway. Interestingly, knockdown of TRIF or MyD88 expression in macrophages had no effect on cytosolic Ld-DNA transfection-mediated IFN-β production, indicating involvement of a TLR independent pathway. Contrastingly, Ld-DNA failed to induce IFNβ in both TBK-1 and IRF3KO knockout macrophages. Although IFNβ was not induced by Ld-DNA in STING- knockout macrophages, STING alone was not enough for the induction. Evidently, besides STING, Ld-DNA recognition for induction of IFNβ critically required cytosolic cyclic GMP-AMP synthase (cGAS). Furthermore, the cGAS dependent targeting of Ld-DNA induced IFNβ over-production that contributed to antimony resistance in L.donovani infection. We provide the first evidence that enhanced cytosolic sensing of Ld-DNA in infection by antimony resistant (SBR-LD), but not antimony sensitive L.donovani strains (SBS-LD), was critically regulated by host MDRs, multi drug resistant associated protein 1 (MRP 1) and permeability glycoprotein (P-gp) in macrophages. Collectively, our results disclose Ld-DNA as a vital pathogen associated molecular pattern (PAMP) driving host Type-I IFN responses and antimony resistance. The findings may help in future development of policies for novel anti-leishmanial therapeutics.