scholarly journals Pathogens and Elicitors Induce Local and Systemic Changes in Triacylglycerol Metabolism in Roots and in Leaves of Arabidopsis thaliana

Biology ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 920
Author(s):  
Sebastian Schieferle ◽  
Beeke Tappe ◽  
Pamela Korte ◽  
Martin J. Mueller ◽  
Susanne Berger
Keyword(s):  
Arabidopsis Thaliana ◽  
Abiotic Stress ◽  
Lipid Metabolism ◽  
Pseudomonas Syringae ◽  
Bacterial Pathogen ◽  
Biotic Stresses ◽  
Triacylglycerol Metabolism ◽  
Triacylglycerol Accumulation ◽  
Insight Into ◽  
Tof Ms

Interaction of plants with the environment affects lipid metabolism. Changes in the pattern of phospholipids have been reported in response to abiotic stress, particularly accumulation of triacylglycerols, but less is known about the alteration of lipid metabolism in response to biotic stress and leaves have been more intensively studied than roots. This work investigates the levels of lipids in roots as well as leaves of Arabidopsis thaliana in response to pathogens and elicitor molecules by UPLC-TOF-MS. Triacylglycerol levels increased in roots and systemically in leaves upon treatment of roots with the fungus Verticillium longisporum. Upon spray infection of leaves with the bacterial pathogen Pseudomonas syringae, triacylglycerols accumulated locally in leaves but not in roots. Treatment of roots with a bacterial lipopolysaccharide elicitor induced a strong triacylglycerol accumulation in roots and leaves. Induction of the expression of the bacterial effector AVRRPM1 resulted in a dramatic increase of triacylglycerol levels in leaves, indicating that elicitor molecules are sufficient to induce accumulation of triacylglycerols. These results give insight into local and systemic changes to lipid metabolism in roots and leaves in response to biotic stresses.

scholarly journals Cysteine protease RD21A regulated by E3 ligase SINAT4 is required for drought-induced resistance to Pseudomonas syringae in Arabidopsis

2020 ◽  
Vol 71 (18) ◽  
pp. 5562-5576
Author(s):  
Yi Liu ◽  
Kunru Wang ◽  
Qiang Cheng ◽  
Danyu Kong ◽  
Xunzhong Zhang ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Cysteine Protease ◽  
Plant Immunity ◽  
Stomatal Closure ◽  
Bacterial Pathogen ◽  
E3 Ligase ◽  
Biotic Stresses ◽  
Ubiquitin E3 Ligase ◽  
Induced Immunity

Abstract Plants can be simultaneously exposed to multiple stresses. The interplay of abiotic and biotic stresses may result in synergistic or antagonistic effects on plant development and health. Temporary drought stress can stimulate plant immunity; however, the molecular mechanism of drought-induced immunity is largely unknown. In this study, we demonstrate that cysteine protease RD21A is required for drought-induced immunity. Temporarily drought-treated wild-type Arabidopsis plants became more sensitive to the bacterial pathogen-associated molecular pattern flg22, triggering stomatal closure, which resulted in increased resistance to Pseudomonas syringae pv. tomato DC3000 (Pst-DC3000). Knocking out rd21a inhibited flg22-triggered stomatal closure and compromised the drought-induced immunity. Ubiquitin E3 ligase SINAT4 interacted with RD21A and promoted its degradation in vivo. The overexpression of SINAT4 also consistently compromised the drought-induced immunity to Pst-DC3000. A bacterial type III effector, AvrRxo1, interacted with both SINAT4 and RD21A, enhancing SINAT4 activity and promoting the degradation of RD21A in vivo. Therefore, RD21A could be a positive regulator of drought-induced immunity, which could be targeted by pathogen virulence effectors during pathogenesis.

scholarly journals Analysis of Resistance Gene-Mediated Defense Responses in Arabidopsis thaliana Plants Carrying a Mutation in CPR5

1998 ◽  
Vol 11 (12) ◽  
pp. 1196-1206 ◽  
Author(s):  
Jens Boch ◽  
Michelle L. Verbsky ◽  
Tara L. Robertson ◽  
John C. Larkin ◽  
Barbara N. Kunkel
Keyword(s):  
Gene Expression ◽  
Arabidopsis Thaliana ◽  
Resistance Gene ◽  
Pseudomonas Syringae ◽  
Bacterial Pathogen ◽  
Defense Responses ◽  
Negative Regulator ◽  
Suppressor Mutations ◽  
Defense Related Gene ◽  
Rapid Activation

In resistant plants, pathogen attack often leads to rapid activation of defense responses that limit multiplication and spread of the pathogen. To investigate the signaling mechanisms underlying this process, we carried out a screen for mutants in the signaling pathway governing resistance in Arabidopsis thaliana to the bacterial pathogen Pseudomonas syringae. This involved screening for suppressor mutations that restored resistance to a susceptible line carrying a mutation in the RPS2 resistance gene. A mutant that conferred resistance by activating defense responses in the absence of pathogens was isolated. This mutant, which carries a mutation at the CPR5 locus and was thus designated cpr5-2, exhibited resistance to P. syringae, spontaneous development of necrotic lesions, elevated PR gene expression in the absence of pathogens, and abnormal trichomes. Resistance gene-mediated defenses, including the hypersensitive response, restriction of pathogen growth, and induction of defense-related gene expression, were functional in cpr5-2 mutant plants. Additionally, in cpr5-2 plants RPS2-mediated induction of PR-1 expression was enhanced, whereas RPM1-mediated induction of ELI3 was not. These findings suggest that CPR5 encodes a negative regulator of the RPS2 signal transduc-tion pathway.

scholarly journals Contrasting functions of Arabidopsis SUMO1/2 isoforms with SUMO3 intersect to modulate innate immunity and global SUMOylome responses

2020 ◽  
Author(s):  
Kishor Dnyaneshwar Ingole ◽  
Mritunjay Kasera ◽  
Harrold A. van den Burg ◽  
Saikat Bhattacharjee
Keyword(s):  
Arabidopsis Thaliana ◽  
Steady State ◽  
Heat Shock ◽  
Pseudomonas Syringae ◽  
Bacterial Pathogen ◽  
Defense Responses ◽  
Vital Role ◽  
Covalent Attachment ◽  
Developmental Defects ◽  
Small Proteins

AbstractReversible covalent attachment of SMALL UBIQUITIN-LIKE MODIFIERS (SUMOs) on target proteins regulate diverse cellular process across all eukaryotes. In Arabidopsis thaliana, most mutants with perturbed global SUMOylome display severe impairments in growth and adaptations to physiological stresses. Since SUMOs self-regulate activities of SUMOylation-associated proteins, existence of multiple isoforms introduces possibilities of their functional intersections which remain unexplored especially in plant systems. Using well-established defense responses elicited against virulent and avirulent Pseudomonas syringae pv. tomato strains, we investigated crosstalks in individual and combinatorial Arabidopsis sum mutants. Here we report that while SUM1 and SUM2 additively, but not equivalently suppress basal and TNL-specific immunity via down-regulation of salicylic acid (SA)-dependent responses, SUM3 promotes these defenses genetically downstream of SA. Remarkably, the expression of SUM3 is transcriptionally suppressed by SUMO1 or SUMO2. The loss of SUM3 not only lowers basal or post-bacterial challenge responsive enhancements of SUMO1/2-congugates but also reduces upregulation dynamics of defensive proteins and SUMOylation-associated transcripts. Combining a sum3 mutation partially attenuates heightened immunity of sum1 or sum2 mutants suggesting intricate functional impingements among these isoforms in optimizing immune amplitudes. Similar SUM1-SUM3 intersections also affect global SUMOylome responses to heat-shock affecting most notably the induction of selective heat-shock transcription factors. Overall, our investigations reveal novel insights into auto-regulatory mechanisms among SUMO isoforms in host SUMOylome maintenance and adjustments to environmental challenges.Author SummaryIn plants, similar to animals, protein functions are regulated at multiple levels. One prevalent mode is to allow covalent linkage of small proteins to specific amino acids on targets thereby affecting its fate and function. One such kind of modification named as SUMOylation involves attachment of SUMO proteins. A plant maintains strict control over its pool of SUMOylated proteins (termed SUMOylome) which upon biotic or abiotic stresses are altered to facilitate appropriate responses, returning back to steady-state when the threat subsides. In mutants of the model plant Arabidopsis thaliana having disturbed steady-state SUMOylome, growth and developmental defects ensue. These mutants are auto-immune showing more resistance to infection by the bacterial pathogen Pseudomonas syringae. However, Arabidopsis SUMO-family are comprised of multiple members raising the question about their specificity or functional crosstalks. We discovered that two SUMO members function in coordination to suppress immunity including the repression of a third member which supports defenses. The expression of this third member during pathogen attack or heat-shock influences the responsive changes in the host SUMOylome likely suggesting SUMOs themselves play vital role in these adaptations. Overall, our work highlights novel intersections of SUMO members in mounting stress-specific responses.

scholarly journals Pseudomonas syringae Catalases Are Collectively Required for Plant Pathogenesis

2012 ◽  
Vol 194 (18) ◽  
pp. 5054-5064 ◽  
Author(s):  
Ming Guo ◽  
Anna Block ◽  
Crystal D. Bryan ◽  
Donald F. Becker ◽  
James R. Alfano
Keyword(s):  
Hydrogen Peroxide ◽  
Arabidopsis Thaliana ◽  
Pseudomonas Syringae ◽  
Bacterial Pathogen ◽  
In Planta ◽  
Tomato Dc3000 ◽  
Triple Mutant ◽  
Content Type ◽  
Catalase Peroxidase ◽  
Plant Pathogenesis

ABSTRACTThe bacterial pathogenPseudomonas syringaepv. tomato DC3000 must detoxify plant-produced hydrogen peroxide (H2O2) in order to survive in its host plant. Candidate enzymes for this detoxification include the monofunctional catalases KatB and KatE and the bifunctional catalase-peroxidase KatG of DC3000. This study shows that KatG is the major housekeeping catalase of DC3000 and provides protection against menadione-generated endogenous H2O2. In contrast, KatB rapidly and substantially accumulates in response to exogenous H2O2. Furthermore, KatB and KatG have nonredundant roles in detoxifying exogenous H2O2and are required for full virulence of DC3000 inArabidopsis thaliana. Therefore, the nonredundant ability of KatB and KatG to detoxify plant-produced H2O2is essential for the bacteria to survive in plants. Indeed, a DC3000 catalase triple mutant is severely compromised in its ability to growin planta, and its growth can be partially rescued by the expression ofkatB,katE, orkatG. Interestingly, our data demonstrate that although KatB and KatG are the major catalases involved in the virulence of DC3000, KatE can also provide some protectionin planta. Thus, our results indicate that these catalases are virulence factors for DC3000 and are collectively required for pathogenesis.

Abscisic acid influences the susceptibility of Arabidopsis thaliana to Pseudomonas syringae pv. tomato and Peronospora parasitica

2003 ◽  
Vol 30 (4) ◽  
pp. 461 ◽  
Author(s):  
Peter G. Mohr ◽  
David M. Cahill
Keyword(s):  
Arabidopsis Thaliana ◽  
Abscisic Acid ◽  
Pseudomonas Syringae ◽  
Bacterial Pathogen ◽  
Peronospora Parasitica ◽  
Aba Signal Transduction ◽  
Pathogen Challenge ◽  
Aba Insensitive ◽  
Avirulent Isolate ◽  
Increased Susceptibility

The phytohormone abscisic acid (ABA) plays a major role in the regulation of many physiological stresses although its role in pathogen-induced stress remains poorly understood. We examined the influence of ABA on interactions of Arabidopsis thaliana (L.) Heynh. (Arabidopsis) with a bacterial pathogen, Pseudomonas syringae pv. tomato and an Oomycete, Peronospora parasitica. Both addition of 100 μM ABA to plants and drought stress stimulated increased susceptibility of Arabidopsis to an avirulent isolate of P. syringae pv. tomato. In contrast, an ABA-deficient mutant of Arabidopsis, aba1-1, displayed reduced susceptibility to virulent isolates of P. parasitica. An ABA-insensitive mutant, abi1-1, that is impaired in ABA signal transduction did not alter in susceptibility to either P. syringae pv. tomato or P. parasitica. These results demonstrate that the concentration of endogenous ABA at the time of pathogen challenge is important for the development of susceptibility in Arabidopsis.

scholarly journals AtERF11 is a positive regulator for disease resistance against a bacterial pathogen, Pseudomonas syringae, in Arabidopsis thaliana

2007 ◽  
Vol 17 (2) ◽  
pp. 235-240
Author(s):  
Tack-Min Kwon ◽  
Yun-Hui Jung ◽  
Soon-Jae Jeong ◽  
Young-Byung Yi ◽  
Jae-Sung Nam
Keyword(s):  
Arabidopsis Thaliana ◽  
Disease Resistance ◽  
Pseudomonas Syringae ◽  
Bacterial Pathogen ◽  
Positive Regulator

scholarly journals Salicylic acid biosynthesis is enhanced and contributes to increased biotrophic pathogen resistance in Arabidopsis hybrids

2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Li Yang ◽  
Bosheng Li ◽  
Xiao-yu Zheng ◽  
Jigang Li ◽  
Mei Yang ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Salicylic Acid ◽  
Pseudomonas Syringae ◽  
Histone H3 ◽  
Bacterial Pathogen ◽  
Pathogen Resistance ◽  
Biosynthesis Pathway ◽  
Acid Biosynthesis ◽  
Histone H3 Acetylation ◽  
H3 Acetylation

Abstract Heterosis, the phenotypic superiority of a hybrid over its parents, has been demonstrated for many traits in Arabidopsis thaliana, but its effect on defence remains largely unexplored. Here, we show that hybrids between some A. thaliana accessions show increased resistance to the biotrophic bacterial pathogen Pseudomonas syringae pv. tomato (Pst) DC3000. Comparisons of transcriptomes between these hybrids and their parents after inoculation reveal that several key salicylic acid (SA) biosynthesis genes are significantly upregulated in hybrids. Moreover, SA levels are higher in hybrids than in either parent. Increased resistance to Pst DC3000 is significantly compromised in hybrids of pad4 mutants in which the SA biosynthesis pathway is blocked. Finally, increased histone H3 acetylation of key SA biosynthesis genes correlates with their upregulation in infected hybrids. Our data demonstrate that enhanced activation of SA biosynthesis in A. thaliana hybrids may contribute to their increased resistance to a biotrophic bacterial pathogen.

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