Arabidopsis Clade I TGA Factors Regulate Apoplastic Defences against the Bacterial Pathogen Pseudomonas syringae through Endoplasmic Reticulum-Based Processes

AbstractUnderstanding how gene expression is regulated in plant pathogens is crucial for pest control and thus global food security. An integrated understanding of bacterial gene regulation in the host is dependent on multi-omic datasets, but these are largely lacking. Here, we simultaneously characterized the transcriptome and proteome of a foliar bacterial pathogen, Pseudomonas syringae, in Arabidopsis thaliana and identified a number of bacterial processes influenced by plant immunity at the mRNA and the protein level. We found instances of both concordant and discordant regulation of bacterial mRNAs and proteins. Notably, the tip component of bacterial type III secretion system was selectively suppressed by the plant salicylic acid pathway at the protein level, suggesting protein-level targeting of the bacterial virulence system by plant immunity. Furthermore, gene co-expression analysis illuminated previously unknown gene regulatory modules underlying bacterial virulence and their regulatory hierarchy. Collectively, the integrated in planta bacterial omics approach provides molecular insights into multiple layers of bacterial gene regulation that contribute to bacterial growth in planta and elucidate the role of plant immunity in controlling pathogens.

Download Full-text

Degeneration of hrpZ gene in Pseudomonas syringae pv. tabaci to evade tobacco defence: an arms race between tobacco and its bacterial pathogen

Molecular Plant Pathology ◽

10.1111/j.1364-3703.2011.00705.x ◽

2011 ◽

Vol 12 (7) ◽

pp. 709-714 ◽

Cited By ~ 9

Author(s):

KAZUHIKO TSUNEMI ◽

FUMIKO TAGUCHI ◽

MIZURI MARUTANI ◽

MEGUMI WATANABE-SUGIMOTO ◽

YOSHISHIGE INAGAKI ◽

...

Keyword(s):

Pseudomonas Syringae ◽

Bacterial Pathogen ◽

Arms Race

Download Full-text

A 2′-O-Methyltransferase Responsible for Transfer RNA Anticodon Modification Is Pivotal for Resistance to Pseudomonas syringae DC3000 in Arabidopsis

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-06-18-0148-r ◽

2018 ◽

Vol 31 (12) ◽

pp. 1323-1336 ◽

Cited By ~ 2

Author(s):

Vicente Ramírez ◽

Beatriz González ◽

Ana López ◽

Maria Jose Castelló ◽

Maria José Gil ◽

...

Keyword(s):

Disease Resistance ◽

Pseudomonas Syringae ◽

Bacterial Pathogen ◽

Transfer Rna ◽

Resistance Response ◽

Chemical Structures ◽

Trna Modifications ◽

Trna Species ◽

Living Organisms ◽

And Function

Transfer RNA (tRNA) is the most highly modified class of RNA species in all living organisms. Recent discoveries have revealed unprecedented complexity in the tRNA chemical structures, modification patterns, regulation, and function, suggesting that each modified nucleoside in tRNA may have its own specific function. However, in plants, our knowledge of the role of individual tRNA modifications and how they are regulated is very limited. In a genetic screen designed to identify factors regulating disease resistance in Arabidopsis, we identified SUPPRESSOR OF CSB3 9 (SCS9). Our results reveal SCS9 encodes a tRNA methyltransferase that mediates the 2′-O-ribose methylation of selected tRNA species in the anticodon loop. These SCS9-mediated tRNA modifications enhance susceptibility during infection with the virulent bacterial pathogen Pseudomonas syringae DC3000. Lack of such tRNA modification, as observed in scs9 mutants, specifically dampens plant resistance against DC3000 without compromising the activation of the salicylic acid signaling pathway or the resistance to other biotrophic pathogens. Our results support a model that gives importance to the control of certain tRNA modifications for mounting an effective disease resistance in Arabidopsis toward DC3000 and, therefore, expands the repertoire of molecular components essential for an efficient disease resistance response.

Download Full-text

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

Journal of Experimental Botany ◽

10.1093/jxb/eraa255 ◽

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.

Download Full-text

James Robert Alfano, A Giant in Phytopathogenic Bacteria Effector Biology

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-12-19-0354-cr ◽

2020 ◽

Vol 33 (3) ◽

pp. 377-381

Author(s):

Alan Collmer

Keyword(s):

Pseudomonas Syringae ◽

Historical Context ◽

Bacterial Pathogen ◽

Research Community ◽

Phytopathogenic Bacteria ◽

The World ◽

Microbe Interactions ◽

The Many ◽

Plant Pathogenesis

The worldwide molecular plant-microbe interactions research community was significantly diminished in November 2019 by the death of James “Jim” Robert Alfano at age 56. Jim was a giant in our field, who gained key insights into plant pathogenesis using the model bacterial pathogen Pseudomonas syringae. As a mentor, collaborator, and, above all, a friend, I know Jim’s many dimensions and accomplishments and, sadly, the depth of loss being felt by the many people around the world who were touched by him. In tracing the path of Jim’s career, I will emphasize the historical context and impact of his advances and, finally, the essence of the person we will so miss.

Download Full-text

Antimicrobial and genetic strategies to defend kiwifruit against the bacterial pathogen Pseudomonas syringae pathovar actinidiae (Psa)

10.26686/wgtn.17148032.v1 ◽

2021 ◽

Author(s):

◽

Mathew Ambrose Storey

Keyword(s):

New Zealand ◽

Pseudomonas Syringae ◽

Best Practice ◽

Gene Knockout ◽

Virulent Strain ◽

Antimicrobial Properties ◽

Bacterial Pathogen ◽

Resistant Mutant ◽

Potential Biocontrol Agent ◽

Near Future

<p>A highly virulent strain of the bacterium Pseudomonas syringae pv. actinidiae (Psa-V), the causative agent of bacterial canker of kiwifruit, is threatening the $1.5 billion New Zealand kiwifruit industry. A strain of Psa-V was first identified in Italy in 2008 and related strain with a similar level of virulence arrived in New Zealand in November 2010. Since then it has been spreading rapidly throughout the country with devastating effects. Currently there is no effective treatment for growers to control Psa-V in their orchards and the potential impact of Psa-V on the New Zealand kiwifruit industry and growers is catastrophic. As part of a collaboration between Seeka Kiwifruit Industries, EastPack NZ, and a group of scientists nationwide (Taskforce Green) this work designed and implemented laboratory tests to quantify the effect of candidate antimicrobial sprays. Novel formulations with strong antimicrobial properties, including silver nanoparticles were also tested. This work was complemented by an investigation into the antibiotic resistance potential of Psa-V. A spontaneous streptomycin resistant mutant of Psa-V was generated and the molecular mechanism of resistance was elucidated. Further, gene knockout strategies aimed at facilitating the study of Psa-V virulence genes and ultimately developing a potential biocontrol agent were tested. Overall, this work together with several recent advances in the field should help advise the kiwifruit industry on best practice around the use of anti-Psa-V agents, and may make it possible to facilitate the generation and testing of candidate biocontrol agents in the near future.</p>

Download Full-text

Molecular characterization of differences between the tomato immune receptors Fls3 and Fls2

10.1101/2020.02.04.934133 ◽

2020 ◽

Author(s):

Robyn Roberts ◽

Alexander E. Liu ◽

Lingwei Wan ◽

Annie M. Geiger ◽

Sarah R. Hind ◽

...

Keyword(s):

Pseudomonas Syringae ◽

Molecular Mechanisms ◽

Bacterial Pathogen ◽

Transcript Abundance ◽

Defense Responses ◽

Structural Features ◽

Host Responses ◽

Pathogen Invasion

AbstractPlants mount defense responses by recognizing indications of pathogen invasion, including microbe-associated molecular patterns (MAMPs). Flagellin from the bacterial pathogen Pseudomonas syringae pv. tomato (Pst) contains two MAMPs, flg22 and flgII-28, that are recognized by tomato receptors Flagellin sensing 2 (Fls2) and Flagellin sensing 3 (Fls3), respectively. It is unknown to what degree each receptor contributes to immunity and if they promote immune responses using the same molecular mechanisms. Characterization of CRISPR/Cas9-generated Fls2 and Fls3 tomato mutants revealed that the two receptors contribute equally to disease resistance both on the leaf surface and in the apoplast. However, striking differences were observed in certain host responses mediated by the two receptors. Compared to Fls2, Fls3 mediated a more sustained production of reactive oxygen species (ROS) and an increase in transcript abundance of 44 tomato genes, with two genes serving as reporters for Fls3. Fls3 had greater in vitro kinase activity and interacted differently with the Pst effector AvrPtoB as compared to Fls2. Using chimeric Fls2/Fls3 proteins, we found that no receptor domain was solely responsible for the Fls3 sustained ROS, suggesting involvement of multiple structural features. This work reveals differences in the immunity outputs between Fls2 and Fls3, suggesting they use distinct molecular mechanisms to activate pattern-triggered immunity in response to flagellin-derived MAMPs.

Download Full-text

The spent culture supernatant ofPseudomonas syringaecontains azelaic acid

10.1101/213637 ◽

2017 ◽

Author(s):

Sree Gowrinadh Javvadi ◽

Paola Cescutti ◽

Roberto Rizzo ◽

Valentina Lonzarich ◽

Luciano Navarini ◽

...

Keyword(s):

Fatty Acid ◽

Dicarboxylic Acid ◽

Pseudomonas Syringae ◽

Azelaic Acid ◽

Culture Supernatant ◽

Fatty Acid Biosynthesis ◽

Bacterial Pathogen ◽

Structural Studies ◽

Metabolome Analysis ◽

Acid Biosynthesis

AbstractPseudomonas syringaepv.actinidiae(PSA) is an emerging kiwifruit bacterial pathogen which since 2008 has caused considerable losses. No quorum sensing (QS) signaling molecule has yet been reported from PSA and the aim of this study was to identify possible intercellular signals produced by PSA. A metabolome analysis resulted in the identification of 83 putative compounds, one of them was the nine carbon saturated dicarboxylic acid azelaic acid which for several reasons was decided to further study. Firstly azelaic acid, which is a straight chained nine-carbon (C9) saturated dicarboxylic acid, has been reported in plants as mobile signal that primes systemic defenses. Secondly its structure, which is associated with fatty acid biosynthesis, is similar to other known bacterial QS signals like the Diffusible Signal Facor (DSF). Analytical and structural studies by NMR spectroscopy confirmed that in the PSA spent supernatant azelaic acid was present. Quantification studies further revealed that 20 µg/L of azelaic acid was present and was also found in spent supernatants of several otherP. syringaepathovars. An RNAseq transcriptome study however did not reveal whether azelaic acid behaved as a QS molecule. This is the first report of the possible natural biosynthesis of azelaic acid by bacteria.

Download Full-text

Isolation of New Arabidopsis Mutants With Enhanced Disease Susceptibility to Pseudomonas syringae by Direct Screening

Genetics ◽

10.1093/genetics/149.2.537 ◽

1998 ◽

Vol 149 (2) ◽

pp. 537-548

Author(s):

Sigrid M Volko ◽

Thomas Boller ◽

Frederick M Ausubel

Keyword(s):

Pseudomonas Syringae ◽

Fungal Pathogen ◽

Systemic Acquired Resistance ◽

Disease Susceptibility ◽

Acquired Resistance ◽

Bacterial Pathogen ◽

Avirulent Strain ◽

Resistance Response ◽

Arabidopsis Mutants ◽

Pathogen Response

Abstract To identify plant defense components that are important in restricting the growth of virulent pathogens, we screened for Arabidopsis mutants in the accession Columbia (carrying the transgene BGL2-GUS) that display enhanced disease susceptibility to the virulent bacterial pathogen Pseudomonas syringae pv. maculicola (Psm) ES4326. Among six (out of a total of 11 isolated) enhanced disease susceptibility (eds) mutants that were studied in detail, we identified one allele of the previously described npr1/nim1/sai1 mutation, which is affected in mounting a systemic acquired resistance response, one allele of the previously identified EDS5 gene, and four EDS genes that have not been previously described. The six eds mutants studied in detail (npr1-4, eds5-2, eds10-1, eds11-1, eds12-1, and eds13-1) displayed different patterns of enhanced susceptibility to a variety of phytopathogenic bacteria and to the obligate biotrophic fungal pathogen Erysiphe orontii, suggesting that particular EDS genes have pathogen-specific roles in conferring resistance. All six eds mutants retained the ability to mount a hypersensitive response and to restrict the growth of the avirulent strain Psm ES4326/avrRpt2. With the exception of npr1-4, the mutants were able to initiate a systemic acquired resistance (SAR) response, although enhanced growth of Psm ES4326 was still detectable in leaves of SAR-induced plants. The data presented here indicate that eds genes define a variety of components involved in limiting pathogen growth, that many additional EDS genes remain to be discovered, and that direct screens for mutants with altered susceptibility to pathogens are helpful in the dissection of complex pathogen response pathways in plants.

Download Full-text