scholarly journals An oomycete effector impairs autophagy in evolutionary distant organisms and favors host infection

2019 ◽  
Author(s):  
Serena Testi ◽  
Marie-Line Kuhn ◽  
Valérie Allasia ◽  
Pascaline Auroy ◽  
Fantao Kong ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Alternative Model ◽  
Single Copy ◽  
Effector Proteins ◽  
Autophagic Flux ◽  
Hypersensitive Cell Death ◽  
Host Infection ◽  
Hyaloperonospora Arabidopsidis ◽  
Green Lineage ◽  
Obligate Biotroph

AbstractAn arsenal of effector proteins from plant pathogenic Phytophthora species manipulates their host from inside the cells. Phytophthora parasitica produces the effector AVH195 during an initial, biotrophic phase of infection. The protein transiently impairs plant immune-associated hypersensitive cell death in Nicotiana. ATG8 Interaction Motifs in the protein indicate that the effector targets the autophagic core machinery. We selected a photosynthetic microalga with a single copy ATG8 gene as an alternative model to dissect AVH195-induced autophagic perturbation. AVH195 slows down autophagic flux in Chlamydomonas reinhardtii thus promoting the accumulation of cargo-rich vesicles. In yeast, membrane-associated AVH195 interacts with ATG8 from Chlamydomonas and with different ATG8 isoforms from Arabidopsis thaliana. The overexpression of Avh195 in Arabidopsis promotes growth of both infecting P. parasitica and Hyaloperonospora arabidopsidis, an obligate biotroph. To our knowledge, this report provides first evidence that an oomycete effector non-selectively targets ATG8 in different organisms from the green lineage to slow down autophagic flux for infection.

Identification of a single-copy gene encoding a Type I chlorophyll a/b-binding polypeptide of photosystem I in Arabidopsis thaliana

1992 ◽  
Vol 84 (4) ◽  
pp. 561-567 ◽  
Author(s):  
Poul E. Jensen ◽  
Michael Kristensen ◽  
Tine Hoff ◽  
Jan Lehmbeck ◽  
Bjarne M. Stummann ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Chlorophyll A ◽  
Photosystem I ◽  
Single Copy ◽  
Type I ◽  
Single Copy Gene ◽  
Gene Encoding ◽  
Copy Gene

scholarly journals Blistering1 Modulates Penicillium expansum Virulence Via Vesicle-mediated Protein Secretion

2019 ◽  
Vol 19 (2) ◽  
pp. 344-361 ◽  
Author(s):  
Wayne M. Jurick ◽  
Hui Peng ◽  
Hunter S. Beard ◽  
Wesley M. Garrett ◽  
Franz J. Lichtner ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Protein Secretion ◽  
Cross Sections ◽  
Fungal Growth ◽  
Single Copy ◽  
Protein Processing ◽  
Culture Broth ◽  
Penicillium Expansum ◽  
Mold Fungus ◽  
Host Infection

The blue mold fungus, Penicillium expansum, is a postharvest apple pathogen that contributes to food waste by rotting fruit and by producing harmful mycotoxins (e.g. patulin). To identify genes controlling pathogen virulence, a random T-DNA insertional library was created from wild-type P. expansum strain R19. One transformant, T625, had reduced virulence in apples, blistered mycelial hyphae, and a T-DNA insertion that abolished transcription of the single copy locus in which it was inserted. The gene, Blistering1, encodes a protein with a DnaJ domain, but otherwise has little homology outside the Aspergillaceae, a family of fungi known for producing antibiotics, mycotoxins, and cheese. Because protein secretion is critical for these processes and for host infection, mass spectrometry was used to monitor proteins secreted into liquid media during fungal growth. T625 failed to secrete a set of enzymes that degrade plant cell walls, along with ones that synthesize the three final biosynthetic steps of patulin. Consequently, the culture broth of T625 had significantly reduced capacity to degrade apple tissue and contained 30 times less patulin. Quantitative mass spectrometry of 3,282 mycelial proteins revealed that T625 had altered cellular networks controlling protein processing in the endoplasmic reticulum, protein export, vesicle-mediated transport, and endocytosis. T625 also had reduced proteins controlling mRNA surveillance and RNA processing. Transmission electron microscopy of hyphal cross sections confirmed that T625 formed abnormally enlarged endosomes or vacuoles. These data reveal that Blistering1 affects internal and external protein processing involving vesicle-mediated transport in a family of fungi with medical, commercial, and agricultural importance.

scholarly journals A chemical screen for suppressors of the avrRpm1-RPM1-dependent hypersensitive cell death response in Arabidopsis thaliana

Planta ◽  
2010 ◽  
Vol 231 (5) ◽  
pp. 1013-1023 ◽  
Author(s):  
Mario Serrano ◽  
David A. Hubert ◽  
Jeffery L. Dangl ◽  
Paul Schulze-Lefert ◽  
Erich Kombrink
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Death ◽  
Hypersensitive Cell Death ◽  
Cell Death Response ◽  
Chemical Screen

scholarly journals An Investigation into the Involvement of Defense Signaling Pathways in Components of the Nonhost Resistance of Arabidopsis thaliana to Rust Fungi Also Reveals a Model System for Studying Rust Fungal Compatibility

2003 ◽  
Vol 16 (5) ◽  
pp. 398-404 ◽  
Author(s):  
Denny G. Mellersh ◽  
Michèle C. Heath
Keyword(s):  
Arabidopsis Thaliana ◽  
Rust Fungus ◽  
Fungal Growth ◽  
Rust Fungi ◽  
Nonhost Resistance ◽  
Wild Type ◽  
Pr Genes ◽  
Hypersensitive Cell Death ◽  
Defense Signaling ◽  
Infection Hypha

Seventeen accessions of Arabidopsis thaliana inoculated with the cowpea rust fungus Uromyces vignae exhibited a variety of expressions of nonhost resistance, although infection hypha growth typically ceased before the formation of the first haustorium, except in Ws-0. Compared with wild-type plants, there was no increased fungal growth in ndr1 or eds1 mutants defective in two of the signal cascades regulated by the major class of Arabidopsis host resistance genes. However, in the Col-0 background, infection hyphae of U. vignae and two other rust fungi were longer in sid2 mutants defective in an enzyme that synthesizes salicylic acid (SA), in npr1 mutants deficient in a regulator of the expression of SA-dependent pathogenesis related (PR) genes, and in NahG plants containing a bacterial salicylate hydroxylase. Infection hyphae of U. vignae and U. appendiculatus but not of Puccinia helianthi were also longer in jar1 mutants, which are defective in the jasmonic acid defense signaling pathway. Nevertheless, haustorium formation increased only for the Uromyces spp. and only in sid2 mutants or NahG plants. Rather than the hypersensitive cell death that usually accompanies haustorium formation in nonhost plants, Arabidopsis typically encased haustoria in calloselike material. Growing fungal colonies of both Uromyces spp., indicative of a successful biotrophic relationship between plant and fungus, formed in NahG plants, but only U. vignae formed growing colonies in the sid2 mutants and cycloheximide-treated wild-type plants. Growing colonies did not develop in NahG tobacco or tomato plants. These data suggest that nonhost resistance of Arabidopsis to rust fungi primarily involves the restriction of infection hypha growth as a result of defense gene expression. However, there is a subsequent involvement of SA but not SA-dependent PR genes in preventing the Uromyces spp. from forming the first haustorium and establishing a sufficient biotrophic relationship to support further fungal growth. The U. vignae-Arabidopsis combination could allow the application of the powerful genetic capabilities of this model plant to the study of compatibility as well as nonhost resistance to rust fungi.

scholarly journals Signatures of Adaptation to Obligate Biotrophy in the Hyaloperonospora arabidopsidis Genome

Science ◽  
2010 ◽  
Vol 330 (6010) ◽  
pp. 1549-1551 ◽  
Author(s):  
Laura Baxter ◽  
Sucheta Tripathy ◽  
Naveed Ishaque ◽  
Nico Boot ◽  
Adriana Cabral ◽  
...  
Keyword(s):  
Plant Pathogens ◽  
Inorganic Nitrogen ◽  
Living Plant ◽  
Rxlr Effectors ◽  
Fungal Plant Pathogens ◽  
Genes Encoding ◽  
Zoospore Formation ◽  
Hyaloperonospora Arabidopsidis ◽  
Obligate Biotrophs ◽  
Obligate Biotroph

Many oomycete and fungal plant pathogens are obligate biotrophs, which extract nutrients only from living plant tissue and cannot grow apart from their hosts. Although these pathogens cause substantial crop losses, little is known about the molecular basis or evolution of obligate biotrophy. Here, we report the genome sequence of the oomycete Hyaloperonospora arabidopsidis (Hpa), an obligate biotroph and natural pathogen of Arabidopsis thaliana. In comparison with genomes of related, hemibiotrophic Phytophthora species, the Hpa genome exhibits dramatic reductions in genes encoding (i) RXLR effectors and other secreted pathogenicity proteins, (ii) enzymes for assimilation of inorganic nitrogen and sulfur, and (iii) proteins associated with zoospore formation and motility. These attributes comprise a genomic signature of evolution toward obligate biotrophy.

Functional analysis of the Arabidopsis thaliana mismatch repair gene MSH2

Genome ◽  
2001 ◽  
Vol 44 (4) ◽  
pp. 651-657 ◽  
Author(s):  
Jules Adé ◽  
Yosr Haffani ◽  
François J Belzile
Keyword(s):  
Arabidopsis Thaliana ◽  
Mismatch Repair ◽  
Dna Mismatch Repair ◽  
Single Copy ◽  
Mismatch Repair Gene ◽  
Single Pair ◽  
Repair Gene ◽  
Dna Mutation ◽  
Over Expression ◽  
Dna Mismatch

The Arabidopsis thaliana MSH2 (AtMSH2) gene encodes a protein that belongs to a family of highly conserved proteins (MutS homologues (MSH)) involved in DNA mismatch repair. Sequence analysis strongly suggests that this single copy gene is indeed a homologue of MSH2, a gene known to play a central role in eukaryotic mismatch repair. In this report, we show that the AtMSH2 protein has functional attributes characteristic of previously described mismatch repair proteins. First, over-expression of this protein in Escherichia coli leads to a mutator phenotype similar to that reported previously for known functional homologues. Second, gel retardation assays revealed that the AtMSH2 protein has a 10-fold greater affinity for DNA containing a single pair of mismatched nucleotides versus perfectly matched DNA. These results provide experimental evidence that AtMSH2 is indeed a functional homologue of MutS.Key words: DNA mismatch repair, heteroduplex DNA, mutation rate.

scholarly journals Stable Fluorescent and Enzymatic Tagging of Bradyrhizobium diazoefficiens to Analyze Host-Plant Infection and Colonization

2015 ◽  
Vol 28 (9) ◽  
pp. 959-967 ◽  
Author(s):  
Raphael Ledermann ◽  
Ilka Bartsch ◽  
Mitja N. Remus-Emsermann ◽  
Julia A. Vorholt ◽  
Hans-Martin Fischer
Keyword(s):  
Fluorescent Proteins ◽  
Root Nodules ◽  
Microscopic Analysis ◽  
Single Copy ◽  
Infection Process ◽  
Model Systems ◽  
Nodule Occupancy ◽  
Developmental Program ◽  
Plant Infection ◽  
Host Infection

Bradyrhizobium diazoefficiens USDA 110 (formerly named Bradyrhizobium japonicum) can fix dinitrogen when living as an endosymbiont in root nodules of soybean and some other legumes. Formation of a functional symbiosis relies on a defined developmental program mediated by controlled gene expression in both symbiotic partners. In contrast to other well-studied Rhizobium-legume model systems that have been thoroughly examined by means of genetically tagged strains, analysis of B. diazoefficiens host infection has been impaired due to the lack of suitable tagging systems. Here, we describe the construction of B. diazoefficiens strains constitutively expressing single-copy genes for fluorescent proteins (eBFP2, mTurquoise2, GFP+, sYFP2, mCherry, HcRed) and enzymes (GusA, LacZ). For stable inheritance, the constructs were recombined into the chromosome. Effectiveness and versatility of the tagged strains was demonstrated in plant infection assays. (i) The infection process was followed from root-hair attachment to colonization of nodule cells with epifluorescent microscopy. (ii) Monitoring mixed infections with two strains producing different fluorescent proteins allowed rapid analysis of nodule occupancy and revealed that the majority of nodules contained clonal populations. (iii) Microscopic analysis of nodules induced by fluorescent strains provided evidence for host-dependent control of B. diazoefficiens bacteroid morphology in nodules of Aeschynomene afraspera and Arachis hypogaea (peanut), as deduced from their altered morphology compared with bacteroids in soybean nodules.

The Arabidopsis thaliana papain-like cysteine protease RD21 interacts with a root-knot nematode effector protein

Nematology ◽  
2015 ◽  
Vol 17 (6) ◽  
pp. 655-666 ◽  
Author(s):  
Laura J. Davies ◽  
Lei Zhang ◽  
Axel A. Elling
Keyword(s):  
Arabidopsis Thaliana ◽  
Cysteine Protease ◽  
Host Plants ◽  
Effector Proteins ◽  
Effector Protein ◽  
Yeast Two Hybrid ◽  
Root Knot Nematode ◽  
Second Stage ◽  
Stage Juvenile ◽  
Two Hybrid

The root-knot nematode Meloidogyne chitwoodi secretes effector proteins into the cells of host plants to manipulate plant-derived processes in order to achieve successful parasitism. Mc1194 is a M. chitwoodi effector that is highly expressed in pre-parasitic second-stage juvenile nematodes. Yeast two-hybrid assays revealed Mc1194 specifically interacts with a papain-like cysteine protease (PLCP), RD21A in Arabidopsis thaliana. Mc1194 interacts with both the protease and granulin domains of RD21A. PLCPs are targeted by effectors secreted by bacterial, fungal and oomycete pathogens and the hypersusceptibility of rd21-1 mutants to M. chitwoodi indicates RD21A plays a role in plant-parasitic nematode infection.

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