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Molecular Plant-microbe Interactions :... Jan 2007Genetic transformation of plant cells by Agrobacterium tumefaciens represents a unique case of trans-kingdom sex requiring the involvement of both bacterial virulence...
Genetic transformation of plant cells by Agrobacterium tumefaciens represents a unique case of trans-kingdom sex requiring the involvement of both bacterial virulence proteins and plant-encoded proteins. We have developed in planta and leaf-disk assays in Nicotiana benthamiana for identifying plant genes involved in Agrobacterium-mediated plant transformation using virus-induced gene silencing (VIGS) as a genomics tool. VIGS was used to validate the role of several genes that are either known or speculated to be involved in Agrobacterium-mediated plant transformation. We showed the involvement of a nodulin-like protein and an alpha-expansin protein (alpha-Exp) during Agrobacterium infection. Our data suggest that alpha-Exp is involved during early events of Agrobacterium-mediated transformation but not required for attaching A. tumefaciens. By employing the combination of the VIGS-mediated forward genetics approach and an in planta tumorigenesis assay, we identified 21 ACG (altered crown gall) genes that, when silenced, produced altered crown gall phenotypes upon infection with a tumorigenic strain of A. tumefaciens. One of the plant genes identified from the screening, Histone H3 (H3), was further characterized for its biological role in Agrobacterium-mediated plant transformation. We provide evidence for the role of H3 in transfer DNA integration. The data presented here suggest that the VIGS-based approach to identify and characterize plant genes involved in genetic transformation of plant cells by A. tumefaciens is simple, rapid, and robust and complements other currently used approaches.
Topics: Agrobacterium tumefaciens; Gene Expression Regulation, Plant; Gene Silencing; Genes, Plant; Histones; Membrane Proteins; Plant Leaves; Plant Proteins; Plant Tumors; Nicotiana; Transformation, Genetic
PubMed: 17249421
DOI: 10.1094/MPMI-20-0041 -
The New Phytologist Jul 2018Agrobacterium tumefaciens constructs an ecological niche in its host plant by transferring the T-DNA from its Ti plasmid into the host genome and by diverting the host...
Agrobacterium tumefaciens constructs an ecological niche in its host plant by transferring the T-DNA from its Ti plasmid into the host genome and by diverting the host metabolism. We combined transcriptomics and genetics for understanding the A. tumefaciens lifestyle when it colonizes Arabidopsis thaliana tumors. Transcriptomics highlighted: a transition from a motile to sessile behavior that mobilizes some master regulators (Hfq, CtrA, DivK and PleD); a remodeling of some cell surface components (O-antigen, succinoglucan, curdlan, att genes, putative fasciclin) and functions associated with plant defense (Ef-Tu and flagellin pathogen-associated molecular pattern-response and glycerol-3-phosphate and nitric oxide signaling); and an exploitation of a wide variety of host resources, including opines, amino acids, sugars, organic acids, phosphate, phosphorylated compounds, and iron. In addition, construction of transgenic A. thaliana lines expressing a lactonase enzyme showed that Ti plasmid transfer could escape host-mediated quorum-quenching. Finally, construction of knock-out mutants in A. tumefaciens showed that expression of some At plasmid genes seemed more costly than the selective advantage they would have conferred in tumor colonization. We provide the first overview of A. tumefaciens lifestyle in a plant tumor and reveal novel signaling and trophic interplays for investigating host-pathogen interactions.
Topics: Agrobacterium tumefaciens; Arabidopsis; Arginine; Bacterial Proteins; Carbon; Cell Wall; Chemotaxis; Ecosystem; Gene Expression Regulation, Bacterial; Genome, Bacterial; Host-Pathogen Interactions; Iron; Mutation; Nitrogen; Plant Tumors; Plants, Genetically Modified; Sugar Phosphates
PubMed: 29701262
DOI: 10.1111/nph.15164 -
Molecular Ecology Jun 2022Plant galls are novel and sometimes dramatic plant organs whose development is initiated and controlled by parasitic microbes, nematodes, insects and mites. For...
Plant galls are novel and sometimes dramatic plant organs whose development is initiated and controlled by parasitic microbes, nematodes, insects and mites. For arthropods, galls provide relative safety from enemies and abiotic stresses while providing nutrition. Galls are formed entirely by the plant, whose transcriptional pathways are modified and coopted to produce a structure specific to the galler species; they comprise a classic example of Dawkins' "extended phenotype". Arthropod-elicited galls are unique in that they are often anatomically complex (Figure 1a), with multiple differentiated tissue types (Figure 1b). A growing number of investigators have studied changes in hostplant gene expression to understand arthropod gall development. In this issue of Molecular Ecology, Martinson et al. (2021) report using RNA sequencing to explore tissue-specific gene expression associated with anatomical and functional gall complexity, demonstrating for the first time that gall tissues are as different transcriptionally as they are anatomically.
Topics: Animals; Gene Expression; Host-Parasite Interactions; Insecta; Plant Tumors; Plants
PubMed: 35466464
DOI: 10.1111/mec.16482 -
BMC Plant Biology Feb 2015The source and sink relationships between insect-induced galls and host plant leaves are interesting. In this research, we collected cup-like galls induced by...
BACKGROUND
The source and sink relationships between insect-induced galls and host plant leaves are interesting. In this research, we collected cup-like galls induced by Bruggmanniella sp. (Diptera: Cecidomyiidae) on host leaves of Litsea acuminata and assessed them to investigate source-sink relationships between galls and host leaves. We characterized several of their photosynthetic characteristics including chlorophyll fluorescence (Fv/Fm), stomatal conductance, and photosynthetic capacity, biochemical components such as total soluble sugar, starches, free amino acids, and soluble proteins. The structural analyses were performed under confocal, light, and scanning electron microscopies.
RESULTS
Compared with host leaves, galls exhibited slightly lower chlorophyll fluorescence; however, stomatal conductance and photosynthetic capacity were not detected at all. Galls accumulated higher total soluble sugars and free amino acids but less soluble proteins than host leaves. No stomata was observed on exterior or interior gall surfaces under light or scanning electron microscopy, but their inner surfaces were covered with fungal hyphae. Confocal imagery showed a gradient of chloroplasts distribution between gall outer and inner surfaces.
CONCLUSIONS
Our results strongly suggest that leaf-derived cecidomyiid galls are a type of chlorophyll-deficient non-leaf green tissue and consists on a novel sink in L. acuminate.
Topics: Amino Acids; Animals; Carbohydrate Metabolism; Carbon Dioxide; Carotenoids; Chlorophyll; Chloroplasts; Diptera; Fluorescence; Litsea; Malondialdehyde; Photosynthesis; Plant Leaves; Plant Proteins; Plant Tumors; Solubility; Starch
PubMed: 25849781
DOI: 10.1186/s12870-015-0446-0 -
Biology Letters Oct 2018Many animals and plants have evolved elaborate water-repellent microstructures on their surface, which often play important roles in their ecological adaptation. Here,...
Many animals and plants have evolved elaborate water-repellent microstructures on their surface, which often play important roles in their ecological adaptation. Here, we report a unique type of water-repellent structure on a plant surface, which develops as an insect-induced plant morphology in a social context. Some social aphids form galls on their host plant, in which they produce large amounts of hydrophobic wax. Excreted honeydew is coated by the powdery wax to form 'honeydew balls', which are actively disposed by soldier nymphs through an opening on their gall. These activities are enabled by a highly water-repellent inner gall surface, and we discovered that this surface is covered with dense trichomes that are not found on normal plant surfaces. The trichomes are coated by fine particles of the insect-produced wax, thereby realizing a high water repellency with a cooperative interaction between aphids and plants. The plant leaves on which the gall is formed often exhibit patchy areas with dense trichomes, representing an ectopic expression of the insect-induced plant morphology. In the pouch-shaped closed galls of a related social aphid species, by contrast, the inner surface was not covered with trichomes. Our findings provide a convincing example of how the extended phenotype of an animal, expressed in a plant, plays a pivotal role in maintaining sociality.
Topics: Adaptation, Physiological; Animals; Aphids; Behavior, Animal; Host-Parasite Interactions; Nymph; Plant Leaves; Plant Tumors; Species Specificity; Ulmaceae; Water; Waxes
PubMed: 30333261
DOI: 10.1098/rsbl.2018.0470 -
Scientific Reports Jun 2020In plants, growth-defense tradeoffs are essential for optimizing plant performance and adaptation under stress conditions, such as pathogen attack. Root-knot nematodes...
In plants, growth-defense tradeoffs are essential for optimizing plant performance and adaptation under stress conditions, such as pathogen attack. Root-knot nematodes (RKNs) cause severe economic losses in many crops worldwide, although little is known about the mechanisms that control plant growth and defense responses during nematode attack. Upon investigation of Arabidopsis thaliana infected with RKN (Meloidogyne incognita), we observed that the atypical transcription factor DP-E2F-like 1 (DEL1) repressed salicylic acid (SA) accumulation in RKN-induced galls. The DEL1-deficient Arabidopsis mutant (del1-1) exhibited excessive SA accumulation in galls and is more resistant to RKN infection. In addition, excessive lignification was observed in galls of del1-1. On the other hand, the root growth of del1-1 is reduced after RKN infection. Taken together, these findings suggest that DEL1 plays an important role in the balance between plant growth and defense responses to RKN infection by controlling SA accumulation and lignification.
Topics: Animals; Arabidopsis; Gene Expression Regulation, Plant; Host-Parasite Interactions; Lignin; Plant Roots; Plant Tumors; Plants, Genetically Modified; Salicylic Acid; Transcription Factors; Tylenchoidea
PubMed: 32483126
DOI: 10.1038/s41598-020-65733-3 -
PloS One 2017VirE2 is a ssDNA binding protein essential for virulence in Agrobacterium tumefaciens. A tetracysteine mutant (VirE2-TC) was prepared for in vitro and in vivo...
VirE2 is a ssDNA binding protein essential for virulence in Agrobacterium tumefaciens. A tetracysteine mutant (VirE2-TC) was prepared for in vitro and in vivo fluorescence imaging based on the ReAsH reagent. VirE2-TC was found to be biochemically active as it binds both ssDNA and the acidic secretion chaperone VirE1. It was also biologically functional in complementing virE2 null strains transforming Arabidopsis thaliana roots and Nicotiana tabacum leaves. In vitro experiments demonstrated a two-color fluorescent complex using VirE2-TC/ReAsH and Alexa Fluor 488 labeled ssDNA. In vivo, fluorescent VirE2-TC/ReAsH was detected in bacteria and in plant cells at time frames relevant to transformation.
Topics: Agrobacterium tumefaciens; Arabidopsis; Bacterial Proteins; DNA, Single-Stranded; DNA-Binding Proteins; Mutation; Optical Imaging; Plant Tumors; Protein Binding; Nicotiana; Virulence Factors
PubMed: 28403156
DOI: 10.1371/journal.pone.0175273 -
Cell Host & Microbe Mar 2010Agrobacterium exports DNA into plant cells, eliciting neoplastic growths on many plant species. During this process, a Skp1-Cdc53-cullin-F-box (SCF) complex that...
Agrobacterium exports DNA into plant cells, eliciting neoplastic growths on many plant species. During this process, a Skp1-Cdc53-cullin-F-box (SCF) complex that contains the bacterial virulence F-box protein VirF facilitates genetic transformation by targeting for proteolysis proteins, the Agrobacterium protein VirE2 and the host protein VIP1, that coat the transferred DNA. However, some plant species do not require VirF for transformation. Here, we show that Agrobacterium induces expression of a plant F-box protein, which we designated VBF for VIP1-binding F-box protein, that can functionally replace VirF, regulating levels of the VirE2 and VIP1 proteins via a VBF-containing SCF complex. When expressed in Agrobacterium and exported into the plant cell, VBF functionally complements tumor formation by a strain lacking VirF. VBF expression is known to be induced by diverse pathogens, suggesting that Agrobacterium has co-opted a plant defense response and that bacterial VirF and plant VBF both contribute to targeted proteolysis that promotes plant genetic transformation.
Topics: Arabidopsis; Bacterial Proteins; F-Box Proteins; Host-Pathogen Interactions; Solanum lycopersicum; Molecular Sequence Data; Plant Proteins; Plant Tumors; Protein Binding; Protein Interaction Mapping; Rhizobium; Sequence Analysis, DNA; Nicotiana; Transformation, Genetic; Two-Hybrid System Techniques; Virulence Factors
PubMed: 20227663
DOI: 10.1016/j.chom.2010.02.009 -
The Plant Cell Sep 2009Agrobacterium tumefaciens causes crown gall disease by transferring and integrating bacterial DNA (T-DNA) into the plant genome. To examine the physiological changes and...
Agrobacterium tumefaciens causes crown gall disease by transferring and integrating bacterial DNA (T-DNA) into the plant genome. To examine the physiological changes and adaptations during Agrobacterium-induced tumor development, we compared the profiles of salicylic acid (SA), ethylene (ET), jasmonic acid (JA), and auxin (indole-3-acetic acid [IAA]) with changes in the Arabidopsis thaliana transcriptome. Our data indicate that host responses were much stronger toward the oncogenic strain C58 than to the disarmed strain GV3101 and that auxin acts as a key modulator of the Arabidopsis-Agrobacterium interaction. At initiation of infection, elevated levels of IAA and ET were associated with the induction of host genes involved in IAA, but not ET signaling. After T-DNA integration, SA as well as IAA and ET accumulated, but JA did not. This did not correlate with SA-controlled pathogenesis-related gene expression in the host, although high SA levels in mutant plants prevented tumor development, while low levels promoted it. Our data are consistent with a scenario in which ET and later on SA control virulence of agrobacteria, whereas ET and auxin stimulate neovascularization during tumor formation. We suggest that crosstalk among IAA, ET, and SA balances pathogen defense launched by the host and tumor growth initiated by agrobacteria.
Topics: Agrobacterium tumefaciens; Arabidopsis; Cyclopentanes; DNA, Bacterial; Ethylenes; Gene Expression Profiling; Gene Expression Regulation, Plant; Hydrogen Peroxide; Indoleacetic Acids; Oligonucleotide Array Sequence Analysis; Oxylipins; Plant Growth Regulators; Plant Tumors; RNA, Plant; Salicylic Acid; Transcriptional Activation
PubMed: 19794116
DOI: 10.1105/tpc.108.064576 -
PloS One 2018Insect galls are atypical plant tissues induced by the invasion of insects. Compared to the host leaf, gall tissues lose photosynthetic ability, but have higher soluble...
BACKGROUND
Insect galls are atypical plant tissues induced by the invasion of insects. Compared to the host leaf, gall tissues lose photosynthetic ability, but have higher soluble sugar content. Although the physiological and biochemical regulation of gall tissues have been demonstrated, the mechanism of genetic regulation has only been analyzed in few studies.
RESULTS
In this study, the transcriptome of cup-shaped galls and its host leaf were de novo assembled. Cellular functional enrichment and differentially expressed gene groups in the gall tissues were analyzed. The genes associated with primary metabolism, including photosynthesis, cell wall turnover, and sugar degradation, were expressed differently in galls and leaves. The examination of gene expression demonstrated that the genes involved in brassinosteroid synthesis and responses exhibited a remarkable modulation in cup-shaped galls, suggesting a potential role of steroid hormones in regulating gall development.
CONCLUSIONS
This study revealed the genetic responses, including those involved in source-sink reallocation and phytohormone metabolism, of galls induced by a dipteran insect.
Topics: Animals; Carbohydrate Metabolism; Diptera; Gene Expression Profiling; Host-Parasite Interactions; Litsea; Photosynthesis; Plant Leaves; Plant Proteins; Plant Tumors; Transcriptome
PubMed: 30356295
DOI: 10.1371/journal.pone.0205265