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Molecular Phylogenetics and Evolution Apr 2022Tumor-inducing (Ti) and root-inducing (Ri) plasmids of Agrobacterium that display a large diversity are involved in crown gall and hairy root plant diseases. Their...
Tumor-inducing (Ti) and root-inducing (Ri) plasmids of Agrobacterium that display a large diversity are involved in crown gall and hairy root plant diseases. Their phylogenetic relationships were inferred from an exhaustive set of Ti and Ri plasmids (including 36 new complete Ti plasmids) by focusing on T-DNA and virulence regions. The opine synthase gene content of T-DNAs revealed 13 opine types corresponding to former classifications based on opines detected in diseased plants, while the T-DNA gene content more finely separate opine types in 18 T-DNA organizations. This classification was supported by the phylogeny of T-DNA oncogenes of Ti plasmids. The five gene organizations found in Ti/Ri vir regions was supported by the phylogeny of common vir genes. The vir organization was found to be likely an ancestral plasmid trait separating "classic" Ti plasmids (with one or two T-DNAs) and "Ri and vine-Ti" plasmids. A scenario generally supported by the repABC phylogeny. T-DNAs likely evolved later with the acquisition of opine characteristics as last steps in the Ti/Ri plasmid evolution. This novel evolutionary classification of Ti/Ri plasmids was found to be relevant for accurate crown gall and hairy root epidemiology.
Topics: DNA, Bacterial; Humans; Neoplasms; Phylogeny; Plant Tumors; Plasmids; Rhizobium; Virulence
PubMed: 35017066
DOI: 10.1016/j.ympev.2022.107388 -
Experimental & Applied Acarology Jul 2010The paper presents recent advances related to both specific and unspecific morphological alterations of plant organs caused by eriophyoid mites. Based on old and new... (Review)
Review
The paper presents recent advances related to both specific and unspecific morphological alterations of plant organs caused by eriophyoid mites. Based on old and new case studies, the diversity of plant malformations, such as galls, non-distortive feeding effects and complex symptoms induced by eriophyoids and/or pathogens vectored by them, is analysed and summarised.
Topics: Animals; Host-Parasite Interactions; Mite Infestations; Mites; Plant Tumors
PubMed: 20012342
DOI: 10.1007/s10493-009-9328-1 -
Progress in Experimental Tumor Research 1967
Topics: Cell Division; Cell Membrane; Culture Media; Culture Techniques; Molecular Biology; Nitrates; Phosphates; Phosphorus Isotopes; Plant Growth Regulators; Plant Tumors; Potassium Chloride
PubMed: 6062162
DOI: No ID Found -
JAMA May 1983
Topics: Photography; Plant Tumors; Rhizobium
PubMed: 6842759
DOI: No ID Found -
Critical Reviews in Microbiology 1986Infections of wounded dicotyledonous plants by Agrobacterium tumefaciens result in the formation of crown gall tumors. The initial step in tumor formation is the... (Review)
Review
Infections of wounded dicotyledonous plants by Agrobacterium tumefaciens result in the formation of crown gall tumors. The initial step in tumor formation is the site-specific attachment of the bacteria to the host cells. The mechanism of recognition and attachment in this interaction has been studied in detail. Current information on the nature of the bacterial binding sites, the nature of the host receptors, the role of bacterial cellulose fibrils, and the genetics of bacterial attachment will be summarized, and a model for the attachment of Agrobacterium to host cells will be presented.
Topics: DNA, Bacterial; Microscopy, Electron, Scanning; Plant Tumors; Plants; Rhizobium
PubMed: 3533427
DOI: 10.3109/10408418609108740 -
Sub-cellular Biochemistry 1979
Review
Topics: Agriculture; Amino Acids; Bacteriophages; Cell Transformation, Neoplastic; DNA, Bacterial; Genes; Plant Tumors; Plasmids; RNA, Bacterial; Rhizobium; Ribosomes; Temperature
PubMed: 377583
DOI: 10.1007/978-1-4615-7945-8_3 -
Trends in Plant Science Aug 2014Cytokinins are essential plant hormones that control almost every aspect of plant growth and development. Their function in mediating plant susceptibility to fungal... (Review)
Review
Cytokinins are essential plant hormones that control almost every aspect of plant growth and development. Their function in mediating plant susceptibility to fungal biotrophs and gall-causing pathogens is well known. Here we highlight the interaction between cytokinins and salicylic acid pathways. Furthermore, we discuss ways in which cytokinin signaling could crosstalk with plant immune networks. Some of these networks are modulated by pathogens to propagate disease, whereas others help the host to mitigate an infection.
Topics: Cytokinins; Plant Development; Plant Immunity; Plant Tumors; Plants; Signal Transduction
PubMed: 24794463
DOI: 10.1016/j.tplants.2014.04.001 -
Annual Review of Phytopathology 2001Rhodococcus fascians infects a wide range of plants, initiating the formation of leafy galls that consist of centers of shoot amplification and shoot growth inhibition.... (Review)
Review
Rhodococcus fascians infects a wide range of plants, initiating the formation of leafy galls that consist of centers of shoot amplification and shoot growth inhibition. R. fascians is an epiphyte but it also can establish endophytic populations. Bacterial signals involved in symptom development initiate de novo cell division and shoot meristem formation in differentiated tissues. The R. fascians signals exert activities that are distinct from mere cytokinin effects, and the evidence points to a process that adopted cytokinin biosynthetic enzymes to form derivatives with unique activity. Genes implicated in leafy gall formation are located on a linear plasmid and are subject to a highly controlling, complex regulatory network, integrating autoregulatory compounds and environmental signals. Leafy galls are considered as centers with specific metabolic features, a niche where populations of R. fascians experience a selective advantage. Such "metabolic habitat modification" might be universal for gall-inducing bacteria.
Topics: Magnoliopsida; Plant Diseases; Plant Growth Regulators; Plant Leaves; Plant Tumors; Rhodococcus; Virulence
PubMed: 11701858
DOI: 10.1146/annurev.phyto.39.1.27 -
The New Phytologist Jan 2022Agrobacterium tumefaciens colonizes the galls (plant tumors) it causes, and the roots of host and nonhost plants. Transposon-sequencing (Tn-Seq) was used to discover...
Agrobacterium tumefaciens colonizes the galls (plant tumors) it causes, and the roots of host and nonhost plants. Transposon-sequencing (Tn-Seq) was used to discover A.tumefaciens genes involved in reproductive success (fitness genes) on Solanum lycopersicum and Populus trichocarpa tumors and S.lycopersicum and Zea mays roots. The identified fitness genes represent 3-8% of A. tumefaciens genes and contribute to carbon and nitrogen metabolism, synthesis and repair of DNA, RNA and proteins and envelope-associated functions. Competition assays between 12 knockout mutants and wild-type confirmed the involvement of 10 genes (trpB, hisH, metH, cobN, ntrB, trxA, nrdJ, kamA, exoQ, wbbL) in A.tumefaciens fitness under both tumor and root conditions. The remaining two genes (fecA, noxA) were important in tumors only. None of these mutants was nonpathogenic, but four (hisH, trpB, exoQ, ntrB) exhibited impaired virulence. Finally, we used this knowledge to search for chemical and biocontrol treatments that target some of the identified fitness pathways and report reduced tumorigenesis and impaired establishment of A.tumefaciens on tomato roots using tannic acid or Pseudomonas protegens, which affect iron assimilation. This work revealed A.tumefaciens pathways that contribute to its competitive survival in plants and highlights a strategy to identify plant protection approaches against this pathogen.
Topics: Agrobacterium tumefaciens; Carbon; Solanum lycopersicum; Plant Roots; Plant Tumors; Virulence
PubMed: 34655498
DOI: 10.1111/nph.17810 -
Gene Nov 1996The virulence (vir) genes of Agrobacterium tumefaciens are induced by low-molecular-weight phenolic compounds and monosaccharides through a two-component regulatory... (Review)
Review
The virulence (vir) genes of Agrobacterium tumefaciens are induced by low-molecular-weight phenolic compounds and monosaccharides through a two-component regulatory system consisting of the VirA and VirG proteins. Although it is clear that the monosaccharides require binding to a periplasmic binding protein before they can interact with the sensor VirA protein, it is not certain whether the phenolic compounds also interact with a binding protein or directly interact with the sensor protein. To shed light on this question, we tested the vir-inducing abilities of several different phenolic compounds using two wild-type strains of A. tumefaciens, KU12 and A6. We found that several compounds such as 4-hydroxyacetophone and p-coumaric acid induced the vir of KU12, but not A6. On the other hand, acetosyringone and several other phenolic compounds induced the vir of A6, but not KU12. By transferring different Ti plasmids into isogenic chromosomal backgrounds, we showed that the phenolic sensing determinant is associated with the Ti plasmid. Subcloning of the Ti plasmid indicated that the virA locus determines which phenolic compounds can function as vir inducers. These results suggest that VirA directly senses the phenolic compounds for vir activation.
Topics: Agrobacterium tumefaciens; Bacterial Proteins; Gene Expression Regulation, Bacterial; Phenols; Plant Tumors; Signal Transduction; Virulence Factors
PubMed: 8955632
DOI: 10.1016/s0378-1119(96)00328-9