-
Molecular & General Genetics : MGG 1984Phenotypic variation of an octopine-type crown gall tumor line resulting from changes in the pattern of T-DNA methylation and expression is described. Variants that grow...
Phenotypic variation of an octopine-type crown gall tumor line resulting from changes in the pattern of T-DNA methylation and expression is described. Variants that grow as unorganized callus always express T-DNA transcripts 1 and 2. In shoot-forming variants (teratomas) only T-DNA transcript 4 is expressed. This line also regenerates normal-appearing, rooted plants in which all T-DNA expression is suppressed. Tissues from these plants require phytohormones for growth in vitro. These plants are self-fertile and transmit T-DNA through meiosis, and T-DNA suppression is maintained in the next generation. After treatment of regenerated plant tissue with 5-azacytidine, an inhibitor of DNA methylation, T-DNA transcription and phytohormone-independent tumorous growth resume. The T-DNA of cell lines in which T-DNA is not expressed is highly methylated, whereas the level of T-DNA methylation is reduced in 5-azacytidine treated cells that resume T-DNA expression and phytohormone-independent growth. The correlation between the degree of T-DNA methylation and the level of T-DNA expression indicates that hypermethylation is responsible for the suppression of T-DNA transcription.
Topics: Azacitidine; Cell Line; DNA; Gene Expression Regulation; Genetic Variation; Meiosis; Methylation; Phenotype; Plant Tumors; Recombination, Genetic; Rhizobium
PubMed: 6084805
DOI: 10.1007/BF00329940 -
The Quarterly Review of Biology Mar 1981A unifying concept that appears to provide an understanding of cancer as a fundamental scientific problem is presented. This concept, which was initially developed on... (Review)
Review
A unifying concept that appears to provide an understanding of cancer as a fundamental scientific problem is presented. This concept, which was initially developed on the basis of experiments using the relatively uncomplicated plant tumor systems, now appears applicable to animal and human tumors as well. Evidence is provided to show that the tumor problem is fundamentally a problem of anomalous cellular differentiation and that the heritable cellular change that underlies the tumorous state is similar to that which underlies cell specialization occurring during the normal course of development in all higher organisms. Both cellular differentiation and tumorigenesis depend for their expression on the persistent activation of select but, in part, different genes (whether normal, foreign, or both) present in the genome of a cell. Since heritable cellular changes of this kind may be induced by physical, chemical, and biological agents of the most diverse type, and since cells may remain totipotent during the time that they exhibit the tumor phenotype, the results reported here suggest that whether the normal or tumor phenotype is expressed is determined by how the genetic information present in a cell is regulated in the cell. Regulation leading to the establishment and maintenance of the tumorous state may be accomplished in different ways by the different types of oncogenic agents. Thus cancer and related neoplastic diseases appear to have a common underlying heritable cellular change in which the diverse manifestations of the tumorous state commonly observed would simply reflect different expressions of this heritable cellular change.
Topics: Animals; Cell Cycle; Cell Division; Cell Transformation, Viral; DNA Replication; Humans; Models, Biological; Neoplasm Regression, Spontaneous; Neoplasms; Neoplasms, Experimental; Phenotype; Plant Tumors; Plant Viruses; Plasmids; Retroviridae
PubMed: 7017788
DOI: 10.1086/412082 -
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 -
Progress in Experimental Tumor Research 1972
Review
Topics: Culture Techniques; Cytogenetics; Genes, Regulator; Hybridization, Genetic; Mutation; Plant Growth Regulators; Plant Tumors; Plants; Plants, Toxic; Radiation Dosage; Radiation Effects; Nicotiana
PubMed: 4552167
DOI: No ID Found -
Current Topics in Microbiology and... 2018Agrobacterium vitis is the primary causal agent of grapevine crown gall worldwide. Symptoms of grapevine crown gall disease include tumor formation on the aerial plant... (Review)
Review
Agrobacterium vitis is the primary causal agent of grapevine crown gall worldwide. Symptoms of grapevine crown gall disease include tumor formation on the aerial plant parts, whereas both tumorigenic and nontumorigenic strains of A. vitis cause root necrosis. Genetic and genomic analyses indicated that A. vitis is distinguishable from the members of the Agrobacterium genus and its transfer to the genus Allorhizobium was suggested. A. vitis is genetically diverse, with respect to both chromosomal and plasmid DNA. Its pathogenicity is mainly determined by a large conjugal tumor-inducing (Ti) plasmid characterized by a mosaic structure with conserved and variable regions. Traditionally, A. vitis Ti plasmids and host strains were differentiated into octopine/cucumopine, nopaline, and vitopine groups, based on opine markers. However, tumorigenic and nontumorigenic strains of A. vitis may carry other ecologically important plasmids, such as tartrate- and opine-catabolic plasmids. A. vitis colonizes vines endophytically. It is also able to survive epiphytically on grapevine plants and is detected in soil exclusively in association with grapevine plants. Because A. vitis persists systemically in symptomless grapevine plants, it can be efficiently disseminated to distant geographical areas via international trade of propagation material. The use of healthy planting material in areas with no history of the crown gall represents the crucial measure of disease management. Moreover, biological control and production of resistant grape varieties are encouraging as future control measures.
Topics: Agrobacterium; Farms; Plant Tumors; Plasmids; Vitis
PubMed: 29556824
DOI: 10.1007/82_2018_85 -
Medical Hypotheses 2006
Topics: Agrobacterium tumefaciens; Animals; Bacterial Infections; Evidence-Based Medicine; Mice; Neoplasms; Plant Tumors
PubMed: 16431032
DOI: 10.1016/j.mehy.2005.12.007 -
Journal of Bacteriology Apr 2023Agrobacterium tumefaciens incites the formation of readily visible macroscopic structures known as crown galls on plant tissues that it infects. Records from biologists... (Review)
Review
Agrobacterium tumefaciens incites the formation of readily visible macroscopic structures known as crown galls on plant tissues that it infects. Records from biologists as early as the 17th century noted these unusual plant growths and began examining the basis for their formation. These studies eventually led to isolation of the infectious agent, A. tumefaciens, and decades of study revealed the remarkable mechanisms by which A. tumefaciens causes crown gall through stable horizontal genetic transfer to plants. This fundamental discovery generated a barrage of applications in the genetic manipulation of plants that is still under way. As a consequence of the intense study of A. tumefaciens and its role in plant disease, this pathogen was developed as a model for the study of critical processes that are shared by many bacteria, including host perception during pathogenesis, DNA transfer and toxin secretion, bacterial cell-cell communication, plasmid biology, and more recently, asymmetric cell biology and composite genome coordination and evolution. As such, studies of A. tumefaciens have had an outsized impact on diverse areas within microbiology and plant biology that extend far beyond its remarkable agricultural applications. In this review, we attempt to highlight the colorful history of A. tumefaciens as a study system, as well as current areas that are actively demonstrating its value and utility as a model microorganism.
Topics: Agrobacterium tumefaciens; Host Microbial Interactions; Plant Tumors; Plant Diseases; Plants; Bacteria; Biology
PubMed: 36892285
DOI: 10.1128/jb.00005-23 -
Results and Problems in Cell... 1986
Review
Topics: Cell Transformation, Neoplastic; Chromosome Mapping; Cloning, Molecular; DNA; Genetic Engineering; Mutation; Plant Cells; Plant Tumors; Plant Viruses; Plants; Plasmids; Transcription, Genetic; Transformation, Genetic
PubMed: 3529269
DOI: 10.1007/978-3-540-39836-3_5 -
Nature Nov 1966
Topics: Cell Nucleus; Cytoplasm; Golgi Apparatus; Insecta; Microscopy, Electron; Plant Tumors; RNA
PubMed: 5988216
DOI: 10.1038/212830a0 -
International Journal of Molecular... Aug 2021Galls are characteristic plant structures formed by cell size enlargement and/or cell proliferation induced by parasitic or pathogenic organisms. Insects are a major... (Review)
Review
Galls are characteristic plant structures formed by cell size enlargement and/or cell proliferation induced by parasitic or pathogenic organisms. Insects are a major inducer of galls, and insect galls can occur on plant leaves, stems, floral buds, flowers, fruits, or roots. Many of these exhibit unique shapes, providing shelter and nutrients to insects. To form unique gall structures, gall-inducing insects are believed to secrete certain effector molecules and hijack host developmental programs. However, the molecular mechanisms of insect gall induction and development remain largely unknown due to the difficulties associated with the study of non-model plants in the wild. Recent advances in next-generation sequencing have allowed us to determine the biological processes in non-model organisms, including gall-inducing insects and their host plants. In this review, we first summarize the adaptive significance of galls for insects and plants. Thereafter, we summarize recent progress regarding the molecular aspects of insect gall formation.
Topics: Animals; Host-Parasite Interactions; Insecta; Plant Tumors; Plants
PubMed: 34502330
DOI: 10.3390/ijms22179424