Disease relevance of Plant Tumors

• Octopine is released from crown gall tumors as a nutrient source and a signal molecule for the plant pathogen Agrobacterium tumefaciens [1].
• Up to thirteen T-DNA-encoded, polyadenylated transcripts of different relative abundance were detected by Northern blot hybridization in the tobacco nopaline BT37 crown gall teratoma tissue [2].
• An E. coli harbouring such a Ti::RP4 plasmid is unable to catabolize octopine and unable to induce crown-gall tumours on plants [3].
• Putrescine, spermidine and spermine were detected in normal and crown gall tumor tissue cultures of tobacco (Nicotiana tabacum var Wisconsin 38) and in tobacco mosaic virus (TMV)-infected freshly excised pith tissue from tobacco which represented non-proliferating tissue [4].

High impact information on Plant Tumors

• The A. tumefaciens transcriptional activator OccR causes a bend at a target promoter, which is partially relaxed by a plant tumor metabolite [1].
• We have identified the gene responsible for synthesis in transformed cells of the phosphorylated sugar, agrocinopine, and at least three additional genes controlling the morphology of plant tumors [5].
• Molecular basis for the auxin-independent phenotype of crown gall tumor tissues [6].
• A variety of samples consisting of purified compounds (of various origins) and ethanol extracts from plants were assayed for their activity on the growth and initiation of crown-gall tumors on potato disks [7].
• These regions code for octopine catabolism, virulence and plant tumor phenotype [8].

Chemical compound and disease context of Plant Tumors

• Agrobacterium tumefaciens-induced plant tumors accumulate considerable concentrations of free auxin [9].
• While Mas1 is required for the synthesis of mannopine (MOP) by crown gall tumor cells, MocC is essential for the utilization of MOP by Agrobacterium spp [10].
• We have isolated a cDNA clone, NT16, encoding a novel glycine-rich/hydrophobic protein from tobacco crown gall tumor tissues, which was induced by the T-DNA genes of Agrobacterium tumefaciens [11].
• Biotype 1 and 2 strains of Agrobacterium tumefaciens were isolated from crown gall tumors of Lippia canescens plants growing as ground cover in Arizona. The isolates were agrocin 84 sensitive, did not catabolize octopine, nopaline, agropine, or mannopine, and were limited in their tumorigenic host range [12].
• Strain K84 is used commercially to biocontrol crown gall caused by agrocin 84-susceptible strains of Agrobacterium tumefaciens [13].

Biological context of Plant Tumors

• Signals necessary for in vivo expression of Ti plasmid T-DNA-encoded octopine and nopaline synthase genes were studied in crown gall tumors by constructing mutated genes carrying various lengths of sequences upstream of the 5' initiation site of their mRNAs [14].
• Comparison of the deduced amino acid sequence of N5-(1-carboxyethyl)-L-ornithine synthase (M(r) = 35,323) to the functionally analogous octopine and nopaline synthases from crown gall tumors showed surprisingly little similarity [15].
• Octopine-type Ti plasmids such as pTi15955, pTiA6 and pTiR10 direct the catabolism of at least eight compounds called opines that are released from crown gall tumours [16].
• Because adequate means do not exist to control crown gall, we created resistant plants by introducing transgenes designed to elicit posttranscriptional gene silencing (PTGS) of iaaM and ipt [17].
• Phenotypic variation of an octopine-type crown gall tumor line resulting from changes in the pattern of T-DNA methylation and expression is described [18].

Anatomical context of Plant Tumors

• Octopine-type tumor tissue was obtained both by infection of plants or isolated protoplasts with Agrobacterium tumefaciens and by somatic hybridization of normal and crown gall tobacco cells [19].
• The alpha-actin gene is not transcribed in plant tumors, whereas transcription of the ovalbumin gene was observed, however the initiation point of transcription was different from the one used in the chicken oviduct [20].
• Strains with mutations in the chvA or chvB gene do not accumulate beta-1,2-glucan in their periplasm and exhibit pleiotropic phenotypes, including inability to form crown gall tumors on plants [21].
• Cloned DNA injected into oocytes consisted of T-DNA sequences derived from octopine type Ti plasmid B6-806 and T-DNA attached to plant DNA sequences at the left junction in crown gall tumors [22].
• In comparison with calli from leaf or stem, Catharanthus roseus crown gall cell cultured on MS basic medium was superior in growth, total indole alkaloids and ajmalicine contents [23].

Associations of Plant Tumors with chemical compounds

• The observed variation in the organization of T-DNA in octopine crown gall tissue did not appear to be a characteristic of the way the tissue was derived [19].
• Genetic analysis of T-DNA transcripts in nopaline crown galls [5].
• Transient expression of a T-DNA-encoded beta-glucuronidase gusA gene is efficient, but the ecotype is deficient in crown gall tumorigenesis, transformation to kanamycin resistance, and stable GUS expression [24].
• The presence of pyronopaline in crown gall tumor tissue and the catabolism of it by the bacterium A. tumefaciens establish it as a new opine [25].
• The Mr 18.000 protein represented a fusion product between chloramphenicol acetyltransferase (CAT) on pACYC184 and a part of lysopine dehydrogenase (LpDH), the enzyme synthesizing octopine and lysopine in plant tumor cells [26].

Gene context of Plant Tumors

• When slices of the crown gall carrying this chimeric gene were placed on plates containing indicator XGal, localized areas of the outgrowth turned deep blue, whereas no such areas were found in the crown gall having promoter-less lacZ [27].
• Nevertheless, important amino acids for the functional activity of VirG were so conserved that the virG included in pUCDG could complement a virG mutant Agrobacterium tumefaciens Mx19 in beta-galactosidase activity assays and on plant tumor tests [28].
• A simple method to transfer, integrate and study expression of foreign genes, such as chicken ovalbumin and alpha-actin in plant tumors [20].
• Purification and characterization of the crown gall specific enzyme nopaline synthase [29].
• High molecular weight deoxyribonucleic acid polymerase from crown gall tumor cells of periwinkle (Vinca rosea) [30].

References