Numerous reports describe phenomena of transgene silencing in plants, yet the underlying genetic and molecular mechanisms are poorly understood. We observed that regeneration of Arabidopsis thaliana plants transgenic for the rolB gene of Agrobacterium rhizogenes results in a selection for transgene silencing. Transgene silencing could be monitored in this system by reversion of the visible RolB...

The Dof proteins are a large family of plant transcription factors that share a single highly conserved zinc finger. The tobacco Dof protein NtBBF1 was identified by its ability to bind to regulatory domain B in the promoter of the rolB oncogene. In this study, we show that the ACT T TA target sequence of NtBBF1 in domain B is necessary for tissue-specific expression of rolB. beta-Glucuronidase...

Phenotypical alterations observed in rolB-transformed plants have been proposed to result from a rise in intracellular free auxin due to a RolB-catalyzed hydrolysis of auxin conjugates (J.J. Estruch, J. Schell, A. Spena [1991] EMBO J 10: 3125-3128). We have investigated this hypothesis in detail using tobacco (Nicofiana tabacum) mesophyll protoplasts isolated from plants transformed with the ro...

alpha-1,4-Linked oligogalacturonides (OGs) inhibit auxin-regulated transcriptional activation of a rolB-beta-glucuronidase (GUS) gene fusion in tobacco (Nicotiana tabacum) leaf explants (D. Bellincampi, M. Cardarelli, D. Zaghi, G. Serino, G. Salvi, C. Gatz, F. Cervone, M. M. Altamura, P. Costantino, G. De Lorenzo [1996] Plant Cell 8: 477-487). In this paper we show that inhibition by OGs is ver...

Tomato (Solanum lycopersicum L.) is the second most important cultivated crop next to potato, worldwide. Tomato serves as an important source of antioxidants in human diet. Alternaria solani and Fusarium oxysporum cause early blight and vascular wilt of tomato, respectively, resulting in severe crop losses. The foremost objective of the present study was to generate transgenic tomato plants wit...

The numbers of chromosomes and nucleoli in cultured cells of Vitis amurensis transformed with the rolB oncogene from A. rhizogenes have been studied. In general, the integration of the rolB gene in grape DNA mostly caused the elevation of the level of the chromosome variability, as well as higher numbers of nucleoli in the cultured cells. The possible influence of the observed chromosomal modif...

The present study deals with the establishment of rolA-transgenic and rolB-transgenic plants for first time through Agrobacterium tumefaciens mediated transformation, exploiting inherent morphogenic potential an important medicinal plant, Bacopa monnieri (L.) Wettst. showed integration expression rolA rolB genes respectively, whereas Ri-transformed rolA, rolB, rolC rolD genes. Morphogenic diffe...

Lactuca serriola L. is a herbaceous species, used for human nutrition and medicinal purposes. The high antioxidant capacity of L. serriola indicates the possibility of enhancing its edible and health potential by increasing the flavonoid and phenolic contents. The present study aimed at enhancing the production of phenolics and flavonoids by hairy root cultures in Lactuca serriola transformed w...

This paper presents the map and DNA sequence analysis of pRi8196 transferred DNA (T-DNA) genes encoding root-inducing and mannopine synthesis functions. A canonical 24-base-pair border repeat as well as two "pseudoborders" are present at the functional right T-DNA border. To the left of this border are homologs of the mas1' and mas2' genes of TR pRiA4. Next to these are five open reading frames...

Potato plants harboring Phytochrome B (PHYB) gene from Arabidopsis thaliana or rol genes from Agrobacterium rhizogenes were used to study the effect of transgene expression on structure and properties of starch in tubers. Thermodynamic characteristics of starch (melting temperature, enthalpy of melting, thickness of crystalline lamellae) were shown to be variable depending on the transgene expr...