Independent and synergistic activity of rol A, B and C loci in stimulating abnormal growth in plants

Abstract

The Ri plasmid A4 of Agrobacterium rhizogenes contains within its T‐DNA genetic information able to trigger root formation in infected plants. Tobacco plants regenerated from transformed roots display the hairy root (hr) syndrome. We show that DNA fragments containing the rol B locus alone are able to induce root formation both in tobacco and kalanchoe tissues. The rol A and the rol C loci by themselves are also able to induce root formation in tobacco but not in kalanchoe. This capacity to induce root formation in either host is greatly increased when the rol A and/or C loci are combined with the rol B locus. Root induction is shown to be correlated with the expression of the rol loci. Transgenic plants exhibit all the characteristics of the hairy root syndrome only when all three loci are present and expressed. Although the activity of the rol encoded functions is synergistic, each of them appears to independently influence host functions involved in the determination of root differentiation.

TherolBGene Suppresses Reactive Oxygen Species in Transformed Plant Cells through the Sustained Activation of Antioxidant Defense

“…The plantlets were transformed with Agrobacterium tumefaciens strain GV3101 harboring the pPCV002-CaMVBT construct (rolB under the 35S Cauliflower mosaic virus promoter; Spena et al, 1987). The control nontransformed culture (R) was established from the same plantlets and cultivated under the same conditions as the transformed ones.…”

The impact of plant rolC oncogene on ginsenoside production by ginseng hairy root cultures

“…These plasmids contain the plant cassette vector pPCV002 [16] containing the gene of interest: rolC and rolB under cauli¯ower mosaic virus (CaMV) 35S promoter control and rolA under the control of its own 5' promoter [1]. Constructions also carry a gene for kanamycin resistance (NPT-II) under eukaryotic control sequences.…”

“…EcoRI 2225 bp fragment of pPCV002-CaMVBT was used as probe DNA for 1c-rolB culture. EcoRI 4480 bp fragment of pPCV002-ABC [1] was used as a probe for 1c-rolA culture.…”

“…The expression of individual rol genes in transgenic plants not only induces rhizogenesis [1], but also a ects the development and physiology of the entire plant [2].…”

Hormone-Resistant Mutants of Arabidopsis Have an Attenuated Response to Agrobacterium Strains

“…Until recently, changes in hormone level were thought to have a limited role in the formation of a hairy root tumor (5). A depends on the synergistic action of three genes called rolA, roiB, and rolC (18,21,22,27). Some experiments indicated that the rol genes, particularly rolB, act by increasing auxin sensitivity in transformed tissue (19,21).…”