Estruch J J, Schell J, Spena A
MPI für Züchtungsforschung, Köln, FRG.
EMBO J. 1991 Nov;10(11):3125-8. doi: 10.1002/j.1460-2075.1991.tb04873.x.
The rolB gene of Agrobacterium rhizogenes, whose expression stimulates the formation of roots by transformed plant tissues and other growth alterations in transgenic plants, codes for a beta-glucosidase able to hydrolyse indole-beta-glucosides. Indeed, we show that extracts of bacteria and/or plant tissue expressing the rolB protein hydrolyse indoxyl-beta-glucoside (plant indican). Because of the structural similarity between indoxyl-beta-glucoside and indole-3-acetyl-beta-glucoside (IAA-beta-glucoside), we propose that the physiological and developmental alterations in transgenic plants expressing the rolB gene could be the result of an increased intracellular auxin activity caused by the release of active auxins from inactive beta-glucosides. Thus two of the oncogenes carried by the T-DNA of the plant pathogen Agrobacterium rhizogenes (rolB and rolC) perturb plant growth and development by coding for beta-glucosidases with distinct specificities. Whereas the rolC beta-glucosidase releases cytokinins from their glucoside conjugates, the rolB encoded protein hydrolyses indole-beta-glucosides. The combined action of these two genes therefore is expected to modulate the intracellular concentration of two of the main growth factors active in plants.
发根农杆菌的rolB基因，其表达可刺激转化植物组织形成根以及转基因植物中的其他生长变化，编码一种能够水解吲哚-β-葡萄糖苷的β-葡萄糖苷酶。实际上，我们发现表达rolB蛋白的细菌和/或植物组织提取物能够水解吲哚酚-β-葡萄糖苷（植物吲哚苷）。由于吲哚酚-β-葡萄糖苷与吲哚-3-乙酰基-β-葡萄糖苷（IAA-β-葡萄糖苷）在结构上相似，我们推测表达rolB基因的转基因植物中的生理和发育变化可能是由于无活性的β-葡萄糖苷释放出活性生长素，导致细胞内生长素活性增加所致。因此，植物病原体发根农杆菌的T-DNA携带的两个致癌基因（rolB和rolC）通过编码具有不同特异性的β-葡萄糖苷酶来干扰植物的生长和发育。rolCβ-葡萄糖苷酶从其葡萄糖苷结合物中释放细胞分裂素，而rolB编码的蛋白则水解吲哚-β-葡萄糖苷。因此，这两个基因的共同作用有望调节植物中两种主要活性生长因子的细胞内浓度。
