Lemcke K, Schmülling T
Universität Tübingen, Germany.
Plant Mol Biol. 1998 Mar;36(5):803-8. doi: 10.1023/a:1005905327898.
Agrobacterium rhizogenes strains of the agropine type harbor on their Ri-plasmid two T-DNAs, a left TL-DNA and a right TR-DNA. The rolB gene of the TL-DNA is the major factor in the pathogenesis of the hairy-root disease and its constitutive expression interfere profoundly with plant morphogenesis. We have tested whether the expression of its sequence related putative homologue from the TR-DNA (rolBTR) may cause also bacterial virulence or affect plant development. Unlike rolB, rolBTR is unable to induce root formation on tobacco leaf discs. Tobacco plants expressing a chimeric 35S::rolBTR gene have reduced stature, off-shoots at the stem base and bent and wrinkled leaves with epinastic growth. 14 N-terminal amino acids which are absent in the rolB protein are indispensable to rolBTR protein activity. The characteristic tyrosine phosphatase super family motif CX5R is absent in the rolBTR protein. For rolB this motif is possibly functionally relevant. We conclude that the rolBTR gene product has morphogenic activity but is not a functional homologue of the rolB protein.
农杆碱型发根农杆菌菌株在其Ri质粒上携带两个T-DNA，即左侧的TL-DNA和右侧的TR-DNA。TL-DNA的rolB基因是毛根病发病机制中的主要因素，其组成型表达会严重干扰植物形态发生。我们测试了来自TR-DNA的与其序列相关的假定同源物（rolBTR）的表达是否也会导致细菌毒力或影响植物发育。与rolB不同，rolBTR无法在烟草叶盘上诱导根的形成。表达嵌合35S::rolBTR基因的烟草植株株高降低，茎基部有侧枝，叶片弯曲且起皱，并伴有偏上性生长。rolB蛋白中不存在的14个N端氨基酸对rolBTR蛋白活性是不可或缺的。rolBTR蛋白中不存在特征性的酪氨酸磷酸酶超家族基序CX5R。对于rolB而言，该基序可能具有功能相关性。我们得出结论，rolBTR基因产物具有形态发生活性，但不是rolB蛋白的功能同源物。
