Failla M C, Maimone F, De Paolis A, Costantino P, Cardarelli M
Dip. Genetica e Biologia Molecolare, Università La Sapienza, Roma, Italy.
Plant Mol Biol. 1990 Nov;15(5):747-53. doi: 10.1007/BF00016124.
The T-DNA regions of three strains of Ri plasmids 1855, 8196, 2659 (agropine, mannopine and cucumopine type respectively) share two highly conserved regions flanking a non-homologous central part. We have cloned segments of the cucumopine Ri plasmid 2659 T-DNA in the binary vector system Bin 19 and infected carrot discs with recombinant Agrobacterium strains. We show here that the central non-conserved region is crucial in hairy root induction as it is sufficient to induce rooting on the apical (auxin-rich) surface of carrot discs; in order to observe rooting on the basal (auxin-depleted) side of the discs, a longer T-DNA fragment, also encompassing part of the right conserved region, had to be utilized in conjunction with a Agrobacterium strain carrying aux genes. Differences of growth properties in culture are exhibited by roots transformed with different fragments of pRi 2659 T-DNA, although all transformed roots show the plagiotropic behaviour typical of hairy roots.
三种发根质粒菌株1855、8196、2659（分别为农杆碱型、甘露碱型和黄瓜碱型）的T-DNA区域在一个非同源的中央部分两侧有两个高度保守的区域。我们已将黄瓜碱型发根质粒2659的T-DNA片段克隆到双元载体系统Bin 19中，并用重组农杆菌菌株感染胡萝卜圆片。我们在此表明，中央非保守区域在毛状根诱导中至关重要，因为它足以在胡萝卜圆片的顶端（富含生长素）表面诱导生根；为了观察圆片基部（生长素缺乏）一侧的生根情况，必须使用一个更长的T-DNA片段（该片段也包含右侧保守区域的一部分）与携带生长素基因的农杆菌菌株联合使用。用pRi 2659 T-DNA的不同片段转化的根在培养中表现出生长特性的差异，尽管所有转化根都表现出毛状根典型的斜向生长行为。
