In vitro growth and tuber formation by transgenic potato plants harboring rolC or rolB genes under control of the patatin promoter.

摘要

Growth and tuber formation by transgenic potato cv. Desiree plants bearing bacterial rolC or rolB genes under the control of tuber-specific class 1 patatin promoter (B33 promoter) were studied in vitro under conditions favourable (5-8% sucrose) or unfavourable (2% sucrose) for tuberization. Wild-type plants grown under similar conditions and plants bearing only a 35S-GUS marker costruction served as controls. Under unfavourable conditions for tuber formation, both types of transformants (B33-rolC and B33-rolB) differed little from control plants. Under conditions promoting tuber formation, B33-rolC plants differed from control plants by active shoot and root growth, suppressed apical dominance, enhanced branching, delayed tuberization, and the formation of abnormally elongated tubers with numerous buds. B33-rolB plants showed no marked changes in growth and tillering activities, but they began to form tubers earlier. These tubers were elongated in shape when they were formed in the light, but notin darkness. It is concluded that the expression of inserted gene constructions B33-rolC and B33-rolB affected some stages of tuber formation, namely tuber initiation and shape determination. The products of the rolC and rolB genes seem to affect tuberformation by changing the sensitivity of cells in the sub-apical zone of the stolon and those of developing tubers toward endogenous cytokinins and/or auxins.