StGA2ox1 is induced prior to stolon swelling and controls GA levels during potato tuber development
The formation and growth of a potato (Solanum tuberosum) tuber is a complex process regulated by different environmental signals and plant hormones. In particular, the action of gibberellins (GAs) has been implicated in different aspects of potato tuber formation. Here we report on the isolation and functional analysis of a potato GA 2-oxidase gene (StGA2ox1) and its role in tuber formation. StGA2ox1 is upregulated during the early stages of potato tuber development prior to visible swelling and is predominantly expressed in the subapical region of the stolon and growing tuber. 35S-over-expression transformants exhibit a dwarf phenotype, reduced stolon growth and earlier in vitro tuberization. Transgenic plants with reduced expression levels of StGA2ox1 showed normal plant growth, an altered stolon swelling phenotype and delayed in vitro tuberization. Tubers of the StGA2ox1 suppression clones contain increased levels of GA20, indicating altered GA metabolism. We propose a role for StGA2ox1 in early tuber initiation by modifying GA levels in the subapical stolon region at the onset of tuberization, thereby facilitating normal tuber development and growth.
Document Type: Research Article
Affiliations: 1: Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Campus Universidad Autónoma de Madrid, c/Darwin 3, 28049 Madrid, Spain, and 2: Graduate School Experimental Plant Sciences, Laboratory of Plant Breeding, Department of Plant Sciences, Wageningen University and Research Centre, PO Box 386, 6700 AJ Wageningen, The Netherlands, 3: Institute of Plant Biology, Technical University of Braunschweig, D-38106 Braunschweig, Germany
Publication date: October 1, 2007