Int. J. Dev. Biol. 45: S37 - S38 (2001)

Vol 45, Issue S1

Regulation of potato tuberization by daylength and gibberellins

Published: 1 June 2001

V Amador, J Bou, J Martinez-Garcia, E Monte, M Rodriguez-Falcon, E Russo, S Prat

CSIC, Cid, Dept Mol Genet, Inst Biol Mol Barcelona, ES-08034 Barcelona, Spain

Abstract

Tuberization of S. tuberosum ssp andigena is induced by short days (SD) and prevented by long days (LD) or by interruption of the long nights with a 30 min night break (SD+NB). Antisense inhibition of the StGA20ox1 gene, encoding the GA 20-oxidase biosynthetic enzyme results in early tuberization in SD, but does not overcome the need of SD conditions for tuber induction. Using RT-PCR differential display of leaves from plants grown under inductive (SD) and non-inductive (SD+NB) conditions we have isolated clone PHOR1 encoding a novel arm-repeat containing protein with homology to Drosophila armadillo. PHOR1 mRNA oscillates with a diurnal rhythm and is up-regulated in plants induced for tuberization. Transgenic lines inhibited in PHOR1 expression are semi-dwarf and show a reduced response to GAs, which is consistent with a function of PHOR1 in GA signaling. These results indicate that changes in GA sensitivity are involved in mediating tuber induction.

Keywords

Phytochrome-b