RRC ID 11901
Author Higuchi Y, Sage-Ono K, Sasaki R, Ohtsuki N, Hoshino A, Iida S, Kamada H, Ono M.
Title Constitutive expression of the GIGANTEA ortholog affects circadian rhythms and suppresses one-shot induction of flowering in Pharbitis nil, a typical short-day plant.
Journal Plant Cell Physiol
Abstract GIGANTEA (GI) is a key regulator of flowering time, which is closely related to the circadian clock function in Arabidopsis. Mutations in the GI gene cause photoperiod-insensitive flowering and altered circadian rhythms. We isolated the GI ortholog PnGI from Pharbitis (Ipomoea) nil, an absolute short-day (SD) plant. PnGI mRNA expression showed diurnal rhythms that peaked at dusk under SD and long-day (LD) conditions, and also showed robust circadian rhythms under continuous dark (DD) and continuous light (LL) conditions. Short irradiation with red light during the flower-inductive dark period did not change PnGI expression levels, suggesting that such a night break does not abolish flowering by affecting the expression of PnGI. In Pharbitis, although a single dusk signal is sufficient to induce expression of the ortholog of FLOWERING LOCUS T (PnFT1), PnGI mRNA expression was not reset by single lights-off signals. Constitutive expression of PnGI (PnGI-OX) in transgenic plants altered period length in leaf-movement rhythms under LL and affected circadian rhythms of PnFT mRNA expression under DD. PnGI-OX plants formed fewer flower buds than the wild type when one-shot darkness was given. In PnGI-OX plants, expression of PnFT1 was down-regulated, suggesting that PnGI functions as a suppressor of flowering, possibly in part through down-regulation of PnFT1.
Volume 52(4)
Pages 638-50
Published 2011-4-1
DOI 10.1093/pcp/pcr023
PII pcr023
PMID 21382978
MeSH Arabidopsis Proteins / genetics Base Sequence Circadian Rhythm / genetics* Circadian Rhythm / radiation effects DNA, Complementary / genetics DNA, Plant / chemistry DNA, Plant / genetics DNA-Binding Proteins / genetics DNA-Binding Proteins / metabolism Darkness Down-Regulation / genetics Flowers / genetics Flowers / metabolism Flowers / physiology* Gene Expression Regulation, Plant / radiation effects Ipomoea nil / genetics Ipomoea nil / growth & development Ipomoea nil / physiology* Ipomoea nil / radiation effects Light Molecular Sequence Data Photoperiod Plant Leaves / genetics Plant Leaves / metabolism Plant Proteins / genetics Plant Proteins / metabolism* Plants, Genetically Modified RNA, Messenger / genetics RNA, Plant / genetics Sequence Analysis, DNA Signal Transduction
IF 4.062
Times Cited 22
Morning Glory EST clones