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Pea LATE BLOOMER 1 is a GIGANTEA ortholog with roles in photoperiodic flowering, de-etiolation and transcriptional regulation of circadian clock gene homologs


Hecht, VFG and Knowles, CL and Vanderschoor, JK and Liew, LC and Jones, SE and Lambert, M and Weller, JL, Pea LATE BLOOMER 1 is a GIGANTEA ortholog with roles in photoperiodic flowering, de-etiolation and transcriptional regulation of circadian clock gene homologs, Plant Physiology, 144, (2) pp. 648-661. ISSN 0032-0889 (2007) [Refereed Article]

DOI: doi:10.1104/pp.107.096818


Genes controlling the transition to flowering have been studied in several species, including Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa), but have not yet received much attention in legumes. Here, we describe a new allelic series of late-flowering, photoperiod-insensitive mutants in the pea (Pisum sativum) LATE BLOOMER1 (LATE1) gene and show that LATE1 is an ortholog of Arabidopsis GIGANTEA. Mutants display defects in phytochrome B-dependent deetiolation under red light and in the diurnal regulation of pea homologs of several Arabidopsis circadian clock genes, including TIMING OF CAB1, EARLY FLOWERING4, and CIRCADIAN CLOCK ASSOCIATED1/LATE ELONGATED HYPOCOTYL. LATE1 itself shows strongly rhythmic expression with a small but distinct acute peak following dark-to-light transfer. Mutations in LATE1 prevent the induction of a FLOWERING LOCUS T (FT) homolog FTL in long days but cause only minor alteration to the rhythmic expression pattern of the only known group Ia CONSTANS homolog COLa. The late-flowering phenotype of late1 mutants can be completely rescued by grafting to the wild type, but this rescue is not associated with a significant increase in FTL transcript level in shoot apices. Genetic interactions of late1 with the photoperiod-insensitive, early-flowering sterile nodes (sn) mutant and impairment of the LATE1 diurnal expression rhythm in sn plants suggest that SN may also affect the circadian clock. These results show that several functions of Arabidopsis GIGANTEA are conserved in its pea ortholog and demonstrate that genetic pathways for photoperiodic flowering are likely to be conserved between these two species. They also suggest that in addition to its role in the floral transition, LATE1 also acts throughout reproductive development. © 2007 American Society of Plant Biologists.

Item Details

Item Type:Refereed Article
Research Division:Biological Sciences
Research Group:Plant biology
Research Field:Plant physiology
Objective Division:Plant Production and Plant Primary Products
Objective Group:Environmentally sustainable plant production
Objective Field:Environmentally sustainable plant production not elsewhere classified
UTAS Author:Hecht, VFG (Dr Valerie Hecht)
UTAS Author:Knowles, CL (Dr Claire Knowles)
UTAS Author:Vanderschoor, JK (Mrs Jacqueline Vanderschoor)
UTAS Author:Liew, LC (Miss Lim Chee Liew)
UTAS Author:Jones, SE (Miss Sarah Jones)
UTAS Author:Lambert, M (Miss Misty Lambert)
UTAS Author:Weller, JL (Associate Professor Jim Weller)
ID Code:50208
Year Published:2007
Web of Science® Times Cited:106
Deposited By:Plant Science
Deposited On:2007-08-01
Last Modified:2009-08-24

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