Wu, Yajun , Cai, Xiaoning , Ballif, Jenny , Endo, Saori , Davis, Elizabeth , Liang, Mingxiang , Chen, Dong , DeWald, Daryll , Kreps, Joel , Zhu, Tong , Harper, Jeffery .
A putative CCAAT-binding transcription factor is a regulator of flowering timing in Arabidopsis.
Flowering at the appropriate time of year is essential for successful reproduction in plants, and abiotic stresses, such as drought, heat and nutrient deficiency, often trigger early flowering. However, very little is known about how various stresses induce early flowering. We found that HAP3b in Arabidopsis, a stress-regulated putative CCAAT-binding transcription factor gene, is involved in controlling flowering timing. Over-expression of HAP3b promotes early flowering while hap3b, a null mutant of HAP3b, is delayed in flowering under a long-day photoperiod. Under short-day conditions, however, hap3b did not show a delayed flowering compared to wild-type based on the leaf number, suggesting that HAP3b may normally be involved in the photoperiod-regulated flowering pathway. Mutant hap3b plants showed earlier flowering upon gibberellic acid or vernalization treatment. Further transcript profiling analysis suggests that HAP3b can promote flowering by enhancing expression of key flowering time genes. Our results provide strong evidence supporting a model in which the up-regulation of HAP3b promotes early flowering in plants grown under long day conditions. Since several environmental stresses appear to up-regulate HAP3b, we propose that HAP3b provides a pathway by which abiotic stress response pathways can promote early flowering.
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1 - Utah State University, Plants Soils and Biometeorology, 4820 Old Main Hill, Logan, UT, 84322, USA
2 - Utah State University
3 - Diversa
4 - Syngenta
5 - University of Nevada, Reno, Biochemistry and Molecular Biology
CCAAT-binding transcription factor
Presentation Type: ASPB Minisymposium
Location: International Ballroom/Hilton
Date: Tuesday, July 10th, 2007
Time: 4:35 PM