Growth and Vegetative Development
Chou, Nanyen , Finlayson, Scott .
Phytochrome Regulation of Branching in Arabidopsis.
The branching habit of plants is a key determinant of overall plant form and function with great relevance to modern agriculture. Maintaining an appropriate branching habit maximizes utilization of resources and production of biomass and/or reproductive structures. Our long term goal is to understand how environmental signals coordinate the generation of plant form, especially branching. Phytochrome B (phyB) is understood to transduce light signals (R:FR) that control axillary bud outgrowth. We have previously shown that the auxin responsive gene DRM1 and the axillary bud regulator Teosinte Branched 1 (TB1) show differential expression in response to light quality and phyB action in sorghum (Kebrom et al., 2006). The objective of this research was to characterize the roles of phytochromes A and B in the control of branching in Arabidopsis. As in sorghum, Arabidopsis phyB mutants have been reported to show reduced branching (Reed et al., 1993). Our preliminary results support this observation- under relatively low PPFD axillary buds form in the phyB-9 mutant, but are delayed in outgrowth compared to WT and fewer branches form. The expression of genes associated with branching, including the branching regulator TBL1 (BRC1) are altered in the buds of phyB-9. We also observe that the double phyA phyB mutant develops even fewer branches than the phyB single mutant. Conversely, the phyA single mutant shows greater branching than WT. Under higher levels of PPFD however, branch numbers in phyB-9 are equivalent to WT. These results indicate that branching depends to a great extent on the energy status of the plant, and suggest that light quality signals may interact with other environmental/developmental cues to regulate branching.
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1 - Texas A&M University, Soil and Crop Sciences, 370 Olsen Blvd., College Station, TX, 77843-2474, USA
2 - Texas A&M University, Soil and Crop Sciences
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM