Submitted to: Plant Biology
Publication Type: Abstract Only
Publication Acceptance Date: 4/15/2005
Publication Date: 6/13/2005
Citation: Kebrom, T.H., Burson, B.L., Finlayson, S.A. 2005. Enhanced apical dominance in phytochrome b mutant sorghum is correlated with increased expression of the teosinte branched 1(TB1) gene in axillary buds [abstract]. American Society of Plant Biologists. p. 229. Interpretive Summary:
Technical Abstract: Environmental light signals perceived by phytochrome B regulate plant development. The phytochrome B null mutant sorghum (phyB-1) shows constitutive shade avoidance responses including increased plant height and inhibition of branching. Investigation of the enhanced apical dominance in phyB-1 sorghum may give clues about the molecular mechanisms regulating shoot branching in response to light signals. Shoot branching involves the formation of axillary meristems in the axil of leaves to form buds followed by outgrowth of the buds. Axillary buds are formed early in seedling growth in both phyB-1 and the wild type (WT) sorghum. Under optimal conditions for branching, the buds of WT sorghum continue growth to form branches. However, bud outgrowth is inhibited in the phyB-1 sorghum. This inhibition is correlated with increased accumulation of the TEOSINTE BRANCHED 1 (TB1) gene mRNA which encodes a putative transcription factor. Previous studies have demonstrated that increased expression of TB1 is correlated with suppression of axillary bud outgrowth in maize and rice (Hubbard et al., 2002; Takeda et al., 2003). We hypothesize that light signals perceived by phytochrome B regulate the expression of the TB1 gene to control apical dominance.