PMID:21808030

Citation	Whipple, CJ, Kebrom, TH, Weber, AL, Yang, F, Hall, D, Meeley, R, Schmidt, R, Doebley, J, Brutnell, TP and Jackson, DP (2011) grassy tillers1 promotes apical dominance in maize and responds to shade signals in the grasses. Proc. Natl. Acad. Sci. U.S.A. 108:E506-12
Abstract	The shape of a plant is largely determined by regulation of lateral branching. Branching architecture can vary widely in response to both genotype and environment, suggesting regulation by a complex interaction of autonomous genetic factors and external signals. Tillers, branches initiated at the base of grass plants, are suppressed in response to shade conditions. This suppression of tiller and lateral branch growth is an important trait selected by early agriculturalists during maize domestication and crop improvement. To understand how plants integrate external environmental cues with endogenous signals to control their architecture, we have begun a functional characterization of the maize mutant grassy tillers1 (gt1). We isolated the gt1 gene using positional cloning and found that it encodes a class I homeodomain leucine zipper gene that promotes lateral bud dormancy and suppresses elongation of lateral ear branches. The gt1 expression is induced by shading and is dependent on the activity of teosinte branched1 (tb1), a major domestication locus controlling tillering and lateral branching. Interestingly, like tb1, gt1 maps to a quantitative trait locus that regulates tillering and lateral branching in maize and shows evidence of selection during maize domestication. Branching and shade avoidance are both of critical agronomic importance, but little is known about how these processes are integrated. Our results indicate that gt1 mediates the reduced branching associated with the shade avoidance response in the grasses. Furthermore, selection at the gt1 locus suggests that it was involved in improving plant architecture during the domestication of maize.
Links	PubMed PMC3158142 Online version:10.1073/pnas.1102819108
Keywords	Gene Expression Regulation, Plant; Genes, Plant; Molecular Sequence Data; Plant Proteins/genetics; Poaceae/physiology; Sunlight; Zea mays/genetics; Zea mays/physiology
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
MAIZE:G1AQA5		GO:0048450: floral organ structural organization	ECO:0000315:		P		Figure 1 A and B show altered floral organ organization in a gt1 mutant.	complete CACAO 5484
MAIZE:G1AQA5		GO:2000032: regulation of secondary shoot formation	ECO:0000315:		P		Figure 1 C, D, and G show that gt1 mutants have more tillers (side shoots) than the wild type.	complete CACAO 5485
MAIZE:G1AQA5	involved_in	GO:0048450: floral organ structural organization	ECO:0000315: mutant phenotype evidence used in manual assertion		P		Seeded From UniProt	complete
MAIZE:G1AQA5	involved_in	GO:2000032: regulation of secondary shoot formation	ECO:0000315: mutant phenotype evidence used in manual assertion		P		Seeded From UniProt	complete

References

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