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ARS Home » Northeast Area » Kearneysville, West Virginia » Appalachian Fruit Research Laboratory » Innovative Fruit Production, Improvement, and Protection » Research » Publications at this Location » Publication #316168

Title: Molecular and genetic regulation of tree branch orientation

Author
item Waite, Jessica
item Hollender, Courtney
item Srinivasan, Chinnathambi
item Scorza, Ralph
item Dardick, Christopher - Chris

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/20/2015
Publication Date: 4/25/2015
Citation: Guseman, J.M., Hollender, C.A., Srinivasan, C., Scorza, R., Dardick, C.D. 2015. Molecular and genetic regulation of tree branch orientation [abstract]. American Society of Plant Biologists. p. 45.

Interpretive Summary:

Technical Abstract: The ability to genetically manipulate tree form can significantly benefit orchard and tree plantation management by enabling higher density plantings, mechanized harvesting, and reduce both chemical use and costly manual labor. Using both Prunus persica and Arabidopsis thaliana, we identified an ancient family of genes which is responsible for both setting up initial lateral branch orientation as well as adjusting it in response to environmental stimuli. TAC1 promotes downward branch growth, as plants lacking TAC1 expression exhibit a “pillar” phenotype with vertically oriented branches. In contrast, LAZY1 promotes upward lateral branch orientations. Arabidopsis and peach LAZY1 mutants have wide branch angles, occasionally rootward growth, and a reduced gravitropic response. The Arabidopsis TAC1;LAZY1 double mutant phenotype indicates that there is genetic interaction between these genes. However, qPCR and RNAseq analysis suggest that this interaction is not a result of direct gene expression regulation. Preliminary yeast-two-hybrid data is currently underway to investigate potential physical interactions between TAC1 and LAZY1 proteins. Previous research revealed connections between these genes and auxin. Thus, we examined the expression of auxin-related genes in TAC1 and LAZY1 Arabidopsis mutants grown under normal and gravistimulated conditions. In addition, qPCR analysis revealed that TAC1 expression is modified by light. We propose that TAC1 and LAZY1 integrate gravity and light signals to direct lateral branch orientation in part through regulating auxin transport.