title: Stronger sink demand for metabolites supports dominance of the apical bud in etiolated growth.
abstract: The potato tuber is a swollen underground stem that can sprout under dark conditions. Sprouting initiates in the tuber apical bud (AP), while lateral buds (LTs) are repressed by apical dominance (AD). Under conditions of lost AD, removal of tuber LTs showed that they partially inhibit AP growth only at the AD stage. Detached buds were inhibited by exogenous application of naphthaleneacetic acid (NAA), whereas 6-benzyladenine (6-BA) and gibberellic acid (GA3) induced bud burst and elongation, respectively. NAA, applied after 6-BA or GA3, nullified the latters' growth-stimulating effect in both the AP and LTs. GA3applied to the fifth-position LT was transported mainly to the tuber's AP. GA3treatment also resulted in increased indole-3-acetic acid (IAA) concentration and cis-zeatin O-glucoside in the AP. In a tuber tissue strip that included two or three buds connected by the peripheral vascular system, treatment of a LT with GA3affected only the AP side of the strip, suggesting that the AP is the strongest sink for GA3, which induces its etiolated elongation. Dipping etiolated sprouts in labeled GA3showed specific accumulation of the signal in the AP. Transcriptome analysis of GA3's effect showed that genes related to the cell cycle, cell proliferation, and hormone transport are up-regulated in the AP as compared to the LT. Sink demand for metabolites is suggested to support AD in etiolated stem growth by inducing differential gene expression in the AP.
authors: Department of Postharvest Science of Fresh Produce, The Volcani Center, ARO, Rishon LeZion, Israel The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, Robert H. Smith Faculty of Agriculture, Food and Environment, Rehovot, Israel.
authors: Yossi
authors: Y
authors: Buskila
authors: Department of Plant Pathology and Weed Science, The Volcani Center, ARO, Rishon LeZion, Israel.
authors: Noa
authors: N
authors: Sela
authors: Department of Postharvest Science of Fresh Produce, The Volcani Center, ARO, Rishon LeZion, Israel.
authors: Paula
authors: P
authors: Teper-Bamnolker
authors: The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.
authors: Iris
authors: I
authors: Tal
authors: The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.
authors: Eilon
authors: E
authors: Shani
authors: The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.
authors: Roy
authors: R
authors: Weinstain
authors: Department of Plant Pathology and Weed Science, The Volcani Center, ARO, Rishon LeZion, Israel.
authors: Victor
authors: V
authors: Gaba
authors: Department of Plant Pathology and Weed Science, The Volcani Center, ARO, Rishon LeZion, Israel.
authors: Yehudit
authors: Y
authors: Tam
authors: Department of Postharvest Science of Fresh Produce, The Volcani Center, ARO, Rishon LeZion, Israel.
authors: Amnon
authors: A
authors: Lers
authors: Department of Postharvest Science of Fresh Produce, The Volcani Center, ARO, Rishon LeZion, Israel dani@agri.gov.il.
authors: Dani
authors: D
authors: Eshel
mesh_terms: D001593:Benzyl Compounds / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000502:physiology; D005875:Gibberellins / Q000494:pharmacology; D005960:Glucosides / Q000378:metabolism; D007210:Indoleacetic Acids / Q000378:metabolism; D009280:Naphthaleneacetic Acids / Q000494:pharmacology; D010937:Plant Growth Regulators / Q000494:pharmacology; D035281:Plant Tubers / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D011687:Purines / Q000494:pharmacology; D011198:Solanum tuberosum / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*
chemical_list: D001593:Benzyl Compounds; D005875:Gibberellins; D005960:Glucosides; D007210:Indoleacetic Acids; D009280:Naphthaleneacetic Acids; D010937:Plant Growth Regulators; D011687:Purines; C095437:zeatin-O-glucoside; C030737:indoleacetic acid; C007842:gibberellic acid; C480551:benzylaminopurine
keywords: Apical dominance; auxin; cytokinin; etiolated growth; gibberellin; potato.