אסיף מאגר המחקר החקלאי

Release of apical dominance in potato tuber is accompanied by programmed cell death in the apical bud meristem

Year:

2012

Source of publication :

Authors :

Volume :

158

Co-Authors:

Teper-Bamnolker, P., Department of Postharvest Science, Bet-Dagan 50250, Israel
Buskila, Y., Department of Postharvest Science, Bet-Dagan 50250, Israel
Lopesco, Y., Department of Postharvest Science, Bet-Dagan 50250, Israel
Ben-Dor, S., The Volcani Center, Agricultural Research Organization, Bet-Dagan 50250, Israel, Bioinformatics and Biological Computing Unit, Department of Biological Services, Weizmann Institute of Science, Rehovot 76100, Israel
Saad, I., Department of Postharvest Science, Bet-Dagan 50250, Israel
Holdengreber, V., Department of Plant Pathology and Weed Research, Bet-Dagan 50250, Israel
Belausov, E., Department of Ornamental Horticulture, Bet-Dagan 50250, Israel
Zemach, H., Department of Fruit Tree Science, Bet-Dagan 50250, Israel
Ori, N., Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Otto Warburg Minerva Center for Agricultural Biotechnology, Faculty of Agriculture, Food, and Environment, Hebrew University of Jerusalem, Rehovot 76100, Israel
Lers, A., Department of Postharvest Science, Bet-Dagan 50250, Israel
Eshel, D., Department of Postharvest Science, Bet-Dagan 50250, Israel

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Abstract:

Potato (Solanum tuberosum) tuber, a swollen underground stem, is used as a model system for the study of dormancy release and sprouting. Natural dormancy release, at room temperature, is initiated by tuber apical bud meristem (TAB-meristem) sprouting characterized by apical dominance (AD). Dormancy is shortened by treatments such as bromoethane (BE), which mimics the phenotype of dormancy release in cold storage by inducing early sprouting of several buds simultaneously. We studied the mechanisms governing TAB-meristem dominance release. TAB-meristem decapitation resulted in the development of increasing numbers of axillary buds with time in storage, suggesting the need for autonomous dormancy release of each bud prior to control by the apical bud. Hallmarks of programmed cell death (PCD) were identified in the TAB-meristems during normal growth, and these were more extensive when AD was lost following either extended cold storage or BE treatment. Hallmarks included DNA fragmentation, induced gene expression of vacuolar processing enzyme1 (VPE1), and elevated VPE activity. VPE1 protein was semipurified from BE-treated apical buds, and its endogenous activity was fully inhibited by a cysteinyl aspartate-specific protease-1-specific inhibitor N-Acetyl-Tyr-Val-Ala-Asp-CHO (Ac-YVAD-CHO). Transmission electron microscopy further revealed PCD-related structural alterations in the TAB-meristem of BE-treated tubers: a knob-like body in the vacuole, development of cytoplasmic vesicles, and budding-like nuclear segmentations. Treatment of tubers with BE and then VPE inhibitor induced faster growth and recovered AD in detached and nondetached apical buds, respectively. We hypothesize that PCD occurrence is associated with the weakening of tuber AD, allowing early sprouting of mature lateral buds. © 2012 American Society of Plant Biologists. All Rights Reserved.

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