Sugar demand, not auxin, is the initial regulator of apical dominance

Mason, Michael G., Ross, John J., Babst, Benjamin A., Wienclaw, Brittany N. and Beveridge, Christine A. (2014) Sugar demand, not auxin, is the initial regulator of apical dominance. Proceedings of the National Academy of Sciences of the United States of America, 111 16: 6092-6097. doi:10.1073/pnas.1322045111


Author Mason, Michael G.
Ross, John J.
Babst, Benjamin A.
Wienclaw, Brittany N.
Beveridge, Christine A.
Title Sugar demand, not auxin, is the initial regulator of apical dominance
Journal name Proceedings of the National Academy of Sciences of the United States of America   Check publisher's open access policy
ISSN 0027-8424
1091-6490
Publication date 2014-04-22
Year available 2014
Sub-type Article (original research)
DOI 10.1073/pnas.1322045111
Open Access Status Not yet assessed
Volume 111
Issue 16
Start page 6092
End page 6097
Total pages 6
Place of publication Washington, DC, United States
Publisher National Academy of Sciences
Language eng
Abstract For almost a century the plant hormone auxin has been central to theories on apical dominance, whereby the growing shoot tip suppresses the growth of the axillary buds below. According to the classic model, the auxin indole-3-acetic acid is produced in the shoot tip and transported down the stem, where it inhibits bud growth. We report here that the initiation of bud growth after shoot tip loss cannot be dependent on apical auxin supply because we observe bud release up to 24 h before changes in auxin content in the adjacent stem. After the loss of the shoot tip, sugars are rapidly redistributed over large distances and accumulate in axillary buds within a timeframe that correlates with bud release. Moreover, artificially increasing sucrose levels in plants represses the expression of BRANCHED1 (BRC1), the key transcriptional regulator responsible for maintaining bud dormancy, and results in rapid bud release. An enhancement in sugar supply is both necessary and sufficient for suppressed buds to be released from apical dominance. Our data support a theory of apical dominance whereby the shoot tip's strong demand for sugars inhibits axillary bud outgrowth by limiting the amount of sugar translocated to those buds.
Keyword Decapitation
Girdling
Long-distance signaling
Shoot branching
Sink demand
Q-Index Code C1
Q-Index Status Confirmed Code
Grant ID DP110100808
DE-AC02-98CH10886
FT100100806
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2015 Collection
School of Biological Sciences Publications
 
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