Strigolactone acts downstream of auxin to regulate bud outgrowth in pea and arabidopsis

Brewer, Philip B., Dun, Elizabeth A., Ferguson, Brett J., Rameau, Catherine and Beveridge, Christine A. (2009) Strigolactone acts downstream of auxin to regulate bud outgrowth in pea and arabidopsis. Plant Physiology, 150 1: 482-493. doi:10.1104/pp.108.134783

Author Brewer, Philip B.
Dun, Elizabeth A.
Ferguson, Brett J.
Rameau, Catherine
Beveridge, Christine A.
Title Strigolactone acts downstream of auxin to regulate bud outgrowth in pea and arabidopsis
Journal name Plant Physiology   Check publisher's open access policy
ISSN 0032-0889
Publication date 2009-05
Sub-type Article (original research)
DOI 10.1104/pp.108.134783
Volume 150
Issue 1
Start page 482
End page 493
Total pages 12
Editor D. R. Ort
Place of publication United States
Publisher American Society of Plant Biologists
Collection year 2010
Language eng
Subject C1
829999 Plant Production and Plant Primary Products not elsewhere classified
060705 Plant Physiology
Formatted abstract
During the last century, two key hypotheses have been proposed to explain apical dominance in plants: auxin promotes the
production of a second messenger that moves up into buds to repress their outgrowth, and auxin saturation in the stem inhibits
auxin transport from buds, thereby inhibiting bud outgrowth. The recent discovery of strigolactone as the novel shootbranching
inhibitor allowed us to test its mode of action in relation to these hypotheses. We found that exogenously applied
strigolactone inhibited bud outgrowth in pea (Pisum sativum) even when auxin was depleted after decapitation. We also found
that strigolactone application reduced branching in Arabidopsis (Arabidopsis thaliana) auxin response mutants, suggesting that
auxin may act through strigolactones to facilitate apical dominance. Moreover, strigolactone application to tiny buds of mutant
or decapitated pea plants rapidly stopped outgrowth, in contrast to applying N-1-naphthylphthalamic acid (NPA), an auxin
transport inhibitor, which significantly slowed growth only after several days. Whereas strigolactone or NPA applied to
growing buds reduced bud length, only NPA blocked auxin transport in the bud. Wild-type and strigolactone biosynthesis
mutant pea and Arabidopsis shoots were capable of instantly transporting additional amounts of auxin in excess of
endogenous levels, contrary to predictions of auxin transport models. These data suggest that strigolactone does not act
primarily by affecting auxin transport from buds. Rather, the primary repressor of bud outgrowth appears to be the auxindependent
production of strigolactones.
Keyword Box protein TIR1
Q-Index Code C1
Q-Index Status Confirmed Code

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Created: Thu, 03 Sep 2009, 08:12:41 EST by Mr Andrew Martlew on behalf of School of Biological Sciences