TY - JOUR
T1 - Strigolactones enhance competition between shoot branches by dampening auxin transport
AU - Crawford, Scott
AU - Shinohara, Naoki
AU - Sieberer, Tobias
AU - Williamson, Lisa
AU - George, Gilu
AU - Hepworth, Jo
AU - Müller, Dörte
AU - Domagalska, Malgorzata A.
AU - Leyser, Ottoline
PY - 2010/9/1
Y1 - 2010/9/1
N2 - Strigolactones (SLs), or their derivatives, were recently demonstrated to act as endogenous shoot branching inhibitors, but their biosynthesis and mechanism of action are poorly understood. Here we show that the branching phenotype of mutants in the Arabidopsis P450 family member, MAX1, can be fully rescued by strigolactone addition, suggesting that MAX1 acts in SL synthesis. We demonstrate that SLs modulate polar auxin transport to control branching and that both the synthetic SL GR24 and endogenous SL synthesis significantly reduce the basipetal transport of a second branch-regulating hormone, auxin. Importantly, GR24 inhibits branching only in the presence of auxin in the main stem, and enhances competition between two branches on a common stem. Together, these results support two current hypotheses: that auxin moving down the main stem inhibits branch activity by preventing the establishment of auxin transport out of axillary branches; and that SLs act by dampening auxin transport, thus enhancing competition between branches.
AB - Strigolactones (SLs), or their derivatives, were recently demonstrated to act as endogenous shoot branching inhibitors, but their biosynthesis and mechanism of action are poorly understood. Here we show that the branching phenotype of mutants in the Arabidopsis P450 family member, MAX1, can be fully rescued by strigolactone addition, suggesting that MAX1 acts in SL synthesis. We demonstrate that SLs modulate polar auxin transport to control branching and that both the synthetic SL GR24 and endogenous SL synthesis significantly reduce the basipetal transport of a second branch-regulating hormone, auxin. Importantly, GR24 inhibits branching only in the presence of auxin in the main stem, and enhances competition between two branches on a common stem. Together, these results support two current hypotheses: that auxin moving down the main stem inhibits branch activity by preventing the establishment of auxin transport out of axillary branches; and that SLs act by dampening auxin transport, thus enhancing competition between branches.
KW - Arabidopsis
KW - Auxin transport
KW - Shoot branching
KW - Strigolactone
UR - http://www.scopus.com/inward/record.url?scp=77956210642&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=77956210642&partnerID=8YFLogxK
U2 - 10.1242/dev.051987
DO - 10.1242/dev.051987
M3 - Article
C2 - 20667910
AN - SCOPUS:77956210642
VL - 137
SP - 2905
EP - 2913
JO - Journal of Embryology and Experimental Morphology
JF - Journal of Embryology and Experimental Morphology
SN - 0950-1991
IS - 17
ER -