Sugar availability suppresses the auxin-induced strigolactone pathway to promote bud outgrowth

• Apical dominance occurs when the growing shoot tip inhibits the outgrowth of axillary buds. Apically-derived auxin in the nodal stem indirectly inhibits bud outgrowth via cytokinins and strigolactones. Recently, sugar deprivation was found to contribute to this phenomenon. • Using rose and pea, we...

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Bibliographic Details
Published in:The New phytologist 2020-01, Vol.225 (2), p.866-879
Main Authors: Bertheloot, Jessica, Barbier, François, Boudon, Frédéric, Perez-Garcia, Maria Dolores, Péron, Thomas, Citerne, Sylvie, Dun, Elizabeth, Beveridge, Christine, Godin, Christophe, Sakr, Soulaiman
Format: Article
Language:English
Subjects:
auxin
branching
bud
Cytokinins - metabolism
Flowers - drug effects
Flowers - growth & development
Flowers - metabolism
hormones
Indoleacetic Acids - pharmacology
Lactones - metabolism
Life Sciences
Models, Biological
Mutation - genetics
Pisum sativum - drug effects
Pisum sativum - growth & development
Plant breeding
Rosa - drug effects
Rosa - growth & development
strigolactones
sucrose
Sucrose - metabolism
sugar
Sugars - metabolism
Vegetal Biology
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Summary:• Apical dominance occurs when the growing shoot tip inhibits the outgrowth of axillary buds. Apically-derived auxin in the nodal stem indirectly inhibits bud outgrowth via cytokinins and strigolactones. Recently, sugar deprivation was found to contribute to this phenomenon. • Using rose and pea, we investigated whether sugar availability interacts with auxin in bud outgrowth control, and the role of cytokinins and strigolactones, in vitro and in planta. • We show that sucrose antagonises auxin’s effect on bud outgrowth, in a dose-dependent and coupled manner. Sucrose also suppresses strigolactone inhibition of outgrowth and the rms3 strigolactone-perception mutant is less affected by reducing sucrose supply. However, sucrose does not interfere with the regulation of cytokinin levels by auxin and stimulates outgrowth even with optimal cytokinin supply. These observations were assembled into a computational model in which sucrose represses bud response to strigolactones, largely independently of cytokinin levels. It quantitatively captures our observed dose-dependent sucrose-hormones effects on bud outgrowth and allows us to express outgrowth response to various combinations of auxin and sucrose levels as a simple quantitative law. • This study places sugars in the bud outgrowth regulatory network and paves the way for a better understanding of branching plasticity in response to environmental and genotypic factors.
ISSN:0028-646X
1469-8137
DOI:10.1111/nph.16201