Etiolated stem branching is a result of systemic signaling associated with sucrose level

Bolaji Babajide Salam, Siva Kumar Malka, Xiaobiao Zhu, Huiling Gong, Carmit Ziv, Paula Teper Bamnolker, Naomi Ori, Jiming Jiang, Dani Eshel*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


The potato (Solanum tuberosum) tuber is a swollen stem. Sprouts growing from the tuber nodes represent loss of apical dominance and branching. Long cold storage induces loss of tuber apical dominance and results in secondary branching. Here, we show that a similar branching pattern can be induced by short heat treatment of the tubers. Detached sprouts were induced to branch by the heat treatment only when attached to a parenchyma cylinder. Grafting experiments showed that the scion branches only when grafted onto heat- or cold-treated tuber parenchyma, suggesting that the branching signal is transmitted systemically from the bud-base parenchyma to the grafted stem. Exogenous supply of sucrose (Suc), glucose, or fructose solution to detached sprouts induced branching in a dose-responsive manner, and an increase in Suc level was observed in tuber parenchyma upon branching induction, suggesting a role for elevated parenchyma sugars in the regulation of branching. However, sugar analysis of the apex and node after grafting showed no distinct differences in sugar levels between branching and nonbranching stems. Vacuolar invertase is a key enzyme in determining the level of Suc and its cleavage products, glucose and fructose, in potato parenchyma. Silencing of the vacuolar invertase-encoding gene led to increased tuber branching in combination with branching-inducing treatments. These results suggest that Suc in the parenchyma induces branching through signaling and not by excess mobilization from the parenchyma to the stem.

Original languageAmerican English
Pages (from-to)734-745
Number of pages12
JournalPlant Physiology
Issue number2
StatePublished - Oct 2017

Bibliographical note

Publisher Copyright:
© 2017 American Society of Plant Biologists. All Rights Reserved.


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