Exploring the role of tryptophan in biennial bearingA mobile molecule that is exported from growing apples but does not suppress flowering
Exploring the role of tryptophan in biennial bearing
A mobile molecule that is exported from growing apples but does not suppress flowering
Dokument öffnen (799.2KB)Datum der Veröffentlichung
23.12.2024Verlag / herausgebende Einrichtung
International Society for Horticultural ScienceVerlagsort
LeuvenMetadaten
Zur Langanzeige
Zitierbarer Link (Handle URI) 
https://hdl.handle.net/20.500.11811/13343
Inhalt
Background of the study – Apple (Malus × domestica Borkh.) production faces significant challenges, with biennial (or alternate) bearing being a major obstacle to stable yields. Natural high crop load (ON-year) considerably reduces return bloom in the following year resulting in low yields (OFF-year) that significantly diminish the profitability of apple production. Previous studies suggested that growing apples may export some unknown signaling molecule(s) to the adjacent bourse buds and thereby inhibit flower bud formation. Objectives – This study addresses the role of tryptophan as a potential signal that triggers biennial bearing. Previously, we found that bourse buds of high-cropping 'Fuji' and 'Gala' trees contain more tryptophan compared to bourse buds of the trees with no crop load. This led to the hypothesis that tryptophan is exported from the growing apples and accumulates in the adjacent bourse buds where it potentially inhibits flower initiation, or further metabolizes to melatonin, which may act as an inhibitor of flower bud formation. Methods – We tested our hypothesis by measuring the export of tryptophan from 'Fuji' and 'Gala' apples. Besides, we carried out foliar applications with tryptophan on 'Nicoter' and 'Gala' trees. In addition, we checked whether tryptophan or melatonin affect the continuous-flowering habit of RNAi transgenic apple plantlets with silenced expression of MdTFL1 cultivated in vitro. Results – Our data shows that growing apple fruits of 'Fuji' and 'Gala' export tryptophan. However, foliar applications with this compound did not affect return bloom in 'Nicoter' or 'Gala'. Finally, neither tryptophan nor melatonin suppressed flowering of MdTFL1-1 RNAi transgenic apple plantlets in vitro. Conclusions – Although the transport of tryptophan from apple fruits to adjacent bourse buds cannot be excluded, we reject the hypothesis on an inhibitory effect of tryptophan and its downstream metabolic product melatonin on flower bud formation in apple.
Schlagwörter
alternate bearing, apple diffusates, Malus × domestica Borkh., flower induction, fruit-bud interaction, melatonin
Klassifikation (DDC)
630 Landwirtschaft, VeterinärmedizinErschienen in
European Journal of Horticultural Science, 2024, vol. 89, iss. 6, S. 1-10Erstpublikation
https://doi.org/10.17660/eJHS.2024/030Milyaev, A.; Klaiber, I.; Tandron-Moya, Y.A.; Lempe, J.; Pfannstiel, J.; Luedeling, E.; Wirén, N. von; Flachowsky, H.: Exploring the role of tryptophan in biennial bearing : A mobile molecule that is exported from growing apples but does not suppress flowering. In: European Journal of Horticultural Science. 2024, vol. 89, iss. 6, 1-10.
Online-Ausgabe in bonndoc: https://hdl.handle.net/20.500.11811/13343
Online-Ausgabe in bonndoc: https://hdl.handle.net/20.500.11811/13343
@article{handle:20.500.11811/13343,
author = {{A. Milyaev} and {I. Klaiber} and {Y.A. Tandron-Moya} and {J. Lempe} and {J. Pfannstiel} and {E. Luedeling} and {N. von Wirén} and {H. Flachowsky}},
title = {Exploring the role of tryptophan in biennial bearing : A mobile molecule that is exported from growing apples but does not suppress flowering},
publisher = {International Society for Horticultural Science},
year = 2024,
month = dec,
journal = {European Journal of Horticultural Science},
volume = 2024, vol. 89,
number = iss. 6,
pages = 1--10,
note = {Background of the study – Apple (Malus × domestica Borkh.) production faces significant challenges, with biennial (or alternate) bearing being a major obstacle to stable yields. Natural high crop load (ON-year) considerably reduces return bloom in the following year resulting in low yields (OFF-year) that significantly diminish the profitability of apple production. Previous studies suggested that growing apples may export some unknown signaling molecule(s) to the adjacent bourse buds and thereby inhibit flower bud formation. Objectives – This study addresses the role of tryptophan as a potential signal that triggers biennial bearing. Previously, we found that bourse buds of high-cropping 'Fuji' and 'Gala' trees contain more tryptophan compared to bourse buds of the trees with no crop load. This led to the hypothesis that tryptophan is exported from the growing apples and accumulates in the adjacent bourse buds where it potentially inhibits flower initiation, or further metabolizes to melatonin, which may act as an inhibitor of flower bud formation. Methods – We tested our hypothesis by measuring the export of tryptophan from 'Fuji' and 'Gala' apples. Besides, we carried out foliar applications with tryptophan on 'Nicoter' and 'Gala' trees. In addition, we checked whether tryptophan or melatonin affect the continuous-flowering habit of RNAi transgenic apple plantlets with silenced expression of MdTFL1 cultivated in vitro. Results – Our data shows that growing apple fruits of 'Fuji' and 'Gala' export tryptophan. However, foliar applications with this compound did not affect return bloom in 'Nicoter' or 'Gala'. Finally, neither tryptophan nor melatonin suppressed flowering of MdTFL1-1 RNAi transgenic apple plantlets in vitro. Conclusions – Although the transport of tryptophan from apple fruits to adjacent bourse buds cannot be excluded, we reject the hypothesis on an inhibitory effect of tryptophan and its downstream metabolic product melatonin on flower bud formation in apple.},
url = {https://hdl.handle.net/20.500.11811/13343}
}
author = {{A. Milyaev} and {I. Klaiber} and {Y.A. Tandron-Moya} and {J. Lempe} and {J. Pfannstiel} and {E. Luedeling} and {N. von Wirén} and {H. Flachowsky}},
title = {Exploring the role of tryptophan in biennial bearing : A mobile molecule that is exported from growing apples but does not suppress flowering},
publisher = {International Society for Horticultural Science},
year = 2024,
month = dec,
journal = {European Journal of Horticultural Science},
volume = 2024, vol. 89,
number = iss. 6,
pages = 1--10,
note = {Background of the study – Apple (Malus × domestica Borkh.) production faces significant challenges, with biennial (or alternate) bearing being a major obstacle to stable yields. Natural high crop load (ON-year) considerably reduces return bloom in the following year resulting in low yields (OFF-year) that significantly diminish the profitability of apple production. Previous studies suggested that growing apples may export some unknown signaling molecule(s) to the adjacent bourse buds and thereby inhibit flower bud formation. Objectives – This study addresses the role of tryptophan as a potential signal that triggers biennial bearing. Previously, we found that bourse buds of high-cropping 'Fuji' and 'Gala' trees contain more tryptophan compared to bourse buds of the trees with no crop load. This led to the hypothesis that tryptophan is exported from the growing apples and accumulates in the adjacent bourse buds where it potentially inhibits flower initiation, or further metabolizes to melatonin, which may act as an inhibitor of flower bud formation. Methods – We tested our hypothesis by measuring the export of tryptophan from 'Fuji' and 'Gala' apples. Besides, we carried out foliar applications with tryptophan on 'Nicoter' and 'Gala' trees. In addition, we checked whether tryptophan or melatonin affect the continuous-flowering habit of RNAi transgenic apple plantlets with silenced expression of MdTFL1 cultivated in vitro. Results – Our data shows that growing apple fruits of 'Fuji' and 'Gala' export tryptophan. However, foliar applications with this compound did not affect return bloom in 'Nicoter' or 'Gala'. Finally, neither tryptophan nor melatonin suppressed flowering of MdTFL1-1 RNAi transgenic apple plantlets in vitro. Conclusions – Although the transport of tryptophan from apple fruits to adjacent bourse buds cannot be excluded, we reject the hypothesis on an inhibitory effect of tryptophan and its downstream metabolic product melatonin on flower bud formation in apple.},
url = {https://hdl.handle.net/20.500.11811/13343}
}
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