Auxin and Gibberellin Interact in Citrus Fruit Set

Gibberellins (GA) and auxin (indole-3-acetic acid, IAA) are considered the main compounds involved in the induction of fruit set. Citrus trees flower profusely but exhibit dramatically low fruit set rates and, in particular, seeded orange cultivars also require pollination for fruit to adequately se...

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Main Authors: Bermejo, Almudena, Granero, Beatriz, Mesejo, Carlos, Reig, Carmina, Tejedo, Vicente, Agustí, Manuel, Primo-Millo, Eduardo, Iglesias, Domingo J.
Format: Artículo
Language:Inglés
Published: 2018
Online Access:http://hdl.handle.net/20.500.11939/6025
http://rdcu.be/wfuM
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author Bermejo, Almudena
Granero, Beatriz
Mesejo, Carlos
Reig, Carmina
Tejedo, Vicente
Agustí, Manuel
Primo-Millo, Eduardo
Iglesias, Domingo J.
author_browse Agustí, Manuel
Bermejo, Almudena
Granero, Beatriz
Iglesias, Domingo J.
Mesejo, Carlos
Primo-Millo, Eduardo
Reig, Carmina
Tejedo, Vicente
author_facet Bermejo, Almudena
Granero, Beatriz
Mesejo, Carlos
Reig, Carmina
Tejedo, Vicente
Agustí, Manuel
Primo-Millo, Eduardo
Iglesias, Domingo J.
author_sort Bermejo, Almudena
collection ReDivia
description Gibberellins (GA) and auxin (indole-3-acetic acid, IAA) are considered the main compounds involved in the induction of fruit set. Citrus trees flower profusely but exhibit dramatically low fruit set rates and, in particular, seeded orange cultivars also require pollination for fruit to adequately set. Consequently, they represent an excellent model to investigate the interactions between both hormones and their effect on fruit set and development. Unpollinated ovaries from ‘Pineapple’ sweet orange trees were treated with IAA and pollinated ones with TIBA (2,3,5-triiodobenzoic acid, inhibitor of auxin transport), and changes in ovaries were registered shortly after the treatments. The highest IAA levels were found in unpollinated ovaries treated with auxin (twofold increase compared to pollinated ones), and the lowest corresponded to pollinated ones supplemented with TIBA (30% reduction). GA content also differed substantially among samples. In general, expression of the GA-biosynthetic gene GA20ox2 in the ovule and pericarp paralleled the changes in GA20 content in both tissues, and also expression of GA3ox1 and GA1 content but only in the ovule. The levels of these GA in unpollinated ovaries were promoted in response to exogenous IAA, whereas expression of the GA-inactivation gene GA2ox1 and the concentration of the GA-catabolite GA8 were reduced by this treatment. Significantly, treatments with GA3 or IAA to unpollinated ovaries recovered fruit set to the level reached by free pollinated ones. Our study demonstrates that IAA alters GA metabolism in citrus leading to marked changes in the active GA1 levels in ovules and pericarp, mainly through the regulation of GA-biosynthetic genes and the inhibition of the catabolic pathway.
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spelling ReDivia60252025-04-25T14:45:57Z Auxin and Gibberellin Interact in Citrus Fruit Set Bermejo, Almudena Granero, Beatriz Mesejo, Carlos Reig, Carmina Tejedo, Vicente Agustí, Manuel Primo-Millo, Eduardo Iglesias, Domingo J. Gibberellins (GA) and auxin (indole-3-acetic acid, IAA) are considered the main compounds involved in the induction of fruit set. Citrus trees flower profusely but exhibit dramatically low fruit set rates and, in particular, seeded orange cultivars also require pollination for fruit to adequately set. Consequently, they represent an excellent model to investigate the interactions between both hormones and their effect on fruit set and development. Unpollinated ovaries from ‘Pineapple’ sweet orange trees were treated with IAA and pollinated ones with TIBA (2,3,5-triiodobenzoic acid, inhibitor of auxin transport), and changes in ovaries were registered shortly after the treatments. The highest IAA levels were found in unpollinated ovaries treated with auxin (twofold increase compared to pollinated ones), and the lowest corresponded to pollinated ones supplemented with TIBA (30% reduction). GA content also differed substantially among samples. In general, expression of the GA-biosynthetic gene GA20ox2 in the ovule and pericarp paralleled the changes in GA20 content in both tissues, and also expression of GA3ox1 and GA1 content but only in the ovule. The levels of these GA in unpollinated ovaries were promoted in response to exogenous IAA, whereas expression of the GA-inactivation gene GA2ox1 and the concentration of the GA-catabolite GA8 were reduced by this treatment. Significantly, treatments with GA3 or IAA to unpollinated ovaries recovered fruit set to the level reached by free pollinated ones. Our study demonstrates that IAA alters GA metabolism in citrus leading to marked changes in the active GA1 levels in ovules and pericarp, mainly through the regulation of GA-biosynthetic genes and the inhibition of the catabolic pathway. 2018-05-09T16:30:56Z 2018-05-09T16:30:56Z 2017 article Bermejo, A., Granero, B., Mesejo, C., Reig, C., Tejedo, V., Agustí, M., Primo-Millo, E., Iglesias, D. J. (2017). Auxin and gibberellin interact in citrus fruit set. Journal of Plant Growth Regulation, 37, 491-500. 1435-8107 http://hdl.handle.net/20.500.11939/6025 10.1007/s00344-017-9748-9 http://rdcu.be/wfuM en Atribución-NoComercial-SinDerivadas 3.0 España http://creativecommons.org/licenses/by-nc-nd/3.0/es/ electronico
spellingShingle Bermejo, Almudena
Granero, Beatriz
Mesejo, Carlos
Reig, Carmina
Tejedo, Vicente
Agustí, Manuel
Primo-Millo, Eduardo
Iglesias, Domingo J.
Auxin and Gibberellin Interact in Citrus Fruit Set
title Auxin and Gibberellin Interact in Citrus Fruit Set
title_full Auxin and Gibberellin Interact in Citrus Fruit Set
title_fullStr Auxin and Gibberellin Interact in Citrus Fruit Set
title_full_unstemmed Auxin and Gibberellin Interact in Citrus Fruit Set
title_short Auxin and Gibberellin Interact in Citrus Fruit Set
title_sort auxin and gibberellin interact in citrus fruit set
url http://hdl.handle.net/20.500.11939/6025
http://rdcu.be/wfuM
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