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Role of abscisic acid on anthocyanin biosynthesis under drought stress in Aristotelia chilensis (mol.) plants

Tesis

637

379

Profesor Guía

Reyes Díaz, Marjorie

Carrera

Doctorado en Ciencias de Recursos Naturales

Autor

González Villagra, Jorge Andrés

Año

2018

Resumen

Drought is the most important stress factor for plants, where abscisic acid (ABA) plays a crucial role to cope with the stress. It is well reported that drought stress increases 9-cis-epoxycarotenoid dioxygenase (NCED) gene expression, which it is an important ABA biosynthetic pathway gene, triggering higher ABA levels in plant subjected to drought stress. Thus, it has been suggested that ABA might be involved on anthocyanin biosynthesis under drought stress. Anthocyanins are plant secondary metabolites, which may help to plants to counteract oxidative damage generated by drought stress as antioxidant; however, there is no evidence to sustain such hypothesis. Aristotelia chilensis (Mol.), also known as Maqui, is an endemic berry in Chile belonging to the Elaeocarpaceae family. A. chilensis is considered as a pioneer species, colonizing and growing on stressed and disturbed environments, thus being an interesting model for studying abiotic stress resistance mechanism. Therefore, the following hypothesis was proposed: “Higher ABA levels produced by induction of nine-cis-epoxycarotenoid dioxygenase (NCED) gene expression triggers anthocyanin biosynthesis due to the induction of UDP-glucose: flavonoid 3-O glucosyltransferase (UFGT) gene expression in Aristotelia chilensis (Mol.) plants under drought stress”. The aim of this work was to study the role of abscisic acid on the regulation of anthocyanin biosynthesis in Aristotelia chilensis (Mol.) under drought stress. First, we described the importance of ABA and anthocyanin biosynthesis in plants subjected to drought stress, and their relationship throughout the interaction of ABA and a microRNA (microRNA156) for anthocyanin biosynthesis. Here, we proposed a molecular model where ABA triggers anthocyanin biosynthesis in drought stressed plants. A drought stress experiment allows us to determine that A. chilensis plants were subjected to severe stress at day 20 after water restriction. At the same time with this severe drought stress coincided with the highest ABA and anthocyanin levels in fully-expanded leaves. Thus, to determine the role of ABA on anthocyanin biosynthesis in drought stressed Aristotelia chilensis plants, we applied fluridone (ABA inhibitor biosynthesis), and subsequent ABA at day 20 of water restriction (when plants were subjected to severe drought stress). In this experiment, we found that ABA regulates anthocyanin biosynthesis through the AcUFGT expression in drought stressed plants. In the last chapter, general discussion has been developed, where the main conclusions were that 1) a negative effects of drought stress on plant growth were ameliorated by ABA and anthocyanin biosynthesis that importantly contributed to drought stress tolerance. 2) That fluridone was an effective ABA inhibitor in A. chilensis stressed plant, and also that ABA application was able to recover both endogenous ABA concentrations in fluridone treated plants as well as increase total anthocyanin and also inducing a different anthocyanin profile. Finally, this thesis leads to the first step in the induction mechanism of anthocyanin biosynthesis under drought stress. However, it will be necessary in future studies to further explore the molecular mechanisms for ABA downstream processes. These processes will allow us a target task for breeders to manage and modify anthocyanin concentrations in plant organs and consequently increase the plant tolerance to drought stress.

Grado Académico

Doctor en Ciencias de Recursos Naturales

Idioma

Inglés

Descripción

xii, 156 hojas ; gráficos, tablas

Editorial

Universidad de La Frontera, Temuco, Chile

Derechos de Autor

Esta obra está bajo una Licencia Creative Commons Atribución-NoComercial-SinDerivar 4.0 Internacional.

Titular derechos de autor

Universidad de La Frontera, Dirección de Bibliotecas y Recursos de Información

Creative Commons

https://creativecommons.org/licenses/by-nc-nd/4.0/

Materia

Temuco, Chile

Materia

Ácido abscísico

Materia

Antocianinas

Materia

Biosíntesis

Materia

Maqui, Chile

Título

Role of abscisic acid on anthocyanin biosynthesis under drought stress in Aristotelia chilensis (mol.) plants

Tipo de Documento

Tesis

Catalogador

MAM
dc.contributor.advisor

Reyes Díaz, Marjorie

dc.contributor.carrera

Doctorado en Ciencias de Recursos Naturales

dc.creator

González Villagra, Jorge Andrés

dc.date

2018

dc.description.abstract

Drought is the most important stress factor for plants, where abscisic acid (ABA) plays a crucial role to cope with the stress. It is well reported that drought stress increases 9-cis-epoxycarotenoid dioxygenase (NCED) gene expression, which it is an important ABA biosynthetic pathway gene, triggering higher ABA levels in plant subjected to drought stress. Thus, it has been suggested that ABA might be involved on anthocyanin biosynthesis under drought stress. Anthocyanins are plant secondary metabolites, which may help to plants to counteract oxidative damage generated by drought stress as antioxidant; however, there is no evidence to sustain such hypothesis. Aristotelia chilensis (Mol.), also known as Maqui, is an endemic berry in Chile belonging to the Elaeocarpaceae family. A. chilensis is considered as a pioneer species, colonizing and growing on stressed and disturbed environments, thus being an interesting model for studying abiotic stress resistance mechanism. Therefore, the following hypothesis was proposed: “Higher ABA levels produced by induction of nine-cis-epoxycarotenoid dioxygenase (NCED) gene expression triggers anthocyanin biosynthesis due to the induction of UDP-glucose: flavonoid 3-O glucosyltransferase (UFGT) gene expression in Aristotelia chilensis (Mol.) plants under drought stress”. The aim of this work was to study the role of abscisic acid on the regulation of anthocyanin biosynthesis in Aristotelia chilensis (Mol.) under drought stress. First, we described the importance of ABA and anthocyanin biosynthesis in plants subjected to drought stress, and their relationship throughout the interaction of ABA and a microRNA (microRNA156) for anthocyanin biosynthesis. Here, we proposed a molecular model where ABA triggers anthocyanin biosynthesis in drought stressed plants. A drought stress experiment allows us to determine that A. chilensis plants were subjected to severe stress at day 20 after water restriction. At the same time with this severe drought stress coincided with the highest ABA and anthocyanin levels in fully-expanded leaves. Thus, to determine the role of ABA on anthocyanin biosynthesis in drought stressed Aristotelia chilensis plants, we applied fluridone (ABA inhibitor biosynthesis), and subsequent ABA at day 20 of water restriction (when plants were subjected to severe drought stress). In this experiment, we found that ABA regulates anthocyanin biosynthesis through the AcUFGT expression in drought stressed plants. In the last chapter, general discussion has been developed, where the main conclusions were that 1) a negative effects of drought stress on plant growth were ameliorated by ABA and anthocyanin biosynthesis that importantly contributed to drought stress tolerance. 2) That fluridone was an effective ABA inhibitor in A. chilensis stressed plant, and also that ABA application was able to recover both endogenous ABA concentrations in fluridone treated plants as well as increase total anthocyanin and also inducing a different anthocyanin profile. Finally, this thesis leads to the first step in the induction mechanism of anthocyanin biosynthesis under drought stress. However, it will be necessary in future studies to further explore the molecular mechanisms for ABA downstream processes. These processes will allow us a target task for breeders to manage and modify anthocyanin concentrations in plant organs and consequently increase the plant tolerance to drought stress.

dc.description.grado

Doctor en Ciencias de Recursos Naturales

dc.language

Inglés

dc.physicaldescription

xii, 156 hojas ; gráficos, tablas

dc.publisher

Universidad de La Frontera, Temuco, Chile

dc.rights

Esta obra está bajo una Licencia Creative Commons Atribución-NoComercial-SinDerivar 4.0 Internacional.

dc.rights.holder

Universidad de La Frontera, Dirección de Bibliotecas y Recursos de Información

dc.rights.uri

https://creativecommons.org/licenses/by-nc-nd/4.0/

dc.subject

Temuco, Chile

dc.subject

Ácido abscísico

dc.subject

Antocianinas

dc.subject

Biosíntesis

dc.subject

Maqui, Chile

dc.title

Role of abscisic acid on anthocyanin biosynthesis under drought stress in Aristotelia chilensis (mol.) plants

dc.type

Tesis

dc.ufro.catalogador

MAM