Metabolic Engineering of Plants by Manipulating Polyamine Transport and Biosynthesis

Metabolic Engineering of Plants by Manipulating Polyamine Transport and Biosynthesis

Bibliographic Details
Main Author: Ahmed, Sheaza
Language:English
Published: Bowling Green State University / OhioLINK 2017
Subjects:
Biology
Molecular Biology
Plant Biology
Polyamine
Polaymine Biosynthesis
Flowering
Polyamine Transport
Online Access:http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1507393675673047
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spelling ndltd-OhioLink-oai-etd.ohiolink.edu-bgsu15073936756730472021-08-03T07:04:23Z Metabolic Engineering of Plants by Manipulating Polyamine Transport and Biosynthesis Ahmed, Sheaza Biology Molecular Biology Plant Biology Polyamine Polaymine Biosynthesis Flowering Polyamine Transport Transport is an essential component of the regulation of polyamines, but to date only onefamily of Polyamine Uptake Transporters (PUTs) have been characterized in plants, and theirimpact on polyamine regulation has not been defined. Here we show that knockout mutants ofput5 in A. thaliana, promote early flowering and result in plants with smaller leaves, thinnerstems, and fewer flowers. In contrast, heterologous expression of the rice gene OsPUT1 in A.thaliana using the Put5 promoter at 22°C produced plants with larger leaves, a two-week delayof flowering and more flowers and siliques. Similar effect on leaf size, flowering time andnumber of siliques also were observed in transgenic plants with constitutive expression ofOsPUT1 or OsPUT3. The delay of flowering was associated with significantly higher levels ofspermidine and spermidine conjugates in the leaves prior to flowering. These experiments outlinethe first genetic evidence for the control of flowering by polyamines. How polyamine levelscontrol the timing of flowering at a molecular level is not yet known, but this delay of floweringhas been demonstrated to be upstream of the stimulation of flowering by the gibberellin andtemperature sensitive response pathways.It has been assumed that there exists a single cytosolic pathway for the synthesis ofputrescine in A. thaliana. Here we show that A. thaliana and Glycine max, have a chloroplastlocalizedputrescine biosynthetic pathway. This pathway comprises of arginine decarboxylaseand an agmatinase to synthesize putrescine from arginine. Analysis of expression data suggeststhat it is the major route of putrescine synthesis in response to stress signals.Since compartmentation of polyamines has been demonstrated to play an essential role inpolyamine homeostasis, the identification of other types of polyamine transporters is a criticalknowledge gap. We show here that PDR11 is an important long-distance transporter ofpolyamines in plants and that OCT5 functions as a vacuolar transporter for polyamines. Taken ,these findings will accelerate interest in manipulating polyamine metabolism to generate morestress responsive crop plants. 2017-11-14 English text Bowling Green State University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1507393675673047 http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1507393675673047 unrestricted This thesis or dissertation is protected by copyright: some rights reserved. It is licensed for use under a Creative Commons license. Specific terms and permissions are available from this document's record in the OhioLINK ETD Center.
collection NDLTD
language English
sources NDLTD
topic Biology
Molecular Biology
Plant Biology
Polyamine
Polaymine Biosynthesis
Flowering
Polyamine Transport
spellingShingle Biology
Molecular Biology
Plant Biology
Polyamine
Polaymine Biosynthesis
Flowering
Polyamine Transport
Ahmed, Sheaza
Metabolic Engineering of Plants by Manipulating Polyamine Transport and Biosynthesis
author Ahmed, Sheaza
author_facet Ahmed, Sheaza
author_sort Ahmed, Sheaza
title Metabolic Engineering of Plants by Manipulating Polyamine Transport and Biosynthesis
title_short Metabolic Engineering of Plants by Manipulating Polyamine Transport and Biosynthesis
title_full Metabolic Engineering of Plants by Manipulating Polyamine Transport and Biosynthesis
title_fullStr Metabolic Engineering of Plants by Manipulating Polyamine Transport and Biosynthesis
title_full_unstemmed Metabolic Engineering of Plants by Manipulating Polyamine Transport and Biosynthesis
title_sort metabolic engineering of plants by manipulating polyamine transport and biosynthesis
publisher Bowling Green State University / OhioLINK
publishDate 2017
url http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1507393675673047
work_keys_str_mv AT ahmedsheaza metabolicengineeringofplantsbymanipulatingpolyaminetransportandbiosynthesis
_version_ 1719452657622450176

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