Replacement of the endogenous starch debranching enzymes ISA1 and ISA2 of Arabidopsis with the rice orthologs reveals a degree of functional conservation during starch synthesis.

This study tested the interchangeability of enzymes in starch metabolism between dicotyledonous and monocotyledonous plant species. Amylopectin--a branched glucose polymer--is the major component of starch and is responsible for its semi-crystalline property. Plants synthesize starch with distinct a...

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Autores principales:	Sebastian Streb, Samuel C Zeeman
Formato:	article
Lenguaje:	EN
Publicado:	Public Library of Science (PLoS) 2014
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/dbac0e0061564f6d862c752df96f0f40
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spelling	oai:doaj.org-article:dbac0e0061564f6d862c752df96f0f402021-11-18T08:27:35ZReplacement of the endogenous starch debranching enzymes ISA1 and ISA2 of Arabidopsis with the rice orthologs reveals a degree of functional conservation during starch synthesis.1932-620310.1371/journal.pone.0092174https://doaj.org/article/dbac0e0061564f6d862c752df96f0f402014-01-01T00:00:00Zhttps://www.ncbi.nlm.nih.gov/pmc/articles/pmid/24642810/pdf/?tool=EBIhttps://doaj.org/toc/1932-6203This study tested the interchangeability of enzymes in starch metabolism between dicotyledonous and monocotyledonous plant species. Amylopectin--a branched glucose polymer--is the major component of starch and is responsible for its semi-crystalline property. Plants synthesize starch with distinct amylopectin structures, varying between species and tissues. The structure determines starch properties, an important characteristic for cooking and nutrition, and for the industrial uses of starch. Amylopectin synthesis involves at least three enzyme classes: starch synthases, branching enzymes and debranching enzymes. For all three classes, several enzyme isoforms have been identified. However, it is not clear which enzyme(s) are responsible for the large diversity of amylopectin structures. Here, we tested whether the specificities of the debranching enzymes (ISA1 and ISA2) are major determinants of species-dependent differences in amylopectin structure by replacing the dicotyledonous Arabidopsis isoamylases (AtISA1 and AtISA2) with the monocotyledonous rice (Oryza sativa) isoforms. We demonstrate that the ISA1 and ISA2 are sufficiently well conserved between these species to form heteromultimeric chimeric Arabidopsis/rice isoamylase enzymes. Furthermore, we were able to reconstitute the endosperm-specific rice OsISA1 homomultimeric complex in Arabidopsis isa1isa2 mutants. This homomultimer was able to facilitate normal rates of starch synthesis. The resulting amylopectin structure had small but significant differences in comparison to wild-type Arabidopsis amylopectin. This suggests that ISA1 and ISA2 have a conserved function between plant species with a major role in facilitating the crystallization of pre-amylopectin synthesized by starch synthases and branching enzymes, but also influencing the final structure of amylopectin.Sebastian StrebSamuel C ZeemanPublic Library of Science (PLoS)articleMedicineRScienceQENPLoS ONE, Vol 9, Iss 3, p e92174 (2014)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Sebastian Streb Samuel C Zeeman Replacement of the endogenous starch debranching enzymes ISA1 and ISA2 of Arabidopsis with the rice orthologs reveals a degree of functional conservation during starch synthesis.
description	This study tested the interchangeability of enzymes in starch metabolism between dicotyledonous and monocotyledonous plant species. Amylopectin--a branched glucose polymer--is the major component of starch and is responsible for its semi-crystalline property. Plants synthesize starch with distinct amylopectin structures, varying between species and tissues. The structure determines starch properties, an important characteristic for cooking and nutrition, and for the industrial uses of starch. Amylopectin synthesis involves at least three enzyme classes: starch synthases, branching enzymes and debranching enzymes. For all three classes, several enzyme isoforms have been identified. However, it is not clear which enzyme(s) are responsible for the large diversity of amylopectin structures. Here, we tested whether the specificities of the debranching enzymes (ISA1 and ISA2) are major determinants of species-dependent differences in amylopectin structure by replacing the dicotyledonous Arabidopsis isoamylases (AtISA1 and AtISA2) with the monocotyledonous rice (Oryza sativa) isoforms. We demonstrate that the ISA1 and ISA2 are sufficiently well conserved between these species to form heteromultimeric chimeric Arabidopsis/rice isoamylase enzymes. Furthermore, we were able to reconstitute the endosperm-specific rice OsISA1 homomultimeric complex in Arabidopsis isa1isa2 mutants. This homomultimer was able to facilitate normal rates of starch synthesis. The resulting amylopectin structure had small but significant differences in comparison to wild-type Arabidopsis amylopectin. This suggests that ISA1 and ISA2 have a conserved function between plant species with a major role in facilitating the crystallization of pre-amylopectin synthesized by starch synthases and branching enzymes, but also influencing the final structure of amylopectin.
format	article
author	Sebastian Streb Samuel C Zeeman
author_facet	Sebastian Streb Samuel C Zeeman
author_sort	Sebastian Streb
title	Replacement of the endogenous starch debranching enzymes ISA1 and ISA2 of Arabidopsis with the rice orthologs reveals a degree of functional conservation during starch synthesis.
title_short	Replacement of the endogenous starch debranching enzymes ISA1 and ISA2 of Arabidopsis with the rice orthologs reveals a degree of functional conservation during starch synthesis.
title_full	Replacement of the endogenous starch debranching enzymes ISA1 and ISA2 of Arabidopsis with the rice orthologs reveals a degree of functional conservation during starch synthesis.
title_fullStr	Replacement of the endogenous starch debranching enzymes ISA1 and ISA2 of Arabidopsis with the rice orthologs reveals a degree of functional conservation during starch synthesis.
title_full_unstemmed	Replacement of the endogenous starch debranching enzymes ISA1 and ISA2 of Arabidopsis with the rice orthologs reveals a degree of functional conservation during starch synthesis.
title_sort	replacement of the endogenous starch debranching enzymes isa1 and isa2 of arabidopsis with the rice orthologs reveals a degree of functional conservation during starch synthesis.
publisher	Public Library of Science (PLoS)
publishDate	2014
url	https://doaj.org/article/dbac0e0061564f6d862c752df96f0f40
work_keys_str_mv	AT sebastianstreb replacementoftheendogenousstarchdebranchingenzymesisa1andisa2ofarabidopsiswiththericeorthologsrevealsadegreeoffunctionalconservationduringstarchsynthesis AT samuelczeeman replacementoftheendogenousstarchdebranchingenzymesisa1andisa2ofarabidopsiswiththericeorthologsrevealsadegreeoffunctionalconservationduringstarchsynthesis
_version_	1718421774407827456

Replacement of the endogenous starch debranching enzymes ISA1 and ISA2 of Arabidopsis with the rice orthologs reveals a degree of functional conservation during starch synthesis.

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