Rice Debranching Enzyme Isoamylase3 Facilitates Starch Metabolism and Affects Plastid Morphogenesis

Debranching enzymes, which hydrolyze α-1 and 6-glucosidic linkages in α-polyglucans, play a dual role in the synthesis and degradation of starch in plants. A transposon-inserted rice mutant of isoamylase3 (isa3) contained an increased amount of starch in the leaf blade at the end of the night, indic...

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Autores principales: Yun, Min-Soo, Umemoto, Takayuki, Kawagoe, Yasushi
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Oxford University Press 2011
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3110883/
https://www.ncbi.nlm.nih.gov/pubmed/21551159
http://dx.doi.org/10.1093/pcp/pcr058
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author Yun, Min-Soo
Umemoto, Takayuki
Kawagoe, Yasushi
author_facet Yun, Min-Soo
Umemoto, Takayuki
Kawagoe, Yasushi
author_sort Yun, Min-Soo
collection PubMed
description Debranching enzymes, which hydrolyze α-1 and 6-glucosidic linkages in α-polyglucans, play a dual role in the synthesis and degradation of starch in plants. A transposon-inserted rice mutant of isoamylase3 (isa3) contained an increased amount of starch in the leaf blade at the end of the night, indicating that ISA3 plays a role in the degradation of transitory starch during the night. An epitope-tagged ISA3 expressed in Escherichia coli exhibited hydrolytic activity on β-limit dextrin and amylopectin. We investigated whether ISA3 plays a role in amyloplast development and starch metabolism in the developing endosperm. ISA3–green fluorescent protein (GFP) fusion protein expressed under the control of the rice ISA3 promoter was targeted to the amyloplast stroma in the endosperm. Overexpression of ISA3 in the sugary1 mutant, which is deficient in ISA1 activity, did not convert water-soluble phytoglycogen to starch granules, indicating that ISA1 and ISA3 are not functionally redundant. Both overexpression and loss of function of ISA3 in the endosperm generated pleomorphic amyloplasts and starch granules. Furthermore, chloroplasts in the leaf blade of isa3 seedlings were large and pleomorphic. These results suggest that ISA3 facilitates starch metabolism and affects morphological characteristics of plastids in rice.
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spelling pubmed-31108832011-06-14 Rice Debranching Enzyme Isoamylase3 Facilitates Starch Metabolism and Affects Plastid Morphogenesis Yun, Min-Soo Umemoto, Takayuki Kawagoe, Yasushi Plant Cell Physiol Regular Papers Debranching enzymes, which hydrolyze α-1 and 6-glucosidic linkages in α-polyglucans, play a dual role in the synthesis and degradation of starch in plants. A transposon-inserted rice mutant of isoamylase3 (isa3) contained an increased amount of starch in the leaf blade at the end of the night, indicating that ISA3 plays a role in the degradation of transitory starch during the night. An epitope-tagged ISA3 expressed in Escherichia coli exhibited hydrolytic activity on β-limit dextrin and amylopectin. We investigated whether ISA3 plays a role in amyloplast development and starch metabolism in the developing endosperm. ISA3–green fluorescent protein (GFP) fusion protein expressed under the control of the rice ISA3 promoter was targeted to the amyloplast stroma in the endosperm. Overexpression of ISA3 in the sugary1 mutant, which is deficient in ISA1 activity, did not convert water-soluble phytoglycogen to starch granules, indicating that ISA1 and ISA3 are not functionally redundant. Both overexpression and loss of function of ISA3 in the endosperm generated pleomorphic amyloplasts and starch granules. Furthermore, chloroplasts in the leaf blade of isa3 seedlings were large and pleomorphic. These results suggest that ISA3 facilitates starch metabolism and affects morphological characteristics of plastids in rice. Oxford University Press 2011-06 2011-05-06 /pmc/articles/PMC3110883/ /pubmed/21551159 http://dx.doi.org/10.1093/pcp/pcr058 Text en © The Author 2011. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. http://creativecommons.org/licenses/by-nc/2.5 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.5), which permits unrestricted non-commercial use distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Regular Papers
Yun, Min-Soo
Umemoto, Takayuki
Kawagoe, Yasushi
Rice Debranching Enzyme Isoamylase3 Facilitates Starch Metabolism and Affects Plastid Morphogenesis
title Rice Debranching Enzyme Isoamylase3 Facilitates Starch Metabolism and Affects Plastid Morphogenesis
title_full Rice Debranching Enzyme Isoamylase3 Facilitates Starch Metabolism and Affects Plastid Morphogenesis
title_fullStr Rice Debranching Enzyme Isoamylase3 Facilitates Starch Metabolism and Affects Plastid Morphogenesis
title_full_unstemmed Rice Debranching Enzyme Isoamylase3 Facilitates Starch Metabolism and Affects Plastid Morphogenesis
title_short Rice Debranching Enzyme Isoamylase3 Facilitates Starch Metabolism and Affects Plastid Morphogenesis
title_sort rice debranching enzyme isoamylase3 facilitates starch metabolism and affects plastid morphogenesis
topic Regular Papers
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3110883/
https://www.ncbi.nlm.nih.gov/pubmed/21551159
http://dx.doi.org/10.1093/pcp/pcr058
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