Analysis of rice glycosyl hydrolase family 1 and expression of Os4bglu12 β-glucosidase

<p>Abstract</p> <p>Background</p> <p>Glycosyl hydrolase family 1 (GH1) β-glucosidases have been implicated in physiologically important processes in plants, such as response to biotic and abiotic stresses, defense against herbivores, activation of phytohormones, lignifi...

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Main Authors: Esen Asim, Akiyama Takashi, Onkoksoong Tassanee, Pomthong Busarakum, Opassiri Rodjana, Ketudat Cairns James
Format: Article
Language:English
Published: BMC 2006-12-01
Series:BMC Plant Biology
Online Access:http://www.biomedcentral.com/1471-2229/6/33
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author Esen Asim
Akiyama Takashi
Onkoksoong Tassanee
Pomthong Busarakum
Opassiri Rodjana
Ketudat Cairns James
author_facet Esen Asim
Akiyama Takashi
Onkoksoong Tassanee
Pomthong Busarakum
Opassiri Rodjana
Ketudat Cairns James
author_sort Esen Asim
collection DOAJ
description <p>Abstract</p> <p>Background</p> <p>Glycosyl hydrolase family 1 (GH1) β-glucosidases have been implicated in physiologically important processes in plants, such as response to biotic and abiotic stresses, defense against herbivores, activation of phytohormones, lignification, and cell wall remodeling. Plant GH1 β-glucosidases are encoded by a multigene family, so we predicted the structures of the genes and the properties of their protein products, and characterized their phylogenetic relationship to other plant GH1 members, their expression and the activity of one of them, to begin to decipher their roles in rice.</p> <p>Results</p> <p>Forty GH1 genes could be identified in rice databases, including 2 possible endophyte genes, 2 likely pseudogenes, 2 gene fragments, and 34 apparently competent rice glycosidase genes. Phylogenetic analysis revealed that GH1 members with closely related sequences have similar gene structures and are often clustered together on the same chromosome. Most of the genes appear to have been derived from duplications that occurred after the divergence of rice and <it>Arabidopsis thaliana </it>lineages from their common ancestor, and the two plants share only 8 common gene lineages. At least 31 GH1 genes are expressed in a range of organs and stages of rice, based on the cDNA and EST sequences in public databases. The cDNA of the <it>Os4bglu12 </it>gene, which encodes a protein identical at 40 of 44 amino acid residues with the N-terminal sequence of a cell wall-bound enzyme previously purified from germinating rice, was isolated by RT-PCR from rice seedlings. A thioredoxin-Os4bglu12 fusion protein expressed in <it>Escherichia coli </it>efficiently hydrolyzed β-(1,4)-linked oligosaccharides of 3–6 glucose residues and laminaribiose.</p> <p>Conclusion</p> <p>Careful analysis of the database sequences produced more reliable rice GH1 gene structure and protein product predictions. Since most of these genes diverged after the divergence of the ancestors of rice and <it>Arabidopsis thaliana</it>, only a few of their functions could be implied from those of GH1 enzymes from <it>Arabidopsis </it>and other dicots. This implies that analysis of GH1 enzymes in monocots is necessary to understand their function in the major grain crops. To begin this analysis, Os4bglu12 β-glucosidase was characterized and found to have high exoglucanase activity, consistent with a role in cell wall metabolism.</p>
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spelling doaj.art-0e0b82a223dc42abbaf7e12f65d901be2022-12-22T02:45:03ZengBMCBMC Plant Biology1471-22292006-12-01613310.1186/1471-2229-6-33Analysis of rice glycosyl hydrolase family 1 and expression of Os4bglu12 β-glucosidaseEsen AsimAkiyama TakashiOnkoksoong TassaneePomthong BusarakumOpassiri RodjanaKetudat Cairns James<p>Abstract</p> <p>Background</p> <p>Glycosyl hydrolase family 1 (GH1) β-glucosidases have been implicated in physiologically important processes in plants, such as response to biotic and abiotic stresses, defense against herbivores, activation of phytohormones, lignification, and cell wall remodeling. Plant GH1 β-glucosidases are encoded by a multigene family, so we predicted the structures of the genes and the properties of their protein products, and characterized their phylogenetic relationship to other plant GH1 members, their expression and the activity of one of them, to begin to decipher their roles in rice.</p> <p>Results</p> <p>Forty GH1 genes could be identified in rice databases, including 2 possible endophyte genes, 2 likely pseudogenes, 2 gene fragments, and 34 apparently competent rice glycosidase genes. Phylogenetic analysis revealed that GH1 members with closely related sequences have similar gene structures and are often clustered together on the same chromosome. Most of the genes appear to have been derived from duplications that occurred after the divergence of rice and <it>Arabidopsis thaliana </it>lineages from their common ancestor, and the two plants share only 8 common gene lineages. At least 31 GH1 genes are expressed in a range of organs and stages of rice, based on the cDNA and EST sequences in public databases. The cDNA of the <it>Os4bglu12 </it>gene, which encodes a protein identical at 40 of 44 amino acid residues with the N-terminal sequence of a cell wall-bound enzyme previously purified from germinating rice, was isolated by RT-PCR from rice seedlings. A thioredoxin-Os4bglu12 fusion protein expressed in <it>Escherichia coli </it>efficiently hydrolyzed β-(1,4)-linked oligosaccharides of 3–6 glucose residues and laminaribiose.</p> <p>Conclusion</p> <p>Careful analysis of the database sequences produced more reliable rice GH1 gene structure and protein product predictions. Since most of these genes diverged after the divergence of the ancestors of rice and <it>Arabidopsis thaliana</it>, only a few of their functions could be implied from those of GH1 enzymes from <it>Arabidopsis </it>and other dicots. This implies that analysis of GH1 enzymes in monocots is necessary to understand their function in the major grain crops. To begin this analysis, Os4bglu12 β-glucosidase was characterized and found to have high exoglucanase activity, consistent with a role in cell wall metabolism.</p>http://www.biomedcentral.com/1471-2229/6/33
spellingShingle Esen Asim
Akiyama Takashi
Onkoksoong Tassanee
Pomthong Busarakum
Opassiri Rodjana
Ketudat Cairns James
Analysis of rice glycosyl hydrolase family 1 and expression of Os4bglu12 β-glucosidase
BMC Plant Biology
title Analysis of rice glycosyl hydrolase family 1 and expression of Os4bglu12 β-glucosidase
title_full Analysis of rice glycosyl hydrolase family 1 and expression of Os4bglu12 β-glucosidase
title_fullStr Analysis of rice glycosyl hydrolase family 1 and expression of Os4bglu12 β-glucosidase
title_full_unstemmed Analysis of rice glycosyl hydrolase family 1 and expression of Os4bglu12 β-glucosidase
title_short Analysis of rice glycosyl hydrolase family 1 and expression of Os4bglu12 β-glucosidase
title_sort analysis of rice glycosyl hydrolase family 1 and expression of os4bglu12 β glucosidase
url http://www.biomedcentral.com/1471-2229/6/33
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