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Functions of multiple genes encoding ADP-glucose pyrophosphorylase subunits in maize endosperm, embryo, and leaf.
Plant Physiol. 2014 Feb; 164(2):596-611.PP

Abstract

ADP-glucose pyrophosphorylase (AGPase) provides the nucleotide sugar ADP-glucose and thus constitutes the first step in starch biosynthesis. The majority of cereal endosperm AGPase is located in the cytosol with a minor portion in amyloplasts, in contrast to its strictly plastidial location in other species and tissues. To investigate the potential functions of plastidial AGPase in maize (Zea mays) endosperm, six genes encoding AGPase large or small subunits were characterized for gene expression as well as subcellular location and biochemical activity of the encoded proteins. Seven transcripts from these genes accumulate in endosperm, including those from shrunken2 and brittle2 that encode cytosolic AGPase and five candidates that could encode subunits of the plastidial enzyme. The amino termini of these five polypeptides directed the transport of a reporter protein into chloroplasts of leaf protoplasts. All seven proteins exhibited AGPase activity when coexpressed in Escherichia coli with partner subunits. Null mutations were identified in the genes agpsemzm and agpllzm and shown to cause reduced AGPase activity in specific tissues. The functioning of these two genes was necessary for the accumulation of normal starch levels in embryo and leaf, respectively. Remnant starch was observed in both instances, indicating that additional genes encode AGPase large and small subunits in embryo and leaf. Endosperm starch was decreased by approximately 7% in agpsemzm- or agpllzm- mutants, demonstrating that plastidial AGPase activity contributes to starch production in this tissue even when the major cytosolic activity is present.

Authors+Show Affiliations

Maize Research Institute, Sichuan Agricultural University, Chengdu 611130, China.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

24381067

Citation

Huang, Binquan, et al. "Functions of Multiple Genes Encoding ADP-glucose Pyrophosphorylase Subunits in Maize Endosperm, Embryo, and Leaf." Plant Physiology, vol. 164, no. 2, 2014, pp. 596-611.
Huang B, Hennen-Bierwagen TA, Myers AM. Functions of multiple genes encoding ADP-glucose pyrophosphorylase subunits in maize endosperm, embryo, and leaf. Plant Physiol. 2014;164(2):596-611.
Huang, B., Hennen-Bierwagen, T. A., & Myers, A. M. (2014). Functions of multiple genes encoding ADP-glucose pyrophosphorylase subunits in maize endosperm, embryo, and leaf. Plant Physiology, 164(2), 596-611. https://doi.org/10.1104/pp.113.231605
Huang B, Hennen-Bierwagen TA, Myers AM. Functions of Multiple Genes Encoding ADP-glucose Pyrophosphorylase Subunits in Maize Endosperm, Embryo, and Leaf. Plant Physiol. 2014;164(2):596-611. PubMed PMID: 24381067.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Functions of multiple genes encoding ADP-glucose pyrophosphorylase subunits in maize endosperm, embryo, and leaf. AU - Huang,Binquan, AU - Hennen-Bierwagen,Tracie A, AU - Myers,Alan M, Y1 - 2013/12/31/ PY - 2014/1/2/entrez PY - 2014/1/2/pubmed PY - 2014/10/14/medline SP - 596 EP - 611 JF - Plant physiology JO - Plant Physiol VL - 164 IS - 2 N2 - ADP-glucose pyrophosphorylase (AGPase) provides the nucleotide sugar ADP-glucose and thus constitutes the first step in starch biosynthesis. The majority of cereal endosperm AGPase is located in the cytosol with a minor portion in amyloplasts, in contrast to its strictly plastidial location in other species and tissues. To investigate the potential functions of plastidial AGPase in maize (Zea mays) endosperm, six genes encoding AGPase large or small subunits were characterized for gene expression as well as subcellular location and biochemical activity of the encoded proteins. Seven transcripts from these genes accumulate in endosperm, including those from shrunken2 and brittle2 that encode cytosolic AGPase and five candidates that could encode subunits of the plastidial enzyme. The amino termini of these five polypeptides directed the transport of a reporter protein into chloroplasts of leaf protoplasts. All seven proteins exhibited AGPase activity when coexpressed in Escherichia coli with partner subunits. Null mutations were identified in the genes agpsemzm and agpllzm and shown to cause reduced AGPase activity in specific tissues. The functioning of these two genes was necessary for the accumulation of normal starch levels in embryo and leaf, respectively. Remnant starch was observed in both instances, indicating that additional genes encode AGPase large and small subunits in embryo and leaf. Endosperm starch was decreased by approximately 7% in agpsemzm- or agpllzm- mutants, demonstrating that plastidial AGPase activity contributes to starch production in this tissue even when the major cytosolic activity is present. SN - 1532-2548 UR - https://www.unboundmedicine.com/medline/citation/24381067/Functions_of_multiple_genes_encoding_ADP_glucose_pyrophosphorylase_subunits_in_maize_endosperm_embryo_and_leaf_ DB - PRIME DP - Unbound Medicine ER -