skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: A single gene mutation that increases maize seed weight

Abstract

The maize endosperm-specific gene shrunken2 (Sh2) encodes the large subunit of the heterotetrameric starch synthetic enzyme adenosine diphosphoglucose pyrophosphorylase (AGP; EC 2.7.7.27). Here we exploit an in vivo, site-specific mutagenesis system to create short insertion mutations in a region of the gene known to be involved in the allosteric regulation of AGP. The site-specific mutagen is the transposable element dissociation (Ds). Approximately one-third (8 of 23) of the germinal revertants sequenced restored the wild-type sequence, whereas the remaining revertants contained insertions of 3 or 6 bp. All revertants retained the original reading frame 3 feet to the insertion site and involved the addition of tyrosine and/or serine. Each insertion revertant reduced total AGP activity and the amount of the SH2 protein. The revertant containing additional tyrosine and serine residues increased seed weight 11-18% without increasing or decreasing the percentage of starch. Other insertion revertants lacking an additional serine reduced seed weight. Reduced sensitivity to phosphate, a long-known inhibitor of AGP, was found in the high seed-weight revertant. This alteration is likely universally important since insertion of tyrosine and serine in the potato large subunit of AGP at the comparable position and expression in Escherichia coli also led to a phosphate-insensitivemore » enzyme. These results show that single gene mutations giving rise to increased seed weight, and therefore perhaps yield, are clearly possible in a plant with a long history of intensive and successful breeding efforts. 20 refs., 5 figs., 5 tabs.« less

Authors:
;  [1];  [2]
  1. Univ. of Florida, Gainesville, FL (United States)
  2. Univ. of Florida, Gainesville, FL (United States)|[Washington State Univ., Pullman, WA (United States)
Publication Date:
OSTI Identifier:
458095
Resource Type:
Journal Article
Resource Relation:
Journal Name: Proceedings of the National Academy of Sciences of the United States of America; Journal Volume: 93; Journal Issue: 12; Other Information: PBD: 11 Jun 1996
Country of Publication:
United States
Language:
English
Subject:
55 BIOLOGY AND MEDICINE, BASIC STUDIES; SEEDS; GENETIC CONTROL; WEIGHT; MAIZE

Citation Formats

Giroux, M.J., Shaw, J., and Hannah, L.C. A single gene mutation that increases maize seed weight. United States: N. p., 1996. Web. doi:10.1073/pnas.93.12.5824.
Giroux, M.J., Shaw, J., & Hannah, L.C. A single gene mutation that increases maize seed weight. United States. doi:10.1073/pnas.93.12.5824.
Giroux, M.J., Shaw, J., and Hannah, L.C. Tue . "A single gene mutation that increases maize seed weight". United States. doi:10.1073/pnas.93.12.5824.
@article{osti_458095,
title = {A single gene mutation that increases maize seed weight},
author = {Giroux, M.J. and Shaw, J. and Hannah, L.C.},
abstractNote = {The maize endosperm-specific gene shrunken2 (Sh2) encodes the large subunit of the heterotetrameric starch synthetic enzyme adenosine diphosphoglucose pyrophosphorylase (AGP; EC 2.7.7.27). Here we exploit an in vivo, site-specific mutagenesis system to create short insertion mutations in a region of the gene known to be involved in the allosteric regulation of AGP. The site-specific mutagen is the transposable element dissociation (Ds). Approximately one-third (8 of 23) of the germinal revertants sequenced restored the wild-type sequence, whereas the remaining revertants contained insertions of 3 or 6 bp. All revertants retained the original reading frame 3 feet to the insertion site and involved the addition of tyrosine and/or serine. Each insertion revertant reduced total AGP activity and the amount of the SH2 protein. The revertant containing additional tyrosine and serine residues increased seed weight 11-18% without increasing or decreasing the percentage of starch. Other insertion revertants lacking an additional serine reduced seed weight. Reduced sensitivity to phosphate, a long-known inhibitor of AGP, was found in the high seed-weight revertant. This alteration is likely universally important since insertion of tyrosine and serine in the potato large subunit of AGP at the comparable position and expression in Escherichia coli also led to a phosphate-insensitive enzyme. These results show that single gene mutations giving rise to increased seed weight, and therefore perhaps yield, are clearly possible in a plant with a long history of intensive and successful breeding efforts. 20 refs., 5 figs., 5 tabs.},
doi = {10.1073/pnas.93.12.5824},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
number = 12,
volume = 93,
place = {United States},
year = {Tue Jun 11 00:00:00 EDT 1996},
month = {Tue Jun 11 00:00:00 EDT 1996}
}