Identification of Mutator insertional mutants of starch-branching enzyme1 (sbe1) in Zea mays L.

Identification of Mutator insertional mutants of starch-branching enzyme1 (sbe1) in Zea mays L. Starch-branching enzymes (SBE) alter starch structure by breaking an α-1,4 linkage and attaching the reducing end of the new chain to a glucan chain by an α1,6 bond. In maize, three isoforms of SBE have been identified. In order to examine the function of the SBEI isoform, a reverse-genetics PCR-based screen was used to identify a mutant line segregating for a Mutator transposon within Sbe1. Compared to wild-type controls, Sbe1 transcripts accumulate at extremely low levels in leaves of the homozygous mutant. Antibodies failed to detect SBEI in leaf tissue of mutants or wild-type controls. In contrast, the level of SBEI in endosperm is undetectable in homozygous mutants while easily detected in wild-type controls. Starches extracted from mutant leaves and endosperm have structures indistinguishable from starches of wild-type controls as determined by size-exclusion chromatography (SEC) of intact starch and high-performance SEC of debranched starch. To investigate the possibility of compensation for the lack of SBEI by expression of the homologous sequence reported by Kim et al. (1998), a genomic fragment (Sbe1b) of this sequence was cloned. Northern hybridizations of mutant leaf, root, tassel, endosperm and embryo tissues with non-specific Sbe1b probes failed to reveal expression of the homologous sequence. These results suggest that the homologous sequence is not compensating for a lack of SBEI in sbe1::Mu mutants. Further study of this sbe1 mutation in the presence of other genetic mutations may help to understand the role of SBEI in determining starch structure in leaves and endosperm. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Plant Molecular Biology Springer Journals

Identification of Mutator insertional mutants of starch-branching enzyme1 (sbe1) in Zea mays L.

Loading next page...
 
/lp/springer_journal/identification-of-mutator-insertional-mutants-of-starch-branching-Ob0w9qa9MR
Publisher
Kluwer Academic Publishers
Copyright
Copyright © 2002 by Kluwer Academic Publishers
Subject
Life Sciences; Biochemistry, general; Plant Sciences; Plant Pathology
ISSN
0167-4412
eISSN
1573-5028
D.O.I.
10.1023/A:1013335217744
Publisher site
See Article on Publisher Site

Abstract

Starch-branching enzymes (SBE) alter starch structure by breaking an α-1,4 linkage and attaching the reducing end of the new chain to a glucan chain by an α1,6 bond. In maize, three isoforms of SBE have been identified. In order to examine the function of the SBEI isoform, a reverse-genetics PCR-based screen was used to identify a mutant line segregating for a Mutator transposon within Sbe1. Compared to wild-type controls, Sbe1 transcripts accumulate at extremely low levels in leaves of the homozygous mutant. Antibodies failed to detect SBEI in leaf tissue of mutants or wild-type controls. In contrast, the level of SBEI in endosperm is undetectable in homozygous mutants while easily detected in wild-type controls. Starches extracted from mutant leaves and endosperm have structures indistinguishable from starches of wild-type controls as determined by size-exclusion chromatography (SEC) of intact starch and high-performance SEC of debranched starch. To investigate the possibility of compensation for the lack of SBEI by expression of the homologous sequence reported by Kim et al. (1998), a genomic fragment (Sbe1b) of this sequence was cloned. Northern hybridizations of mutant leaf, root, tassel, endosperm and embryo tissues with non-specific Sbe1b probes failed to reveal expression of the homologous sequence. These results suggest that the homologous sequence is not compensating for a lack of SBEI in sbe1::Mu mutants. Further study of this sbe1 mutation in the presence of other genetic mutations may help to understand the role of SBEI in determining starch structure in leaves and endosperm.

Journal

Plant Molecular BiologySpringer Journals

Published: Oct 13, 2004

References

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 12 million articles from more than
10,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Unlimited reading

Read as many articles as you need. Full articles with original layout, charts and figures. Read online, from anywhere.

Stay up to date

Keep up with your field with Personalized Recommendations and Follow Journals to get automatic updates.

Organize your research

It’s easy to organize your research with our built-in tools.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve Freelancer

DeepDyve Pro

Price
FREE
$49/month

$360/year
Save searches from Google Scholar, PubMed
Create lists to organize your research
Export lists, citations
Access to DeepDyve database
Abstract access only
Unlimited access to over
18 million full-text articles
Print
20 pages/month
PDF Discount
20% off