A minor form of starch branching enzyme in potato (Solanum tuberosum L.) tubers has a major effect on starch structure: cloning and characterisation of multiple forms of SBE A

Jobling, Stephen A., Schwall, Gerhard P., Westcott, Roger J., Sidebottom, Christopher M., Debet, Martine, Gidley, Michael J., Jeffcoat, Roger and Safford, Richard (1999) A minor form of starch branching enzyme in potato (Solanum tuberosum L.) tubers has a major effect on starch structure: cloning and characterisation of multiple forms of SBE A. Plant Journal, 18 2: 163-171. doi:10.1046/j.1365-313X.1999.00441.x


Author Jobling, Stephen A.
Schwall, Gerhard P.
Westcott, Roger J.
Sidebottom, Christopher M.
Debet, Martine
Gidley, Michael J.
Jeffcoat, Roger
Safford, Richard
Title A minor form of starch branching enzyme in potato (Solanum tuberosum L.) tubers has a major effect on starch structure: cloning and characterisation of multiple forms of SBE A
Journal name Plant Journal   Check publisher's open access policy
ISSN 0960-7412
1365-313X
Publication date 1999-04-01
Sub-type Article (original research)
DOI 10.1046/j.1365-313X.1999.00441.x
Volume 18
Issue 2
Start page 163
End page 171
Total pages 9
Place of publication Oxford, United Kingdom
Publisher Wiley-Blackwell
Language eng
Abstract Full length cDNAs encoding a second starch branching enzyme (SBE A) isoform have been isolated from potato tubers. The predicted protein has a molecular mass of 101 kDa including a transit peptide of 48 amino acids. Multiple forms of the SBE A gene exist which differ mainly in the length of a polyglutamic acid repeat at the C-terminus of the protein. Expression of the mature protein in Escherichia coil demonstrates that the gene encodes an active SBE. Northern analysis demonstrates that SBEA mRNA is expressed at very low levels in tubers but is the predominant isoform in leaves. This expression pattern was confirmed by Western analysis using isoform specific polyclonal antibodies raised against E. coli expressed SBE A. SBE A protein is found predominantly in the soluble phase of tuber extracts, indicating a stromal location within the plastid. Transgenic potato plants expressing an antisense SBE A RNA were generated in which almost complete reductions in SBE A were observed. SBE activity in the leaves of these plants was severely reduced, but tuber activity was largely unaffected. Even so, the composition and structure of tuber starch from these plants was greatly altered. The proportion of linear chains was not significantly increased but the average chain length of amylopectin was greater, resulting in an increase in apparent amylose content as judged by iodine binding. In addition, the starch had much higher levels of phosphorous.
Keyword Maize endosperm
Pisum sativum
Rice seeds
Zeamays
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ
Additional Notes Article first published online: 5 January 2002.

Document type: Journal Article
Sub-type: Article (original research)
Collection: Centre for Nutrition and Food Sciences Publications
 
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