High-amylose wheat generated by RNA interference improves indices of large-bowel health in rats

Ahmed Regina; Anthony Bird; David Topping; Sarah Bowden; Judy Freeman; Tina Barsby; Behjat Kosar-Hashemi; Zhongyi Li; Sadequr Rahman; Matthew Morell

doi:10.1073/pnas.0510737103

New Research In

Communicated by William James Peacock, Commonwealth Scientific and Industrial Research Organization, Canberra, Australia, December 14, 2005 (received for review October 4, 2005)

Abstract

Foods high in resistant starch have the potential to improve human health and lower the risk of serious noninfectious diseases. RNA interference was used to down-regulate the two different isoforms of starch-branching enzyme (SBE) II (SBEIIa and SBEIIb) in wheat endosperm to raise its amylose content. Suppression of SBEIIb expression alone had no effect on amylose content; however, suppression of both SBEIIa and SBEIIb expression resulted in starch containing >70% amylose. When the >70% amylose wheat grain was fed to rats in a diet as a wholemeal, several indices of large-bowel function, including short-chain fatty acids, were improved relative to standard wholemeal wheat. These results indicate that this high-amylose wheat has a significant potential to improve human health through its resistant starch content.

Footnotes

^¶To whom correspondence should be addressed. E-mail: matthew.morell{at}csiro.au
Author contributions: A.R., A.B., D.T., J.F., T.B., Z.L., S.R., and M.M. designed research; A.R., A.B., S.B., and B.K.-H. performed research; A.R., A.B., D.T., S.B., J.F., T.B., B.K.-H., Z.L., S.R., and M.M. analyzed data; and A.R., A.B., D.T., J.F., B.K.-H., S.R., and M.M. wrote the paper.
Conflict of interest statement: No conflicts declared.
Abbreviations:
NSP,
nonstarch polysaccharides;
RS,
resistant starch;
SCFA,
short-chain fatty acid;
DP,
degree of polymerization;
SBE,
starch-branching enzyme;
RNAi,
RNA interference;
SEC,
size exclusion chromatography.
© 2006 by The National Academy of Sciences of the USA