Mutation of the maize sbe1a and ae genes alters morphology and physical behavior of wx-type endosperm starch granules

Ji Hong Li, Mark J. Guiltinan, Donald B. Thompson

Research output: Contribution to journalArticle

14 Scopus citations

Abstract

In maize, three isoforms of starch-branching enzyme, SBEI, SBEIIa, and SBEIIb, are encoded by the Sbe1a, Sbe2a, and Amylose extender (Ae) genes, respectively. The objective of this research was to explore the effects of null mutations in the Sbe1a and Ae genes alone and in combination in wx background on kernel characteristics and on the morphology and physical behavior of endosperm starch granules. Differences in kernel morphology and weight, starch accumulation, starch granule size and size distribution, starch microstructure, and thermal properties were observed between the ae wx and sbe1a ae wx plants but not between the sbe1a wx mutants when compared to wx. Starch from sbe1a ae wx plants exhibited a larger granule size with a wider gelatinization temperature range and a lower endotherm enthalpy than ae wx. Microscopy shows weaker iodine staining in sbe1a ae wx starch granules. X-ray diffraction revealed A-type crystallinity in wx and sbe1a wx starches and B-type in sbe1a ae wx and ae wx. This study suggests that, while the SBEIIb isoform plays a dominant role in maize endosperm starch synthesis, SBEI also plays a role, which is only observable in the presence of the ae mutation.

Original languageEnglish (US)
Pages (from-to)2619-2627
Number of pages9
JournalCarbohydrate Research
Volume342
Issue number17
DOIs
StatePublished - Dec 10 2007

All Science Journal Classification (ASJC) codes

  • Analytical Chemistry
  • Biochemistry
  • Organic Chemistry

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