科研之友
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摘要
Recent food industry applications have increased interest in high amylose starch. Starch from the maize endosperm is typically around 25% amylose, but increases to around 50% in plants that are homozygous for the recessive amylose-extender1 (ae1) allele. A maize (Zea mays L.) line, GEMS-0067 (Reg. no. GP-550, PI 643420), has been demonstrated to produce starch with up to 70% amylose. We were interested in locating genetic modifiers that influence endosperm amylose in GEMS-0067. An F-1 population was made by crossing GEMS-0067 with H99ae, the latter with an amylose content of approximately 55%. Generations were advanced to produce F-2 and F-3 populations. Amylose content of samples from the advanced generations was measured by amylose-iodine colorimetry and the genotypes of F-2 and F-3 individuals were scored for polymorphisms of simple sequence repeat (SSR) markers. A major quantitative trait locus (QTL), which explained 43% of the total variance and demonstrated additive inheritance, was detected on the short arm of chromosome 5. The starch branching enzyme 1 (sbe1) gene lies within the interval of this QTL. Sequences of sbe1 from both GEMS-0067 and H99ae indicated that the two translated proteins had six amino acid polymorphisms. The amino acid sequence for GEMS-0067 appeared to be unique, while H99ae was nearly identical to the translated sbe1 sequences represented in previous publications on this general topic. We proposed that sbe1 is a strong candidate gene for this QTL.
- 出版日期2015-6
