Genetic analysis of high amylose content in maize (Zea mays L.) using a triploid endosperm model

Abstract

Traditionally, high amylose starch (HAS) from maize (Zea mays L.) has been mainly used as an ingredient in gum candies and as an adhesive for corrugated cardboard. Two recent advances have increased interest in the use of HAS. The first one has been the development of starch-based biodegradable thermo plastics. Second, high amylose maize is a source of resistant starch (RS), a type of starch that resists digestion. As a food additive, consumers can benefit from added RS since it will lower the glycemic index and the risk of colon cancer in accordance with recent research in food science. Normal maize has about 25% amylose starch. A maize inbred line, GEMS-0067 (Reg. no GP-550, PI 643420) possesses high amylose modifier gene(s) that, together with the recessive amylose extender (ae) gene, raises the starch amylose percentage to at least 70%. The objective of this study was to determine the gene effects, nonallelic interactions and heritability of high amylose content in maize using Bogyo's triploid model. Nine populations were derived from a cross between H99ae, a maize inbred line with 55% amylose starch, and GEMS-0067. Data were collected from two locations in Missouri (MO) and South Dakota (SD) over 2 years (2005 and 2006). Incomplete dominance explained some of the inheritance of HAS. Maternal effects were also detected. The triploid models for MO and SD were separately established based on the corresponding data in 2005 and 2006. The additive and type 1 dominance effects in MO, and the additive, type 1 dominance, type 2 dominance, and additive 9 additive in SD were significantly different from zero meaning that those effects played an important role in amylose synthesis. Both broad-sense and narrowsense heritabilities were high indicating that high amylose content could be effectively selected for in a segregating population.

Progress in High-Amylose Cereal Crops through Inactivation of Starch Branching Enzymes

“…By introducing a modifier gene or by coupling with isozyme deficiencies related to starch biosynthesis on the base of inactivation of SBEII, additive effects show a more profound meaning on AC in cereal crops (Wu et al, 2009; Jiang et al, 2010b; Asai et al, 2014). …”

“…When an unknown number of high-amylose modifier (HAM) gene is introduced into a homozygous ae -mutant background in maize, AC is further increased (Wu et al, 2009). The commercial maize GEMS-0067, which is the highest known AC-contained line (>85%), is derived from the predigree of [GUAT209:S13 × (OH43ae × H99ae)] (Li et al, 2008; Wu et al, 2009).…”

Importance of amylases for physiological quality in maize seeds

“…In Zea mays, α-and β-amylases are important because maize seed is rich in starch, the main reserve substance, which represents 70% of the total grain weight (WU et al, 2009). Common maize starch is a mixture of approximately 28% amylose and 72% amylopectin.…”

Molecular marker-assisted selection of the ae alleles in maize

“…Amylose content is much higher in maize endosperm possessing the ae alleles, which are single recessive endosperm mutant alleles (Fisher et al, 1996;Kim et al, 1998). Wu et al (2009) found that the amylose content of a maize ae homozygote, possessing the modified gene, was elevated by 50-80%, relative to a cultivar without the modified gene.…”

“…Maize grain is high in starch, amounting to 70% of the total weight of grain (Wu et al, 2009). Common maize starch is a mixture of approximately 28% amylose and 72% amylopectin.…”