The genetic architecture of amylose biosynthesis in maize kernel

Abstract

SummaryStarch is the most abundant storage carbohydrate in maize kernel. The content of amylose and amylopectin confers unique properties in food processing and industrial application. Thus, the resurgent interest has been switched to the study of individual amylose or amylopectin rather than total starch, whereas the enzymatic machinery for amylose synthesis remains elusive. We took advantage of the phenotype of amylose content and the genotype of 9,007,194 single nucleotide polymorphisms from 464 inbred maize lines. The genome‐wide association study identified 27 associated loci involving 39 candidate genes that were linked to amylose content including transcription factors, glycosyltransferases, glycosidases, as well as hydrolases. Except the waxy gene that encodes the granule‐bound starch synthase, the remaining candidate genes were located in the upstream pathway of amylose synthesis, while the downstream members were already known from prior studies. The linked candidate genes could be transferred to manipulate amylose content and thus add value to maize kernel in the breeding programme.

Genomic‐Wide Association Study of Popping Expansion in Tropical Popcorn and Field Corn Germplasm

“…This gene model is related with a pentatricopeptide repeat (PPR) protein, which is one of the largest protein families and is widely distributed among eukaryotes (Schmitz‐Linneweber et al, 2006). Pentatricopeptide repeat proteins were already identified in an association study for amylose biosynthesis (Li et al, 2018) and also for tocopherol contents (Li et al, 2012) in maize kernels. Also, a study performed by Gutierrez‐Marcos et al (2007) reveals an important role of the PPR‐coding gene empty pericarp ( emp ) over the correct expression of a small subset of transcripts in the maize endosperm.…”

Maize yield, biomass and grain quality traits responses to delayed sowing date and genotypes in rain-fed condition

“…Seed quality is important for human and animal food consumption. As known, maize grain nutrients concentration is not only varied between crop genotypes but susceptible affected by agronomic practices and growth environment as well (Li et al, 2015;Li et al, 2018). In present study, significant differences (P<0.01) of maize grain starch, protein, and oil content were observed among maize genotypes (G), maize cultivar LM33 had significant higher protein and oil concentration than hybrids ZD958, but opposite to starch content.…”

“…Grain test weight, associated with kernel size, shape, moisture content and internal structure, is one of the important indexes to estimate grain quality (Cabral et al, 2018). As known, genetic diversity and environmental variability for test weight are present, and the highprotein or oil maize genotypes generally have lower grain test weight than ordinary cultivars (Oikeh et al, 1998;Abbas et al, 2013;Li et al, 2018). In this study, variety ZD958 with higher seed starch concentration and grain test weight was observed.…”

Supersweet and waxy: meeting the diverse demands for specialty maize by genome editing

“…The positions of these two genes on the biochemical pathway to synthesize starch from sucrose in maize endosperm, which involves over 20 genes, are simplified in Fig. a (Li et al ., ).…”

“…Introgression of recessive mutant alleles into elite modern receptor lines by backcrossing is a long and laborious process and is unavoidably subject to the undesirable linkage drag effect (Li et al, 2017). For SWC production, the epistasis of SH2 over WX makes it more intriguing in phenotypic selection (Tracy, 2001;Li et al, 2018). Otherwise, a tedious marker-assisted selection on the wx allele has to be employed across the backcross scheme.…”