Rhodes Davina H, Hoffmann Leo, Rooney William L, Herald Thomas J, Bean Scott, Boyles Richard, Brenton Zachary W, Kresovich Stephen
Center for Grain and Animal Health Research, USDA-ARS, 1515 College Ave, Manhattan, Kansas, 66502, USA.
Department of Soil & Crop Sciences, Texas A&M University, College Station, TX, 77843, USA.
BMC Genomics. 2017 Jan 5;18(1):15. doi: 10.1186/s12864-016-3403-x.
Sorghum [Sorghum bicolor (L.) Moench] is an important cereal crop for dryland areas in the United States and for small-holder farmers in Africa. Natural variation of sorghum grain composition (protein, fat, and starch) between accessions can be used for crop improvement, but the genetic controls are still unresolved. The goals of this study were to quantify natural variation of sorghum grain composition and to identify single-nucleotide polymorphisms (SNPs) associated with variation in grain composition concentrations.
In this study, we quantified protein, fat, and starch in a global sorghum diversity panel using near-infrared spectroscopy (NIRS). Protein content ranged from 8.1 to 18.8%, fat content ranged from 1.0 to 4.3%, and starch content ranged from 61.7 to 71.1%. Durra and bicolor-durra sorghum from Ethiopia and India had the highest protein and fat and the lowest starch content, while kafir sorghum from USA, India, and South Africa had the lowest protein and the highest starch content. Genome-wide association studies (GWAS) identified quantitative trait loci (QTL) for sorghum protein, fat, and starch. Previously published RNAseq data was used to identify candidate genes within a GWAS QTL region. A putative alpha-amylase 3 gene, which has previously been shown to be associated with grain composition traits, was identified as a strong candidate for protein and fat variation.
We identified promising sources of genetic material for manipulation of grain composition traits, and several loci and candidate genes that may control sorghum grain composition. This survey of grain composition in sorghum germplasm and identification of protein, fat, and starch QTL contributes to our understanding of the genetic basis of natural variation in sorghum grain nutritional traits.
高粱[Sorghum bicolor (L.) Moench]是美国旱地地区以及非洲小农户的重要谷类作物。不同高粱种质间籽粒成分（蛋白质、脂肪和淀粉）的自然变异可用于作物改良，但其遗传调控仍未明确。本研究的目的是量化高粱籽粒成分的自然变异，并鉴定与籽粒成分浓度变异相关的单核苷酸多态性（SNP）。
在本研究中，我们使用近红外光谱（NIRS）对一个全球高粱多样性群体中的蛋白质、脂肪和淀粉进行了量化。蛋白质含量范围为8.1%至18.8%，脂肪含量范围为1.0%至4.3%，淀粉含量范围为61.7%至71.1%。来自埃塞俄比亚和印度的都拉高粱和双色都拉高粱蛋白质和脂肪含量最高，淀粉含量最低，而来自美国、印度和南非的卡菲尔高粱蛋白质含量最低，淀粉含量最高。全基因组关联研究（GWAS）鉴定出了高粱蛋白质、脂肪和淀粉的数量性状位点（QTL）。利用先前发表的RNAseq数据在GWAS QTL区域内鉴定候选基因。一个推测的α-淀粉酶3基因，先前已被证明与籽粒成分性状相关，被鉴定为蛋白质和脂肪变异的有力候选基因。
我们鉴定出了用于操控籽粒成分性状的有前景的遗传物质来源，以及几个可能控制高粱籽粒成分的位点和候选基因。对高粱种质籽粒成分的这项调查以及蛋白质、脂肪和淀粉QTL的鉴定有助于我们理解高粱籽粒营养性状自然变异的遗传基础。
