Quantitative Trait Locus Analysis of Protein and Oil Content in Response to Planting Density in Soybean (Glycine max [L.] Merri.) Seeds Based on SNP Linkage Mapping

Xiaocui Tian; Kaixin Zhang; Shulin Liu; Xu Sun; Xiyu Li; Jie Song; Zhongying Qi; Yue Wang; Yanlong Fang; Jiajing Wang; Sitong Jiang; Chang Yang; Zhixi Tian; Wen-Xia Li; Hailong Ning

doi:10.3389/fgene.2020.00563

Quantitative Trait Locus Analysis of Protein and Oil Content in Response to Planting Density in Soybean (Glycine max [L.] Merri.) Seeds Based on SNP Linkage Mapping

Front Genet. 2020 Jun 25:11:563. doi: 10.3389/fgene.2020.00563. eCollection 2020.

Authors

Xiaocui Tian^{1

2

3}, Kaixin Zhang^{1

2

3}, Shulin Liu⁴, Xu Sun^{1

2

3}, Xiyu Li^{1

2

3}, Jie Song^{1

2

3}, Zhongying Qi^{1

2

3}, Yue Wang^{1

2

3}, Yanlong Fang^{1

2

3}, Jiajing Wang^{1

2

3}, Sitong Jiang^{1

2

3}, Chang Yang^{1

2

3}, Zhixi Tian⁴, Wen-Xia Li^{1

2

3}, Hailong Ning^{1

2

3}

Affiliations

¹ Key Laboratory of Soybean Biology, Ministry of Education, Northeast Agricultural University, Harbin, China.
² Key Laboratory of Soybean Biology and Breeding/Genetics, Ministry of Agriculture, Northeast Agricultural University, Harbin, China.
³ Soybean Research Institute, Northeast Agricultural University, Harbin, China.
⁴ State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.

Abstract

Soybean varieties suitable for high planting density allow greater yields. However, the seed protein and oil contents, which determine the value of this crop, can be influenced by planting density. Thus, it is important to understand the genetic basis of the responses of different soybean genotypes to planting density. In this study, we quantified the protein and oil contents in a four-way recombinant inbred line (FW-RIL) soybean population under two planting densities and the response to density. We performed quantitative trait locus (QTL) mapping using a single nucleotide polymorphism (SNP) linkage map generated by inclusive composite interval mapping. We identified 14 QTLs for protein content and 17 for oil content at a planting density of 2.15 × 10⁵ plant/ha (D1) and 14 QTLs for protein content and 20 for oil content at a planting density 3.0 × 10⁵ plant/ha (D2). Among the QTLs detected, two oil-content QTLs was detected at both plant densities. In addition, we identified 38 QTLs for the responses of protein and oil contents to planting density. Of the QTLs detected, 70 were identified in previous studies, while 33 were newly identified. Fourty-five QTLs accounted for over 10% of the phenotypic variation of the corresponding trait, based on 23 QTLs at a marker interval distance of ~600 kb detected under different densities and with the responses to density difference. Pathway analysis revealed four candidate genes involved in protein and oil biosynthesis/metabolism. These results improve our understanding of the genetic underpinnings of protein and oil biosynthesis in soybean, laying the foundation for enhancing protein and oil contents and increasing yields in soybean.

Keywords: density; density response; gene; protein and oil content; soybean.