ABSTRACT
Mapping the soybean genome Xiaobo Wang, Anhui Agricultural University, China; and Lijuan Qiu, Chinese Academy of Agricultural Sciences, China
1 Introduction
2 Mapping the soybean genome: development of genome maps
3 New mapping techniques: specific-locus amplified fragment sequencing (SLAF-seq) mapping, whole-genome re-sequencing mapping and comparative genome mapping
4 Case study: comparing wild and cultivated soybean varieties
5 Case study: identifying salinity tolerance in soybean
6 Summary
7 Future trends
8 Where to look for further information
9 References
Soybean [Glycine max (L.) Merr.] is one of the most important grain legumes (Li et al., 2014). It is an important source of plant protein and oil, and is also a natural source of nutraceutical compounds such as isoflavones and lunasin (de Lumen, 2005; MateosAparicio, 2008). The development of new cultivars has played an important role in improving the crop. As soybean is a strict self-pollination crop, and the natural outcrossing rate is less than 1%, its genetic mapping has been relatively underdeveloped compared to other crops (Nakayama and Yamaguchi, 2002), which has limited the molecular breeding of modern soybean. The soybean community has made significant progress in mapping the soybean genome. With the appearance of DNA molecular markers, which have greatly facilitated genetic mapping, it has been possible to build up a density linkage map of soybean. In many research fields, genetic mapping has played an important role from marker-assisted selection (MAS) in plant improvement to map-based cloning (MBC) in molecular genetic studies. The development of a precise, high-density linkage map has thus made an important contribution to soybean research. In recent years, many essential agronomic and quality traits have been studied by developing a genetic linkage map and identifying quantitative trait loci (QTLs) or genes to improve yield and nutritional quality, as well as biotic and abiotic stress tolerances (Concibido
et al., 2004; Panthee et al., 2006; Tuyen et al., 2010; Cardinal et al., 2014; Kato et al., 2014). Additionally, the next-generation sequencing (NGS) technology provides the capacity for parallel sequencing of genomes and development of a sequencing-based high-throughput genotyping method that combines the advantages of ultra-high-density marker coverage, while eliminating the likelihood of overlooking double crossovers (Huang et al., 2009; Xu et al., 2010). The technology ensures high mapping accuracy and resolution together with more comparable genome and genetic maps among the mapping populations (Huang et al., 2009).
