title: Assessment of genetic diversity and population structure of mung bean (Vigna radiata) germplasm using EST-based and genomic SSR markers.
abstract: Mung bean is an important legume crop in tropical and subtropical countries of Asia and has high nutritional and economic value. However the genetic diversity of mung bean is poorly characterized. In this study, our goal was to develop and use microsatellite simple sequence repeat (SSR) markers for germplasm evaluation. In total, 500 novel expression sequence tag EST-based SSRs (eSSRs) and genomic SSRs (gSSRs) were developed from mung bean transcriptome and genome sequences. Of these, only 58 were useful for diversity evaluation in a panel of 157 cultivated and wild mung bean accessions from different collection sites in East Asia. A total of 2.66 alleles were detected on average per locus which shows that polymorphism is generally low for the species. The average polymorphic information content (PIC) of gSSRs was higher than eSSRs and most of the polymorphic gSSRs were composed of di- and tri-nucleotide repeats (52.4% and 38.1% of all loci, respectively). The genotypes were differentiated into nine subgroups by cluster analysis, and the wild mung bean accessions separated well from the cultivated accessions. Analysis of molecular variance indicated that 22% of variance was observed among populations and 78% was due to differences within populations. Clustering, population structure analyses showed that non-Chinese cultivated and wild mung bean accessions were separated from Chinese accessions, but no geographical distinctions existed between genotypes collected in China. Interestingly, the average PIC value of cultivated mung bean (0.36) was higher than that of wild mung bean (0.25) showing that further collecting and wide crosses are necessary for mung bean improvement.
authors.affiliation: National Key Facility for Crop Gene Resources Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
authors.forename: Honglin
authors.initials: H
authors.lastname: Chen
authors.affiliation: National Key Facility for Crop Gene Resources Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China; College of Agriculture, Shanxi Agricultural University, Taigu 030801, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Qiao
authors.affiliation: National Key Facility for Crop Gene Resources Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
authors.forename: Lixia
authors.initials: L
authors.lastname: Wang
authors.affiliation: National Key Facility for Crop Gene Resources Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
authors.forename: Suhua
authors.initials: S
authors.lastname: Wang
authors.affiliation: Department of Agricultural and Environmental Sciences, Tennessee State University, Nashville, TN 37209, USA.
authors.forename: Matthew Wohlgemuth
authors.initials: MW
authors.lastname: Blair
authors.affiliation: National Key Facility for Crop Gene Resources Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China. Electronic address: chengxuzhen@caas.cn.
authors.forename: Xuzhen
authors.initials: X
authors.lastname: Cheng
mesh_terms: D001483:Base Sequence; D017931:DNA Primers; D020224:Expressed Sequence Tags; D007887:Fabaceae / Q000235:genetics*; D017343:Genes, Plant; D005819:Genetic Markers; D014644:Genetic Variation; D018895:Microsatellite Repeats; D016133:Polymerase Chain Reaction
chemical_list: D017931:DNA Primers; D005819:Genetic Markers
keywords: Genetic diversity; Population structure; Simple sequence repeat (SSR) markers