Development of eSSR-Markers in Setaria italica and Their Applicability in Studying Genetic Diversity, Cross-Transferability and Comparative Mapping in Millet and Non-Millet Species

PLoS One. 2013 Jun 21;8(6):e67742. doi: 10.1371/journal.pone.0067742. Print 2013.

Abstract

Foxtail millet (Setariaitalica L.) is a tractable experimental model crop for studying functional genomics of millets and bioenergy grasses. But the limited availability of genomic resources, particularly expressed sequence-based genic markers is significantly impeding its genetic improvement. Considering this, we attempted to develop EST-derived-SSR (eSSR) markers and utilize them in germplasm characterization, cross-genera transferability and in silico comparative mapping. From 66,027 foxtail millet EST sequences 24,828 non-redundant ESTs were deduced, representing ~16 Mb, which revealed 534 (~2%) eSSRs in 495 SSR containing ESTs at a frequency of 1/30 kb. A total of 447 pp were successfully designed, of which 327 were mapped physically onto nine chromosomes. About 106 selected primer pairs representing the foxtail millet genome showed high-level of cross-genera amplification at an average of ~88% in eight millets and four non-millet species. Broad range of genetic diversity (0.02-0.65) obtained in constructed phylogenetic tree using 40 eSSR markers demonstrated its utility in germplasm characterizations and phylogenetics. Comparative mapping of physically mapped eSSR markers showed considerable proportion of sequence-based orthology and syntenic relationship between foxtail millet chromosomes and sorghum (~68%), maize (~61%) and rice (~42%) chromosomes. Synteny analysis of eSSRs of foxtail millet, rice, maize and sorghum suggested the nested chromosome fusion frequently observed in grass genomes. Thus, for the first time we had generated large-scale eSSR markers in foxtail millet and demonstrated their utility in germplasm characterization, transferability, phylogenetics and comparative mapping studies in millets and bioenergy grass species.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Chromosome Mapping
  • Chromosomes, Plant / metabolism
  • DNA, Plant / chemistry
  • DNA, Plant / isolation & purification
  • DNA, Plant / metabolism
  • Databases, Genetic
  • Expressed Sequence Tags
  • Genetic Markers
  • Genetic Variation*
  • Microsatellite Repeats / genetics*
  • Oryza / genetics
  • Phylogeny
  • Seeds / anatomy & histology
  • Sequence Alignment
  • Sequence Analysis, DNA
  • Setaria Plant / classification
  • Setaria Plant / genetics*
  • Sorghum / genetics
  • Zea mays / genetics

Substances

  • DNA, Plant
  • Genetic Markers

Grants and funding

This work was financially supported by the core grant of National Institute of Plant Genome Research (NIPGR), New Delhi, India. MM acknowledges the award of Junior Research Fellowship from University Grants Commission, New Delhi. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.