Development and Characterization of SSR Markers in Proso Millet Based on Switchgrass Genomics

Santosh G Rajput,Dipak K Santra,Tammy Plyler-Harveson

doi:10.4236/ajps.2014.51023

Abstract

Proso millet (Panicummiliaceum) has highwater use efficiency (WUE), a short growing-season, and is highly adapted to a semi-arid climate. Genomic resources for proso millet are very limited. Large numbers of DNA markers and other genomic tools in proso millet can readily be developed by using genomic resources in related grasses. The objectives of the present report were to 1) test and characterize switchgrass SSR markers for use in proso millet, and 2) elucidate repeat-motifs in proso millet based on new SSR marker analysis. A total of 548 SSR markers were tested on 8 proso millet genotypes. Out of these, 339 amplified SSR markers in proso millet. This showed that 62% of the switchgrass SSR markers were transferable to proso millet. Of these 339 markers, 254 were highly polymorphic among the 8 proso genotypes. The resolving power of these 254 polymorphic SSR markers ranged from 0.25-14.75 with an average of 2.71. The 254 polymorphic SSR markers amplified 984 alleles in the ranges of 50 bp to 1300 bp. The majority of the SSR markers (221 of 254) amplified dinucleotide repeats. Based on SSR marker analysis, AG/GA was the most abundant repeat-motifs in proso millet. Switchgrass genomic information seems to be the most useful for developing DNA markers in proso millet. Markers developed in this study will be helpful for linkage map construction, mapping agronomic traits and future molecular breeding efforts in proso millet.

Highlights

Proso millet (Panicum miliaceum L.) is reported to have been domesticated about 10,000 years ago in central and Eastern Asia and made its way from China to the Black Sea region of Europe by 5000 BC [1]
Of the 548 switchgrass simple sequence repeat (SSR) markers screened, 339 (62%) amplified and 209 markers (38%) did not amplify in proso millet
Of the 339 amplified markers, 254 (46%) were polymorphic. Many of these 254 markers were found to be highly polymorphic among the set of 8 proso millet genotypes as represented by one such SSR marker PVCA 21-22 (Figure 1)

Summary

Introduction

Proso millet (Panicum miliaceum L.) is reported to have been domesticated about 10,000 years ago in central and Eastern Asia and made its way from China to the Black Sea region of Europe by 5000 BC [1]. Proso millet is known as common millet, millet, and hog millet in the United States of America (USA); broomcorn millet in China; common millet in Japan, Korea, and other Pacific Asian countries; “hersey” millet in Germany; and French white in France [3]. It is currently grown in Asia, Australia, North America, Europe, and Africa [3,4,5]. Proso millet is highly diversified, has excellent nutritional properties and could become an important crop for food diversification [8] It is used primarily for human consumption in Asia. In the USA, it is grown primarily for birdseed and livestock [8,9]

Objectives

Methods

Results