Genome-wide microsatellites in amaranth: development, characterization, and cross-species transferability

Amaranth ( Amaranthus spp.) belonging to Amaranthaceae, is known as “the crop of the future” because of its incredible nutritional quality. Amaranthus spp. (> 70) have a huge diversity in terms of their plant morphology, production and nutritional quality; however, these species are not well characterized at molecular level due to unavailability of robust and reproducible molecular markers, which is essential for crop improvement programs. In the present study, 13,051 genome-wide microsatellite motifs were identified and subsequently utilized for marker development using A . hypochondriacus (L.) genome (JPXE01.1). Out of those, 1538 motifs were found with flanking sequences suitable for primer designing. Among designed primers, 225 were utilized for validation of which 119 (52.89%) primers were amplified. Cross-species transferability and evolutionary relatedness among ten species of Amaranthus ( A. hypochondriacus , A. caudatus , A. retroflexus , A. cruentus , A. tricolor , A. lividus , A. hybridus , A. viridis , A. edulis , and A. dubius ) were also studied using 45 microsatellite motifs. The maximum (86.67%) and minimum (28.89%) cross-species transferability were observed in A. caudatus and A. dubius , respectively, that indicated high variability present across the Amaranthus spp. Total 97 alleles were detected among 10 species of Amaranthus. The averages of major allele frequency, gene diversity, heterozygosity and PIC were 0.733, 0.347, 0.06, and 0.291, respectively. Nei’s genetic dissimilarity coefficients ranged from 0.0625 (between A. tricolor and A. hybridus ) to 0.7918 (between A. viridis and A. lividus ). The phylogenetic tree grouped ten species into three major clusters. Genome-wide development of microsatellite markers and their transferability revealed relationships among amaranth species which ultimately can be useful for species identification, DNA fingerprinting, and QTLs/gene(s) identification.