Insight to the ancestral relations and varietal diversity of Indian tea [Camellia sinensis (L.) Kuntze] through plastid and nuclear phylogenetic markers

Abstract

Traces of genetic introgression from wild donors that occurred during the origin trajectory of a crop would be concealed in the existing gene pool of its cultivated varieties. Dissection of signature motifs from wild relatives and diverse genotypes of a crop, not only can elucidate the probable ancestry but also offer a potential tool to authenticate varieties with a particular phenotype. We selected twenty-two distinct genotypes representing diverse commercial tea germplasms of both assamica and sinensis lineage to trace genetic signatures of their wild ancestors. A total of 176 sequences were generated from eight coding and non-coding loci belonging to both plastid and nuclear genome of the commercial tea accessions and compared with corresponding homologous loci from various wild Camellia species. The concatenated multi-locus tree of the selected cultivars and the allied species was constructed to examine phylogenetic relatedness among and within the species. Present study uncovered several signature motifs that carry evidence of multiple hybridization events during the origin trajectory of the cultivated tea plant. Identified genotype-specific indels of chloroplast and nuclear non-coding regions might imitate their varietal origin.