Higher efficiency of <scp>ISSR</scp> markers over plastid <i>psbA‐trnH</i> region in resolving taxonomical status of genus <i>Ocimum</i> L.

Abstract

High level of morphological as well as chemical variability exists within the genus <i>Ocimum</i>, and its taxonomy and phylogenetic relationships are still doubtful. For evaluating interspecific genetic relationships among the <i>Ocimum</i> species, genotyping with intersimple sequence repeat (ISSR) markers and sequence analyses of noncoding <i>psbA-trnH</i> intergenic region belonging to chloroplast DNA were carried out. Although ISSR markers are highly efficient and reproducible, they have not been used extensively in phylogenetic studies. The use of the plastidial barcode candidate was expected to provide more variable and informative insight into evolutionary rates, and was thus employed as a phylogenetic marker to assess interspecific relationships. This study revealed that the ISSR markers were more efficient than <i>psbA-trnH</i> sequences in resolving the current status of <i>Ocimum</i> L. genus. Distance- and character-based methodological approaches applied on the molecular data with biparental and maternal inheritance were used for deducing the phylogenetic relationships among <i>Ocimum</i> species. Average polymorphic information content (0.344) and resolving power (6.285) depicted through ISSR markers proved to be efficient in discriminating the studied species of <i>Ocimum</i>. The primers used in this study revealed 99.585% polymorphism across the species demonstrating the polymorphic nature of ISSR markers.