Phylogenetics of Sarcocystis fusiformis isolates based on 18S rRNA and cox 1 genes

Sarcocystosis is a significant meat borne coccidian disease with immense zoonotic potential. Sarcocystis fusiformis is the most prevalent Sarcocystis spp. affecting buffaloes across the globe. Most of the molecular characterization works on S. fusiformis are from Egypt and there is no record of such work from India. In the present study, 21 isolates of S. fusiformis from Northern India were characterized for 18S rRNA (MF595821-MF595841) and cox 1 (MF423105-MF423119 and MH899162-MH899167) genes. S. fusiformis was seen as a monophyletic sister group to S. cafferi on the phylogenetic tree comprising of different Sarcocystis spp. Both genes placed S. fusiformis close to those Sarcocystis spp. which have felids as definitive hosts in comparison to those with canids as definitive host. A total of 15 and 7 haplotypes were noticed for both the genes, respectively. The studied Indian isolates showed 99.1-100.0% and 99.2-100.0% nucleotide homologies within themselves for both the respective gene loci. Over all, cox 1 gene was found to be better in delineating the evolutionary phylogenetics in comparison to 18S rRNA gene. The findings are important from evolutionary point of view.

Automated summary

Sarcocystis fusiformis is the most prevalent species in buffaloes globally, with Indian isolates showing high nucleotide homologies in both 18S rRNA and cox 1 genes, suggesting the cox 1 gene is better for delineating evolutionary phylogenetics.