Molecular characterization of (Myxozoa, Myxosporea, Bivalvulida) infecting gill lamellae of minor carp (Ham.).

As new pathogenic strains are emerging and threatening aquaculture development, myxosporeans (Myxozoa) are receiving much attention in recent years. Myxosporean taxonomy is traditionally based on morphology of the myxospore stage. Molecular data on Indian myxosporeans are rare. In this report, the 18S rRNA gene sequence of Myxobolus cuttacki infecting gill lamellae of minor carp (Ham.) and its phylogenetic relationship with other myxobolids are described for the first time. The plasmodia of were 0.5-0.9 mm in size and whitish with a round to oval shape. The mean mature spore size was 16.10×7.05 μm. The 18S rRNA nucleotide sequence with 1703 bp of (accession number KF465682) clustered phylogenetically with other spp. infecting cyprinid gills with 78-90% homogeneity. The gill lamellae infecting (KC933944) and (KF448527) of Indian major carp from India, exhibited 86% and 81% homogeneity with , respectively. The infection rate was low to moderate on the gills which can have a negative impact on respiratory and physiological functions and subsequently on fish production.