Morphological and molecular identification of Acetabularia species from Andaman and Nicobar Islands, India
Acetabularia is an extant genus of green alga in order dasycladales. It is a single celled alga having a rhizoid, stalk and a cap. In this study, Acetabularia sample collected from Andaman Nicobar Islands is identified by using morphological and molecular studies. DSLR camera, Light microscope and Scanning Electron microscope (SEM) were used for the morphological identification. Cap charactors of the sample were given more importance because it is unique with species. Stalk length and number of hairs in the inner ring of lobes of the sample are morphologicaly very different from the related species. DNA sequence analysis and phylogenetic tree construction were done. Specific primers 1722 (F) and 1547(F) with ITS2 (R) were used for amplifying the 18S rDNA region of the sample. The PCR amplified product is sequenced by Sanger sequencing method to produce the DNA sequence. The BLASTn result of the DNA sequence showed 75% query cover and 95% identity cover with Acetabularia dentata. The phylogenetic tree was made by MEGA software and sample showed a different clade showing monophyly with Acetabularia dentata. Both morphological and molecular studies supported that the sample may be a new species of Acetabularia. More studies will authenticate the results to propose the species is a new one.
Keywords: Acetabularia, Cap morphology, Scanning Electron Microscope, 18S rDNA, Sangers sequencing, Phylogenetic tree