Marine conditions in Andaman Sea shape the unique genetic structure of Sargassum plagiophyllum C.Agardh

Abstract

Abstract The Andaman Sea-Malacca Strait is one area with high maritime complexity and process with seaweed rich biodiversity. Sargassum plagiophyllum C.Agardh is one typical brown seaweed abundant in the area. However, its population genetics has not been studied. Here, we used the nuclear Internal Transcribed Spacer 2 of the ribosomal cistron (ITS2) and the mitochondrial cytochrome c oxidase subunit 1 gene (cox1) as genetic markers to determine the its population genetic structure along the entire west coast of Thailand. One total of 351 indviduals from the ten populations were genotyped. Nine different haplotypes and 17 different ribotypes were verified. Genrally, S. plagiophyllum populations are genetically homogeneous. Most individuals belonged to the one single ribotype and haplotype. Ocean currents are belived to influence S. plagiophyllum distributions and itsgenetic exchange between the populations. Higher phosphate concentrations during northeast monsoon season could promote its growth. Our study implied that the temporal and spatial transformation of marine environment in Andaman Sea influenced both S. plagiophyllum distribution, biomass and population genetic structure, our results are positive to the conservation seaweed resources preservations.