Abstract
Benthic diatoms isolated from tidal flats in the west coast of Korea were identified through both traditional morphological method and molecular phylogenetic method for methodological comparison. For the molecular phylogenetic analyses, we sequenced the 18S rRNA and the ribulose bisphosphate carboxylase large subunit coding gene, rbcL. Further, the comparative analysis allowed for the assessment of the suitability as a genetic marker for identification of closely related benthic diatom species and as potential barcode gene. Based on the traditional morphological identification system, the 61 isolated strains were classified into 52 previously known taxa from 13 genera. However, 17 strains could not be classified as known species by morphological analyses, suggesting a hidden diversity of benthic diatoms. The Blast search on NCBI’s Genebank indicated that the reference sequences for most of the species were absent for the benthic diatoms. Of the two genetic markers, the rbcL genes were more divergent than the 18S rRNA genes. Furthermore, a long branch attraction artefact was found in the 18S rRNA phylogeny. These results suggest that the rbcL gene is a more appropriate genetic marker for identification and classification of benthic diatoms. Considering their high diversity and simple shapes, and thus the difficulty associated with morphological classification of benthic diatoms, a molecular approach could provide a relatively easy and reliable classification system. However, this study suggests that more effort should be made to construct a reliable database containing polyphasic taxonomic data for diatom classification.
Highlights
Diatoms are the most dominant taxa among the various microalgae and are known to account for ca. 40% of the total primary production in the ocean [1, 2]
Since the classification system is based on morphological characteristics of the type specimen, it is difficult to determine whether species having a similar form that appear in a variety of environments are the same species or different ones
We attempted to identify and classify benthic diatoms by the polyphasic approach using both morphological characteristics and molecular markers and suggested that molecular approach using rbcL gene could become a better alternative to traditional morphological classification approach
Summary
Diatoms are the most dominant taxa among the various microalgae and are known to account for ca. 40% of the total primary production in the ocean [1, 2]. Benthic diatoms are the most dominant and diverse group and are key organisms that contribute to the preservation of the ecological functions of tidal flats such as primary production, nutrient cycling, and sediment stabilization [4,5,6,7]. The ecology and diversity of diatoms in tidal. Benthic diatom diversity in tidal flats flats has received attention for a long time [8,9,10,11]. The study of diatom diversity has a relatively long history, overcoming the limitations of morphological classifications remains to be problematic. The small size and simple forms of benthic diatoms have made it difficult to study their diversity [12,13,14]. Since the classification system is based on morphological characteristics of the type specimen, it is difficult to determine whether species having a similar form that appear in a variety of environments are the same species or different ones
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call