Research Article |
Corresponding author: Narongrit Muangmai ( ffisnrm@ku.ac.th ) Academic editor: Wolf-Henning Kusber
© 2024 Richard V. Dumilag, Lawrence M. Liao, Aki Kato, Juliet Brodie, Narongrit Muangmai.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Dumilag RV, Liao LM, Kato A, Brodie J, Muangmai N (2024) New record of Gracilaria phuquocensis (Gracilariaceae, Rhodophyta) in the Philippines. PhytoKeys 241: 169-176. https://doi.org/10.3897/phytokeys.241.123302
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While reliance on morphology has been at the expense of clearly distinguishing gracilarioid species, molecular data have proven to be more reliable in discriminating between taxa. Gracilaria phuquocensis was originally described, based on materials collected from Vietnam. Since it was described in 2020, there have been no further reports of this species. Meanwhile, a question has been raised as to whether the identity of a rhodophyte gracilarioid alga collected from the Philippines that has been referred to as an unidentified species of Gracilaria, could be G. phuquocensis. Based on comparative morpho-anatomical features and a molecular phylogeny based on rbcL gene sequences, establishing the identity of the Philippine material has led to the finding of the new record of G. phuquocensis outside its type locality. In addition to the discovery of G. phuquocensis in the Philippines, the species here is also identified as a newly-reported host for the adelphoparasite resembling Gracilaria babae.
Agarophyte, distributional records, Gracilaria babae, rbcL, taxonomy
Members of Gracilaria Greville are a major source of agar, a valuable substance widely used in various industries (
Gracilaria phuquocensis N.H. Le, N. Muangmai, G.C. Zuccarello was established based on a specimen collected from Phu Quoc Island in Vietnam (
With the aim of exploring the diversity of Gracilaria, a recent collection of flattened gracilarioids was made in Bulusan (12°43'N, 124°08.3'E), Sorsogon, Philippines. The specimens were processed as dried herbarium voucher specimens and housed at the Natural History Museum of the National Science Museum (THNHM), Thailand and at the Herbarium Sorsogonense (HS), the Philippines. Morphological characters of the thallus in cross section were examined by light microscopy.
For molecular analyses, total DNA was extracted from apical portions of dried algal specimens using a QIAGEN DNeasy Plant Mini Kit (QIAGEN, Hilden, Germany). The ribulose-bisphosphate carboxylase (rbcL) gene was selected for PCR amplification as this is a powerful molecular marker for phylogenetic analyses in Gracilaria (
Phylogenetic trees were reconstructed using Maximum-Likelihood (ML) and Bayesian Inference (BI) methods using IQ-TREE (
. Philippines • Sorsogon, Brgy Dancalan, in front of Villa Luisa Celeste Resort; 28 February 2023; N. Muangmai leg.; THNHM-P-2023-0089 (A563), GenBank: OR427952; THNHM-P-2023-0090 (A585), GenBank: OR427953; THNHM-P-2023-0091 (A586), GenBank: OR427954; THNHM-P-2023-0092; THNHM-P-2023-0093; • Dancalan Beach, 28 February 2023, J.D. Dig leg.; HS1698.
Thallus (Fig.
The adelphoparasites are parasites that are taxonomically closely related to their host species, which represent the majority of red algal parasites (
The rbcL sequences from the Philippine specimens of G. phuquocensis were closely related to that of the holotype (GenBank accession: MK935561) from Vietnam, as indicated by high support values (ML = 87%, BI = 0.91) in Fig.
Maximum Likelihood (ML) tree, based on partial rbcL gene sequences showing the position of Gracilaria phuquocensis (bold letter) from Bulusan, Sorsogon, Philippines. ML bootstrap values (left) and Bayesian posterior probabilities (right) are indicated at the nodes. Bootstrap values of > 80% for ML and > 0.90 for BI are presented and full support are indicated by asterisk (*).
Gracilaria phuquocensis from Vietnam had been previously identified as Gracilaria mammillaris (Montagne) M. Howe. However, G. mammillaris is considered to have a wide distribution in the western Atlantic (
The presence of an adelphoparasite resembling Gracilaria babae observed for the first time in G. phuquocensis, increases the number of gracilarioid species from which such neoplastic parasites (sensu
Our study suggests that the Philippines seems to present hidden diversity of gracilarioid species, at least in the southeast Asia (
Yet another concerning issue is that the taxonomic accuracy underpinning gracilarioid names need updating (see
We are grateful to Jomari D. Dig for his assistance during field collections. We are also deeply grateful to Suttikarn Sutti for helping with the deposition of voucher specimens at the National Science Museum in Thailand.
The authors have declared that no competing interests exist.
No ethical statement was reported.
This work was funded by the LinnéSys: Systematics Research Fund grant (funded by the Linnean Society of London and the Systematics Association) awarded to RVD and JB and by the Commission on Higher Education under the Leading the Advancement of Knowledge in Agriculture and Science (CHED – LAKAS) Project, Phytochemical characterization of macroalgae for food and high value products (PhycoPRO) (LAKAS 2021-035) and DOST-PCAARRD (Department of Science and Technology–Philippine Council for Agriculture, Aquatic and Natural Resources Research and Development) through the SERD (Socio-economics Research Division) under the project “Enhancing the Development and Growth of Seaweed-based Enterprises in Sorsogon” (EDGES). A travel grant to LML and NM was provided by the Graduate School of Integrated Sciences for Life of Hiroshima University. The publication fee for this manuscript was supported by Faculty of Fisheries of Kasetsart University.
Richard V. Dumilag and Narongrit Muangmai, the project leaders, made invaluable contributions by participating in field investigations, confirming taxonomic identifications and drafting the original manuscript. Narongrit Muangmai and Aki Kato applied their expertise in performing the molecular analyses. Lawrence M. Liao and Juliet Brodie provided valuable guidance and contributed to enhancing the manuscript.
Richard V. Dumilag https://orcid.org/0000-0002-7590-0009
Lawrence M. Liao https://orcid.org/0000-0001-5484-6560
Aki Kato https://orcid.org/0000-0001-6124-9676
Juliet Brodie https://orcid.org/0000-0001-7622-2564
Narongrit Muangmai https://orcid.org/0000-0001-7954-7348
All of the data that support the findings of this study are available in the main text.