Phylogeographic Pattern of <i>Sargassum hemiphyllum</i> var. <i>chinense</i> (Phaeophyceae, Ochrophyta) in Chinese Coastal Waters

<i>Sargassum hemiphyllum</i> var. <i>chinense</i> is a common brown seaweed along the southeastern coast of China, playing a significant ecological role and possessing considerable resource utilization value. However, its genetic diversity and phylogeographic patterns remain...

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Main Authors: Zepan Chen, Weizhou Chen, Hong Du
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Plants
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Online Access:https://www.mdpi.com/2223-7747/14/9/1269
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author Zepan Chen
Weizhou Chen
Hong Du
author_facet Zepan Chen
Weizhou Chen
Hong Du
author_sort Zepan Chen
collection DOAJ
description <i>Sargassum hemiphyllum</i> var. <i>chinense</i> is a common brown seaweed along the southeastern coast of China, playing a significant ecological role and possessing considerable resource utilization value. However, its genetic diversity and phylogeographic patterns remain poorly understood. In this study, we employed multiple molecular markers, including the nuclear ITS sequence (ribosomal internal transcribed spacer), the plastid <i>rbcL</i> gene (encoding the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase), and the mitochondrial <i>cox3</i> and <i>cox1</i> genes (encoding cytochrome c oxidase subunits III and I, respectively), to elucidate the genetic and phylogeographic structure of <i>S. hemiphyllum</i> var. <i>chinense</i>. Our findings demonstrate that the combined use of plastid and mitochondrial gene sequences is suitable for phylogeographic studies of this species. Genetic structure difference was observed among 15 populations which localities covering most of its distribution range, likely resulting from colonization by ancestors of different origins and limited gene flow among populations. The study revealed two distinct lineages of <i>S. hemiphyllum</i> var. <i>chinense</i>, exhibiting a north–south geographical distribution with a mixed zone in the southern Fujian–eastern Guangdong coastal region. These lineages are inferred to have diverged during the Middle to Late Pleistocene due to the isolation of the East China Sea and South China Sea during glacial periods. Sub-lineage differentiation was also detected within the northern lineage. The southern lineage experienced demographic expansion following the end of the Last Glacial Maximum, while the northern lineage remained stable. The southern Fujian–eastern Guangdong region, characterized by high genetic diversity, may have served as a glacial refugium or a contact zone for the post-glacial recolonization of the two lineages. Global warming may lead to range contraction and reduced genetic diversity in this species. The high genetic diversity area should be prioritized for conservation efforts. Overall, these findings provide insights into the genetic structure status and causes of <i>S. hemiphyllum</i> var. <i>chinense</i> and offer a scientific basis for proposing reasonable measures for its resource management.
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spelling doaj-art-becf7f4ba86e46709a93db687228a2852025-08-20T01:49:18ZengMDPI AGPlants2223-77472025-04-01149126910.3390/plants14091269Phylogeographic Pattern of <i>Sargassum hemiphyllum</i> var. <i>chinense</i> (Phaeophyceae, Ochrophyta) in Chinese Coastal WatersZepan Chen0Weizhou Chen1Hong Du2Marine Science Institute, Shantou University, Shantou 515063, ChinaMarine Science Institute, Shantou University, Shantou 515063, ChinaMarine Science Institute, Shantou University, Shantou 515063, China<i>Sargassum hemiphyllum</i> var. <i>chinense</i> is a common brown seaweed along the southeastern coast of China, playing a significant ecological role and possessing considerable resource utilization value. However, its genetic diversity and phylogeographic patterns remain poorly understood. In this study, we employed multiple molecular markers, including the nuclear ITS sequence (ribosomal internal transcribed spacer), the plastid <i>rbcL</i> gene (encoding the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase), and the mitochondrial <i>cox3</i> and <i>cox1</i> genes (encoding cytochrome c oxidase subunits III and I, respectively), to elucidate the genetic and phylogeographic structure of <i>S. hemiphyllum</i> var. <i>chinense</i>. Our findings demonstrate that the combined use of plastid and mitochondrial gene sequences is suitable for phylogeographic studies of this species. Genetic structure difference was observed among 15 populations which localities covering most of its distribution range, likely resulting from colonization by ancestors of different origins and limited gene flow among populations. The study revealed two distinct lineages of <i>S. hemiphyllum</i> var. <i>chinense</i>, exhibiting a north–south geographical distribution with a mixed zone in the southern Fujian–eastern Guangdong coastal region. These lineages are inferred to have diverged during the Middle to Late Pleistocene due to the isolation of the East China Sea and South China Sea during glacial periods. Sub-lineage differentiation was also detected within the northern lineage. The southern lineage experienced demographic expansion following the end of the Last Glacial Maximum, while the northern lineage remained stable. The southern Fujian–eastern Guangdong region, characterized by high genetic diversity, may have served as a glacial refugium or a contact zone for the post-glacial recolonization of the two lineages. Global warming may lead to range contraction and reduced genetic diversity in this species. The high genetic diversity area should be prioritized for conservation efforts. Overall, these findings provide insights into the genetic structure status and causes of <i>S. hemiphyllum</i> var. <i>chinense</i> and offer a scientific basis for proposing reasonable measures for its resource management.https://www.mdpi.com/2223-7747/14/9/1269<i>Sargassum hemiphyllum</i> var. <i>chinense</i>phylogeographygenetic diversityDNA markersITS<i>rbcL</i>
spellingShingle Zepan Chen
Weizhou Chen
Hong Du
Phylogeographic Pattern of <i>Sargassum hemiphyllum</i> var. <i>chinense</i> (Phaeophyceae, Ochrophyta) in Chinese Coastal Waters
Plants
<i>Sargassum hemiphyllum</i> var. <i>chinense</i>
phylogeography
genetic diversity
DNA markers
ITS
<i>rbcL</i>
title Phylogeographic Pattern of <i>Sargassum hemiphyllum</i> var. <i>chinense</i> (Phaeophyceae, Ochrophyta) in Chinese Coastal Waters
title_full Phylogeographic Pattern of <i>Sargassum hemiphyllum</i> var. <i>chinense</i> (Phaeophyceae, Ochrophyta) in Chinese Coastal Waters
title_fullStr Phylogeographic Pattern of <i>Sargassum hemiphyllum</i> var. <i>chinense</i> (Phaeophyceae, Ochrophyta) in Chinese Coastal Waters
title_full_unstemmed Phylogeographic Pattern of <i>Sargassum hemiphyllum</i> var. <i>chinense</i> (Phaeophyceae, Ochrophyta) in Chinese Coastal Waters
title_short Phylogeographic Pattern of <i>Sargassum hemiphyllum</i> var. <i>chinense</i> (Phaeophyceae, Ochrophyta) in Chinese Coastal Waters
title_sort phylogeographic pattern of i sargassum hemiphyllum i var i chinense i phaeophyceae ochrophyta in chinese coastal waters
topic <i>Sargassum hemiphyllum</i> var. <i>chinense</i>
phylogeography
genetic diversity
DNA markers
ITS
<i>rbcL</i>
url https://www.mdpi.com/2223-7747/14/9/1269
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AT hongdu phylogeographicpatternofisargassumhemiphyllumivarichinenseiphaeophyceaeochrophytainchinesecoastalwaters