Establishing community-wide DNA barcode references for conserving mangrove forests in China

Xiaomeng Mao,Zixiao Guo,Xinnian Li,Suhua Shi,Wei Xie

doi:10.1186/s12870-021-03349-z

Xiaomeng Mao, Zixiao Guo + Show 3 more

Open Access

https://doi.org/10.1186/s12870-021-03349-z

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Abstract

BackgroundMangrove ecosystems have been the focus of global attention for their crucial role in sheltering coastal communities and retarding global climate change by sequestering ‘blue carbon’. China is relatively rich in mangrove diversity, with one-third of the ca. 70 true mangrove species and a number of mangrove associate species occurring naturally along the country’s coasts. Mangrove ecosystems, however, are widely threatened by intensifying human disturbances and rising sea levels. DNA barcoding technology may help protect mangrove ecosystems by providing rapid species identification.ResultsTo investigate this potential, 898 plant specimens were collected from 33 major mangrove sites in China. Based on the morphologic diagnosis, the specimens were assigned to 72 species, including all 28 true mangrove species and all 12 mangrove associate species recorded in China. Three chloroplast DNA markers rbcL, trnH-psbA, matK, and one nuclear marker ITS2 were chosen to investigate the utility of using barcoding to identify these species. According to the criteria of barcoding gaps in genetic distance, sequence similarity, and phylogenetic monophyly, we propose that a single marker, ITS2, is sufficient to barcode the species of mangroves and their associates in China. Furthermore, rbcL or trnH-psbA can also be used to gather supplement confirming data. In using these barcodes, we revealed a very low level of genetic variation among geographic locations in the mangrove species, which is an alert to their vulnerability to climate and anthropogenic disturbances.ConclusionWe suggest using ITS2 to barcode mangrove species and terrestrial coastal plants in South China. The DNA barcode sequences we obtained would be valuable in monitoring biodiversity and the restoration of ecosystems, which are essential for mangrove conservation.

Highlights

Mangroves are well-known as crucial ecosystems restricted to the marine intertidal zone of tropical and subtropical areas [1]
True mangrove species occur exclusively below high tide lines while mangrove associate species occur in both intertidal zones and inland terrestrial environments
True mangrove species commonly occupy middle to low tide regions though they are found in high tide regions

Summary

Introduction

Mangroves are well-known as crucial ecosystems restricted to the marine intertidal zone of tropical and subtropical areas [1]. A mangrove species is classified into true mangroves or mangrove associates, according to whether it occurs exclusively in intertidal environments or not. True mangrove species occur exclusively below high tide lines while mangrove associate species occur in both intertidal zones and inland terrestrial environments. Mangrove associate species usually grow in high tide regions where are less inundated by seawater. China has 23 indigenous true mangroves (excluding the hybrid Sonneratia paracaseolaris) and 12 native mangrove associates which distribute throughout the tropical and subtropical coasts of South China [5]. 70 true mangrove species and a number of mangrove associate species occurring naturally along the country’s coasts. DNA barcoding technology may help protect mangrove ecosystems by providing rapid species identification

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