Abstract
AimDNA barcoding has been widely applied to species diversity assessment in various ecosystems, including temperate forests, subtropical forests, and tropical rain forests. However, tropical coral islands have never been barcoded before due to the difficulties in field exploring. This study aims at barcoding the flowering plants from a unique ecosystem of the tropical coral islands in the Pacific Ocean and supplying valuable evolutionary information for better understanding plant community assembly of those particular islands in the future.LocationXisha Islands, China.MethodsThis study built a DNA barcode database for 155 plant species from the Xisha Islands using three DNA markers (ITS, rbcL, and matK). We applied the sequence similarity method and a phylogenetic‐based method to assess the barcoding resolution.ResultsAll the three DNA barcodes showed high levels of PCR success (96%–99%) and sequencing success (98%–100%). ITS performed the highest rate of species resolution (>95%) among the three markers, while plastid markers delivered a relatively poor species resolution (85%–90%). Our analyses obtained a marginal increase in species resolution when combining the three DNA barcodes.Main conclusionsThis study provides the first plant DNA barcode data for the unique ecosystem of tropical coral islands and considerably supplements the DNA barcode library for the flowering plants on the oceanic islands. Based on the PCR and sequencing success rates, and the discriminatory power of the three DNA regions, we recommend ITS as the most successful DNA barcode to identify the flowering plants from Xisha Islands. Due to its high sequence variation and low fungal contamination, ITS could be a preferable candidate of DNA barcode for plants from other tropical coral islands as well. Our results also shed lights on the importance of biodiversity conservation of tropical coral islands.
Highlights
The primary application of DNA barcoding is to identify unknown samples, and the emergence of DNA barcoding has greatly promoted the survey of biodiversity (Gregory, 2005)
As molecular information makes the interpretation of phylogenetic relationships easier and more reliable (Webb, Ackerly, McPeek, & Donoghue, 2002), DNA barcoding data could be useful in plant community ecology concerning the relationships among coexisting species
Since 2014, we have explored the flora of 19 islands of the Xisha Islands and conducted a comprehensive plant sampling by species through different seasons
Summary
The primary application of DNA barcoding is to identify unknown samples, and the emergence of DNA barcoding has greatly promoted the survey of biodiversity (Gregory, 2005). The high cost of exploring these islands, combined with unstable weather condition, contributes to the poor knowledge concerning their plant biodiversity Both the Chinese version Flora Reipublicae Popularis Sinicae (FRPS) (1959–2004) and the English version Flora of China were fully compiled (Wu, Raven, & Hong, 1994–2013), the collections of plant specimens from the oceanic islands are still rare. The soil of Xisha Islands is basically made of phospho calcic soil and coastal saline soil that developed from coral and shell remnants, and is often dominant with salt‐tolerant plant species. Our study filled the gap on the barcode library from tropical coral islands in the Pacific Ocean and recovered the lineage relationships for this unique flora. Our study provides a precise snapshot of plant biodiversity in tropical oceanic coral islands, and the DNA sequence data could contribute to comprehensively. | 10589 understanding biodiversity patterns of island floras in future studies
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