Study On DNA Barcode Of Halo-Tolerant Plants In Coastal Of China

The coastal wetland ecosystem,mainly composed of halo-tolerant plants,is one of the most important system with high eco-service value per unit area.In this study,562 samples of coastal halo-tolerant plants(including 53 families,97 genera and 116 species)have been collected from the coastal zone of 11 provinces,ranging from Liaoning to Hainan.Three chloroplast DNA loci(matK,rbcL and trnH-psbA)and one nuclear DNA marker(ITS)were amplified and sequenced.The DNA quality,the universality of primers and the rate of sequence availability were analysed.In terms of amplification and sequencing,all samples could be amplified by two primer pairs(matK-390F/matK-1326 and matK 3F-KIM/matK IR-KIM)for matK,and the rate of sequence availability achieved 96.38%.ITS was amplified by 18sdir/ITS4 and the rate of sequence availability is 86.27%.The all-to-all BLASTn searches indicated that the species resolution rate of ITS is the highest(73.36%)while rbcL is the lowest(46.41%).Phylogenetic trees(neighbour-joining trees)indicated that species resolution rate of matK is among the highest(82.3%).NMDS and PCoA results demonstrated that both chloroplast DNA maker and nuclear DNA maker should be considered in coastal DNA barcoding studies.Based on the above results,we suggest that the combination of ITS+matK should be regarded as the barcode for halo-tolerant plants in coastal region of China.Additionally,the 1939 newly acquired sequences in this study established the foundation of a costal halo-tolerant plants datebase.