Coastal/Inland Halo-tolerant Plant DNA Barcoding Evaluation Of Poaceae And Chenopodiaceae

The special habitat of coastal salt marsh makes its plants own unique genetic characteristics,which affects the evaluating of DNA barcoding.In this study,343 ITS,367 matK,346 rbcL,362 trnH-psbA,226 rps16,190 ndhF,156 trnL-F and 153 atpB-rbcL sequences were newly produced.By evaluating of the six loci(ITS,rbcL,matK,trnH-psbA,rps16 and ndhF)with the 223 samples distributed in China coastal salt marshes and 641 inland samples from 53 Poaceae species,as well as the six loci(ITS,rbcL,matK,trnH-psbA,trnL-F,atpB-rbcL)with the 144 samples in coastal salt marshes and 186 inland samples from 15 Chenopodiaceae plants,we concluded that the optimal DNA barcode for halo-tolerant Poaceae plants is ITS,while for Chenopodiaceae it is matK.According to the optimal DNA barcoding,sampling strategy for Arundinella hirta,Chloris virgata,Dactyloctenium aegyptium,Digitaria ciliaris,Eleusine indica,Imperata cylindrica,Setaria viridis,Chenopodium album,Chenopodium glaucum and Dysphania ambrosioides were evaluated.We found that by the fundation of inland samples,adding samples from the coastal salt marshes,the number of haplotypes increased in Arundinella hirta,Digitaria ciliaris,Eleusine indica,Imperata cylindrica,Setaria viridis and Chenopodium glaucum.In the PCA analysis for intraspecific genetic distances,the same 6 species showed increased genetic differences when adding samples from coastal salt marshes.Mann-Whitney tests indicated significant difference between the samples from inland and inland + coastal salt marshes in Digitaria ciliaris,Eleusine indica,Imperata cylindrica and Setaria viridis.These results suggest that additional samples from special habitat will reveal more genetic differences and beneficial to the application of DNA barcoding.The results of random sampling analyses demonstrated that the average intraspecific distance tends to be clustering significantly when adding samples.For Chloris virgata,Chenopodium glaucum and Dysphania ambrosioides,the average intraspecific distance tends to be stable when the number of sample rose to 11.And for Setaria viridis,the stable number is 13,for Eleusine indica,Imperata cylindrica and Chenopodium album,it is 15.It revealed that the amount of sampling individuals should be expanded from traditionally suggested 5-10 to 11-15 for widespread species.In addition,we should ponder the necessary minimum sample amount of widespread species according to its intraspecific genetic differentiation,habitat diversity,and its size of distribution area comprehensively.