Identification Of Endangered Plants In Guangdong Province By DNA Barcodes Technique

This academic paper`s experimental materials are mainly based on Guangdong Province.Guangdong Province,which has a subtropical and tropical monsoon climate,is located in the south of China.It has abundant plant resources,some of which are rare and endangered.Reasons for their endangerousness vary,including human activities like deforestation and overusing,global warmings and so on.In order to protect these species,the first thing we should do is to identify them.We compared and evaluated the candidate sequences of plant DNA barcode(rbcL,matK,ycf1,ITS2),trying to screen out the DNA barcode sequences suitable for identification of rare and endangered plants in Guangdong Province.Methods:Rare plants in Guangdong Province were used as materials for extract their DNA by modified CTAB method.Common primers of rbcL,matK and ycf1 sequences were used for amplification and bidirectional sequencing.The products of ITS2 were cloned and then sequenced.After we got the sequences they were corrected and stitched.Finally,the sample support rate for identified species was determined by sequence amplification and sequencing success rate,constructed Neighbour-Joining and Maximum Likelihood trees,similarity search method.According to the above-mentioned indicators,we tried to evaluate the barcode markers.Conclusions:1.Four candidate DNA barcode markers(rbcL,matkK,ycf1,ITS2)were used for amplifing and sequencing 202 samples of 79 plant species,70 of which were rare and endangered plants in Guangdong Province.The results showed rbcL marker amplification and sequencing success rate were the highest,about 97.52% and 97.03%,ITS2 marker amplification and sequencing success rate were both 76.24%,matK sequence amplification and sequencing success rate were 59.90% and 57.92%,ycf1 sequence amplification and sequencing success rate were the lowest,only 50.49% and 49.50%.2.The analysis of four DNA sequences of various families showed that the ITS2 marker had the highest of mutation sites,while the rbcL marker had the least mutation sites.Meanwhile,the evaluation based on various indicators showed that ITS2 marker had the highest identification success rate(69%),ycf1 sequence followed by 59%;rbcL marker and matK marker had similar identification success rate(42% and 40%).