Screening of DNA Barcode of Quarantine Phytophthora

摘要

Phytophtkora is genus of plant-damaging Oomycetes,whose member species are capable of causing enormous economic losses on crops worldwide.In the present study,four candidate genes ITS,CO1,EF-1α and β-tubulin were tested using 123 strains of 80 species of Phytophthora to investigate the feasibility of serving as DNA barcoding markers.The results showed that among the four candidate genes,ITS and CO1 had the highest success rate of PCR amplification and sequencing,up to 100%and 96.7%.There were obvious barcode gaps in ITS,CO1 and β-tubulin,but their frequency distributions of intra-and interspecific genetic distances were slightly overlapped.Wilcoxon rank sum test on intraspecific genetic distances of the four genes showed ITS = CO1 = β-tubulin = EF-1α,indicating they had the same effect on intraspecific discrimination,while the test on interspecific genetic distances of the four genes showed ITS > CO1 > β-tubulin > EF-1α.In summary,ITS and CO1 should be used in combination as the primary barcodes,β-tubulin as the complementary barcode for the identification of 11 quarantine Phytophthora species.