Repetitive sequence analysis and detection primer screening of Candidatus Liberibacter asiaticus
Huanglongbing(HLB),caused by Candidatus Liberibacter asiaticus(CLas),poses significant threat to citrus industry.Strengthening pathogen detection is beneficial to avoid disease spreading.Though primers coming from high-copy repetitive sequence is helpful to enhance the sensitivity of HLB detection,the polymorphism of repetitive sequence remains challenge to keep the detection instability.In this study,we identified conserved repetitive sequences among 11 CLas strains to develop universal primers of CLas detection.The results revealed there are four kinds of conserved repetitive sequence in CLas genome with sequence length above 50 base pairs and high-copy.Based on these sequences,we developed six pairs of CLas-specific primers,which were tested to have ability in keeping instability of HLB detection.The melting curve of these primers showed single absorption peak and maintained consistent melting temperature among different HLB samples.Among the six primer pairs,IR16-fr,derived from a fiive-copy repetitive sequence,displayed the highest sensitivity.Fifty field citrus leaf samples were tested using IR16-fr and the conventional primer CQULas-FR,and the results showed that the detection rate of CLas by CQULas-FR was 20％,while that of IR 16-fr was 26％.The new primer IR 16-fr can provide technical support to enhance the efficiency of CLas detection.
万方数据
维普
