云南茶树蓟马种类DNA条形码分析及临沧茶区优势种群动态调查

DNA barcoding of Yunnan tea plant thrips and investigation of the dynamics of the dominant thrip populations in the Lincang tea-growing area

【目的】分析DNA条形码技术应用于云南茶树蓟马种类鉴定的可行性,明确茶树不同部位的蓟马优势种群,为监测临沧茶区蓟马优势种群的动态发生规律及其防控提供理论依据。【方法】广泛调查云南茶树蓟马种类,并采集样本,通过扩增蓟马的线粒体COⅠ基因序列,分析蓟马种间和种内遗传距离和系统发育关系;采用5点取样法对云南临沧茶区蓟马优势种的周年发生动态进行调查。【结果】对采集的3399头蓟马成虫标本进行鉴定,共鉴定出3科19属27种,经分子测序共获得茶树27种蓟马的54条COⅠ基因序列,平均种间遗传距离为0.2692,种内遗传距离为0.0077,种间和种内遗传距离存在明显的条形码间隙,贝叶斯系统发育分析结果与形态学鉴定结果一致,每一个单系分支对应一个物种。比较茶树不同部位的蓟马种类和数量,茶树花中褐三鬃蓟马Lefroyothrips lefroyi数量最多,占总数的81.26%;茶树嫩梢上贡山喙蓟马Mycterothrips gongshanensis发生数量最多,占总数的76.63%。贡山喙蓟马在云南临沧茶区周年发生,发生动态呈双峰型,第1峰出现在4月中旬至5月中旬,第2峰出现在9月上旬至10月上旬。【结论】基于线粒体COⅠ基因的DNA条形码技术可有效用于茶树蓟马不同种类的鉴定。临沧茶区茶树花朵和嫩梢上发生数量最多的分别是褐三鬃蓟马和贡山喙蓟马,根据贡山喙蓟马的周年发生动态,在虫口数量开始上升时的2月下旬和8月下旬是防治的关键时期。

[Objectives]To analyze the feasibility of using DNA barcoding technology to identify tea(Camellia sinensis)plant thrip species in Yunnan,clarify the dominant thrip populations on different parts of tea plants,and monitor the population dynamics of this population in the Lincang tea-growing area.[Methods]Samples of tea plant thrips in Yunnan were extensively investigated and collected.Mitochondrial COⅠgene sequences of different species were amplified,and their inter-and intra-specific genetic distances and phylogenetic relationships analyzed.Finally,the five-point sampling method was used to investigate the annual occurrence dynamics of dominant thrip species in the Lincang tea-growing area.[Results]A total of 3399 adult thrips specimens were collected,which were classified to 27 species,19 genera and 3 families.A total of 54COⅠgene sequences of 27 species of tea plant thrips were obtained by molecular sequencing.These had a mean interspecific genetic distance of 0.2692 and a mean intraspecific genetic distance of 0.0077.There was an obvious barcoding gap between inter-and intra-specific genetic distances.The results of a Bayesian phylogenetic analysis were consistent with the results of morphological identification;each monophyletic branch corresponds to a single species.Most(81.26%)thrips on tea flowers were Lefroyothrips lefroyi,whereas the majority(76.63%)on young shoots were Myctorothrips gongshanensis.Myctorothrips gongshanensis occurs annually in the Lincang tea-growing area and has two annual peaks in abundance,the first from mid-April to mid-May and the second from early September to early October.[Conclusion]DNA barcoding technology based on the mitochondrial COⅠgene can rapidly and accurately identify tea plants thrips.The critical period for controlling Myctorothrips gongshanensis in the Lincang tea-growing area is late February and late August when the population begins to increase.