中国蛛缘蝽科物种DNA条形码研究

DNA barcoding of broad-headed bugs(Hemi ptera: Alydidae) from China

【目的】本研究旨在探讨DNA条形码对中国蛛缘蝽科(半翅目:缘蝽总科)物种界定的适用性。【方法】对中国蛛缘蝽科13属23种207个样本的线粒体COI基因DNA条形码序列进行扩增,并扩增稻缘蝽属Leptocorisa 3个物种的31条内转录间隔区1(ITS-1)序列作为辅助标记。使用MEGA 11软件计算种间和种内遗传距离(Kimura 2-parameter,K2P);采用邻接法(neighbor-joining,NJ)进行物种聚类分析;利用中介邻接网络算法构建单倍型网络图。【结果】基于线粒体COI DNA条形码序列得出测试的中国蛛缘蝽科所有23个种的种内平均K2P距离在2%以下,种间K2P距离在0.98%~23.98%之间(平均17.50%)。多数物种彼此能够被较好地分开,且支持率较高。其中,中稻缘蝽Leptocorisa chinensis和大稻缘蝽L.oratoria共享部分COI单倍型,造成COI条形码无法区分二者,可通过ITS-1序列在单倍型网络分析中将二者区分。【结论】本研究得出的中国蛛缘蝽科中绝大部分物种的DNA条形码数据分析结果与基于形态特征的分类单元一致。然而,对于其中亲缘关系极近的物种,单靠线粒体数据尤其是COI条形码序列无法进行准确界定,需引入其他DNA序列或其他类型数据进行区分。

【Aim】The aim of the study is to test the validity of DNA barcoding for the identification of broad-headed bugs(Hemiptera:Coreidae)from China.【Methods】The DNA barcode sequences of mitochondrial COI gene of 207 samples from 23 species of 13 genera of Alydidae from China were amplified,and 31 internal transcribed spacer 1(ITS-1)sequences of three Leptocorisa species were amplified as auxiliary markers.The interspecific and intraspecific genetic distances(Kimura 2-parameter model,K2P)were calculated by MEGA 11 software.The species cluster analysis was performed using neighborjoining(NJ)method.The holotype networks were constructed using median joining network algorithm.【Results】Based on the DNA barcode sequences of mitochondrial COI,the mean intraspecific K2P distances of all the tested 23 species of Alydidae from China were below 2%,and the interspecific K2P distances ranged from 0.98%to 23.98%,with an average of 17.50%.Most species were separated from each other with a high bootstrap value.This COI barcode section could not distinguish between Leptocorisa chinensis and L.oratoria because of the partial COI haplotypes they shared.The ITS-1 sequences did distinguish the two species in the haplotype network analysis.【Conclusion】The DNA barcoding results from our data are congruent with most of the taxonomic units of the family Alydidae from China based on morphological characteristics.However,for extremely closely related species,mitochondrial data alone,especially COI barcode sequences,sometimes are insufficient for accurate species delimitation,and other DNA sequences or other types of data need to be introduced.