Khamis F M, Rwomushana I, Ombura L O, Cook G, Mohamed S A, Tanga C M, Nderitu P W, Borgemeister C, Sétamou M, Grout T G, Ekesi S
International Centre of Insect Physiology and Ecology (icipe) Kenya.
Citrus Research International (Pty) Limited, South Africa.
J Econ Entomol. 2017 Dec 5;110(6):2637-2646. doi: 10.1093/jee/tox283.
Citrus (Citrus spp.) production continues to decline in East Africa, particularly in Kenya and Tanzania, the two major producers in the region. This decline is attributed to pests and diseases including infestation by the African citrus triozid, Trioza erytreae (Del Guercio) (Hemiptera: Triozidae). Besides direct feeding damage by adults and immature stages, T. erytreae is the main vector of 'Candidatus Liberibacter africanus', the causative agent of Greening disease in Africa, closely related to Huanglongbing. This study aimed to generate a novel barcode reference library for T. erytreae in order to use DNA barcoding as a rapid tool for accurate identification of the pest to aid phytosanitary measures. Triozid samples were collected from citrus orchards in Kenya, Tanzania, and South Africa and from alternative host plants. Sequences generated from populations in the study showed very low variability within acceptable ranges of species. All samples analyzed were linked to T. erytreae of GenBank accession number KU517195. Phylogeny of samples in this study and other Trioza reference species was inferred using the Maximum Likelihood method. The phylogenetic tree was paraphyletic with two distinct branches. The first branch had two clusters: 1) cluster of all populations analyzed with GenBank accession of T. erytreae and 2) cluster of all the other GenBank accession of Trioza species analyzed except T. incrustata Percy, 2016 (KT588307.1), T. eugeniae Froggatt (KY294637.1), and T. grallata Percy, 2016 (KT588308.1) that occupied the second branch as outgroups forming sister clade relationships. These results were further substantiated with genetic distance values and principal component analyses.
在东非，柑橘（柑橘属）产量持续下降，尤其是在该地区的两个主要生产国肯尼亚和坦桑尼亚。这种下降归因于病虫害，包括非洲柑橘木虱（Trioza erytreae (Del Guercio)，半翅目：木虱科）的侵害。除了成虫和未成熟阶段的直接取食危害外，非洲柑橘木虱还是“非洲韧皮杆菌”（‘Candidatus Liberibacter africanus’）的主要传播媒介，该病菌是非洲黄龙病的病原体，与黄龙病密切相关。本研究旨在为非洲柑橘木虱建立一个新的条形码参考文库，以便将DNA条形码作为一种快速工具，准确鉴定该害虫，以辅助植物检疫措施。从肯尼亚、坦桑尼亚和南非的柑橘园以及替代寄主植物上采集了木虱样本。研究中种群产生的序列在物种可接受范围内显示出非常低的变异性。所有分析样本均与GenBank登录号为KU517195的非洲柑橘木虱相关联。本研究中的样本与其他木虱参考物种的系统发育关系采用最大似然法推断。系统发育树是并系的，有两个不同的分支。第一个分支有两个聚类：1）所有分析种群的聚类，其GenBank登录号为非洲柑橘木虱；2）除2016年的T. incrustata Percy（KT588307.1）、T. eugeniae Froggatt（KY294637.1）和2016年的T. grallata Percy（KT588308.1）外，所有其他分析的木虱属物种的GenBank登录号的聚类，后三者作为外类群占据第二个分支，形成姐妹进化枝关系。这些结果通过遗传距离值和主成分分析得到了进一步证实。
