Zhang Yuan-Chen, Lei Hai-Xia, Miao Ning-Hui, Liu Xiang-Dong
Department of Entomology, Nanjing Agricultural University, Nanjing 210095, China (
J Econ Entomol. 2017 Apr 1;110(2):702-710. doi: 10.1093/jee/tox029.
Host specialization is an ubiquitous character in aphid populations. Many polyphagous aphid populations usually consist of several subpopulations that have strong fidelity to a specific host or a subset of host range. Host specialization is an evolutional result of food habit of insects. However, genetic basis and molecular mechanism of host specialization are still unclear. In this study, we presented a comparative analysis on global gene expression profiles of three lineages of Aphis gossypii Glover: cotton-specialized (CO), cucurbit-specialized (CU), and CU reared on cowpea (CU-cowpea), using RNA-Seq method. More than 157 million clean reads and 38,398 different unigenes were generated from transcriptomes of these three aphid lineages. The 1,106 down- and 2,835 up-regulated genes were found between CO and CU, and 812 down- and 14,492 up-regulated genes between CU-cowpea and CU. Differentially expressed genes between CO and CU were enriched in sugar metabolism, immune system process, pathogen infection or symbiosis, and salivary secretion. Genes associated with cytochrome P450, major facilitator superfamily, and salivary effector were differentially expressed between CO and CU, which might be involved in determining host specialization. UDP-glycosyltransferases genes were sensitive to host shift. Carboxylesterases and digestion-related protease genes were related to both the host specialization and host shift of aphids. Expression levels of 22 out of 24 genes of CO and CU measured by RT-qPCR method were as similar as the results from RNA-seq method. This study provides a road map for future study on molecular mechanism of host specialization in aphids.
寄主专化性是蚜虫种群中普遍存在的特征。许多多食性蚜虫种群通常由几个亚种群组成，这些亚种群对特定寄主或寄主范围的一个子集具有很强的忠诚度。寄主专化性是昆虫食性的进化结果。然而，寄主专化性的遗传基础和分子机制仍不清楚。在本研究中，我们使用RNA-Seq方法对棉蚜（Aphis gossypii Glover）的三个谱系进行了全基因组表达谱的比较分析：棉花专化型（CO）、葫芦科专化型（CU）以及在豇豆上饲养的CU（CU-豇豆）。从这三个蚜虫谱系的转录组中产生了超过1.57亿条干净 reads 和38398个不同的单基因。在CO和CU之间发现了1106个下调基因和2835个上调基因，在CU-豇豆和CU之间发现了812个下调基因和14492个上调基因。CO和CU之间差异表达的基因在糖代谢、免疫系统过程、病原体感染或共生以及唾液分泌中富集。与细胞色素P450、主要促进剂超家族和唾液效应器相关的基因在CO和CU之间差异表达，这可能参与决定寄主专化性。UDP-糖基转移酶基因对寄主转移敏感。羧酸酯酶和消化相关蛋白酶基因与蚜虫的寄主专化性和寄主转移都有关。通过RT-qPCR方法测量的CO和CU的24个基因中有22个的表达水平与RNA-seq方法的结果相似。本研究为未来蚜虫寄主专化性分子机制的研究提供了路线图。
