Kim Donghun, Jaworski Deborah C, Cheng Chuanmin, Nair Arathy D S, Ganta Roman R, Herndon Nic, Brown Susan, Park Yoonseong
Department of Entomology, Kansas State University, Manhattan, KS 66506, USA.
Center of Excellence for Vector-Borne Diseases, Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS 66506, USA.
J Asia Pac Entomol. 2018 Sep;21(3):852-863. doi: 10.1016/j.aspen.2018.05.009. Epub 2018 May 22.
The lone star tick, , is an obligatory ectoparasite of many vertebrates and the primary vector of , the causative agent of human monocytic ehrlichiosis. This study aimed to investigate the comparative transcriptomes of underlying the processes of pathogen acquisition and of immunity towards the pathogen. Differential expression of the whole body transcripts in six different treatments were compared: females and males that were non-exposed, -exposed/uninfected, and -exposed/infected. The Trinity assembly pipeline produced 140,574 transcripts from trimmed and filtered total raw sequence reads (approximately 117M reads). The gold transcript set of the transcriptome data was established to minimize noise by retaining only transcripts homologous to official peptide sets of and ESTs and transcripts covered with high enough frequency from the raw data. Comparison of the gene ontology term enrichment analyses for the six groups tested here revealed an up-regulation of genes for defense responses against the pathogen and for the supply of intracellular Ca for pathogen proliferation in the pathogen-exposed ticks. Analyses of differential expression, focused on functional subcategories including immune, sialome, neuropeptides, and G protein-coupled receptor, revealed that -exposed ticks exhibited an upregulation of transcripts involved in the immune deficiency (IMD) pathway, antimicrobial peptides, Kunitz, an insulin-like peptide, and bursicon receptor over unexposed ones, while transcripts for metalloprotease were down-regulated in general. This study found that ticks exhibit enhanced expression of genes responsible for defense against .
孤星蜱是许多脊椎动物的专性体外寄生虫，也是人单核细胞埃立克体病病原体嗜吞噬细胞无形体的主要传播媒介。本研究旨在调查孤星蜱在病原体获取过程和对病原体免疫过程中的比较转录组。比较了六种不同处理下全身转录本的差异表达：未接触病原体的雌性和雄性、接触病原体但未感染的雌性和雄性，以及接触病原体且感染的雌性和雄性。Trinity组装流程从经过修剪和过滤的原始总序列读数（约1.17亿条读数）中产生了140,574条转录本。通过仅保留与嗜吞噬细胞无形体和秀丽隐杆线虫官方肽集同源的转录本以及原始数据中覆盖频率足够高的转录本，建立了转录组数据的黄金转录本集，以尽量减少噪音。对这里测试的六组进行基因本体术语富集分析的比较显示，在接触病原体的蜱中，针对病原体的防御反应基因以及为病原体增殖提供细胞内钙的基因上调。对差异表达的分析集中在包括免疫、唾液酸组、神经肽和G蛋白偶联受体在内的功能亚类上，结果显示，与未接触病原体的蜱相比，接触病原体的蜱中参与免疫缺陷（IMD）途径、抗菌肽、库尼茨型、一种胰岛素样肽和bursicon受体的转录本上调，而金属蛋白酶的转录本总体下调。本研究发现，蜱对嗜吞噬细胞无形体的防御相关基因表达增强。
