Xie Yue, Wang Sen, Wu Shuangyang, Gao Shenghan, Meng Qingshu, Wang Chengdong, Lan Jingchao, Luo Li, Zhou Xuan, Xu Jing, Gu Xiaobin, He Ran, Yang Zijiang, Peng Xuerong, Hu Songnian, Yang Guangyou
Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China.
Agricultural Genomics Institute, Chinese Academy of Agricultural Sciences, Shenzhen 518120, China.
Genomics Proteomics Bioinformatics. 2022 Apr;20(2):366-381. doi: 10.1016/j.gpb.2021.08.002. Epub 2021 Sep 3.
Baylisascaris schroederi, a roundworm (ascaridoid) parasite specific to the bamboo-feeding giant panda (Ailuropoda melanoleuca), represents a leading cause of mortality in wild giant panda populations. Here, we present a 293-megabase chromosome-level genome assembly of B. schroederi to infer its biology, including host adaptations. Comparative genomics revealed an evolutionary trajectory accompanied by host-shift events in ascaridoid parasite lineages after host separations, suggesting their potential for transmission and rapid adaptation to new hosts. Genomic and anatomical lines of evidence, including expansion and positive selection of genes related to the cuticle and basal metabolisms, indicate that B. schroederi undergoes specific adaptations to survive in the sharp-edged bamboo-enriched gut of giant pandas by structurally increasing its cuticle thickness and efficiently utilizing host nutrients through gut parasitism. Additionally, we characterized the secretome of B. schroederi and predicted potential drug and vaccine targets for new control strategies. Overall, this genome resource provides new insights into the host adaptation of B. schroederi to the giant panda as well as the host-shift events in ascaridoid parasite lineages. Our findings on the unique biology of B. schroederi will also aid in the development of prevention and treatment measures to protect giant panda populations from roundworm parasitism.
斯氏贝蛔虫（Baylisascaris schroederi）是一种专性寄生于以竹子为食的大熊猫（Ailuropoda melanoleuca）体内的蛔虫（蛔科）寄生虫，是野生大熊猫种群死亡的主要原因。在此，我们展示了斯氏贝蛔虫293兆碱基的染色体水平基因组组装，以推断其生物学特性，包括宿主适应性。比较基因组学揭示了蛔科寄生虫谱系在宿主分离后伴随着宿主转换事件的进化轨迹，表明它们具有传播潜力以及快速适应新宿主的能力。包括与角质层和基础代谢相关基因的扩增和正选择在内的基因组和解剖学证据表明，斯氏贝蛔虫通过在结构上增加角质层厚度并通过肠道寄生有效利用宿主营养，从而进行特定的适应性变化以在大熊猫边缘锋利且富含竹子的肠道中生存。此外，我们对斯氏贝蛔虫的分泌蛋白组进行了表征，并预测了新控制策略的潜在药物和疫苗靶点。总体而言，这一基因组资源为斯氏贝蛔虫对大熊猫的宿主适应性以及蛔科寄生虫谱系中的宿主转换事件提供了新的见解。我们对斯氏贝蛔虫独特生物学特性的研究结果也将有助于制定预防和治疗措施，以保护大熊猫种群免受蛔虫寄生。
