Genome of the giant panda roundworm illuminates its host shift and parasitic adaptation

Baylisascaris schroederi, a bamboo-feeding giant panda (Ailuropoda melanoleuca)-specific roundworm (ascaridoid) parasite, is the causative agent of baylisascariasis, which represents a leading reason for the mortality of wild giant panda populations and therefore poses a significant threat to giant panda conservation. Here we present a 293-Mb chromosome-level genome assembly of B. schroederi to inform 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 transmissions and fast adaptations to hosts. Genomic and anatomical lines of evidence, including expansion and positive selection of genes related to cuticle and basal metabolisms, indicates that B. schroederi undergoes specific adaptations to survive in the sharp-edged bamboo enriched gut of giant panda by structurally increasing its cuticle thickness and efficiently utilizing host nutrients during gut parasitism. Also, we characterized the secretome and predicted potential drug and vaccine targets for new interventions. Overall, this genome resource provides new insights into the host adaptation of B. schroederi to giant panda as well as the host-shift events in ascaridoid parasite lineages. These findings also add to our knowledge on the unique biology of the giant panda roundworm and aid the development of much-needed novel strategies for the control of baylisascariasis and thus the protection of giant panda populations.

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Microhabitat separation during winter among sympatric giant pandas, red pandas, and tufted deer: the effects of diet, body size, and energy metabolism

Canadian Journal of Zoology ◽

10.1139/z04-129 ◽

2004 ◽

Vol 82 (9) ◽

pp. 1451-1458 ◽

Cited By ~ 30

Author(s):

Zejun Zhang ◽

Fuwen Wei ◽

Ming Li ◽

Baowei Zhang ◽

Xuehua Liu ◽

...

Keyword(s):

Body Size ◽

Energy Metabolism ◽

Giant Panda ◽

Sichuan Province ◽

Ailuropoda Melanoleuca ◽

Giant Pandas ◽

Republic Of China ◽

Red Panda ◽

Open Land ◽

Selection Of

The giant panda (Ailuropoda melanoleuca (David, 1869)), red panda (Ailurus fulgens F.G. Cuvier, 1825), and tufted deer (Elaphodus cephalophus Milne-Edwards, 1872) are endemic to the Himalayan Hengduan Mountains; the red panda extends into India, Burma, Bhutan, and Nepal, and the tufted deer extends marginally into Burma, while the giant panda is endemic to China. In Sichuan Province, uniquely, all three species occur sympatrically. We investigated microhabitat characteristics at 150 fecal-group sites from November 2002 to March 2003 to improve understanding of microhabitat separation among the three species at the Fengtongzhai Nature Reserve, Baoxing County, Sichuan Province, People's Republic of China. Density and height of bamboo were greater in the giant and red pandas' micro habitats than in those of the tufted deer. The red panda preferred microhabitats with greater tree-stump density, smaller trees, and shorter fallen log dispersion distance than the other two species. Tufted deer often occurred at sites with greater shrub density and herb cover and more open land with poorer concealment conditions than sites where the two panda species occurred. Both pandas' microhabitats were mostly concentrated on the upper hillside, unlike those of the tufted deer. The giant panda preferred microhabitats with a gentler slope and lower density of fallen logs. Selection of specific microhabitats by each species is an ecological adaptation dependent on behavior linked to its diet, body size, energy metabolism, and other factors. Microhabitat separation among these species reflects the integrated effects of their differences in diet, body size, and energy metabolism, which could facilitate their successful coexistence.

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