The chromosome level genome of the Blueberry Stem Gall Wasp, Hemadas nubilipennis (Hymenoptera: Ormyridae) on lowbush blueberry (Vaccinium angustifolium) reveals repeat-driven expansion
- 1Agriculture Research Service Pacific Basin Agricultural Research Center
Abstract
Gall-inducing wasps are emerging models for studying plantinsect coevolution, host manipulation, host plant adaptation, and speciation, yet chromosome-level resources remain scarce for most lineages. The blueberry stem gall wasp (BSGW), Hemadas nubilipennis (Hymenoptera: Ormyridae), is native to North America where it induces galls on both lowbush (Vaccinium angustifolium) and highbush blueberries (V. corymbosum). Recently, BSGW has reached outbreak densities in cultivated highbush production. Given that (a) the biology has been characterized primarily from natural lowbush-associated populations, (b) the absence of genomic resources limits comparative analyses, and (c) populations on cultivated highbush represent a recent host shift, we generated the first chromosome-level genome from wild lowbush blueberry. The BSGW genome consists of five chromosome-scale scaffolds totaling 1.08 Gb (N50 = 218 Mb), the second largest known in Chalcidoidea. Comparative analysis reveals that genome size variation is driven primarily by transposable element proliferation (R = 0.96, p < 0.001), with BSGW exhibiting a high proportion of unclassified TEs. Gene-body methylation is conserved, enriched in exons of broadly expressed core genes, and correlates with gene density. The mitochondrial genome (18,697 bp) exhibits extensive gene rearrangement, and COI sequences reveal 4.35.4% divergence from geographically distant populations, suggesting a complex of cryptic species. Additionally, we assemble a near-complete genome of the endosymbiont Wolbachia pipientis (Supergroup A), which encodes PifA and PifB effectors potentially linked to parthenogenesis. These resources establish a foundation for population genomics, taxonomic revision, and applied management, while providing insights into genome architecture, epigenetics, and symbiont interactions.
Related
- Integrated fertilization with brazide-mediated regulation improves stem mechanical strength, yield, and water-use efficiency of blueberry under semi-arid conditions
- Genetic control underlying dynamics of blueberry bioactive compounds during postharvest can drive breeding for functional fruits
- Likelihood of same diapause fate for nest-adjacent siblings of alfalfa leafcutting bees (Megachile rotundata, Hymenoptera: Megachilidae)
- Characteristics of AgifCSP9 and Its Potential Involvement in Host Location by Aphidius gifuensis (Hymenoptera: Braconidae)
- Host Suitability and Parasitic Activity of Local Groups of Habrobracon hebetor (Say, 1836) (Hymenoptera: Braconidae) as a Factor in the Management of Lepidopteran Pest Populations in Corn Agroecosystems
BibTeX
@misc{zhang2026chromosome,
title = {{The chromosome level genome of the Blueberry Stem Gall Wasp, Hemadas nubilipennis (Hymenoptera: Ormyridae) on lowbush blueberry (Vaccinium angustifolium) reveals repeat-driven expansion}},
author = {Y. M. Zhang and A. Kranz and S. Mukhopadhyay and E. O. Martinson and M. Sergeant and R. L. Corpuz and G. R. Hood and S. M. Geib and S. B. Sim},
howpublished = {bioRxiv},
year = {2026},
month = sep,
doi = {10.64898/2026.09.21.753281},
url = {https://www.biorxiv.org/content/10.64898/2026.09.21.753281v1},
note = {CC0},
}
RIS
TY - UNPB
TI - The chromosome level genome of the Blueberry Stem Gall Wasp, Hemadas nubilipennis (Hymenoptera: Ormyridae) on lowbush blueberry (Vaccinium angustifolium) reveals repeat-driven expansion
AU - Y. M. Zhang
AU - A. Kranz
AU - S. Mukhopadhyay
AU - E. O. Martinson
AU - M. Sergeant
AU - R. L. Corpuz
AU - G. R. Hood
AU - S. M. Geib
AU - S. B. Sim
PY - 2026
DA - 2026/09/21
PB - bioRxiv
DO - 10.64898/2026.09.21.753281
UR - https://www.biorxiv.org/content/10.64898/2026.09.21.753281v1
AB - Gall-inducing wasps are emerging models for studying plantinsect coevolution, host manipulation, host plant adaptation, and speciation, yet chromosome-level resources remain scarce for most lineages. The blueberry stem gall wasp (BSGW), Hemadas nubilipennis (Hymenoptera: Ormyridae), is native to North America where it induces galls on both lowbush (Vaccinium angustifolium) and highbush blueberries (V. corymbosum). Recently, BSGW has reached outbreak densities in cultivated highbush production. Given that (a) the biology has been characterized primarily from natural lowbush-associated populations, (b) the absence of genomic resources limits comparative analyses, and (c) populations on cultivated highbush represent a recent host shift, we generated the first chromosome-level genome from wild lowbush blueberry. The BSGW genome consists of five chromosome-scale scaffolds totaling 1.08 Gb (N50 = 218 Mb), the second largest known in Chalcidoidea. Comparative analysis reveals that genome size variation is driven primarily by transposable element proliferation (R = 0.96, p < 0.001), with BSGW exhibiting a high proportion of unclassified TEs. Gene-body methylation is conserved, enriched in exons of broadly expressed core genes, and correlates with gene density. The mitochondrial genome (18,697 bp) exhibits extensive gene rearrangement, and COI sequences reveal 4.35.4% divergence from geographically distant populations, suggesting a complex of cryptic species. Additionally, we assemble a near-complete genome of the endosymbiont Wolbachia pipientis (Supergroup A), which encodes PifA and PifB effectors potentially linked to parthenogenesis. These resources establish a foundation for population genomics, taxonomic revision, and applied management, while providing insights into genome architecture, epigenetics, and symbiont interactions.
ER -