USDA and university researchers develop system close to CHR

LOGAN, Utah, July 1, 2024 – Scientists from the United States Department of Agriculture (USDA) Agricultural Research Service (ARS) and academic research partners have developed a near-chromosomal genome for the Mojave poppy bee, a specialized pollinator of conservation concern, according to a recent study. Journal of Heredity paper.

The development of the Mojave poppy bee genome is part of the Beenome100 project, a groundbreaking effort to create a library of high-quality, highly detailed genome maps of 100 or more diverse bee species found in the United States. Beenome100 is a collaborative effort led by ARS and the University of Illinois, with researchers from ARS and universities across the United States and Canada contributing. The hope is that these genomes will help researchers answer big questions about bees, such as what genetic differences make a bee species more vulnerable to climate change or whether a bee species is likely to be more sensitive to a pesticide.

Limited to the eastern Mojave Desert, the Mojave poppy bee (Perdita meconis) is a solitary mining bee of the family Andrenidae, specialized in pollinating the Las Vegas bear poppy (Arctomecon California) and the dwarf poppy (Arctomecon humilis) – the latter being protected by the U.S. Endangered Species Act since 1979. Poppies are found primarily in gypsum deposits, which are rare and scattered throughout the region.

The Mojave poppy bee and the Las Vegas short-billed poppy are also being considered for endangered species listing. Both species will be assessed based on their potential population declines and their vulnerability to extinction due to climate change and habitat loss from urban development and mining in their native regions.

Researchers have assembled the genome or genetic map that will help better understand the biological traits of the Mojave poppy bee.

“The genome, with additional genetic sampling of individuals, will also potentially give us information about the genetic basis of host plant specialization, pesticide sensitivity, and drought sensitivity and climate tolerance,” said Rena Schweizer, a research entomologist in the ARS Pollinator Insect Systematics, Management and Biology Unit in Logan, Utah.

The Mojave poppy bee is notably able to survive years of drought by remaining in the soil in a state of stasis, a phenomenon called diapause. This characteristic is not yet well understood by researchers, and by sequencing its genome, they could learn more about the genes and regulatory pathways that make this adaptation possible.

They will also use the genome to assess the genetic health of the species, find insights into how bees can be specialists or generalists, and examine what the tradeoffs are in terms of a bee's long-term fitness.

“It could also allow us to uncover genetic signs of decline,” Schweizer said. “By studying the genome of this bee, we could perhaps help to better conserve it and identify other species in decline through genetic information.”

To develop the genome of the tiny, mighty bee, the researchers isolated DNA from a single, tiny male specimen.

Schweizer said the genome assembly is impressive given the bee's diminutive size (a male is on average about five to seven millimeters long). The researchers collected the specimen in the field, in a remote, wild location.

“What is also remarkable about this research is that the specimen used for the genome was collected under less than ideal preservation methods,” Schweizer said. “Nevertheless, we obtained high-quality DNA from a field-collected specimen thanks to advances in sequencing technology and learned more about this unique bee. We hope that our research will serve as a basis for developing genomes for other bee species.”

The detailed, high-resolution map of the reference genome is available in the National Center for Biotechnology Information database.

The research was conducted in collaboration with the University of Montana, Utah State University, and the ARS Tropical Pest Genetics and Molecular Biology Research Unit in Hilo, Hawaii.

THE Agricultural Research Service is the lead internal scientific research agency of the United States Department of Agriculture. Every day, ARS focuses on solving the agricultural problems that affect America. Every dollar invested in agricultural research generates $20 in economic impact.

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