Pollinators such as honeybees produce special enzymes that detoxify defence chemicals produced by plants, new research shows.

Many plants produce alkaloids as protection against herbivores, and these toxins are also found in their nectar and pollen.

The new study, by the University of Exeter and Bayer AG, examined the genes of several species in a group called Hymenoptera – insects including bees, wasps, ants and sawflies that share a common ancestor about 280 million years ago.

Remarkably, all the species tested produce the same group of enzymes (the CYP336 family of cytochrome P450 enzymes) to tackle alkaloid toxins.

“These species differ greatly, but one thing they share is this ability to detoxify alkaloids,” said Dr Angie Hayward, from Exeter’s Penryn Campus in Cornwall.

“We were fascinated to discover this family of genes has been preserved across almost 300 million years of evolution by a whole order of insects with very diverse lifestyles.

“Although some of these species have very little contact with certain key alkaloids, such as nicotine, they appear to have retained the ability to metabolise them, almost as an aspect of their genetic heritage, rather like the case of the human tailbone or appendix.”

The researchers examined the genomes of key hymenopteran species, creating an “evolutionary tree” for the family.

They also extracted the enzymes produced by these species and placed them in a cell-line to see how they would react with alkaloids – and found they do indeed detoxify them.

“Understanding how insects react to specific toxins is vital – it should inform how we produce any new chemicals such as pesticides and insecticides,” said Dr Bartek Troczka, also from the University of Exeter.

“To avoid environmental damage, we need very specific compounds that do very specific things.

“Our paper feeds into the wider attempt to understand how chemicals are broken down by insects and to what extent the genes responsible persist across insect groups.”

Dr Julian Haas, insect toxicologist at Bayer AG, said: “This study highlights the promise of multidisciplinary teamwork to better understand the molecular and evolutionary basis of detoxification mechanisms in insects which will ultimately aid with the understanding of their interaction with other toxins including insecticides.”

The study was funded by the Biotechnology and Biological Sciences Research Council (BBSRC) and Bayer AG.

The paper, published in the journal Science Advances, is entitled: “A conserved hymenopteran-specific family of cytochrome P450s protect bee pollinators from toxic nectar alkaloids.”



About the University of Exeter

The University of Exeter is a Russell Group university that combines world-class research with very high levels of student satisfaction. Exeter has over 22,000 students and is amongst the top 150 universities worldwide according to the Times Higher Education World University Rankings 2019, the most influential global league table.
Exeter is also ranked 12th in The Times and The Sunday Times Good University Guide 2019 (Best in the South West) and 14th in the Guardian University Guide 2019. In the 2014 Research Excellence Framework (REF), the University ranked 16th nationally, with 98% of its research rated as being of international quality, while in 2017, Exeter was awarded a Gold rating in the Teaching Excellence Framework (TEF) assessment. Exeter was named The Times and The Sunday Times Sports University of the Year 2015-16, in recognition of excellence in performance, education and research.  Exeter was The Sunday Times University of the Year 2012-13.

The University has four campuses. The Streatham and St Luke’s campuses are in Exeter and there are two campuses in Cornwall, Penryn and Truro. In a pioneering arrangement in the UK, the Penryn Campus is jointly owned and managed with Falmouth University. At the campus, University of Exeter students can study programmes in the following areas: Animal Behaviour, Business, Conservation Biology and Ecology, English, Environmental Science, Evolutionary Biology, Geography, Geology, History, Human Sciences, Law, Mathematical Sciences, Marine Biology, Mining and Minerals Engineering, Politics and International Relations, Renewable Energy and Zoology.

The University launched its flagship Global Systems Institute in 2018, a world-class, interdisciplinary community of researchers, students, citizens and partners that will solve global challenges through transformative research and education. This follows recent investments of more than £350 million worth of new facilities across its campuses in recent years; including the Living Systems Institute in 2016 in Exeter, and the Environment and Sustainability Institute on the Penryn Campus in Cornwall, together with new student services hubs, and new facilities for Biosciences, the Business School and Renewable Energy.