Using an Endosymbiotic Microbe to Combat Wheat Stem Sawflies

(Photo by R. K. D. Peterson)

The wheat stem sawfly damages cereal crops and native grasses to the tune of ~$350 million over the Northern Great Plains. Adult flies deposit their eggs into the hollow stems of wheat. Damage to the stem occurs when the larvae emerge and feed on the internal parenchyma and vascular tissue of the plant affecting photosynthesis and causing lodging – weakening the stem to the point where the plant simply falls over in large swaths

In collaboration with the Montana State University Wheat Stem Sawfly Project, headed by entomologist Dr. David Weaver, we have identified a bacterial symbiont of the genus Spiroplasma that is associated with the sawfly and are characterizing the Spiroplasma (currently named Spiroplasma sp. WSS) and its relationship with the Wheat Stem Sawfly.

This project was initially funded by the Montana Wheat & Barley Committee to help obtain a more complete understanding of how this species of bacteria can impact the fitness of these agricultural pests. The ultimate goal of this project is to provide a unique approach that manipulates the host:microbe relationship to manage this significant pest.

In our initial efforts, we applied a metagenomic approach to capture the genome of Spiroplasma sp. WSS and then used this to increase our understanding of the bacterium’s metabolic capability and contributions to the sawfly host. Through this analysis, we found evidence that Spiroplasma sp. WSS may break down sugars the insect eats and help them to manufacture other nutrients they don’t get from their carbohydrate-heavy diet, including key B vitamins. Using this information we are attempting to examine if these insect-microbial relationships could be exploited as alternate measures to control WSS damage in crops. Further inquiries on Wheat Stem Sawfly biology and pest management may be directed towards Dr. David Weaver ( Further questions specifically on Spiroplasma sp. WSS may be directed towards Dr. Yeoman.

Related Publications

Yeoman CJ, Brutscher LM, Esen Ö, İbaoğlu F, Fowler C, Eren AM, Wanner K, Weaver DK. 2019. Genome-resolved insights into a novel Spiroplasma symbiont of the Wheat Stem Sawfly (Cephus cinctus). PeerJ 7:e7548 DOI: 10.7717/peerj.7548