Educating insect pathologists to prevent infectious diseases in mass-reared insects
Diversity and dynamics of the Insect microbiome
May 6, 2022
My name is Loretta Mugo-Kamiri, ESR 14. During the past 20 months of my PhD, I have been working on Spodoptera exigua at the Univeristy of Tours, France and Plutella xylostella at the University of Exeter, Penryn, UK; two globally devastating crop pests. The objective of my study is to understand the tripartite interaction between diet, gut microbiota and pathogens in the control of these pests.
Previously, literature has shown gut microbiota may confer a resistance to pathogens or on the contrary, increase their susceptibility, and that this may depend on host diet. We have so far assessed the effect of two diets on the fitness and performance of S. exigua and on its microbiota by using DNA metabarcoding. Although quite similar in terms of their macro nutrient composition, the two diet treatments produced significant differences in insect fitness parameters as well as on the metabolically active gut microbiota.
Using axenic Plutella xylostella, we sought to find out whether some microbes previously isolated from them, have an effect on growth when re-inoculated in the gut either individually or as a mixed community. By analyzing the growth rate of caterpillars, we have seen that the diet formulation alters the role of Enterobacter spp, whereby in some nutrient conditions the bacteria is parasitic while in others it is not. Moving forward, we seek to understand the mechanisms underlying this kind of interactions by looking at the host and bacteria’s transcriptome.
This current phase of my PhD is much more involving because as I continue with lab work, I am also engaged with data analysis and writing. While it is no small feat, we have had good training through the INSECTDOCTORS courses and workshops such as course IV on metagenomics and most recently a workshop on how to write highly cited papers. For me, these meetings have not only been useful for knowledge sharing but also for experiencing new culture, new languages and making lasting connections within the consortium, especially now that it possible to meet in-person again.
This PhD has been life changing for me and I can only hope to reciprocate by positively influencing the world through new knowledge that I contribute through this research and beyond.