Prof. Dr. Elena CROTTI
University of Milan — Department of Food, Environmental and Nutritional Sciences
Agricultural, Food and Environmental Microbiology Disciplinary Group
Milan, Italy
Talk title
Interfering with the transmission of pathogens in insect vectors by paratransgenesis
Abstract
By genetically modifying symbiotic microorganisms associated with insect vectors, paratransgenesis has emerged as an interesting strategy for the control of vector-borne diseases, including Chagas disease and malaria. This contribution aims to present the paratransgenesis approach, outline its principal characteristics, and discuss its application to insect vectors. Among the different systems under investigation, the association between mosquitoes and their bacterial symbionts offers a particularly attractive model for paratransgenesis. In particular, Asaia has emerged as a promising tool for malaria vector control.
Among mosquito vectors, bacteria of the genus Asaia have attracted particular attention for their intimate and persistent association with Anopheles mosquitoes. These acetic acid bacteria establish stable colonization of multiple mosquito tissues and organs—including the midgut, reproductive organs, and salivary glands—which are key sites for the development and transmission of Plasmodium parasites. Their ecological versatility, ease of cultivation, diverse routes of transmission, and capacity to rapidly occupy ecological niches within the mosquito microbiota make them interesting paratransgenic agents. Through targeted genetic engineering to express antiparasitic effector molecules, Asaia has the potential to disrupt parasite development within the vector, thereby reducing or preventing onward transmission. Overall, these properties highlight the value of Asaia as a promising platform for the development of paratransgenic strategies aimed at reducing malaria transmission.
Assoc. Prof. Dr. Anna MICHALICK
Jagiellonian University, Faculty of Biology — Institute of Zoology and Biomedical Research
Department of Developmental Biology and Morphology of Invertebrates
Kraków, Poland
Talk title
Hidden players in Auchenorrhyncha biology: Microbiome composition, drivers,
and ecological significance
Abstract
In addition to ancient heritable symbionts, Auchenorrhyncha harbor diverse facultative and recently acquired microorganisms that play central roles in shaping their biology. These symbionts can complement or replace ancestral partners in key nutritional functions, while also promoting rapid adaptation to new ecological niches and environmental challenges, and influencing interactions with other organisms, including vectored plant pathogens.
Our broad surveys spanning taxonomically diverse Auchenorrhyncha, and combining amplicon sequencing, metagenomics, and microscopy, revealed extensive variation in microbial communities across species and populations. We observed recurrent patterns of symbiont gain, loss, and replacement. In several lineages, facultative and other recently acquired symbionts appear to complement or substitute functionally degraded ancestral partners, contributing to metabolic capacity and host fitness. Notably, we frequently identify bacteria closely related to known plant pathogens, whose distribution patterns suggest stable, if often geographically restricted, associations with host insects. These discoveries reveal that microbiome composition is strongly associated with host ecology, with geographic distribution and habitat emerging as the major structuring factors. At the same time, the broad distribution of confirmed phytopathogens such as Phytoplasma highlights several species' roles as plant disease vectors. Our results highlight a potential link between microbiome structure and vector competence, suggesting that shifts in symbiont communities may directly influence the ability of Auchenorrhyncha to acquire and transmit plant pathogens.
Overall, Auchenorrhyncha microbiota are dynamic and shaped by interacting evolutionary and ecological factors. Facultative symbionts play a central role in the process of their host-plant adaptation, ecological diversification, and potentially modulating insect-mediated disease transmission. These findings underscore the importance of microbiome variability in understanding the ecology and evolution of insect vectors.
Dr. Patricia SANCHES
ETH Zürich — Department of Environmental Systems Science
Biocommunication Research Group — LFO G 22
Zürich, Switzerland
Talk title
Hidden partners, shifting outcomes: how insect vector endosymbionts influence plant virus transmission
Abstract
Insect-borne plant viruses can alter host plant and insect vector traits in ways that favor transmission, but whether microbial symbionts commonly harbored by insect vectors modify these effects remains poorly understood. In this talk, I will argue that endosymbionts of insect vectors are integral components of plant virus pathosystems and can influence transmission across behavioral, physiological, and ecological scales.
Drawing on work in the pea aphid–pea enation mosaic virus system, I will show that endosymbiont background can affect transmission-relevant traits ranging from host plant preference and performance on infected plants to virus acquisition, inoculation, and plant defense-related responses. I will also show that these effects are strongly context-dependent and can differ, for example, between winged and wingless aphids, highlighting the breadth and complexity with which microbial interactions can influence disease transmission.
Finally, I will address how these findings support a more mechanistically informed, step-resolved view of transmission and broaden our understanding of hemipteran-borne viral pathosystems. More broadly, a microbiome-aware view of these interactions highlights opportunities for plant disease ecology and management.
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