Inhibition of Asaia in Adult Mosquitoes Causes Male-Specific Mortality and Diverse Transcriptome Changes.

Maria Vittoria Mancini,Sarah M Short,Aida Capone,Paolo Rossi,Irene Ricci,Ulisse Ulissi,Guido Favia,Aurelio Serrao,Cristina Kalogris,George Dimopoulos,Alessia Cappelli,Augusto Amici,Claudia Damiani

doi:10.3390/pathogens9050380

Abstract

Mosquitoes can transmit many infectious diseases, such as malaria, dengue, Zika, yellow fever, and lymphatic filariasis. Current mosquito control strategies are failing to reduce the severity of outbreaks that still cause high human morbidity and mortality worldwide. Great expectations have been placed on genetic control methods. Among other methods, genetic modification of the bacteria colonizing different mosquito species and expressing anti-pathogen molecules may represent an innovative tool to combat mosquito-borne diseases. Nevertheless, this emerging approach, known as paratransgenesis, requires a detailed understanding of the mosquito microbiota and an accurate characterization of selected bacteria candidates. The acetic acid bacteria Asaia is a promising candidate for paratransgenic approaches. We have previously reported that Asaia symbionts play a beneficial role in the normal development of Anopheles mosquito larvae, but no study has yet investigated the role(s) of Asaia in adult mosquito biology. Here we report evidence on how treatment with a highly specific anti-Asaia monoclonal antibody impacts the survival and physiology of adult Anopheles stephensi mosquitoes. Our findings offer useful insight on the role of Asaia in several physiological systems of adult mosquitoes, where the influence differs between males and females.

Highlights

Mosquito-borne diseases, and more generally vector-borne diseases, pose serious threats to public health; about 700,000 people die each year due to direct or indirect consequences of them [1]
We have shown that Asaia may activate the basal level of mosquito immunity, interfering with development of the malaria parasite in Anopheles stephensi [7]
The specificity of the anti-Asaia monoclonal antibody (mAb) was assessed through a double-step approach

Summary

Introduction

Mosquito-borne diseases, and more generally vector-borne diseases, pose serious threats to public health; about 700,000 people die each year due to direct or indirect consequences of them [1]. Paratransgenesis is an increasingly intriguing approach in which bacteria are genetically modified to secrete anti-pathogen molecules and introduced into mosquito vectors. These bacteria interfere with vector competence or with important host physiological traits (e.g., reproduction, development). Paratransgenesis may become an important tool for the control of mosquito-borne diseases and, more generally, vector control [3] To successfully implement this approach, a detailed, system-based understanding of the microbiota and its interactions with the host is critical. We have shown that Asaia is able to accelerate the developmental transition from larvae to adults in An. stephensi [9,10] Despite this very promising progress, not much is known about the physiological role(s) exerted by this bacterium on the mosquito host.

Results and Discussion

Production of Monoclonal anti-Asaia IgG

Mosquito Survival Test

Mosquito Transcriptome Analysis by Microarray Assay