Agradecimentos: We thank all members of the Nobile lab for insightful discussions on the topic of this manuscript. We are especially grateful to Pegah Mosharaf Ghahfarokhy for her assistance with the analysis of the .czi files from the CSLM experiments. We thank Robert Shields at Arkansas State University and Jonathon Baker at the J. Craig Venter Institute for providing S. mutans strains. This work was supported by the National Institutes of Health (NIH) National Institute of General Medical Sciences (NIGMS) award number R35GM124594, and by the Kamangar family in the form of an endowed chair to C.J.N. We are grateful to the Coordenação de Pessoal de Ensino Superior (CAPES) foundation of Brazil for providing a scholarship (001/88887.508855/2020-00) to L.M.-F. The CSLM data were obtained using a confocal microscope acquired through the National Science Foundation (NSF) MRI Award Number DMR-1625733. The funders had no role in the study design, data collection and interpretation, or the decision to submit the work for publication Ver menos

Abstract: Candida albicans and Streptococcus mutans are known to synergistically interact with each other in the oral cavity. For example, glucosyltransferase B (GtfB), secreted by S. mutans, can bind to the C. albicans cell surface, promoting dual-species biofilm formation. However, the fungal factors mediating interactions with S. mutans are unknown. The C. albicans adhesins Als1, Als3, and Hwp1 are key players in C. albicans single-species biofilm formation, but their roles, if any, in interacting with S. mutans have not been assessed. Here, we investigated the roles of the C. albicans cell wall adhesins Als1, Als3, and Hwp1 on forming dual-species biofilms with S. mutans. We assessed the abilities of the C. albicans wild-type als1'delta'/'delta', als3'delta'/'delta', als1'delta'/'delta'/als3'delta'/'delta', and hwp1'delta'/'delta' strains to form dual-species biofilms with S. mutans by measuring optical density, metabolic activity, cell enumeration, biomass, thickness, and architecture of the biofilms. We observed that the C. albicans wild-type strain formed enhanced dual-species biofilms in the presence of S. mutans in these different biofilm assays, confirming that C. albicans and S. mutans synergistically interact in the context of biofilms. Our results reveal that C. albicans Als1 and Hwp1 are major players in interacting with S. mutans, since dual-species biofilm formation was not enhanced when the als1'delta'/'delta' or hwp1'delta'/'delta' strains were cultured with S. mutans in dual-species biofilms. Als3, however, does not seem to play a clear role in interacting with S. mutans in dual-species biofilm formation. Overall, our data suggest that the C. albicans adhesins Als1 and Hwp1 function to modulate interactions with S. mutans and could be potential targets for future therapeutics Ver menos