AUTHOR=Cailleau Guillaume , Hanson Buck T. , Cravero Melissa , Zhioua Sami , Hilpish Patrick , Ruiz Celia , Robinson Aaron J. , Kelliher Julia M. , Morales Demosthenes , Gallegos-Graves La Verne , Bonito Gregory , Chain Patrick S.G. , Bindschedler Saskia , Junier Pilar 

TITLE=Associated bacterial communities, confrontation studies, and comparative genomics reveal important interactions between Morchella with Pseudomonas spp.

JOURNAL=Frontiers in Fungal Biology

VOLUME=4

YEAR=2023

URL=https://www.frontiersin.org/journals/fungal-biology/articles/10.3389/ffunb.2023.1285531

DOI=10.3389/ffunb.2023.1285531

ISSN=2673-6128

ABSTRACT=<p>Members of the fungal genus <italic>Morchella</italic> are widely known for their important ecological roles and significant economic value. In this study, we used amplicon and genome sequencing to characterize bacterial communities associated with sexual fruiting bodies from wild specimens, as well as vegetative mycelium and sclerotia obtained from <italic>Morchella</italic> isolates grown <italic>in vitro</italic>. These investigations included diverse representatives from both Elata and Esculenta <italic>Morchella</italic> clades. Unique bacterial community compositions were observed across the various structures examined, both within and across individual <italic>Morchella</italic> isolates or specimens. However, specific bacterial taxa were frequently detected in association with certain structures, providing support for an associated core bacterial community. Bacteria from the genus <italic>Pseudomonas</italic> and <italic>Ralstonia</italic> constituted the core bacterial associates of <italic>Morchella</italic> mycelia and sclerotia, while other genera (e.g., <italic>Pedobacter</italic> spp., <italic>Deviosa</italic> spp., and <italic>Bradyrhizobium</italic> spp.) constituted the core bacterial community of fruiting bodies. Furthermore, the importance of <italic>Pseudomonas</italic> as a key member of the bacteriome was supported by the isolation of several <italic>Pseudomonas</italic> strains from mycelia during <italic>in vitro</italic> cultivation. Four of the six mycelial-derived <italic>Pseudomonas</italic> isolates shared 16S rDNA sequence identity with amplicon sequences recovered directly from the examined fungal structures. Distinct interaction phenotypes (antagonistic or neutral) were observed in confrontation assays between these bacteria and various <italic>Morchella</italic> isolates. Genome sequences obtained from these <italic>Pseudomonas</italic> isolates revealed intriguing differences in gene content and annotated functions, specifically with respect to toxin-antitoxin systems, cell adhesion, chitinases, and insecticidal toxins. These genetic differences correlated with the interaction phenotypes. This study provides evidence that <italic>Pseudomonas</italic> spp. are frequently associated with <italic>Morchella</italic> and these associations may greatly impact fungal physiology.</p>