AUTHOR=Vazquez-Ortiz Karina , Pineda-Mendoza Rosa María , González-Escobedo Román , Davis Thomas S. , Salazar Kevin F. , Rivera-Orduña Flor N. , Zúñiga Gerardo 

TITLE=Metabarcoding of mycetangia from the Dendroctonus frontalis species complex (Curculionidae: Scolytinae) reveals diverse and functionally redundant fungal assemblages

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.969230

DOI=10.3389/fmicb.2022.969230

ISSN=1664-302X

ABSTRACT=<p><italic>Dendroctonus</italic>-bark beetles are associated with microbes that can detoxify terpenes, degrade complex molecules, supplement and recycle nutrients, fix nitrogen, produce semiochemicals, and regulate ecological interactions between microbes. Females of some <italic>Dendroctonus</italic> species harbor microbes in specialized organs called mycetangia; yet little is known about the microbial diversity contained in these structures. Here, we use metabarcoding to characterize mycetangial fungi from beetle species in the <italic>Dendroctonus frontalis</italic> complex, and analyze variation in biodiversity of microbial assemblages between beetle species. Overall fungal diversity was represented by 4 phyla, 13 classes, 25 orders, 39 families, and 48 genera, including 33 filamentous fungi, and 15 yeasts. The most abundant genera were <italic>Entomocorticium</italic>, <italic>Candida</italic>, <italic>Ophiostoma-Sporothrix</italic>, <italic>Ogataea</italic>, <italic>Nakazawaea</italic>, <italic>Yamadazyma</italic>, <italic>Ceratocystiopsis</italic>, <italic>Grosmannia-Leptographium</italic>, <italic>Absidia</italic>, and <italic>Cyberlindnera</italic>. Analysis of α-diversity indicated that fungal assemblages of <italic>D</italic>. <italic>vitei</italic> showed the highest richness and diversity, whereas those associated with <italic>D</italic>. <italic>brevicomis</italic> and <italic>D</italic>. <italic>barberi</italic> had the lowest richness and diversity, respectively. Analysis of β-diversity showed clear differentiation in the assemblages associated with <italic>D</italic>. <italic>adjunctus</italic>, <italic>D</italic>. <italic>barberi</italic>, and <italic>D</italic>. <italic>brevicomis</italic>, but not between closely related species, including <italic>D</italic>. <italic>frontalis</italic> and <italic>D</italic>. <italic>mesoamericanus</italic> and <italic>D</italic>. <italic>mexicanus</italic> and <italic>D</italic>. <italic>vitei</italic>. A core mycobiome was not statistically identified; however, the genus <italic>Ceratocystiopsis</italic> was shared among seven beetle species. Interpretation of a tanglegram suggests evolutionary congruence between fungal assemblages and species of the <italic>D</italic>. <italic>frontalis</italic> complex. The presence of different amplicon sequence variants (ASVs) of the same genus in assemblages from species of the <italic>D</italic>. <italic>frontalis</italic> complex outlines the complexity of molecular networks, with the most complex assemblages identified from <italic>D</italic>. <italic>vitei</italic>, <italic>D</italic>. <italic>mesoamericanus</italic>, <italic>D</italic>. <italic>adjunctus</italic>, and <italic>D</italic>. <italic>frontalis</italic>. Analysis of functional variation of fungal assemblages indicated multiple trophic groupings, symbiotroph/saprotroph guilds represented with the highest frequency (∼31% of identified genera). These findings improve our knowledge about the diversity of mycetangial communities in species of the <italic>D</italic>. <italic>frontalis</italic> complex and suggest that minimal apparently specific assemblages are maintained and regulated within mycetangia.</p>