Characterization of FsXEG12A from the cellulose-degrading ectosymbiotic fungus Fusarium spp. strain EI cultured by the ambrosia beetle

Abstract

Despite the threat of Fusarium dieback posed due to ambrosia fungi cultured by ambrosia beetles such as Euwallacea spp., the wood-degradation mechanisms utilized by ambrosia fungi are not fully understood. In this study, we analyzed the 16S rRNA and 18S rRNA genes of the microbial community from the Ficus tree tunnel excavated by Euwallacea interjectus and isolated the cellulose-degrading fungus, Fusarium spp. strain EI, by enrichment culture with carboxymethyl cellulose as the sole carbon source. The cellulolytic enzyme secreted by the fungus was identified and expressed in Pichia pastoris, and its enzymatic properties were characterized. The cellulolytic enzyme, termed FsX-EG12A, could hydrolyze carboxymethyl cellulose, microcrystalline cellulose, xyloglucan, lichenan, and glucomannan, indicating that the broad substrate specificity of FsXEG12A could be beneficial for degrading complex wood components such as cellulose, xyloglucan, and galactoglucomannan in angiosperms. Inhibition of FsXEG12A function is, thus, an effective target for Fusarium dieback caused by Euwallacea spp.

Dynamics and drivers of fungal communities in a multipartite ant-plant association

“…colonies investigated. Given their typical saprotrophic feeding strategy [67][68][69], members of these groups may be able to initiate organic matter decomposition processes in cellulose-dominated patches of early stages of the ant colony. Apart from the Azteca-Cecropia complex, Fusarium was detected in domatia of the myrmecophytic plants Acacia drepanolobium from Africa [37] and Myrmecodia beccari from Australia [36].…”

Recent advances toward the sustainable management of invasive Xylosandrus ambrosia beetles

“…To cite one example, functional inhibition of cellulolytic enzyme secreted by fungal symbionts, such as Fusarium spp. cultured by Euwallacea interjectus (Blandford) attacking fig trees, can be an effective target for host decline (wood degradation) associated with ambrosia beetles (Sakai et al 2020). Targeted alteration of the beetle's microbiomes with mycoparasitic fungi and antagonistic bacteria could be a critical management tool that circumvent dependence on insecticide treatments as the first line of defense.…”

The biological relevance of the FspTF transcription factor, homologous of Bqt4, in Fusarium sp. associated with the ambrosia beetle Xylosandrus morigerus

“…as symbionts of ambrosia beetles are focused on its isolation and identification, phylogenetic analyzes, symbiotic interaction, and biological and chemical control (Eskalen et al, 2012;Freeman et al, 2013;O'Donnell et al, 2015;Carrillo et al, 2016Carrillo et al, , 2020Short et al, 2017;Guevara-Avendaño et al, 2018Kehelpannala et al, 2018;Mayorquin et al, 2018;Na et al, 2018;Grosman et al, 2019;Huang et al, 2020;Lynn et al, 2020;Takashina et al, 2020;Carreras-Villaseñor et al, 2022). However, there are scarce molecular analyzes related to genomics, transcriptomics, metabolomics, among others (Sánchez-Rangel et al, 2018;Sakai et al, 2020;Gutiérrez-Sánchez et al, 2021;Pérez-Torres et al, 2021;Ibarra-Laclette et al, 2022) that can give clues of the biological processes that are required for the infection of the plant host.…”