Diversity and Evolution of Entomocorticium (Russulales, Peniophoraceae), a Genus of Bark Beetle Mutualists Derived from Free-Living, Wood Rotting Peniophora

Symbiosis between insects and fungi arose multiple times during the evolution of both groups, and some of the most biologically diverse and economically important are mutualisms in which the insects cultivate and feed on fungi. Among these are bark beetles, whose ascomycetous cultivars are better known and studied than their frequently-overlooked and poorly understood basidiomycetous partners. In this study, we propose five new species of Entomocorticium, fungal mutualists in the Russulales (Basidiomycota) that are mutualistic symbionts of scolytine beetles. We have isolated these fungi from the beetle mycangia, which are structures adapted for the selective storage and transportation of fungal mutualists. Herein, we present the most complete phylogeny of the closely related genera Entomocorticium and Peniophora and provide insights into how an insect-associated taxon (Entomocorticium) evolved from within a wood-decaying, wind-dispersed lineage (Peniophora). Our results indicate that following a transition from angiosperms to gymnosperms, fungal domestication by beetles facilitated the evolution and diversification of Entomocorticium. We additionally propose four new species: Entomocorticium fibulatum Araújo, Li & Hulcr, sp. nov.; E. belizense Araújo, Li & Hulcr, sp. nov.; E. perryae Araújo, Li & Hulcr, sp. nov.; and E. macrovesiculatum Araújo, Li, Six & Hulcr, sp. nov. Our findings highlight the fact that insect-fungi associations remain an understudied field and that these associations harbor a large reservoir of novel fungal species.

Effects of Culture Conditions on Growth and Cyclooligomer Depsipeptides Biosynthesis of Cordyceps sp. CPA14V

Cordyceps sp. CPA14V was isolated from insect-fungi sample that was collected from Copia - Son La Nature Reserve. The strain was able to biosynthesize cyclooligomer depsipeptides (CODs). This study aimed to identify Cordyceps sp. CPA14V to species using DNA sequence analysis and to estimate the effects of carbon, nitrogen, pH of culture broth on its growth and COD producing capacity. The results showed that the studied strain was Cordyceps cateniannulata CPA14V. This is the first record of the species in Vietnam. Glucose, yeast extract and pH=8.0 were the most suitable for growth and CODs synthesis of C. cateniannulata CPA14V. This is also the first report of CODs produced by a C. cateniannulata.

Protective Effect of Simplicillium sp. Ethyl Acetate Extract against High Glucose-Induced Oxidative Stress in HUVECs

This study aimed at investigating the cytoprotective effect of an ethyl acetate extract of insect fungi against high glucose- (HG-) induced oxidative damage in human umbilical vein endothelial cells (HUVECs). An insect fungus strain termed CH180672 (CH) was found for protecting HUVECs from HG-induced damage. In this study, CH was identified as Simplicillium sp. based on a phylogenetic analysis of ITS‐rDNA sequences. Ethyl acetate extract (EtOAc) of this strain (CH) was subjected to the following experiments. Cell viability was examined with the MTT method. To evaluate the protection of CH, intracellular reactive oxygen species (ROS), malondialdehyde (MDA) levels, and the activities of antioxidant enzymes were measured and the expression of oxidation-associated proteins was assessed. In the current study, it has been found that CH can increase the survival rate of HUVECs induced by HG. Additionally, we found that HG-induced nuclear factor-erythroid 2-related factor 2 (Nrf2) and heme oxygenase 1 (HO-1) signal decreased and increased the intracellular ROS and MDA generation in HUVECs. However, CH treatment strongly promoted the translocation of Nrf2 and its transregulation on HO-1 and ultimately inhibited the high level of ROS and MDA induced by HG. The regulatory ability of CH was similar to Nrf2 agonist bardoxolone, while the effect was abolished by ML385, suggesting that Nrf2 mediated the inhibition of CH on HG-induced oxidative stress in HUVECs. Taken together, CH can improve HG-induced oxidative damage of HUVECs, and its mechanism may be related to the regulation of the Nrf2/HO-1 pathway.

The diversity of entomopathogenic fungi collected from leaves and rhizospheres of rice implementing integrated pest management

Afandhi A, Pertiwi EP, Purba DP, Widjayanti T, Leksono AS. 2020. The diversity of entomopathogenic fungi collected from leaves and rhizospheres of rice implementing integrated pest management. Biodiversitas 21: 2690-2695. Rice is an important food source for most of the world’s population. However, its production often faces pest and disease problems. This study aimed to determine the diversity of entomopathogenic fungi from the leaves and rhizospheres of rice plants, implementing applied integrated pest management (IPM), and to test the pathogenicity of insect fungi species against Spodoptera litura and Tenebrio molitor larvae collection. Entomopathogenic fungi were collected from the leaves and rhizospheres of two rice fields: a field in which IPM is implemented and a conventional field. A total of 24 species were collected from the leaves and rhizospheres in three locations. Pathogenicity test against S. litura larvae was conducted using the Beauveria sp. isolate, whereas pathogenicity test against T. molitor was conducted using the other isolates. Paddy fields in which IPM has been implemented have higher diversity and species richness compared with a conventional field. Location 1 (3 years of IPM implementation) has the highest diversity (2.04 of leaf collection and 1.65 of rhizosphere collection), location 2 has the lowest fungi diversity collected from rhizosphere, whereas location 3 (conventional implementation) has the lowest diversity of leaf collection (1.68). Laboratory testing of Beauveria spp. against S. litura revealed that all species were effective for pest control. Entomopathogenic fungi collected from leaves (Paecilomyces sp.) increased T. molitor mortality by 60%, whereas those isolated from rhizospheres had no effective control of the pest.

Acquisition of fungi from the environment modifies ambrosia beetle mycobiome during invasion

Microbial symbionts can play critical roles when their host attempts to colonize a new habitat. The lack of symbiont adaptation can in fact hinder the invasion process of their host. This scenario could change if the exotic species are able to acquire microorganisms from the invaded environment. Understanding the ecological factors that influence the take-up of new microorganisms is thus essential to clarify the mechanisms behind biological invasions. In this study, we tested whether different forest habitats influence the structure of the fungal communities associated with ambrosia beetles. We collected individuals of the most widespread exotic (Xylosandrus germanus) and native (Xyleborinus saxesenii) ambrosia beetle species in Europe in several old-growth and restored forests. We characterized the fungal communities associated with both species via metabarcoding. We showed that forest habitat shaped the community of fungi associated with both species, but the effect was stronger for the exotic X. germanus. Our results support the hypothesis that the direct contact with the mycobiome of the invaded environment might lead an exotic species to acquire native fungi. This process is likely favored by the occurrence of a bottleneck effect at the mycobiome level and/or the disruption of the mechanisms sustaining co-evolved insect-fungi symbiosis. Our study contributes to the understanding of the factors affecting insect-microbes interactions, helping to clarify the mechanisms behind biological invasions.

Identification and Expression of Ligninase Enzymes from Tropical Asia Wood Insect for Agro-Pulp Biodelignification: A Theoretical Framework

Current pulp-processing in pulp and paper based industries are inefficient in removing the lignin as this compound is recalcitrant towards degradation. Transitioning from conventional pulping process into bio-delignification through utilisation of ligninase enzymes is one of the alternatives to improve the ability to fully utilize all components of wood to produce high quality fibres. Extensive research efforts have been focused on increase the production of ligninase enzymes from white rot fungi as a whole organism for industrial applications. However, enzymes activity produced from fungi are rather low as lignin modification is a secondary metabolism in which the enzyme only be expressed under particular conditions. Using genetic manipulations to incorporate genes associate for delignification isolated from different organisms such as tropical Asian wood-feeding insect into bacteria expression system will allow rapid enzyme production. This theoretical framework aims to produce an enzyme with high ligninase activity that will be used for removal of lignin during pulp-processing. These enzymes are thought to be more economically efficient in degrading lignin and involves less use of chemicals thus make this processing more environmentally friendly.Keywords: Biodelignification, Asian wood tropical insect, fungi, ligninase enzyme, bacterial expression system

Fungi associated with Tomicus minor on Pinus sylvestris in Poland and their succession into the sapwood of beetle-infested windblown trees

The study identified and measured frequency of fungal species associated with Tomicus minor (Hart.) on Pinus sylvestris L. (Scots pine) in Poland. Additionally, fungal succession in P. sylvestris sapwood was investigated during a 12 week period following an attack by this insect. Fungi were isolated from five populations of overwintered adult beetles and their galleries with 59 species of fungi being represented among the 2880 cultures obtained. The most frequent species, Ophiostoma canum (Münch) Syd. & P. Syd., Hormonema dematioides Lagerb. & Melin, and Ambrosiella tingens (Lagerb. & Melin) L.R. Batra, appeared to be specifically associated with T. minor. The succesional changes in species composition during a 12 week period following an attack by T. minor were observed. The pattern of fungal succession in P. sylvestris sapwood essentially agreed with a general scheme of fungal succession in tree sapwood infested by bark beetles. Ambrosiella tingens was the first invader of sapwood and occurred most frequently in its deeper layers. Ophiostoma canum, H. dematioides, and other molds were also often isolated from the sapwood; however, they were most common at a depth of 5 mm during the initial phase of fungal colonization. Later, Ophiostoma canum followed A. tingens in the sapwood invasion.