Phylogenetic Position of Geosmithia spp. (Hypocreales) Living in Juniperus spp. Forests (Cupressaceae) with Bark Beetles of Phloeosinus spp. (Scolytinae) from the Northeast of Mexico

Aguirre-Ojeda Nallely Guadalupe,Cuellar-Rodríguez Gerardo,Hernández-García Juan Alfredo,Villa-Tanaca Lourdes,Hernández-Rodríguez César,Armendáriz-Toledano Francisco

doi:10.3390/f11111142

Aguirre-Ojeda Nallely Guadalupe, Cuellar-Rodríguez Gerardo + Show 4 more

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https://doi.org/10.3390/f11111142

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Abstract

Geosmithia members are mitosporic filamentous fungi commonly recorded and isolated from bark beetles of the Scolytinae subfamily and their respective host’s species. This genus includes 18 species formally described and 38 phylogenetic species recorded in several localities from Africa, Asia, Australia, Europe, and North and South America, where they exhibit frequent associations with phloeophagous and wood-boring bark beetles. Among phloephagous bark beetle species, specifically, in members of the genus Phloeosinus Chapuis, almost 10% of Geosmithia strains have been isolated. By its physiographic elements and high bark beetle and conifer species richness, Mexico is a potential region to host a high diversity of Geosmithia species and potential new species. In the present study, we systematically sampled and isolated, cultured, and molecularly identified members of the Geosmithia species associated with Phloeosinus spp. and their Juniperus spp. host trees at the north of Sierra Madre Oriental, at Nuevo Leon State, Mexico. Phylogenetic analyses based on 378 internal transcribed spacer region (ITS) sequences supported the presence of strains from Geosmithia langdonii-Geosmithia sp. 32 clade associated with Phloeosinus serratus vector and with Juniperus coahuilensis (JC) host, and the presence of strains from Geosmithia sp. 21-Geosmithia xerotolerans clade with Phloeosinusdeleoni and Juniperus flaccida (JF) in this geographical region. The genetic and morphological differences found in our strains with respect to those previously described in the species from both clades (Geosmithia langdonii-Geosmithia sp. 32 and Geosmithia sp. 21-G. xerotolerans) suggest that both Geosmithia lineages from Nuevo Leon correspond to two potential new species in the genus.

Highlights

Associations among fungi and bark beetles constitute one of the most successful ecological adaptations that promoted complex and dynamic interactions in this insect group [1]
Bark beetles were attracted to six of 11 cut branches used as lures and traps, two belonging to J. coahuilensis from the Galeana municipality and four belonging to J. flaccida from the Iturbide municipality (Figure 1)
Two species of Phloeosinus were identified on these hosts, Phloeosinus deleoni Blackman in J. flaccida, and P. serratus in J. coahuilensis

Summary

Introduction

Associations among fungi and bark beetles constitute one of the most successful ecological adaptations that promoted complex and dynamic interactions in this insect group [1]. Some bark beetles maintain obligatory functional and physiological dependent associations with filamentous fungi [3]. These insects actively cultivate the fungi within the gallery tunnels, constituting agricultural systems that provide a source of food to both larvae and adults, and in some cases, hormones associated with the molting and metamorphosis processes [4]. Bark beetles with facultative associations do not cultivate the fungi and do not need them to complete their life cycle, in some species they can enrich their diet and increase their fitness [5]

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