Lateral Transmission of Yeast Symbionts Among Lucanid Beetle Taxa.

Gaku Ueki,Kôhei Kubota,Koji Tojo,Xiu-Jun Wen,Xue-Jiao Zhu,Sheng-Nan Zhang

doi:10.3389/fmicb.2021.794904

Gaku Ueki, Kôhei Kubota + Show 4 more

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https://doi.org/10.3389/fmicb.2021.794904

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Abstract

To deepen understanding the evolutionary process of lucanid–yeast association, the lateral transmission process of yeast symbionts among stag beetle genera Platycerus and Prismognathus around the border between Japan and South Korea was estimated based on molecular analyses and species distribution modelings. Phylogenetic analyses were based on yeast ITS and IGS sequences and beetle COI sequences using Prismognathus dauricus from the Tsushima Islands and Pr. angularis from Kyushu, Japan, as well as other sequence data from our previous studies. The range overlap based on the species distribution model (SDM) and differentiation in ecological space were analyzed. Based on the IGS sequences, Clade II yeast symbionts were shared by Platycerus hongwonpyoi and Pr. dauricus in South Korea and the Tsushima Islands, and Platycerus viridicuprus in Japan. Clade III yeasts were shared by Pr. dauricus from the Tsushima Islands and Pr. angularis in Japan. During the Last Interglacial period when the land bridge between Japan and the Korean Peninsula existed, range overlap was predicted to occur between Pl. viridicuprus and Pr. dauricus in Kyushu and between Pr. dauricus and Pr. angularis in Kyushu and the Tsushima Islands. The ecological space of Pl. hongwonpyoi was differentiated from that of Pl. viridicuprus and Pr. angularis. We demonstrated the paleogeographical lateral transmission process of Scheffersomyces yeast symbionts among lucanid genera and species: putative transmission of yeasts from Pr. dauricus to Pl. viridicuprus in Kyushu and from Pr. angularis to Pr. dauricus in Kyushu or the Tsushima Islands. We also found that the yeast symbionts are likely being replaced in Pr. dauricus on the Tsushima Islands. We present novel estimates of the lateral transmission process of microbial symbionts based on phylogenetic, SDM and environmental analyses among lucanid beetles.

Highlights

In studies of insect–fungus symbiotic associations, particular attention has been paid to the mode of fungal transmission, because it is deeply related to the dependency between partners and the evolution of symbiotic systems
Taxonomic Position of Yeast Symbionts Inferred From Internal Transcribed Spacer Phylogeny None of the internal transcribed spacer (ITS) sequences of the yeast symbionts from the two Prismognathus angularis collected in Japan exhibited any sequence variation
The phylogenetic analysis based on the ITS sequences revealed that the yeast symbionts of the Prismognathus and Platycerus species constitute a distinct lineage to the clade of yeast symbionts of all other lucanid species, including environmental Scheffersomyces (Figure 3 and Supplementary Table 2)

Summary

Introduction

In studies of insect–fungus symbiotic associations, particular attention has been paid to the mode of fungal transmission, because it is deeply related to the dependency between partners and the evolution of symbiotic systems. García) Kurtzman and Suzuki, 2010 or closely related species (Tanahashi et al, 2010; Kubota et al, 2020) It is nearly the only fungus found in almost all female mycangia of Platycerus Geoffroy, 1762; Prismognathus Motschulsky, 1860; Dorcus MacLeay, 1819; Lucanus Scopoli, 1763; and other lucanid species that feed on white rot wood (Tanahashi et al, 2010, 2017; Kubota et al, 2020). These Scheffersomyces yeast symbionts appear to serve an important role for the host stag beetles, their exact symbiont function remains unknown (Kubota et al, 2020)

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