Patterns of community composition and diversity in latent fungi of living Quercus serrata trunks across a range of oak wilt prevalence and climate variables in Japan

Abstract

Given that forest dieback due to emerging pests is increasing under global warming, understanding the relationships between pests, climate, and forest biodiversity is an urgent priority. In Japan, mass attacks of an ambrosia beetle, vectoring a pathogenic fungus, cause oak wilt outbreaks in recent decades. Here, the associations of oak wilt and climate with wood-inhabiting fungal communities in apparently healthy Quercus serrata trunks were investigated using DNA metabarcoding in seven sites along a climatic gradient in Japan. Amplicon sequencing of the fungal internal transcribed spacer 1 region generated 1,339,958 sequence reads containing 879 fungal operational taxonomic units (OTUs) in 234 wood samples. OTU compositions were significantly different between sites with and without oak wilt. OTU richness increased with temperature and precipitation at sites where oak wilt was present, but this relationship was not observed at sites without oak wilt, possibly due to interaction between oak wilt and climate. • Oak wilt disease is correlated with fungal communities in living oak trees. • OTU richness increased with temperature and precipitation at sites with oak wilt. • OTU richness was not correlated with macroclimate at sites without oak wilt. • Oak wilt was correlated with absence of some white-rot decomposer fungi. • Precipitation had a negative correlation with the species richness of brown-rot fungi.