Seasonal and needle age-dependent changes of the endophytic mycobiota in Pinus thunbergii and Pinus densiflora needles

Abstract

Monthly changes in the endophytic mycobiota in Pinus thunbergii Parl. and Pinus densiflora Sieb. et Zucc. needles were detected by tissue culture. Endophytic mycobiota of these pine needles were dominated by four taxa: the Leptostroma anamorph of the Lophodermium pinastri (Schrad. ex Hook.) Chev. complex, Phialocephala sp., Cenangium ferruginosum Fr.:Fr., and an unidentified hyphomycete species (BrS). The mycobiota differed with host pine species, position on the needle, and needle age. Virtually no endophytes were detected in needles just after emergence, but most segments of the older needles harbored endophytes. The endophytic mycobiota changed slowly with needle aging, except for the periods of rapid increase in the detection frequency of Leptostroma and Phialocephala sp. Detection frequency of Leptostroma, the most frequently detected endophyte taxon in the needles of the two pine species, continuously increased with needle aging, while that of Phialocephala sp., the endophyte mainly detected from the basal segments of Pinus densiflora, slowly decreased with needle aging after a massive emergence in current-year needles.Key words: Pinus thunbergii, Pinus densiflora, pine needle, endophytic fungi.