Geographic Survey of Fungal Endophyte Community Composition in Leaves of Coastal Redwood

Abstract

This geographic survey of the leaf fungal endophytes in Sequoia sempervirens (coastal redwood) is the initial stage in a larger study to explore their symbiotic relationships. Leaves from six sites along a north to south transect, representing the range of Sequoia sempervirens from southern Oregon to the central coast of California, were sampled for endophytes within a 31-day period. Of the 16 species identified, one endophyte Pleuroplaconema sp. was isolated most frequently from all sites, being detected in 55.4%-74.6% of leaves. The lowest percentage of Pleuroplaconema sp. at the southernmost site also had the lowest total infection frequency with 18.6% of leaves being uninfected. Redwood at all other sites had between 1–4% frequency of uninfected leaves. Other species with consistent presence in the redwood populations were: Cryptosporiopsis abietina, Phomopsis occulta, Hypoxylon bipapillatum, Gelatinosporium sp., Nodulisporium sp., Geniculosporium sp, Aureobasidium sp., and Phlyctema sp. The relatively constant endophyte composition in Sequoia sempervirens leaves along this north to south transect provides a basis to explore the mutualistic, pathogenic and saprobic nature of these endophytic relationships.