Date of Award


Document Type


Degree Name

Master of Science (MS) in Biology




"Fungal endophytes (microbial fungi that live in plant tissues without causing disease) are ubiquitous in plants studied to date. Many conifers host endophytes that produce important bioactive secondary metabolites. While the endophytes in Pinus ponderosa roots have been studied, the endophyte communities within the needles are not well characterized by molecular means: thus, the goal of this study was to do so. Needles were sampled at two sites located five kilometers apart along a slight precipitation gradient in Eastern Washington State. Fungal DNA (along with pine DNA) was isolated directly from needles of two ages. Internal transcribed spacer regions of the ribosomal RNA gene form fungi were amplified by PCR, cloned, and sequenced. Many of the sequences described have high homology matches in GenBank with known fungi, though most have not previously been directly associated with ponderosa pine. Some sequences were highly homologous with previously published sequences of fungi that have yet to be assigned a taxonomic designation , which suggests some previously undescribed fungi occupy ponderosa pine needles. Despite the proximity of sites, only 18% of the endophytes sequenced were common to both sites. Forty one percent of endophytes were unique to needles from 2012, while 45% of endophytes were unique to needles that emerged in 2014. Although more data from a deep sequencing project will be required to confirm this, the results presented here suggests that fungal endophyte communities in ponderosa pine are fairly diverse geographically, and that communities in the same tree differ depending on the age of the needles"--Leaf iv.