Seth Kauppinen

   I'm interested in symbiosis as a structuring element in biology, at 

ecological- and evolutionary timescales. My thesis research centers on 

horizontally transmitted foliar endophytes--a guild of fungi that live 

inside leaf tissues without harming the host plant, and spread via 

spores. The ecology of these organisms is poorly known, and probably 

comprises a spectrum of host-symbiont interactions from light 

parasitism through commensalism and mutualism. Over evolutionary time, 

the harmlessness that defines endophytes appears to be a labile trait, 

with lineages alternating between the endophytic- and pathogenic state 

in response to unknown selective pressures.

        In Amazonian Peru, I'm exploring several aspects of foliar endophyte biology: first, with culture-based techniques and high-throughput sequencing I'm evaluating the persistence of endophytic taxa in leaf litter, to establish whether the life cycle includes an important saprobic component. Second, I'm addressing host-affinity in a 

phylogenetic framework, sampling endophytes from a dozen plant 

lineages at nested scales of phylogenetic distance. This will provide 

insight for estimates of global fungal biodiversity, and clarify the 

context under which mutualism might (or might not) evolve. Third, I'm 

attempting to find chemical signatures of endophyte infection in host 

tissues. Constitutively expressed 'symbiotic phytochemistry'--if 

present--will provide targets for testing a hypothesis of host 

defense. And fourth, I'd like to determine whether endophyte 

communities differ between white sand- and clay forest sites (both in 

ambient spore composition and within-host diversity). The habitat 

mosaics of the western Amazon play a significant role in plant 

diversification; it's unknown whether symbiotic microbes will respond 

to habitat gradients in the same way.

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