Colby Pearson, Utah Valley University
Life Sciences
Many lichens synthesize unique secondary metabolites, such as atranorin (AT), which may serve as photo-protection against harmful UV radiation. Our study investigates changes in metabolism and internal levels of atranorin in lichens under various light conditions and atranorin supplementation. We will expose 60 Physcia adscendens (Fr.) H. Olivier lichen thalli to one of three different light levels (UV +PAR; PAR only; and neither UV nor PAR). Half of our experimental thalli will be supplemented with AT. Lichen biomass, AT concentration via HPLC, and photosynthetic and respiration rates will be measured before and after the experiment to measure metabolic responses of both supplemented and non-AT-supplemented thalli under each light level.
We expect that non-AT-supplemented lichens exposed to UV and PAR will show an increase in AT concentration, but will have unchanged biomass, photosynthetic, and respiration rates relative to controls. Alternatively, we anticipate AT-supplemented lichens exposed to both UV + PAR and PAR alone will have similar biomass, photosynthetic and respiration rates relative to controls and no up-regulation of AT, because optimal photosynthetic rates are achieved with available PAR, and production of excess AT beyond normal levels is unnecessary. We predict, however, that in conditions with neither UV nor PAR, in which UV photo-protection is unnecessary and photosynthesis is not possible, the lichen will metabolize atranorin, as evidenced by decreased atranorin concentrations following supplementation, unchanged photosynthetic rates, and greater CO2 production through cellular respiration relative to controls. Research on secondary lichen metabolites is sparse and the contribution of metabolites to the direct energy needs of the lichen has never been investigated. Our study will demonstrate if P. adscendens is capable of metabolizing atranorin in an experimental setting. Our findings may have implications for other lichen species being able to metabolize their secondary metabolites for energy use.”