Fungal symbiotic lifestyles, lifestyle switching and the interplay between mutualism and parasitism
Russell J Rodriguez, Symbiogenics and the University of Washington
April 26, 2012 @ 12:00 pm to 01:00 pm
203 Millennium Science Complex
Since the first description of symbiosis in the 1800 s, it has become clear that all plants and animals on earth are symbiotic with microorganisms._ These symbioses span a continuum from detrimental (parasitism) to beneficial (mutualism)._ My lab has been asking some basic questions about plant-fungal symbioses such as: What factors determine the outcome of these associations?_ How do pathogens and mutualists differ?_ What are the ecological dynamics of symbionts and symbioses?_ We have found that individual fungal endophytes (symbionts that reside inside plant tissues) can switch symbiotic lifestyles from parasitism to mutualism based on environmental and genetic factors._ As pathogens they decimate hosts and as mutualists they confer fitness benefits including disease protection._ ___________ In natural ecosystems, plant diseases are uncommon and usually associated with extended environmental stresses (e.g. drought, extreme temperatures)._ Yet, fungal pathogens are commonly isolated from healthy plants._ This paradox can be partially explained by the fact that plant health and fitness are based on symbiotic associations with fungal endophytes._ For example, plants in natural ecosystems adapt to biotic and abiotic stress by forming symbiotic associations with fungal endophytes. Without the endophytes, the plants are not stress tolerant and do not survive in the habitats to which they are adapted._ Although several genetic and biochemical processes have been correlated to plant stress tolerance, few processes correlate with symbiotically conferred stress tolerance. Symbiotically conferred stress tolerance involves altered plant gene regulation, increased photosynthetic efficiency, and an increased ability to manage reactive oxygen species._ ___________ I will discuss various aspects of this research and describe a new symbiotic strategy for mitigating impacts of climate change in agriculture to improve human health and decrease suffering in developing nations._
Contact
Charissa de Bekker
c.debekker@psu.edu