Symbiogenics: An Epigenetic Approach to Mitigating Impacts of Climate Change On Plants

The greatest threats to agricultural sustainability in the 21^st century are drought, increasing temperatures, and soil salinization, all of which are being exacerbated by climate change (http://www.copenhagendiagnosis.com). Three approaches are currently being taken to develop stress tolerant plants: genetic modification, mutational selection, and breeding traits from wild plants. However, these efforts have had limited success presumably because 1) stress tolerance involves genetically complex processes and 2) the ecological and evolutionary mechanisms responsible for stress tolerance in plants are poorly defined.

We have found that plants in natural ecosystems adapt to 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. Symbiotically conferred stress tolerance typically occurs in a habitat-specific manner and is based on interactions between environmental factors and both plant and fungal genomes. We have designated this phenomenon as Habitat Adapted Symbiosis (HAS).  Although several 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 metabolic efficiency, and an increased ability to manage reactive oxygen species.  A symbiotic strategy for mitigating impacts of climate change in agriculture will be discussed.