PS 15-189 - Breaking up the microbiome factors that influence leaf heat tolerance. What can help plants be more tolerant to heat.

Abstract: Tropical forests are biodiversity hotspots. Global temperature has increased by 1oC in the last century and the climate models predict that it will increase by about 2oC more by the end of the century. However, little is known about how the richest biome on Earth will respond to raising temperature.
Exposure to high temperature can lead to cell tissue damage and eventually leaf loss. Leaf heat tolerance (LTH) is a foliar trait that directly influences how tropical forests can react to climate change. Tropical plants tend to exhibit low tolerance to temperature changes because of the low amount of temperature variation they experience.
Previous studies have shown that the soil microbiome could influence plant species LTH. Additionally, climate change was shown to alter soil biotic communities. Therefore, we predict that climate change could alter LTH by inducing changes in the soil microbial communities. We hypothesis that 1) LHT is plastic and varies in response to the soil microbiome, and 2) warming will change the soil biota communities and influence LHT.
To test these hypotheses, we set up a greenhouse experiment in Puerto Rico at the Tropical Response for Altered Climate Experiment site. We grew seedlings from two species with a soil inoculum collected from either control or warmed plots and applied four biotic treatment (control, sterile, no pathogens, no arbuscular mycorrhizal fungi). After three months, we collected 15 leaf discs per pots and measured LHT. We compared LTH across treatment using an analysis of the variance.
We expect that LTH will be higher for the individuals which grew with microbe, pathogens, and arbuscular mycorrhizal fungi. then individuals that cultivated their absence. We expect the soil source (control or warmed plots) to significantly influence LHT by changing the microbiome composition. Preliminary results are consistent with some changes in the microbiome communities associated with warming and large degree of plasticity in LHT within species. This study will further support our understanding of what drives LHT and will contribute to enhancing the models about how global warming will impact tropical forests.