Codominant grasses differ in gene expression under experimental climate extremes in native tallgrass prairie

Area of Science:

• Plant biology
• Ecology
• Climate change science

Background:

• Climate change is increasing the frequency and intensity of extreme weather events like heat waves and droughts.
• Plant species exhibit varied responses to environmental stressors, impacting ecosystem dynamics.
• Understanding these responses is crucial for predicting future vegetation changes.

Purpose of the Study:

• To investigate the transcriptional responses of two key C4 grass species, Andropogon gerardii and Sorghastrum nutans, to experimental heat waves and drought.
• To compare the stress tolerance mechanisms of A. gerardii and S. nutans under simulated climate extremes.
• To provide insights into the potential success of these species in a changing climate.

Main Methods:

• Experimental imposition of heat wave and drought conditions on tallgrass prairie ecosystems.
• Assessment of gene expression patterns in A. gerardii and S. nutans using transcriptomics.
• Functional annotation of differentially expressed genes to infer stress response mechanisms.

Main Results:

• Sorghastrum nutans displayed greater sensitivity to water stress, upregulating stress and catabolism genes while downregulating non-coding RNAs.
• Andropogon gerardii showed less drought sensitivity and upregulated cellular and protein metabolism genes.
• A. gerardii exhibited minimal response to heat, while S. nutans showed no response to increased temperature.

Conclusions:

• A. gerardii and S. nutans employ different strategies to cope with climate extremes: A. gerardii maintains molecular function, while S. nutans prioritizes avoidance.
• S. nutans may utilize abscisic acid response and catabolism for rapid stress adaptation.
• Differential responses suggest varying success for these grasses under future climate scenarios, impacting tallgrass prairie ecosystems.