Divergence between transcriptomic, physiological, and whole-plant responses to precipitation extremes

Precipitation is a key driver of plant performance in ecosystems worldwide, yet the linear relationship between precipitation and plant performance sometimes breaks down as precipitation becomes more extreme. Understanding why precipitation extremes (both wet and dry) can cause non-linearity in plant functions and whether these functions are impacted differently by these two extremes can improve our ability to understand ecosystem functioning in a changing world. We examined whole-plant, physiological, and transcriptomic responses of the candidate biofuel species, switchgrass, to precipitation extremes. Specifically, this study included five tetraploid (4x) switchgrass genotypes that originated between 27 N and 35 N. Gene expression and paired physiological phenotypes (leaf water potentials, leaf relative water content, leaf osmotic potential) were measured in summer (July 2013 and July 2014) in two rainout shelter facilities at the USDA-ARS Grassland Soil and Water Research Lab in Temple, Texas, USA and the Lady Bird Johnson Wildflower Center in Austin, Texas, USA.N.B.: This submission includes only samples collected during the 2013 field season.