Changes in leaf economic trait relationships across a precipitation gradient are related to differential gene expression in a C4 perennial grass

In the candidate bioenergy grass, switchgrass, we examined the impacts of water availability (extreme drought, extremely wet conditions) on the relationship between gene expression and the expression of three phenotypes that describe leaf economics strategies (leaf nitrogen concentration, leaf mass per area, photosynthetic rate on a leaf mass basis). This study included six tetraploid (4x) switchgrass genotypes that originated between 27 N and 40 N. Gene expression and phenotypes were measured in early summer (June 2012) in a rainout shelter facility at the USDA-ARS Grassland Soil and Water Research Lab in Temple, Texas, USA.