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 2014 field season.

降水是全球生态系统中调控植物表现的关键驱动因子，然而随着降水趋于极端化，降水与植物表现之间的线性关系时常失效。探明极端降水（涵盖极端湿润与极端干旱）为何会引发植物功能的非线性响应，以及两类极端降水对植物功能的影响是否存在差异，有助于我们深化对变化环境下生态系统运转机制的理解。本研究针对候选生物燃料物种柳枝稷（switchgrass），探究了其对极端降水的整株、生理与转录组响应。具体而言，本研究纳入了5个起源于北纬27°至35°区间的四倍体（4x）柳枝稷基因型。本研究于2013年7月与2014年7月的夏季，分别在美国德克萨斯州坦普尔市的USDA-ARS草原水土研究实验室，以及美国德克萨斯州奥斯汀市的Lady Bird Johnson Wildflower Center两处防雨棚设施中，测定了基因表达量与配套生理表型指标（叶片水势、叶片相对含水量、叶片渗透势）。注：本次提交仅包含2014年野外采样季采集的样本。