Natural variation in response to combined water and nitrogen deficiencies in Arabidopsis.

Understanding plant responses to individual stresses does not mean that we understand real-world situations, where stresses usually combine and interact. These interactions arise at different levels, from stress exposure to the molecular networks of the stress response. Here, we built an in-depth multiomic description of plant responses to mild water (W) and nitrogen (N) limitations, either individually or combined, among 5 genetically different Arabidopsis (Arabidopsis thaliana) accessions. We highlight the different dynamics in stress response through integrative traits such as rosette growth and the physiological status of the plants. We also used transcriptomic and metabolomic profiling during a stage when the plant response was stabilized to determine the wide diversity in stress-induced changes among accessions, highlighting the limited reality of a "universal" stress response. The main effect of the W × N interaction was an attenuation of the N-deficiency syndrome when combined with mild drought, but to a variable extent depending on the accession. Other traits subject to W × N interactions are often accession specific. Multiomic analyses identified a subset of transcript-metabolite clusters that are critical to stress responses but essentially variable according to the genotype factor. Including intraspecific diversity in our descriptions of plant stress response places our findings in perspective.