Proteomic responses to drought vary widely among eight diverse genotypes of rice (Oryza sativa)

Rice is a critically important food source but yields worldwide are vulnerable to periods of drought. We exposed eight genotypes of upland and lowland rice (Oryza sativa L. ssp. japonica and indica) to drought stress at the late vegetative stage and harvested leaves for protein extraction and subsequent label-free shotgun proteomics. Gene ontology analysis revealed some differentially expressed proteins were induced by drought in all eight genotypes; we speculate that these play a universal role in drought tolerance. However, some highly genotype-specific patterns of response to drought suggest that some mechanisms of metabolic reprogramming are not universal. Such proteins had largely uncharacterized functions, making them biomarker candidates for drought tolerance screens.