Enhancing Omics Research of Crop Responses to Drought under Field Conditions

Crop production relies heavily on rainfall during the growing season, especially in developing countries. Drought, due largely to the effects of soil water deficit, is the most serious abiotic stress limiting crop production, accounting for ∼70% potential yield loss worldwide (Salekdeh et al., 2009). Therefore, a major goal for global agriculture is to develop drought-tolerant crops. To this end, a fully understanding of physiological, biochemical, and gene regulatory networks relating to drought tolerance in plants is essential (Valliyodan and Nguyen, 2006). In this aspect, tremendous advances have been made over the past decade. Particularly, morphological, physiological traits, and biochemical changes that are relevant for drought tolerance have been well documented combinations of them—systems biology, have been used to elucidate the complex mechanisms of drought stress responses in crops (Shanker et al., 2014; Budak et al., 2015). However, the systematic mechanism of drought responses in crops and its application in drought tolerance improvement remain largely unclear, because of limited systematic biology data available from field experiments and genotype × environment interaction in complex, often unknown ways. A search in PubMed (Oct 29, 2016) for original, omics articles on drought responses in major crops showed that proteomics, transcriptomics studies were much more than metabolomics studies (Figure 1A), and laboratory-based studies were overwhelming compared with those conducted in field (Supplementary Table 1). In all 151 original articles, only 11 reports on cotton, wheat, rice and maize were involved in field trials. Despite large amounts of biological information have been obtained from laboratory-grown seedlings, the results do not really reflect the performance of those in the field conditions, where the expression of drought tolerance trait of crops is most likely dependent on the interaction (abiotic and biotic) of genotype × environment. In other words, field assays are necessary to conclude results, and are closer to real conditions than the laboratory-studies. So, there is an urgent need to enhance omics analysis of crop responses to drought under the field, drought conditions. This is very valuable for crop improvement in the context of a changing climate and an increasing world population. Since proteins are directly involved in plant stress responses, proteomic studies can eventually contribute to dissect the possible relationships between protein changes and plant stress tolerance. To date, numerous drought responsive-proteins have been identified with proteomic approaches in crops (Mousavi et al., 2016), which provide a wealth of data to elucidate the mechanisms of drought …