Modulating rice stress tolerance by transcription factors

Plants are non-mobile organisms and have to adapt to environmental stresses mostly by modulating their growth and development in addition to physiological and biochemical changes. Transcription factors (TFs) regulate genome expression in response to environmental and physiological signals, and some of them switch on plant adaptive developmental and physiological pathways. One TF is encoded by a single gene but regulates the expression of several other genes leading to the activation of complex adaptive mechanisms and hence represents major molecular targets to genetically improve the tolerance of crop plants against different stresses. In this review an updated account of the discovery of TFs involved in biotic and abiotic stress tolerance in the model monocotyledonous plant, rice (Oryza sativa L.) is presented. We illustrate how the elucidation of the function of these TFs can be used to set up genetic engineering strategies and to rationalize molecular breeding using molecular assisted selection towards enhancement of rice tolerance to various stresses. Attempts have also been made to provide information on the molecular mechanisms involved in stress resistance or tolerance processes. We discuss how the comparison of the action of TFs isolated from the dicotyledonous model plant Arabidopsis thaliana in rice and vice versa can contribute to determine whether common or divergent mechanisms underlie stress tolerance in the two plant species. Lastly, we discuss the necessity to discover TFs controlling specifically the root adaptive development which constitutes a major way for the plant to escape to several stresses such as water deficit or mineral nutrient deficiency.