Plant Abiotic Stress Challenges from the Changing Environment

The challenges of abiotic stress on plant growth and development are evident among the emerging ecological impacts of climate change (Bellard et al., 2012), and the constraints to crop production exacerbated with the increasing human population competing for environmental resources (Wallace et al., 2003). Climate change is predicted to affect agricultural production the most, primarily at low latitudes populated by developing countries, with adverse effects of increasing carbon dioxide and high temperature, challenging researchers toward devising adaptation strategies (Rosenzweig et al., 2014). These constraints to global food supply and a balanced environment encourage research and development of climate smart crops, resilient to climate change (Wheeler and Von Braun, 2013). The field of plant abiotic stress encompasses all studies on abiotic factors or stressors from the environment that can impose stress on a variety of species (Sulmon et al., 2015). These stressors include extreme levels of light (high and low), radiation (UV-B and UV-A), temperature [high and low (chilling, freezing)], water (drought, flooding, and submergence), chemical factors (heavy metals and pH), salinity due to excessive Na + , deficient or in excess of essential nutrients, gaseous pollutants (ozone, sulfur dioxide), mechanical factors, and other less frequently occurring stressors. Since combinations of these stresses such as heat and drought frequently occur under field conditions, and can cause unique effects that cannot be predicted from individual stressors (Suzuki et al., 2014), a multiplicity of physiological interactions can be expected, needing individual novel solutions. Plants are rooted in the environment they grow in, and have to adapt to the changing conditions brought about by the multitude of environmental factors, with extreme levels eliciting abiotic stress. A grand challenge in abiotic stress biology is to decipher how plants perceive the different stressors, how the early signals are transduced within the plant, what is the diversity of response pathways elicited by them, and how are they genetically determined (Yoshida et al., 2014). Beyond model plants and reference genotypes, the challenge is to identify how signaling pathways have evolved within a species to program a suite of responses differing in signals and regulatory networks, and constitute genotypes that are adapted to specific stressful environments. Many studies have begun to deal with the comparison of a few genotypes, such as tolerant and sensitive within a species, for the analysis of differential responses to a defined stress. Since these responses can be due to differences in sets of genes, …