Enhancing Rapeseed Tolerance to Heat and Drought Stresses in a Changing Climate: Perspectives for Stress Adaptation from Root System Architecture

Abstract

Abstract Globally, the increase in climatic variability is responsible for more frequent extreme heat and drought stress events. Heat and water stress have a devastating impact on plant growth, development, and formation of the yield components of rapeseed/canola, an important oilseed crop for human consumption and a renewable feedstock for biodiesel production. The growing demand for rapeseed/canola will not be met unless strategies are rapidly developed to sustain and improve crop yields and product quality in the context of global climate change. Therefore, the objective of this review is to discuss the development of rapeseed/canola varieties with enhanced tolerance to heat and drought stresses, as the most promising solution to improve crop productivity in the future. The genetic basis of stress tolerance has provided plant breeders with new options for efficient breeding programs that support high yield potentials under both favorable and stressful environments. This review provides an update on recent advances in characterizing the response of rapeseed/canola to heat and drought stresses, from the molecular level (i.e., signal transduction) to phenotypes at the whole-plant and agroecosystem scales. Of particular interest is the ability of the root system to alleviate abiotic stressors. Roots, as the “hidden half” of the plant, play a central role in acquiring water and nutrients (i.e., improving water and nutrient use efficiencies) as well as anchoring the crop so it can resist lodging and tolerate heat and drought stresses. Considering the urgent need to achieve sustainable production of rapeseed/canola under changing climatic conditions, it is essential to determine how the root system can mitigate abiotic stress. Modern methodologies to quantify root system architecture are presented. Finally, we describe root-specific tolerance mechanisms to abiotic stress and explain how this information can be used to direct breeding programs and decide on agronomic practices that support sustainable rapeseed/canola production now and under future climate change scenarios.