Consideration of Combined Stress: A Crucial Paradigm for Improving Multiple Stress Tolerance in Plants

In the wake of shrinking arable land and widespread changes in climate, global agriculture is threatened. Global losses in agricultural production due to abiotic stresses are estimated at US$ 120 billion. Radical changes in research strategies are urgently warranted to overcome yield losses and ensure food security for the rapidly growing population. Under field conditions, plants are challenged by simultaneous occurrence of two or more stresses. Yet most studies on stresses focus on single perturbations. Recent studies have shown that plants mount unique physiological, molecular, and biochemical responses to a combination of stresses that is not just an additive effect of the responses observed when the stresses are imposed singly. In this chapter, I outline the importance of analyzing stress combinations that are likely to co-occur and the challenges associated with such studies. For plant biotechnologies to deliver the promise of a second green revolution, a systems biology approach of examining multiple stresses at several developmental stages is necessary.