Pre-Drought Priming

Abstract

Abstract Grain development is the final and most critical growth stage in wheat life cycle. During this phase, developing grains accumulate energy reserves to form the economic yield of the crop and staple for the humanity. Grain development is severely influenced by environmental stresses. For example, drought during this phase primarily reduces grain size formation as well as the rate, duration, and quality of grain filling, resulting in impaired grain formation and substantial yield losses. Extensive yield loss due to post-anthesis drought in wheat is mainly attributed to enhanced flag leaf senescence, suppressed carbon assimilation, and poor remobilization. These result in source-deprived grain filling, imbalanced production of growth hormones, and altered enzyme activities involved in carbon metabolism in both source and sink organs of the plant. Therefore, improving tolerance to drought stress, especially during reproductive period, has become target for increasing yield sustainability in drought-prone areas of wheat cultivation. Some recent studies in different crop species explore an intriguing possibility of developing stress tolerance in plants through the preexposure of plants to stress conditions, referred to as “priming.” Studies show that plants can perceive and accrue information about earlier experiences and recall this information to respond to later environmental challenges. Recently, priming strategy has gained a great attention in plant stress physiology due to its feasibility, efficiency, and cost- and labor-effectiveness. In this chapter, we accumulated the information about the role of pre-drought priming to sustain grain development under post-anthesis drought stress by regulating carbon assimilation, translocation, leaf senescence, grain size initiation, grain filling, levels of growth hormones, and activities of enzyme related to grain development. In addition, recent advances made in prestress priming for improving tolerance against a range of environmental stresses in different crop species are also discussed in this chapter.