Improving Crop Stress Tolerance under Climate Change

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Global food demand will require double the current yield of major food crops to feed the increasing population by 2050. Drought and high temperature pose a major challenge to meet this demand by substantially curtailing plant growth, survival and crop yield. Climate change is expected to further aggravate this challenge by intensifying the exposure of field crops to extreme temperatures, and increased drought severity and frequency. It is, therefore, urgently necessary to adapt our cultivation practices and develop stress tolerant crop cultivars best suited to the changing environment. Improving crop adaptability to drought and heat stress under increasing CO2 is one of the most important and challenging targets. This challenge can be approached through the identification of stress-related traits at the physiological, biochemical and molecular levels and their deployment in new crop cultivars. Yet the lack of data on how plants detect and respond to drought and heat stress, as well as limited availability of high-throughput techniques to assess many crop germplasms, constitute major research gaps. Thus, my research program has two broad scientific goals. The first is to investigate the physiological, biochemical and molecular mechanisms that govern plant tolerance to drought and high temperature under increasing CO2. Elucidation of such mechanisms will help identify key traits that provide considerable potential for breeding new cultivars that can sustain or even enhance crop yield under changing environmental conditions. The second broad scientific goal of the research program is to develop remote sensing approaches for high-throughput phenotyping of leaf physiological and biochemical traits for rapid and precise screening of a large and diverse crop germplasms. We have recently established that variations in potato genotypes to tolerate drought stress is associated with differences in photosynthetic adjustment. In the proposed research, we will combine gas exchange and fluorescence with biochemical and molecular analyses including metabolite assays and gene expression profiling to elucidate the precise mechanism of photosynthetic adjustment and drought tolerance at ambient CO2.  Leaf reflectance pattern is primarily governed by its physiological activity and biochemical composition. Thus, in the proposed research, we will test the hypothesis that the variations in drought- related physiological and biochemical traits are mirrored by differences in reflectance patterns across potato genotypes. This information will be used to develop new spectral indices that can best predict the leaf physiological activity and biochemistry. Subsequently, we will examine how the interactions between drought and high temperature impact photosynthesis, gene expression profiles and reflectance patterns at elevated CO2. Another important overall goal of the research proposal is the mentorship and training of two graduate students and five undergraduate students.