Mechanistic insights into the temperature regulation of plant immunity

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Plant diseases combined with climate change-associated temperature anomalies pose serious threats to agriculture and food security. Previous studies have led to significant insights into how plants defend themselves against pathogens and pests. One of these crucial defence responses is the production of the hormone salicylic acid (SA), which allows host plants to globally control thousands of genes necessary to resist a broad range of pathogens. However, the molecular mechanisms underlying how environmental factors (e.g. elevated temperature) affect the plant SA pathway are not well-understood. My research aims to address this important knowledge gap. My previous work showed that elevated temperature suppresses SA production in the model plant Arabidopsis thaliana by downregulating the expression of CALMODULIN-BINDING PROTEIN 60g (CBP60g). CBP60g encodes a master transcription factor controlling many immune regulators in plants, including genes involved in producing SA. Because the CBP60g gene is a central hub in integrating temperature and immune pathways, how it is regulated at the molecular level will provide clues on how temperature influences the plant SA pathway. Additionally, whether temperature-sensitive immunity is conserved in other plant species is also unclear. My long-term vision is to create an integrative model that defines how plants resist pathogens in the context of a changing environment. My research program will integrate molecular, genetic and biochemical approaches in order to pursue three major aims in the next five years. First, we will identify essential transcription factors of CBP60g gene expression using both in silico and in vivo methods. Second, we will perform a genetic screen to discover new regulators of CBP60g gene expression at high temperature and validate the results using mutational approaches. Third, we will determine if temperature suppression of host immunity is conserved in other plant species, by studying CBP60g gene expression and SA production of the agriculturally important tomato crop. Overall, my research program would more accurately address the complexity of plant diseases in the natural environment, by identifying the essential genes and mechanisms that lead to compromised SA production at high temperature. This knowledge should help us better understand plant resilience to various stresses and contribute to strategies in improving crop disease resistance in Canada and worldwide. For the proposed research, HQP will acquire excellent laboratory and practical skills that are important for their chosen careers.