Systems Biology and Synthetic Biology in Relation to Drought Tolerance or Avoidance in Plants

The dwindling supply of blue water (surface and ground) resources resulting from urbanization, increasing human population and changes in global temperature and precipitation is a major challenge for sustainable crop production for food, feed, fiber, and bioenergy in this century. Plants employ two main strategies for overcoming drought: drought tolerance (e.g., maintaining cell turgor through osmotic adjustments or cell wall elasticity) and drought avoidance (e.g., changing in stomatal patterning, stomatal physiology, root and leaf anatomy, root physiology). Engineering improved drought resistance requires deep understanding of molecular mechanisms underlying drought tolerance or avoidance in model crop and non-crop species and in plants adapted to water-limited habitats. Systems Biology research, empowered by high-throughput omics (e.g., transcriptomics, proteomics, metabolomics) and genome-editing technologies, enables unprecedented insights into gene function, regulatory networks and signaling pathways relevant to plant drought tolerance or avoidance. The knowledge gained through Systems Biology research lays a solid foundation for redesigning the gene modules or pathways to accelerate the adaptation of plants to water-limited environments using synthetic biology approaches, which is a relatively new discipline aiming at redesigning existing biological systems using completely new parts and devices through iterative Design-Build-Test-Learn cycles. There is a resurgence of interest in crassulacean acid metabolism (CAM), a drought avoidance strategy and potential biological solution to the challenges in crop production caused by water limitation. Derived from C3 photosynthesis, CAM is a water-use efficient photosynthetic pathway that has been evolved independently in diverse lineages of plants. New genomics resources have been established in multiple CAM species and international efforts are being made to engineer CAM machinery into C3 photosynthesis plants for sustainable crop production in water-limited environments.

This Research Topic features system biology research for unravelling the molecular basis of plant adaptation to water-limited conditions and utilization of synthetic biology technology for engineering of drought tolerance or avoidance traits. All types of articles are welcome, with a preference for Original Research, Reviews, and Perspectives focusing on the following aspects:
• Discovery of genes and/or gene networks associated with plant response to drought stress through analysis of transcriptome, proteome, and/or metabolome.
• Functional characterization of genes involved in drought tolerance or avoidance in C3, C4 and CAM photosynthesis plants through loss- and/or gain-of-function mutagenesis generated by genome editing technologies (e.g., CRISPR-Cas9 or CRISPR- Cpf1).
• Discovery and characterization of genes involved in stomatal development and movement.
• Molecular basis of leaf succulence in relation to drought avoidance.
• Comparative genomics analysis of CAM and non-CAM plants to identify candidate genes for CAM-into-C3 photosynthesis engineering.
• Engineering of CAM plant genes into C3 photosynthesis plants to increase water-use efficiency.