Motivation or “but can a ~3.5 billion years old process be optimized?”
If nothing unexpected happens, world’s productivity requirements will pose a severe threat to global sustainability and environmental goals before the middle of the current century. Resting on a vast knowledge base, photosynthesis is regarded as a promising target to provide the large increases in productivity required to keep pace with the demand of population growth, as it is becoming more widely accepted that yield does depend on photosynthesis.
But can we truly optimize a ~3.5 billion years old process? We think that Yes, we can. First, since modern agriculture has altered the conditions in which plants carry out photosynthesis (denser canopies, shorter growth cycles, etc.). And second, since there has been continued selection pressure due to everchanging conditions (atmospheric CO2, temperature, rainfall). Further, there is ample support to the untapped potential of this approach, from numerous cases where replacement or modification of a single gene or pathway had profound effects on plant biomass yield and photosynthetic performance.
Elucidating the role of photosynthetic metabolism in abiotic stress response When we think of abiotic stress resistance, we typically envision more stable proteins, favorable membrane composition, or durable biophysical designs. However, facing harsh extremes, different properties of metabolic performance, e.g. efficiency, flexibility or capacity, can be a virtue.
We applied multi-omics studies to demonstrated that vast basal metabolic capacity renders cells “stress-ready”, involving prompt redox-poising and oxidation. We also identified novel response nodes associated with this metabolic robustness under photoinhibitory stress, a process which significantly lowers global productivity.
Follow-up studies will aim at manipulating these key regulators to shed light on the cellular mechanisms underlying metabolism-mediated extreme illumination response, and raise promising targets to improve photosynthesis in a changing world.
Dissecting the effects of photosynthetic metabolic efficiency on plant growth Plant growth is a spatio-temporally resolved process, whose dynamics depend on the underlying biochemical, physiological and developmental events or signals as well as biotic and abiotic interactions. Here, we tackle the role of photosynthetic metabolism as a determinant of growth.
Using a tailored microfluidic setup, we were recently able to resolve the very short half-timed metabolic fluxes in photosynthesis in several algae and plants, pointing to potential bottlenecks in plant metabolism. Implementing a synthetic approach, we will import genes associated with these target reactions from fast into slower growing algae, to test their effects on the metabolic network and eventually, on growth rate. In addition, we will upscale this novel setup to study a range of algal species and conditions, and reveal new candidate targets.
Exploring algal metabolic adaptations in extreme environments As outlined in the other sections, algal metabolic diversity, represents a valuable and underexploited resource for photosynthesis research and prospective engineering goals. Further perspectives may emerge from exploring of algal diversity, especially from under-sampled extreme environments, including desert sand crusts, polar habitats and intertidal zones, simply since unique capabilities are more likely to be found in organisms that must cope with severe stress conditions.
Previous work by our lab and others has shown that some extremophilic algae from deserts and Antarctic lakes possess outstanding metabolic performance compared with major crops or model algae, but these examples are just beginning to scratch the surface of algal metabolism breadth. We will conduct a metabolic-phenotype-directed survey of algal isolates from several extreme habitats to identify novel metabolic adaptations in uncharacterized algal strains.