Periodic Reporting for period 2 - UNREDE (Understanding Non-Photochemical Quenching Regulation in a Dynamic Environment.)
Okres sprawozdawczy: 2020-01-15 do 2021-01-14
The study of NPQ regulation is essential to predict how photosynthetic organisms will behave under changes in light, atmospheric CO2 levels, temperature and nutrient availability, and, therefore, it will also impact strategies for improving photosynthetic efficiency and tolerance to harsh conditions. A better understanding of these processes at the molecular level has already allowed improving crop productivity by 15% in tobacco. In addition, beyond the ecological implications, this project might have a significant impact on the use of photosynthetic organisms for biotechnological purposes. Microalgae, widely used in industry, waste a large part of the absorbed solar radiation as heat (NPQ). The study of NPQ regulation and the capacity to control it can improve both the production of biomass and the synthesis and accumulation of high-value products.
NPQ mechanisms vary between plants and photosynthetic microbes. In plants, the PSBS protein works in collaboration with the light-harvesting complexes (LHCs) to mediate this process in chloroplasts, but in photosynthetic microorganisms, there exist other proteins involved in the fast NPQ (LHCSRs and LHCXs in algae and diatoms respectively, or OCP in cyanobacteria). Chlamydomonas reinhardtii, the model green alga used in this project, is one of the few organisms having genes encoding PSBSs and LHCSRs proteins on its genome. However, we know very little about the regulation and role of these proteins in NPQ. Our goals are to understand the regulation of LHCSRs and PSBS expression in a wide variety of physiological conditions (different light intensity and quality, CO2 concentrations and nutrient deprivation), to characterize their role and to identify molecular signals that control the induction and functionality of NPQ.
Our results have unraveled a fine-tuned and very complex network of regulation that integrates different pathways in order to control a progressive induction of NPQ. This gradual induction allows cells to anticipate excess light and to be ready for photoprotection. We have studied different pathways that can impact the transcriptional regulation of NPQ in an independent or additive way. Moreover, we have improved our knowledge about how cells integrate the information present in sunlight (intensity and quality) in order to acclimate to a dynamic environment.
Some of the results related to polyphosphate have been published in Science Advances (DOI: 10.1126/sciadv.abb5351) and another publication related to the transcriptional regulation of the NPQ (qE) genes is in preparation. Moreover, the project and part of the results have also been disseminated in different media to a general audience (https://www.eurekalert.org/pub_releases/2020-10/cifs-ppf101520.php; https://carnegiescience.edu/news/phosphate-polymer-forms-cornerstone-metabolic-control; https://cordopolis.es/2019/12/06/las-microalgas-revelan-las-estrategias-de-defensa-de-las-plantas-contra-el-exceso-de-energia-solar; https://profesionaleshoy.es/jardineria/2019/12/10/las-microalgas-revelan-las-estrategias-de-defensa-de-las-plantas-contra-el-exceso-de-energia-solar/20108)
Altogether these data will help us understand NPQ regulation and will provide us with the tools to engineer the pathways involved in NPQ to improve photosynthesis and to obtain higher benefits from photosynthetic organisms in agriculture and the biotechnological industry.