Unraveling the Complexity of Plant Photosynthesis at the Atomic Level

Unraveling the Complexity of Plant Photosynthesis at the Atomic Level
by Sophie Jenkins
London, UK (SPX) Mar 11, 2024

Researchers at the John Innes Centre have made groundbreaking discoveries in understanding the atomic intricacies of photosynthesis, the vital process that allowed the Earth to flourish with life over a billion years ago. By employing cryogenic electron microscopy (cryo-EM), a cutting-edge imaging technique, the team has shed light on the formation of photosynthetic proteins, a breakthrough published in the journal Cell.

This research unveils a detailed model of the chloroplast polymerase, offering a rich resource for further exploration in the realm of photosynthesis and the development of resilient crops. Dr. Michael Webster, a group leader at the John Innes Centre and co-author of the study, emphasized the significance of comprehending chloroplast gene transcription to enhance plant growth and photosynthetic efficiency.

Photosynthesis occurs in chloroplasts, cell compartments with their own DNA, tracing back to their origins as independent photosynthetic bacteria. The study delves into the production of photosynthetic proteins, essential for converting carbon dioxide and water into sugars and oxygen. A pivotal stage in this process is transcription, facilitated by the enzyme RNA polymerase, unique to chloroplasts and surprisingly complex compared to its bacterial ancestors and even human counterparts.

The research team's use of cryo-EM allowed them to construct a model detailing over 50,000 atoms within the chloroplast RNA polymerase. This model elucidates the roles of various components in transcription, including a protein that aligns DNA for transcription and another that likely protects the resulting mRNA from degradation.

The findings underscore the essential nature of each component within the chloroplast RNA polymerase, as plants lacking any of these components fail to produce photosynthetic proteins and, thus, cannot perform photosynthesis effectively. Joint first authors Dr. Angel Vergara-Cruces and Dr. Ishika Pramanick highlighted the study's potential to illuminate the roles of chloroplast transcription proteins in plant growth, adaptation, and response to environmental stresses.

The research points to a future where understanding chloroplast transcription could lead to crops capable of maintaining photosynthesis under adverse conditions such as heat, drought, and salinity. The John Innes Centre's work paves the way for agricultural innovations that harness the full potential of photosynthesis, aiming for a future of more robust and resilient crops.

Research Report:Structure of the plant plastid-encoded RNA polymerase