Uncovering the Role of DLDG1, a Photoprotective “Safety Valve” in Photosynthesis

August 29, 2025

New Insights into How Plants Protect Themselves from Excess Light

Plants possess a protective mechanism known as non-photochemical quenching (NPQ), which dissipates excess light energy as heat. However, many aspects of this process remain unclear. An international research group, including researchers from RIKEN CSRS and Tokyo University of Science, focused on DLDG1, an ion transporter in the chloroplast envelope, and clarified how it contributes to the regulation of NPQ. This discovery has the potential to support the development of crops with enhanced tolerance to environmental stresses such as intense light and drought, contributing to stable food production and sustainable agriculture.

Previous studies showed that the loss of DLDG1 leads to excessive NPQ activity, but the underlying mechanism was not well understood. To investigate this, the researchers generated a double mutant by crossing a DLDG1-deficient plant with the hope2 mutant, which has impaired chloroplast ATP synthase function. Experiments using this double mutant revealed that DLDG1 works with ATP synthase to modulate NPQ intensity and maintain pH balance within chloroplasts. This study provides a new perspective on the regulatory mechanism of the photoprotective “safety valve” that helps plants adapt to environmental stresses such as intense light, drought, and temperature fluctuations. These findings could help improve photosynthetic efficiency and stress resilience in crops.

 

Original article

Plant Physiology　doi: 10.1093/plphys/kiaf373

M. D. L. Trinh, E. Esmailpourmoghadam, R. Sato, C. Miyake, M. Palmgren, S. Masuda,

"Chloroplast envelope-localized DLDG1 modulates H⁺ translocation across thylakoid membranes via plastidial ATP synthase".

Contact

Ryoichi Sato
Research Scientist
Metabolic Systems Research Team