Microbe-induced coordination of plant iron-sulfur metabolism enhances high light stress tolerance of Arabidopsis

High light stress in subtropical and tropical regions strongly limits agricultural production due to photo-oxidative damage, decreased growth and yield. Here, we investigated whether beneficial microbes can protect plants under high light stress. We found that Enterobacter sp. SA187 (SA187) supports Arabidopsis thaliana growth under high light stress by reducing the accumulation of reactive oxygen species (ROS) and maintaining photosynthesis. When subjected to high light stress, SA187 triggers dynamic changes in Arabidopsis gene expression related to fortified iron metabolism and redox regulation thereby enhancing the plant anti-oxidative glutathione/glutaredoxin redox system. Genetic analysis shows that SA187-enhanced iron and sulfur metabolism are coordinated by ethylene signaling. In summary, beneficial microbes could be an effective and inexpensive means for enhancing high light stress tolerance in plants.