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

High-light stress strongly limits agricultural production in subtropical and tropical regions owing to photo-oxidative damage, decreased growth, and decreased yield. Here, we investigated whether beneficial microbes can protect plants under high-light stress. We found that Enterobacter sp. SA187 (SA187) supports the growth of Arabidopsis thaliana under high-light stress by reducing the accumulation of reactive oxygen species and maintaining photosynthesis. Under high-light stress, SA187 triggers dynamic changes in the expression of Arabidopsis genes related to fortified iron metabolism and redox regulation, thereby enhancing the antioxidative glutathione/glutaredoxin redox system of the plant. Genetic analysis showed that the enhancement of iron and sulfur metabolism by SA187 is coordinated by ethylene signaling. In summary, beneficial microbes could be an effective and inexpensive means of enhancing high-light-stress tolerance in plants. This study demonstrates that Enterobacter sp. SA187 enhances the tolerance of Arabidopsis thaliana to high-light stress by improving iron and sulfur metabolism through ethylene signaling. SA187 promotes the synthesis of Fe–S cluster proteins and strengthens the antioxidative redox system, thereby maintaining photosynthesis and overall plant growth under conditions of high-light stress.