The photosynthetic bacteria delayed tomato leaf senescence under weak light conditions by regulating
Lina Cheng1, Jianzhong Tie2, Jiayu Qi2
1College of Plant Protection, Shenyang Agricultural University, Shenyang, Liaoning, 110866, China.
Plant Physiology and Biochemistry : PPB
|December 15, 2025
Summary
Photosynthetic bacteria Rhodopseudomonas palustris enhance tomato photosynthesis under weak light. This method improves crop yield by delaying leaf senescence and boosting chlorophyll levels via cytokinin regulation.
Area of Science:
- Plant Science
- Microbiology
- Agricultural Science
Background:
- Weak light conditions significantly reduce crop yield by inhibiting photosynthesis and plant growth.
- Photosynthetic bacteria, such as Rhodopseudomonas palustris, can photosynthesize in low-light environments where plants struggle.
- The potential of using photosynthetic bacteria to enhance plant photosynthesis under weak light is an underexplored area.
Purpose of the Study:
- To investigate the effects of Rhodopseudomonas palustris on tomato photosynthesis and growth under weak light conditions.
- To elucidate the molecular mechanisms by which photosynthetic bacteria influence plant physiology in low-light environments.
Main Methods:
- Foliar application of Rhodopseudomonas palustris strain CGA009 to tomato plants.
- Measurement of chlorophyll levels, leaf senescence, and photosynthetic rates.
- Gene expression analysis of key regulators involved in plant hormone biosynthesis and light signaling pathways.
- Gene silencing experiments to confirm the role of specific cytokinin biosynthesis genes.
Main Results:
- Rhodopseudomonas palustris treatment delayed leaf senescence and enhanced tomato photosynthesis under weak light.
- Bacterial application maintained chlorophyll levels by promoting the degradation of SlPIF4, a negative regulator.
- This process relieved repression of cytokinin biosynthesis genes (SlIPT6/SlLOG8), increasing active cytokinin levels (iP and cZ).
- Silencing SlIPT6 and SlLOG8 rendered plants insensitive to the bacterial treatment, confirming their crucial role.
Conclusions:
- Rhodopseudomonas palustris effectively rescues photosynthetic capacity in tomatoes under weak light stress.
- The mechanism involves transcriptional regulation, specifically the modulation of cytokinin biosynthesis pathways.
- This study presents a novel strategy for enhancing crop yield in low-light conditions through photosynthetic bacteria-mediated plant photosynthesis improvement.
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