Distinct phytochrome-specific regulation of tomato sugar metabolism and plant architecture by far-red light.

PhyE is essential for regulating carbohydrate levels in tomato under far-red light, with phyB1 and phyB2 controlling source-sink dynamics, and phyA potentially acting as a negative regulator of sink strength.

• Why it matters: Understanding how different phytochromes influence sugar metabolism and plant architecture under far-red light can inform crop improvement strategies, as these responses affect growth and yield.
• What they did: Using reverse genetics and far-red light trials in tomato, five phytochromes were studied to determine their roles in architectural, physiological, and sugar metabolism changes, including analysis of phy mutants.
• The result: The study found that phyE plays a critical role in carbohydrate regulation, while phyB1 and phyB2 modulate source-sink dynamics, and phyA may negatively regulate sink strength, revealing distinct phytochrome functions in FR responses.