UoH researchers identify phosphate mechanism in tomato plants

University of Hyderabad researchers have identified a molecular mechanism that helps tomato plants move stored phosphate from older leaves to younger tissues. The findings could aid efforts to improve phosphate use efficiency in crops and reduce dependence on chemical fertilisers.

Hyderabad: The University of Hyderabad (UoH) researchers uncovered a vital molecular regulatory mechanism underlying phosphate remobilisation in tomato plants.

The study demonstrated that the tomato purple acid phosphatase gene, PAP26b, acts as a primary driver for transferring stored phosphate (Pi) from older leaves to younger, growing tissues in seedlings. The breakthrough offers critical insights that could help develop high-yielding crops requiring significantly less chemical fertilizer. The research team was led by Prof Rahul Kumar and Abhishek Roychowdhury, among others.

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When PAP26b is silenced, older leaves lose their ability to effectively remobilise phosphate. This triggers a systemic Pi starvation response (PSR) in young leaves and roots—via master regulator SlPHL1 and microRNA miR399—even under normal nutrient conditions, the researchers said.

The team discovered that while young leaves and roots signal nutrient deficiency, older leaves on the same plant remain unaffected. This proves that different leaf nodes within a single plant maintain distinct phosphate signaling and balance mechanisms.

By identifying how PAP26b modulates the SlSPX2–SlPHL1 regulatory pathway, scientists now have a genetic target to enhance internal phosphate use efficiency (PUE) in crops.

Manipulating this mechanism could lead to resilient crop varieties that utilise internal nutrient reserves far more efficiently, cutting farmer input costs and mitigating soil degradation caused by excess fertilizer usage, the researchers added. The research findings have been published in the Journal of Experimental Botany.