New Research into the mode of action of MTU®

MTU® is a unique single molecule biostimulant with a proven track record. MTU® formulated with pidolic acid is CE marked for improved nutrient use efficiency, tolerance to abiotic stress, yield and quality traits, under the EU FPR.

A newly published study provides the first mechanistic insight into how MTU® influences photosynthetic regulation at the molecular level. Using Arabidopsis leaves exposed to prolonged darkness, a well-established inducer of photosynthetic stress and senescence, the authors demonstrated that it triggers extensive transcriptional reprogramming affecting photosynthesis, chloroplast function and light-signalling pathways.

Importantly, MTU® does not behave as a conventional cytokinin. Although it exhibits only weak classical cytokinin activity, it induces a distinct molecular response characterised by strong upregulation of phytochrome A (PHYA), moderate downregulation of phytochrome B (PHYB) and activation of genes involved in chloroplast electron transport. The study further demonstrated that MTU® modifies the regulation of photosystem II (PSII) to protect it during stress.

These findings show that MTU® activates a previously unrecognised photosynthetic acclimation pathway involving phytochrome-associated signalling and chloroplast electron transport regulation. The strong induction of PHYA, together with the PHYB-dependent physiological response, points to activation of regulatory mechanisms normally associated with adaptation to low-light environments. Such acclimation responses help maintain chloroplast integrity and photosynthetic competence under conditions (such as shade or low-light) that normally accelerate chloroplast decline and leaf senescence, providing a potential mechanistic link between the molecular effects of MTU® and its previously reported benefits on crop productivity.

What could this mean for crops under stress?

While the study was performed using detached Arabidopsis leaves under controlled laboratory conditions, the results provide important clues about how MTU® may function in living plants exposed to environmental stress.

Drought, heat, nutrient limitation and fluctuating light all disrupt Photosystem I and photosynthetic electron transports, accelerating chloroplast degradation and leaf senescence. The ability of MTU® to stabilize Photosystem I via altered phytochrome-associated signalling suggests that treated plants enter an acclimation state better suited to maintaining photosynthetic function under challenging conditions.

This interpretation is consistent with previously reported greenhouse and field observations showing delayed senescence, improved stress tolerance and enhanced productivity in crops treated with MTU®.