Tandem MADS-Box Genes FUL2 and MADS1 Form a Regulatory Module to Repress Serotonin Biosynthesis via Direct ASMT5 Activation in Tomato Fruit.
Xu Y, Jia H, Tang D, Zhang L, Liu X
Crispr
The tomatoes on your kitchen counter are quietly managing their own serotonin levels as they ripen — and now we know the genetic switch that controls it, opening a real path to breeding tomatoes (and other crops) with tailored levels of health-relevant compounds.
Tomatoes naturally produce serotonin — yes, the same molecule linked to mood in humans — and a pair of genes called FUL2 and MADS1 work together to keep serotonin levels low as the fruit ripens. When researchers used CRISPR gene-editing to disable these genes, serotonin levels in the tomatoes shot up ten times higher than normal. This discovery gives plant breeders a clear target for designing fruits with more serotonin or other beneficial compounds baked right in.
Key Findings
CRISPR knockout of FUL2 caused a 10-fold increase in serotonin levels in tomato fruit compared to normal plants.
The FUL2 and MADS1 proteins physically interact to form a complex that directly binds and activates the ASMT5 gene (which converts serotonin to melatonin), while simultaneously repressing TDC1 (which makes serotonin), effectively capping serotonin accumulation.
Loss of either FUL2 or MADS1 alone produced the same phenotype — delayed ripening, smaller fruit, and serotonin overload — confirming they function as a single regulatory unit.
chevron_right Technical Summary
Scientists discovered that two genes in tomatoes act as a team to suppress serotonin buildup in ripening fruit. By switching off these genes using CRISPR editing, serotonin levels jumped 10-fold, revealing a new way to engineer the nutritional and defensive chemistry of crops.
Abstract Preview
The regulation of serotonin metabolism during fruit development and ripening remains poorly understood, despite its potential roles in plant defence and human nutrition. Here, we demonstrated that ...
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The tomato is a plant whose fruit is an edible berry that is eaten as a vegetable. The tomato is a member of the nightshade family that includes tobacco, potato, and chili peppers. It originated from western South America, and may have been domesticated there, in Mexico, or in Central America. Th...