Team:UNITN-Trento

Hi everybody!

Our team is proud to introduce to you B. fruity, a new environmentally friendly way to control climacteric and non-climacteric fruit ripening by exploiting an engineered, light regulated strain of B. subtilis. The system works by synthesizing ethylene or methyl salicylate (MeSA) upon photoinduction.

Ethylene is a plant hormone widely used to ripen fruit such as bananas, kiwifruit, apples, and others. However, the synthesis, handling, and storage of ethylene is expensive and dangerous. In contrast, B. fruity produces ethylene from inexpensive material by hijacking a metabolic intermediate, 2-oxoglutarate, from the TCA cycle and converting this metabolite to ethylene throught the activity of an ethylene forming enzyme (EFE, 2-oxoglutarate oxygenase/decarboxylase) from Pseudomonas syringae.

B. fruity does not just accelerate ripening, but can also slow the process down, when desired, through the incorporation of a methyl salicylate (MeSA) synthesis pathway. MeSA was previously shown to inhibit the ripening of kiwi and tomatoes. The explored MeSA pathway builds upone the 2006 MIT iGEM project “Eau de coli”.

As a proof of concept, we engineered E. coli with the above systems plus the YF1/FixJ blue light receptor device.

We are hopeful that B. fruity will simplify the process of bringing fresh fruit from the field to the consumer.