Accelerating evolution: engineering invertase enzymes to enhance fructan metabolism in Musa spp. (banana)

Bananas are produced in more than 120 countries and around 85% of the crop is retained as a vital food source for 400 million people. With a worldwide production of 145 million tons, banana represents one of the most important food crops. The major threat to banana cultivation is drought, which causes yield losses up to 65%. Climate change is a leading human and environmental crisis of the 21st century. Banana fruits can accumulate smaller amounts of inulin-type fructans, fructose containing oligoand polysaccharides that are well-known because of their prebiotic, immunomodulatory and antioxidant properties contributing to human health. Additionally, inulin-type fructans are emerging as important signals during plant stress responses. In banana, fructans are produced by one or more vacuolar invertase enzymes (VIs) that are “on their way” to becoming “genuine” fructan biosynthetic enzymes or fructosyl transferases (FTs), as occurring in plants that accumulate fructans more abundantly. It is widely accepted that FTs evolved from VIs in plants. In this project we will use the CRISPR/Cas 9 technology to edit the banana genome in such a way that evolution is accelerated by transforming two banana VIs into FTs, with the aim of: (1) increasing fructan levels in banana fruit, as a strategy to launch these health-improving compounds into human diets, and (2) to increasing fructan levels in other parts of the banana plants to counteract stresses (specially drought stress).