Raffinose as a novel inducer of autophagy in plants
S. MAGEN , T. AVIN WITTENBERG
The Hebrew University of Jerusalem, Department of Plant and Environmental Sciences.

Autophagy, an intracellular degradation and recycling process, is gaining attention as a stress-coping mechanism in eukaryotes. It is induced by many nutrient-deprivation conditions and biotic and abiotic stresses in plants. Over-expression of autophagy-related genes in several plant species increased plant size, yield, and stress resistance. Yet, regulatory restrictions on transgenic plants hinder the direct modulation of autophagy in crops, and the constitutive induction of autophagy might prove unuseful in all environmental conditions. Thus, other means of modulating autophagy are needed. Previous works from plant and animal systems demonstrated the possible role of regulatory sugars in autophagy stimulation. Our research aims to find a natural sugar that activates autophagy in plants by spraying. We identified the trisaccharide raffinose as an autophagy inducer in plants. We demonstrate that raffinose treatment increased the performance of several crop species, both monocot and eudicot, and seed yield in an autophagy-dependent mannerin growth room and field conditions. The data gained in this project will help elucidate how regulatory sugars influence autophagy in plants. Moreover, it will serve as the basis for developing raffinose, and possibly other autophagy regulators, as agrochemicals to improve crop plant growth and yield.