Supplemental red LED light promotes plant productivity, ?photomodulate? fruit quality and increases Botrytis cinerea tolerance in strawberry

This work provides new evidences on the effect of pre-harvest red (R), green (G), blue (B), and white (W - R:G:B; 1:1:1) LED light supplementation on production, nutraceutical quality and Botrytis cinerea control of harvested strawberry fruit. Yield, fruit color, firmness, soluble solid content, titratable acidity, primary and specialized metabolites, expression of targeted genes and mold development were analyzed in fruit from light-supplemented plants, starting from the strawberry flowering, radiating 250 mu mol m-2 s-1 of light for five hours per day (from 11:00 to 16:00 h), until the fruit harvest. Briefly, R light induced the highest productivity and targeted antho-cyanin accumulation, whilst B and G lights increased the accumulation of primary and secondary metabolites especially belonging to ellagitannin and proanthocyanidin classes. R light also promoted pathogen tolerance in fruit by the upregulation of genes involved in cell wall development (F x aPE41), inhibition of fungus poly-galacturonases (F x aPGIP1) and the degradation of B. cinerea beta-glucans (F x aBG2-1). Our dataset highlights the possibility to use red LED light to increase fruit yield, "photomodulate" strawberry fruit quality and increase B. cinerea tolerance. These results can be useful in terms of future reduction of agrochemical inputs through the use of R light, enhancing, at the same time, fruit production and quality. Finally, further analyses might clarify the effect of pre-harvest supplemental G light on postharvest fruit quality.