dsRNA as a promising eco-friendly treatment to control postharvest diseases

Pathogenic fungi are a main cause of postharvest loss. The most effective treatment against postharvest diseases is fungicides. However, due to growing concern for their harmful influences, there is a need to develop new strategies. One of the new environmentally friendly approaches is the use of dsRNA. By designing dsRNA construct which targets essential genes in pathogenic fungi, we were able to reduce decay development. However, the dsRNA treatment suffers from two major disadvantages: not all fungal species have the propensity to uptake dsRNA, and low stability of dsRNA in the natural environment.? By examining the uptake of cy5-labeled dsRNA by various pathogenic fungi we demonstrated that the uptake of dsRNA by Botrytis cinerea occurs in the emergence zone of the germination tube, whereas Colletotrichum gloeosporioides presented no uptake.? We studied the fungi's mechanical properties using atomic force microscopy. The elastic moduli measured for both conidia and germination tubes of C. gloeosporioides were remarkably higher than for B. cinerea indicating that dsRNA penetration to the fungi is dependent on the fungi's stiffness.? Upon this observation we developed new techniques which allowed the penetration of the dsRNA to C. gloeosporioides.? Next, to overcome the instability of the dsRNA it was loaded onto layered double-hydroxide (LDH), which protected the dsRNA from degradation and served as a slow-release device.? The dsRNA display an ability to serve as a selective treatment which decreased only the targeted fungi without affecting other species during storage. The LDH-dsRNA complex had a prolonged effect and maintained its efficiency in decreasing decay development up to six weeks post-treatment.? Moreover, storage conditions affected the release pattern of the dsRNA from the LDH.? Overall, this study advances the use of dsRNA one step closer to an applicative ecofriendly alternative to conventional postharvest fungicides. SourcesdsRNA as a promising eco-friendly treatment to control postharvest diseasesDanielle Duanis-Assaf, Tal Duanis-Assaf, Ortal Galsurker, Ilya Shlar, Olga Davydov, Dalia Maurer, Oleg Feygenberg, Elena Poverenov, Meital Reches, Robert Fluhr & Noam AlkanPostharvest Unlimited Conference & Postharvest Ornamentals Symposium, Wageningen University & Research, May 2023https://www.wur.nl/en/show/postharvest-unlimited-conference-postharvest-ornamentals-symposium.htm Picture,?kindly sent by Dr. Alkan from a?previous publication in Postharvest Biology and Technology 2022