Extracellular vesicles isolated from dsRNA sprayed barley plants exhibit no growth inhibition or gene silencing in Fusarium graminearum

Abstract

Incorporating a double-stranded RNA (dsRNA)-expressing transgene into plants or applying dsRNA by spraying it onto plant leaves successfully protects plants against invading pathogens with RNA interference (RNAi). How dsRNAs or siRNAs are transferred between donor host cells and recipient fungal cells is largely unknown It is speculated that plant extracellular vesicles (EVs) function as RNA shuttles between plants and their interacting pathogens. Recently, we found that EVs isolated from HIGS or SIGS plants contained dsRNA-derived siRNAs. In this study, we evaluated whether isolated EVs from RNA-sprayed barley ( Hordeum vulgare ) plants affected the growth of the phytopathogenic ascomycete Fusarium graminearum ( Fg ). Encouraged by our previous finding that dropping barley-derived EVs on Fg cultures caused fungal stress phenotypes, we conducted an in vitro growth experiment in microtiter plates where we co-cultivated Fg with plant EVs isolated from dsRNA-sprayed barley leaves. We observed that co-cultivation of Fg macroconidia with barley EVs did not affect fungal growth. Furthermore, plant EVs containing SIGS-derived siRNA appeared not to affect Fg growth and showed no gene silencing activity on FgCYP51 genes. We conclude that either the amount of spray-derived sRNA was insufficient to induce target gene silencing (SIGS) in Fg or Fg uptake of plant EVs from liquid cultures was inefficient or impossible.

A Combinatorial Nanobased Spray-Induced Gene Silencing Technique for Crop Protection and Improvement

“…Using the spray induced gene silencing (SIGS) method for plant disease prevention and protection, it was observed that when siRNAs or dsRNA was drizzled over barley crops, a particular fungal pathogen known as Fusarium graminearum quickly took the foliar spray, and therefore, the genes CYP51A , CYP51B , and CYP51C were targeted. The growth of F. graminearum halted as only CYP51A got silenced . Microbes like M. oryzae and F. graminearum experienced drastic inhibition by the administration of foliar dsRNA spray over H. vulgare crops. , DICER and ARGONAUTE genes of F. graminearum were chosen to interact with RNAi-based SIGS biopesticides concerning barley.…”

“…The growth of F. graminearum halted as only CYP51A got silenced. 54 Microbes like M. oryzae and F. graminearum experienced drastic inhibition by the administration of foliar dsRNA spray over H. vulgare crops. 6 , 55 DICER and ARGONAUTE genes of F. graminearum were chosen to interact with RNAi-based SIGS biopesticides concerning barley.…”