Botrytis cinerea small RNAs are associated with tomato AGO1 and silence tomato target genes supporting cross-kingdom RNAi between the fungal pathogen B. cinerea and its tomato host
Cross-kingdom or cross-species RNA interference (RNAi) is broadly present in many interacting systems between microbes/parasites and their plant and animal hosts. A recent study by Qin et al. (2022) performed correlation analysis using global sRNA- and mRNA-deep sequencing data of cultured B. cinerea and B. cinerea-infected tomato leaves and claimed that cross-kingdom RNAi may not occur in B. cinerea-tomato interaction (Qin et al., 2022). Here, we use experimental evidence and additional bioinformatics analysis of the datasets produced by Qin et al. (2022) to identify the key reasons why a discrepancy between the conclusion of Qin et al. 2022 and previously published findings occurred. We also provided additional experimental evidence to support the presence of cross-kingdom RNAi between tomato and B. cinerea. We believe it is important to clarify the basic concept and mechanism of cross-kingdom/cross-species sRNA trafficking and illustrate proper bioinformatics analyses in this regard for all the scientists and researchers in this field.