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. Recent study by [Qin et al . (2022)][1] 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][1]). In this response letter, we use experimental evidence and additional bioinformatics analysis of the datasets produced by [Qin et al . (2022)][1] to identify the key reasons why a discrepancy with previously published findings occurred. Here, 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. ### Competing Interest Statement The authors have declared no competing interest. [1]: #ref-18