Re-analysis of mobile mRNA datasets raises questions about the extent of long-distance mRNA communication

Short-read RNA-seq studies of grafted plants have led to the proposal that thousands of messenger RNAs (mRNAs) move over long distances between plant tissues^1-7, potentially acting as signals^8-12. Transport of mRNAs between cells and tissues has been shown to play a role in several physiological and developmental processes in plants, such as tuberization¹³, leaf development¹⁴ and meristem maintenance¹⁵; yet for most mobile mRNAs, the biological relevance of transport remains to be determined^16-19. Here we perform a meta-analysis of existing mobile mRNA datasets and examine the associated bioinformatic pipelines. Taking technological noise, biological variation, potential contamination and incomplete genome assemblies into account, we find that a high percentage of currently annotated graft-mobile transcripts are left without statistical support from available RNA-seq data. This meta-analysis challenges the findings of previous studies and current views on mRNA communication.