Brenya et al. (2020) gently brushed Arabidopsis thaliana seedlings, starting at 10–12 days old, for 8–10 seconds twice daily, eight hours apart, for seven days. After challenge with the fungus Alternaria brassicicola, basal rosette leaves from brushed wild-type plants developed smaller lesions four and six days later than unbrushed controls. In a separate assay, leaves that developed later on flowering stems showed no statistically significant difference in disease susceptibility, although some defense-gene expression changed. These assays differed in tissue, developmental stage and elapsed time, so they do not isolate tissue alone as the cause. This finding concerns the specified Arabidopsis treatment and fungal assay; it does not establish lasting whole-plant protection.

Source: Brenya et al. (2020)