Airborne fungus-induced biosynthesis of anthocyanins in Arabidopsis thaliana via jasmonic acid and salicylic acid signaling

Anthocyanins are plant-specific pigments, the biosynthesis of which is stimulated by pathogen infection in several plant species. A. thaliana seedlings injected with airborne fungi can accumulate a high content of anthocyanins. The mechanism involved in fungus-induced anthocyanin accumulation in plants has not been fully described. In this study, the fungus Penicillium corylophilum (P. corylophilum), isolated from an Arabidopsis culture chamber, triggered jasmonic acid (JA), salicylic acid (SA), and anthocyanin accumulation in A. thaliana. Inhibitors of JA and SA biosynthesis suppressed the anthocyanin accumulation induced by P. corylophilum. The anthocyanin content was minimal in both the null mutant of JA-receptor coi1 and the null mutant of SA-receptor npr1 under P. corylophilum stimulation. The results indicate that JA and SA signaling mediated fungus-induced anthocyanin biosynthesis in A. thaliana. P. corylophilum led to different levels of anthocyanin generation in null mutants for MYB75, bHLH, EGL3, and GL3 transcription factors and WD40 protein, demonstrating that multiple MYB-bHLH-WD40 transcription factor complexes participated in fungus-induced anthocyanin accumulation in A. thaliana. The present study will help further elucidate the mechanism of plant resistance to pathogen infection.