Changes in MicroRNAs expression mediate molecular mechanism underlying the effect of MeJA on the biosynthesis of podophyllotoxin in Linum album cells

Podophyllotoxin (PTOX), produced by Linum album, is a monolignol that participates in plant defense strategies. Our previous study established that methyl jasmonate (MeJA) significantly stimulates PTOX production in L. album cells. However; the mechanisms by which MeJA regulates PTOX biosynthesis are uncovered. In the present study, we demonstrated that MeJA induces a time-dependent hydrogen peroxide (H₂O₂) and salicylic acid (SA) accumulation but reduces nitric oxide (NO) generation in L. album cells. PTOX biosynthetic genes such as PAL, CCR, CAD, and PLR were upregulated in response to MeJA exposure. Furthermore, the results of RT-qPCR revealed a positive correlation between the expression of PTOX biosynthetic genes and MeJA-induced upregulation of four miRNAs such as miR156, miR159, miR172, and miR396 at 12 h. Generally, this study revealed that MeJA mediates PTOX biosynthesis in L. album cells by inducing H₂O₂ and SA formation, which can probably upregulate the expression level of some miRNAs and biosynthetic genes in a redox balance-dependent manner.