Glutathione (GSH) induces embryogenic response in in vitro cultured explants of Arabidopsis thaliana via auxin-related mechanism

To gain insight into the relationship between oxidative stress and somatic embryogenesis (SE) induction, we analysed the effects of a reduced glutathione (GSH) of antioxidant activity on the embryogenic potential of in vitro cultured explants of the model plant Arabidopsis. The results showed that the GSH treatment resulted in SE induction in the explants that had been cultured on an auxin-depleted medium. The GSH-induced SE was shown to be associated with auxin biosynthesis and the accumulation of both the YUCCA transcripts ( YUC10/11 ) and the indolic compounds that are indicative for IAA. Inversely, 2,4-D treatment was found to increase the GSH level in the cultured explants and thus, complex interactions between the auxin and oxidative stress were assumed to control SE induction. The genetic regulators of auxin-induced SE, the LEC1 and LEC2 genes, were also up-regulated in the GSH-triggered SE. In contrast, the expression profiles of BBM and MYB118 were distinctly different in the GSH- than in 2,4-D-induced SE, which suggests differences in the genetic regulation of these alternative embryogenic pathways. Collectively, the study provides evidence that the GSH-imposed changes in the oxidative stress level affect auxin production, which triggers embryogenic development in the cultured explants.