Poly (ADP-ribose) polymerase inhibitor 3-methoxybenzamide enhances in vitro plant growth, microtuberization, and transformation efficiency of blue potato (Solanum tuberosum L. subsp. andigenum)

Abstract

Poly(ADP-ribose) polymerases (PARP) are involved in the regulation of plant growth and development, especially under stress conditions. These enzymes post-translationally modify target proteins by adding ADP-ribose polymers. This study presents the effect of PARP chemical inhibitor 3-methoxybenzamide (3 MB) on in vitro plant growth, microtuber formation, and Agrobacterium-mediated transformation of blue potato (Solanum tuberosum L. subsp. andigenum). The addition of 3 MB (0.2 to 0.6 mM) significantly increased the growth and microtuber formation of in vitro propagated plants. The highest gain in plant fresh weight, root mass, and microtuberization was observed in clonal propagation medium with 0.4 mM 3 MB. Transformation frequency of blue potato internodes increased to 43%, 2.7-fold over the non-treated control (16%), when 0.2 mM 3 MB was included in the culture medium during the whole process. The addition of 3 MB during Agrobacterium transformation did not affect transgene copy number in regenerated plants. Southern blot analyses and histochemical staining for s-glucuronidase activity confirmed the presence and expression, respectively, of the uidA transgene in plant tissues. From these results, it can be concluded that the inhibition of PARP activity can increase biomass production and transformation rates for genetic improvement of blue potato.