Red and Blue Light-Emitting Diodes Significantly Improve in vitro Tuberization of Potato (Solanum tuberosum L.)

The tuberization phenomenon in potatoes (Solanum tuberosum L.) is a highly synchronized morphophysiological process occurring on the underground stolons under the influence of various intrinsic and extrinsic factors. This involves the participation of the phytochrome sensory system, transport of sucrose from source to stolon, and several regulatory pathways including tuber-inducing hormone biosynthetic lipoxygenase (StLOX1) gene and major calcium-mediated signaling pathway genes (StCDPK and StCaM1). This study was aimed to explore the impacts of distinctive qualities of the light-emitting diode (LED) light with a specific wavelength on in vitro tuberization of potato. Single nodal segments of potato ‘Kufri Jyoti’ were incubated in vitro on the growth medium at a temperature of 22 ± 2 °C and exposed to various combinations of red (R) and blue (B) LED light. The results showed that the combination of 30% red + 70% blue LED light (R₃₀B₇₀) significantly shortened the tuber induction period, increased the number of tubers, and their yield compared with these parameters in the tissues exposed to the white light (W₁₀₀). The induction of the in vitro tuberization correlated with the enhanced expression of the major tuberizing pathway genes, including the lipoxygenase (StLOX1), calmodulin (CaM1), and calcium-dependent protein kinase (StCDPK). The current study indicated that the combination of red and blue LED lights at R₃₀B₇₀ is the best spectrum for effective in vitro tuberization of potatoes.