Transcriptome analysis reveals effects of red and blue light-emitting diodes (LEDs) on the growth, chlorophyll fluorescence and endogenous plant hormones of potato (Solanum tuberosumL.) plantlets cultured in vitro

Red and blue light illumination has been reported to significantly affect plantlet growth. Potato is an important food and feed crop in the world and potato plantlet cultured in vitroplays an important role in potato production. However, few studies have documented the effects of red and blue light on the growth of potato plantlets revealed at the transcriptome level. The objective of this study was to determine the growth and physiological responses of potato plantlets cultured in vitrounder monochromatic red (RR), monochromatic blue (BB) as well as combined red and blue (RB) LEDs using the RNA-Seq technique. In total, 3150 and 814 differentially expressed genes (DEGs) were detected in potato plantlets under RR and BB, respectively, compared to RB (used as control). Compared to the control, the DEGs enriched in “photosynthesis” and “photosynthesis-antenna proteins” metabolic pathways were up-regulated and down-regulated by BB and RR, respectively, which might be responsible for the increases and decreases of maximum quantum yield (Fv/Fm), photochemical quantum yield (ϕPSII), photochemical quenching (qp) and electron transfer rate (ETR) in BB and RR, respectively. Potato plantlets exhibited dwarfed stems and extended leaves under BB, whereas elongated stems and small leaves were induced under RR. These dramatically altered plantlet phenotypes were associated with variable levels of endogenous plant hormones gibberellin (GAs), indoleacetic acid (IAA) and cytokinins (CKs), as assessed in stems and leaves of potato plantlets. In addition, monochromatic red and blue LEDs trigged the opposite expression profiles of DEGs identified in the “plant hormone signal transduction” metabolic pathway, which were closely related to the endogenous plant hormone levels in potato plantlets. Our results provide insights into the responses of potato plantlets cultured in vitroto red and blue LEDs at the transcriptomic level and may contribute to improvements in the micro-propagation of potato plantlets cultured in vitrofrom the light spectrum aspect.