Red–Blue Light Promotes Potato Minituber Yield by Regulating Hormone Networks and Senescence-Related Pathways

Aeroponics is an important approach for the production of virus-free seed potatoes. The propagation efficiency of aeroponically grown potatoes is affected by light conditions. However, the effects of different supplemental light conditions on potato yield and their underlying mechanisms remain unclear. Here, multiple light conditions are applied to investigate their influences on potato minituber production. The results show that red–blue light supplementation significantly increases plant yield. Physiologically, it enhances chlorophyll and carotenoid contents, thereby increasing net photosynthetic rate and CO2 utilization efficiency. Red–blue light temporally regulates hormone balance by increasing the GA/ABA ratio at the early stage to promote vegetative growth, and maintaining higher trans-zeatin content at the late stage, potentially sustaining cell division. These synergistic effects may enhance yield by delaying senescence and prolonging the tuberization period. Transcriptomic analysis reveals that red–blue light treatment enriches pathways related to hormone signaling, senescence-associated, and zeatin biosynthesis at the late growth stage, and upregulates key tuberization genes (StSP6A, StSP3D, StFTL1), which may be associated with tuber formation. Red–blue light treatment optimizes photosynthesis, remodels hormone networks, and induces temporal transcriptional reprogramming, while also increasing the yield of virus-free seed potatoes in aeroponic culture. This study provides theoretical and technical support for the efficient aeroponic breeding of virus-free seed potatoes.