Transcriptomics combined with physiology reveals the effect of different light qualities on the development of Fritillaria cirrhosa in the Qinghai Tibet Plateau

Fritillaria cirrhosa, a high-altitude plant susceptible to environmental conditions, commonly grows beneath bushes and is categorized as shade-tolerant. The development and secondary metabolite synthesis of F. cirrhosa are significantly influenced by light quality. This study investigated the physiological responses and molecular mechanisms of F. cirrhosa to different light qualities using colored agricultural film treatments. The results demonstrated that the number of sprout tumbles in F. cirrhosa was significantly reduced by the different colored film treatments. The quality of the fruits exhibited a notable improvement under the blue film (BF) treatment compared to the other groups (P < 0.05). The guanosine content showed a substantial increase of 440.55% under the BF treatment relative to the white film (WF), and the uracil content significantly increased by 171.27% in BF and by 296.38% in the green film (GF). Leaf thickness was considerably higher under the GF treatment than under the other conditions. F. cirrhosa demonstrated enhanced photosynthesis when exposed to BF and GF (P < 0.05). The transcriptome results indicated 75 differentially expressed genes (DEGs) involved in photosynthesis-related pathways that regulated photosynthetic utilization efficiency by encoding photosynthetic antenna proteins (Lhca and Lhcb), photosynthetic electron transporters (PsbE, PsbP, and PetA), and carbon fixation enzymes (PPC, PPDK, and rbcL). Most these genes were upregulated in BF and GF, improving the light energy conversion efficiency, photosynthetic electron transport rate, and CO2 assimilation ability in F. cirrhosa. Notably, 44 DEGs involved in flavonoid metabolic pathways (PAL, HCT, 4CL, CHS, CHI, and ANS) showed higher expression levels in WF and yellow film (YF), differing in the regulation of the photosynthetic pathway. This suggested that F. cirrhosa can utilize nutrients produced by photosynthesis more efficiently under BF and GF, and does not require excessive amounts of flavonoids for maintaining cell homeostasis. These results offer valuable insights into the transcriptional changes and molecular processes occurring in F. cirrhosa in response to different light qualities and provide a basis for research on the mechanisms of photo regulation, cultivation, and ecological adaptation in F. cirrhosa.