Carotenoids are involved in the formation of plant leaf color as well as photosystem photoprotection.  This study showed that blue light significantly induced up-regulation of the total carotenoid content in the inner leaves of orange-head Chinese cabbage (OHCC).  Furthermore, the transcriptomic analysis revealed that blue light treatment induced up-regulation of genes in photosynthesis (BrHY5-2, BrCOP1 and BrDET1) and the methylerythritol 4-phosphate pathways (BrGGPS, BrDXS and BrHDR) upstream of the carotenoid metabolic pathway.  Carotenoid metabolomic analysis revealed that the accumulation of several orange and red carotenoids (lycopene, zeaxanthin, β-carotene, lutein, and β-cryptoxanthin) after blue light treatment contributed to the deepening of the leaf coloration, suggesting that short-term blue light treatment could be used to boost nutritional quality.  The light signal gene BrHY5-2 participated in the blue light-induced transcriptional regulation of carotenoid biosynthesis in OHCC.  Overexpression of BrHY5-2 in Arabidopsis significantly increased the total carotenoid content and the sensitivity to blue light.  The above findings revealed new insights about blue-light-induced carotenoid synthesis and accumulation in OHCC lines.  They suggested a new engineering approach to increase the nutritional value of vegetables.

The objective of this study was to evaluate the effects of low ambient temperature (LAT) and dietary vitamin C (VC) supplementation on pulmonary vascular remodeling (PVR) and the relative expression of hypoxia inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF) and its receptor 2 (VEGFR-2) mRNA of lungs in 21-d-old broilers. 400 1-d-old male Cobb broilers were assigned randomly to 4 treatments as follows for 21 d: 1) LAT and a basal diet; 2) LAT and a basal diet supplemented with 1 000 mg kg–1 VC (LAT+VC); 3) normal ambient temperature (NAT) and a basal diet; 4) NAT and a basal diet supplemented with 1 000 mg kg–1 VC (NAT+VC). Each treatment was composed of 10 replicates of 10 birds per replicate. Samples of lung were collected after the broilers were killed at d 21. LAT increased the ratio of vessel wall area to vessel total area (WA/TA, %) and mean media thickness in pulmonary arterioles (mMTPA, %) (P<0.05). Dietary VC supplementation decreased mMTPA (P<0.05), but had no effect on the WA/TA. LAT increased (P<0.05) the relative mRNA expression of HIF-1α, VEGF and VEGFR-2, while adding VC to the diet could decrease (P<0.05) their relative mRNA expression. A significant positive correlation existed between the level of VEGF mRNA expression and the value of WA/WT (P<0.05) or mMTPA (P<0.05). These results suggested LAT resulted in pulmonary vascular remodeling, and the increase of HIF-1α, VEGF and VEGFR-2 mRNA expression, and dietary VC supplementation can alleviate pulmonary vascular remodeling in broiler by affecting these gene expression.