3.6 DEGs from carotenoid and ABA metabolism
The carotenoid pathway genes, such as phytoene synthase (PSY ),β -carotene hydroxylase (BCH ), and carotenoid β -ring hydroxylase of cytochrome P450 family (CYP450 -BCH), were up-regulated in both red and blue light treatments with the exception ofζ -carotene desaturase (ZDS) and lutein deficient 1-like(Lut1) with lower expression levels in blue light treatment (Figure 6). In addition, the important carotenoid cleavage geneNCED , the key cleavage gene in abscisic acid biosynthesis, was up-regulated in both the light treatments but higher in red light treatment (Figure 6). On the other hand, ABA-8’ hydroxylase , which is the first step in the ABA catabolism route was highly up-regulated only under red light treatment but down-regulated (to -1.88-fold change) in blue light treatment. There were three unigenes identified as ABA-receptors pyrabactin resistance like gene (PYL-4,5,8 ) of which two of them (PYL 5,8 ) were down-regulated to 2-3 folds lower in response to blue light (Figure 6b). ABA insensitive (ABI5 ) TF was found in similar levels in both the light treatments.
The related gene expression obtained from qRT-PCR analyses for all the key anthocyanin and ABA biosynthetic genes discussed above (CHS, F3’H, F3’5’H, DFR, ANS, UFGT, MYBA1, NCED ) and identified unigenes from RNA-seq dataset were correlated which showed a higher correlation R2 values of 0.9 with red vs control and 0.8 with blue vs control contrasts (Figure S7).