3.6 qRT-PCR verification
To confirm the reliability and validity of the results of RNA-sequencing, nine structural genes and their potential eight regulatory genes (Table S2) were randomly selected for qRT-PCR analysis under CK and UV-B stress conditions. As expected, the qRT-PCR profiles showed consistent results with RNA-sequencing, with 15 up-regulated and only two (GGT3 and IDH ) down-regulated expression under UV-B stress (Table S5, S7). In general, the expression of regulatory genes was more enhanced than that of structural genes. However, the expression levels of a structural genes, GSTU8 , were higher than their regulatory genes after UV-B stress (Fig. 4).