De novo Transcriptome Sequencing of MeJA-Induced Taraxacum koksaghyz Rodin to Identify Genes Related to Rubber Formation

Increase in the consumption of natural rubber (NR) has necessitated the identification of alternative sources of NR. The quality of NR produced by Taraxacum koksaghyz Rodin (TKS) is comparable to that from Hevea brasiliensis (H.brasiliensis), and therefore, TKS is being considered as an alternative source of NR. Here, we sequenced the TKS root transcriptome after wild TKS seedlings were treated with methyl jasmonate (MeJA) for 0, 6, and 24 h. The clean reads generated for each experimental line were assembled into 127,833 unigenes. The Kyoto encyclopedia of genes and genomes pathway prediction suggested that methyl jasmonate regulated secondary metabolism in TKS. Differential expression analysis showed that the expression of HMGCR, FPPS, IDI, GGPPS, and REF/SRPP increased with methyl jasmonate treatment. Interestingly, differential expression analysis of the jasmonate (JA)-related transcription factors (TFs), indicated that certain genes encoding these transcription factors (namely, bHLH, MYB, AP2/EREBP, and WRKY) showed the same expression pattern in the lines treated for 6 h and 24 h. Moreover, HMGCR was up-regulated in the transgenic seedlings overexpressing DREB. We predicted that methyl jasmonate regulated secondary metabolism and affected rubber biosynthesis via the interaction of the JA-related TFs with genes associated with rubber biosynthesis in TKS.