Isolation And Transcript Expression Of 4-Coumarate Coenzyme A Ligase (4CL) Gene Family In Betula Platyphylla Suk.

4-Coumarate:CoA ligase (4CL) the key enzyme of phenylpropanoid pathway which provides the precursors for a large variety of important plant secondary products for plant, such as flavonoids, lignin, et al. In the lignin biosynthesis,4CL catalyzes caffeic acid,p-coumaric acid, sinapic acid and ferulic acid into corresponding CoA.Two Bpl4CL genes with length of 2069bp and 1974bp were cloned by RT-PCR and RACE. The ORF were 1629bp and 1656bp encoding 543 and 552 amino acids, respectively.The amino acids sequences and structures of Bpl4CLs were analyzed using bioinformatics software. Bp14CL3 appears differences in the stable motifs of most 4CLs, representing its new function.We get the DNA sequences of Bp14CLs:the length of Bpl4CL1 is 1755bp including a 126bp intron; that of Bpl4CL2 is 3185bp with 318bp and 798bp intron; that of Bpl4CL3 is 3280bp with 758bp,173bp and 283bp introns.In order to select a proper internal control gene for real-time PCR in Betula platyphylla, expression stability of four housekeeping genes which were 18S rRNA, Actin, Ubiquitin and Tubulin respectively in different tissues and periods were analyzed,. The results showed that the expression of 18S rRNA, Actin and Ubiquitin were stable, so they can be used as internal control genes to analyze expression level of target genes in B. platyphylla.With Actin as the internal control gene, the real-time PCR was used to detect the expression pattern of Bpl4CLs: the expression level of Bpl4CL3 was higher in the mature tissues, but the level of Bp14CL1 is higher in young tissues than that of in the mature tissues. The expression level of Bpl4CL2 was highest in male flower.