Cloning and Sequence Analysis of Partial Fragments of Critical Genes Involved in Flax Lignin Synthesis

Abstract

Flax is an important bast fiber crop. High content of lignin in the fiber greatly reduces fiber quality after degumming. The cDNA fragments of the critical genes involved in flax lignin biosynthesis were amplified from the flax bark mRNA by RT-PCR using the degenerate primers designed from conservative regions of existing homologous gene sequences. Thirteen distinct bands were obtained from agarose gel electrophoresis. The fragments from these bands were ligated to T-vector. The recombinant plasmids were transformed into E. coli. Five to eight separate clones transformed from each band were chosen to be sequenced. Sequence analysis and GenBank BLAST revealed eight new sequences, including two CCoAOMT (EF214740, EF214741) genes, three 4CL (EF214737, EF214738, EF214739) genes, and three F5H (EF214745, EF214746, EF214747) genes. This implies that these are multi-gene families for the genes encoding the three key enzymes in flax lignin biosynthesis. These partial cDNA sequence data are useful for cloning full length cDNA and characterizing the functions and regulations of the critical genes involved in flax lignin biosynthesis.