Abstract:

MYB transcription factors represent a family of genes that include the conserved MYB DNA-binding domain, and they are widely involved in the regulation of plant development and secondary metabolism. In this study, Part of sequences of two MYB transcription factors was determined through the cDNA microarray hybridization and selection of cDNA library derived from tender shoots. The full-length cDNAs of the genes were obtained with RT-PCR and RACE, and they were 1 132 bp and 1 020 bp, named as CsMYB1 and CsMYB2 (GenBank accession No. HQ660373 and HQ660374), and contained ORFs of 879 bp and 675 bp encoding 292 and 224 amino acids,respectively. Sequences analysis showed that the deduced protein molecular weight of the two genes were 32.9 ku and 25.4 ku, and the proteins contained two conserved MYB domains near the N-terminus and a conserved C1 motif near the R3 domains. The deduced amino acid sequence of CsMYB1 and CsMYB2 from tea plant showed high identity with that of other plants, for instance CsMYB1 shared 57% homology with MYB1 of Gossypium hirsutum and CsMYB2 shared 75% homology with MYBC2 of Vitis vinifera. The result of real time-PCR analysis showed the two genes were expressed constitutively in all tissues with different expression levels, e.g. the relative expression level of CsMYB2 in leaf was hundred times higher than that in root. Additionally, shading enhanced CsMYB1 expression, while the treatment did not alter the expression level of CsMYB2.

Key words: tea plant (Camellia sinensis), MYB transcription factors, gene cloning, expression