关键词: 茶树, 细胞色素P450, 克隆, 亚家族基因, 胁迫, 表达相反

Abstract: The full cDNA sequences of cytochrome P450 genes, CYP71A26 and CYP71B34 were cloned from Camellia sinensis Tieguanyin leaves based on NCBI transcriptome database. The complete cDNA lengths of CYP71A26 and CYP71B34 were 1β879βbp and 1β764βbp, containing the open reading frames (ORF) of 1β539βbp and 1β533βbp, which encoded 513 and 511 amino acids, respectively. The alignment of amino acid sequences showed 42.47% of conservation between CYP71A26 and CYP71B34, which indicated that the two genes belonged to different subfamilies. The structure analysis showed that both CYP71A26 and CYP71B34 contained the classic P450 structure domains, such as helix C, helix I, helix K, Meander and heme binding domain. Phylogenetic tree analysis illustrated that there were two branches of molecular evolution for the two genes with different genetic relationship. Via predicting of their tertiary structures and functional domains, the results indicated that both genes were constituted by β-pleated structure in N-terminal, α-helix structure in C-terminal, and had a P450 protein structure domain (Pfam domain). qRT-PCR results showed that the expression of two genes in leaves showed opposite trends under pest damage treatments. Moreover, the decrease of CYP71A26 and increase of CYP71B34 in expression levels were detected under cold or thermal stresses. In total, CYP71A26 and CYP71B34 genes were respond to biotic (like pest) and abiotic (like temperature) stresses, but the changing trends of the two genes were opposite, which might be correlated with opposite regulation systems.

Key words: Camellia sinensis, cytochrome P450, clone, subfamily gene, stress, expression opposite