Optimization of callus culture conditions for Taxus chinensis var. mairei and effect of gene expression of Taxol accumulation.

Objective The callus induction and subculture condition of Taxus chinensis var.mairei were optimized in the experiment.High Taxol-yielding callus was obtained,and the correlation between expression patterns of Taxol biosynthesis related genes and Taxol content was defined.Methods Optimal hormone composition and concentration for induction and subculture of callus derived from T.chinensis var.mairei were briefly studied.The growth characteristics and Taxol content of calli derived from T.chinensis var.mairei(including vitro embryos,juvenile stems,and juvenile buds),T.media(vitro embryos) and T.brevifolia(vitro embryos) were compared.Expression of Taxol biosynthesis related genes in the above different calli was analyzed.Results MS Medium supplemented with 3.0 mg/L 2,4-D was suitable for callus induction of T.chinensis var.mairei,the induced rate is up to 92%.Subculture medium supplemented with 2.0 mg/L 2,4-D and 1.0 mg/L 6-BA was suitable for Taxol biosynthesis of T.chinensis var.mairei.Under the same culture conditions,Taxol content of calli derived from vitro embryos of T.chinensis var.mairei was the highest and had reached 0.027% of callus dry weight.The genes of Taxol biosynthesis related enzymes— geranylgeranyl diphosphate synthase(GGPPS),taxadiene synthase(TASY),taxane-10β-hydroxylase(T10βH),10-deacetylbaccatinⅢ-β-10-O-acetyltransferase(DBAT),phenylalanine aminomutase(PAM),and 3′-N-debenzoyltaxol N-benzoyltransferase(DBTNBT),were expressed at the high level in the high Taxol-producing callus.Conclusion Vitro embryos can be used as the first choice explant source to obtain high Taxol-yielding callus.To improve gene expression level of GGPPS,TASY,T10βH,DBAT,PAM,and DBTNBT would promote Taxol biosynthesis.