尾叶桉COMT和CCoAOMT基因定向调控木质素单体合成的烟草转化研究

Directional Regulation of Lignin Monomer Synthesis in Tobacco by Using COMT Gene and CCo AOMT Gene of Eucalyptus urophylla

目的：利用烟草遗传转化体系,研究尾叶桉（Eucalyptus urophylla）咖啡酸氧甲基转移酶基因（Eu COMT）和咖啡酰Co A氧甲基转移酶基因（Eu CCo AOMT）对木质素单体合成的定向调控效果。方法：分别利用Eu COMT的正义片段、Eu CCo AOMT的全长RNAi片段进行单基因和二价基因的烟草转化研究,并对转基因烟草植株中目标基因表达水平、木质素和纤维素的含量、茎部解剖结构及木质素单体含量进行检测。结果：分别获得了转基因植株C-S（转Eu COMT正义片段）、CR（转Eu CCo AOMT全长RNAi片段）、C-CR（Eu COM和Eu CCo AOMT二价基因转化）。烟草中转入的正义Eu COMT的片段能够正常表达,而Eu CCo AOMT的全长RNAi片段对烟草CCo AOMT基因引发了强烈的抑制。转基因烟草的生长形态、木质素、纤维含量及解剖结构与野生型无显著差异。转基因植株C-S中G木质素含量升高17.72%,S/G值降低17.99%;CR中S/G值升高61.62%,CCR中G木质素降幅达到57.38%,S/G比值升幅达到114.94%。结论：抑制CCo AOMT对G木质素合成具有显著的抑制效果,Eu COMT和Eu CCo AOMT二价基因转化对S/G比值的定向调控效果最为理想。

Directional regulation effect of Eucalyptus urophylla COMT gene and CCo AOMT gene on lignin monomer synthesis were studied by tobacco transformation system. Transgenic plants C-S（ contain sense Eu COMT fragment）,CR（ contain full-length RNAi fragment of Eu CCo AOMT）,C-CR（ contain Eu COM and Eu CCo AOMT dual-gene） were obtained,and the expression of sense Eu COMT fragment was detected in transgenic tobacco,while the RNAi fragment of Eu CCo AOMT caused strong inhibition on tobacco CCo AOMT gene. The growth morphology,lignin content,fiber content and anatomical structure of transgenic tobacco were not significantly different from those of wild type. The results of lignin monomer detection showed the G lignin content increased17. 72% and S/G ratio decreased 17. 99% in transgenic plant C-S,meanwhile the S/G ratio increased 61. 62%in CR. In C-CR,G lignin content decreased 57. 38%,and S/G ratio increased 114. 94%. The result showed that the inhibition of CCo AOMT had a significant inhibitory effect on lignin synthesis in G,and the dual-gene transformation of Eu COMT and Eu CCo AOMT showing the best directional regulation effect.