cDNA encoding caffeoyl CoA O-methyltransferase (CCoAOMT) from Chinese white poplar ( Populus tomentosa Carr.) was cloned by RT-PCR and sequenced. Northern analysis displayed that the CCoAOMT was expressed specifically in the developing secondary xylem and its expression was coincident with lignification. The antisense CCoAOMT cDNA was transformed into P. tremula×P. alba mediated by Agrobacterium tumefaciens (Smith et Townsend) Conn. Transgenic plants were identified with PCR, PCR-Southern and Southern analysis. Lignin content in 5- to 6-month-old transgenic plants was measured. One of the transgenic lines had significant reduction of 17.9% in Klason lignin content as compared with that of untransformed poplar. The results demonstrate that antisense repression of CCoAOMT is an efficient way to reduce lignin content for improving pulping property in engineered trees.
毛白杨CCoA0MT cDNA片段的克隆与转基因杨木质素含量的调控
魏建华 赵华燕 张景昱 刘惠荣 宋艳茹*
（中国科学院植物研究所，北京100093）
摘要： 用RT-PCR方法从毛白杨（Populus tomentosa Carr）中克隆了CC0AOMT 基因的cDNA 片段，并对其序列进行了分析。Northern杂交表明该基因在毛白杨正在木质化的次生木质部高水平表达，且与木质化进程同步。构建了该基因反义表达载体，根癌土壤杆菌（Agrobacterium tumefaciens ( Smith et Townsend)Conn）介导转化杂交杨（欧洲山杨>银白杨，P.tremulaxP.alba）。采用PCR,PCR-Southern及Southern杂交对获得的转基因植株进行分子检测，并测定移栽5-6 个月的转基因植株的Klason木质素含量，其中一个转基因株系的Klason木质素含量比未转基因对照杨树下降17.9%。结果表明利用反义RNA技术对杨树CCoAOMT 基因的表达可以降低转基因植株的木质素含量，达到改善其造纸性能的目的。
关键词： RT-PCRGP；毛白杨CCoAOMT；反义RNA；木质素
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