白桦反义CCoAOMT基因调控木质素生物合成

Antisense CCoAOMT Gene Regulates Lignin Biosynthesis in Betula platyphylla

白桦是我国北方重要的造林树种,但其中的高木质素含量严重制约了它作为造纸资源植物的开发利用。本文利用RACE技术获得了白桦咖啡酰辅酶A-3-O-甲基转移酶(CCoAOMT)基因全长ORF序列,并构建了白桦CCoAOMT基因的反义表达载体,通过农杆菌介导法将其导入到白桦中。PCR检测表明反义CCoAOMT基因已整合到白桦的基因组中。对转化植株的半定量PCR检测显示转基因株系的CCoAOMT基因表达量下降;Wiesner染色发现,与野生型相比,转基因植株木质素含量有所下降。对七年生的转基因白桦和野生型对照进行了化学成分分析,结果表明转基因白桦的苯醇抽提物和Klason木质素显著减少,聚戊糖含量升高。上述结果暗示BpCCoAOMT基因参与白桦木质素的合成,反义表达该基因后木质素含量减少,更易于去除。白桦CCoAOMT基因对木质素的合成起重要作用,这为培育低木质素含量的制浆新品种白桦奠定了基础。

Betula platyphylla is an important forestation tree species in northern China,but its high lignin content severely restricts its development and utilization as a papermaking resource plant.In this paper,the full-length ORF sequence of CCoAOMT(Caffeoyl-coenzyme A-3-O-methyltransferase)gene was obtained using RACE technology.The antisense CCoAOMT expression vector was constructed and transformed into B.platyphylla by Agrobacterium infection method.The molecular detection indicated that the CCoAOMT antisense gene had been successfully integrated into B.platyphylla.By semi-quantitative PCR analysis of the transgenic plants,the CCoAOMT gene expression of the transgenic lines was decreased.Compared to the wild type,by the Wiesner staining,the lignin content of the transgenic plants was decreased.Chemical compositions of seven-year-old transgenic and wild-type birch were analyzed.The phenyl alcohol extracts and Klason lignin of transgenic birch were significantly reduced,and the pentosan content was increased.The BpCCoAOMT gene plays an important role in the synthesis of lignin,which lays a foundation for the cultivation of a new species of birch with low lignin content.