Molecular Biology Laboratory, Department of Biochemistry and Molecular Biology, University of Dhaka, Dhaka-1000, Bangladesh.
Dept. Plant Biotechnology IRNAS-CSIC P.O. Box 1052, 41080-Seville, Spain.
Sci Rep. 2017 Jan 4;7:39984. doi: 10.1038/srep39984.
Lignin, a cross-linked macromolecule of hydrophobic aromatic structure, provides additional rigidity to a plant cell wall. Although it is an integral part of the plant cell, presence of lignin considerably reduces the quality of the fiber of fiber-yielding plants. Decreasing lignin in such plants holds significant commercial and environmental potential. This study aimed at reducing the lignin content in jute-a fiber crop, by introducing hpRNA-based vectors for downregulation of two monolignoid biosynthetic genes- cinnamate 4-hydroxylase (C4H) and caffeic acid O-methyltransferase (COMT). Transgenic generations, analyzed through Southern, RT-PCR and northern assays showed downregulation of the selected genes. Transgenic lines exhibited reduced level of gene expression with ~ 16-25% reduction in acid insoluble lignin for the whole stem and ~13-14% reduction in fiber lignin content compared to the control lines. Among the two transgenic plant types one exhibited an increase in cellulose content and concomitant improvement of glucose release. Composition of the lignin building blocks was found to alter and this alteration resulted in a pattern, different from other plants where the same genes were manipulated. It is expected that successful COMT-hpRNA and C4H-hpRNA transgenesis in jute will have far-reaching commercial implications leading to product diversification and value addition.
木质素是一种具有疏水性芳香结构的交联大分子，为植物细胞壁提供了额外的刚性。尽管它是植物细胞的一个组成部分，但木质素的存在大大降低了纤维植物纤维的质量。降低此类植物中的木质素具有重要的商业和环境潜力。本研究旨在通过引入基于 hpRNA 的载体下调两个单木质素生物合成基因-肉桂酸 4-羟化酶（C4H）和咖啡酸 O-甲基转移酶（COMT），从而降低黄麻（一种纤维作物）中的木质素含量。通过 Southern、RT-PCR 和 northern 分析检测到转基因世代中选定基因的下调。与对照系相比，转基因系表现出较低的基因表达水平，整个茎的酸不溶性木质素减少了约 16-25%，纤维木质素含量减少了约 13-14%。在两种转基因植物类型中，有一种表现出纤维素含量的增加和葡萄糖释放的协同改善。木质素结构单元的组成被发现发生了变化，这种变化导致了一种不同于其他操纵相同基因的植物的模式。预计黄麻中 COMT-hpRNA 和 C4H-hpRNA 的成功转基因将具有深远的商业意义，导致产品多样化和附加值增加。
