Lignin genetic engineering for improvement of wood quality: Applications in paper and textile industries, fodder and bioenergy production

• Overview of lignin biosynthesis in dicots and monocots was presented.
• Biotechnological strategies to alter lignin content/composition in plants were reviewed.
• Various agroindustrial applications of lignin manipulation were discussed in detail.
• Results of own study pertaining to down-regulation of OMT were reported.
• Impacts of lignin manipulation on plants and environment to be addressed were presented.

Lignin, a complex racemic phenolic heteropolymer present in plant cell walls, plays crucial role in the adaptive strategies of vascular plants. But from agroindustrial perspective, lignin exerts a negative impact on the utilization of plant biomass in pulp and paper industry, textile industry, forage digestibility and production of biofuel. In this direction, lignin manipulation by genetic engineering approaches serves as a promising strategy. The researches on lignin biosynthesis, especially monolignol biosynthesis, have demonstrated that alteration of lignin content and composition can be attained to acquire economic and environmental benefits. Thus, transgenic plants with modified lignin content and composition can cope with large shifts in p-hydroxyphenyl/guaiacyl/syringyl lignin ratios and modified lignin can serve as improved feedstock for production of paper, biofibers, biofuels and forage. This review provides an overview of lignin genetic engineering in plants to yield new insights into the lignin biosynthetic pathway and quality amelioration of wood for efficient pulping, ease of forage digestibility, and production of biofiber and biofuel.