Achievements and prospects of genetic engineering in poplar: a review

Poplars play important role in global forestry. Besides being cultivated as an agro-forestry crop, they provide mankind with fuel wood, timber wood, plywood, sports goods, raw material for paper industry and recently, they are being used as a potential biofuel source. However, a number of biotic and abiotic stresses reduce poplar yield and productivity. Further, there is a strong felt need of paper and pulp industries to have reduced lignin content or modified lignin composition of poplar wood, which will assist in manufacturing better quality paper using less environmentally hazardous chemicals. Because of the non-availability of resistance donor sources and long generation period, conventional breeding could achieve success in genetic improvement of poplars. To circumvent these bottlenecks, genetic engineering interventions have been applied for poplar crop improvement. With the availability of Populus trichocarpa genome sequence in public domain, now numerous genes and transcription factors governing various metabolic pathways got identified, which can be targeted for genetic engineering for poplar improvement. Genome editing technology has really expedited the pace of poplar improvement programmes. This review provides an insight into various research efforts focused on poplar genetic engineering for improvement of silviculturally important traits.