Altered physiological responses of LlaNAC gene of Lepidium latifolium over-expressing tobacco plants

Abstract

Four tobacco lines over-expressing LlaNAC (FJ423495) gene have been assessed for various parameters like abiotic stress response, phytochemical constituents, biomass composition, response to elevated carbon dioxide (CO2), etc. All the analyses have been carried out in T2 generation of the transgenic plants with proven genetic stability. In response to the heat and drought stress, the accumulation of antioxidant enzymes elevated up to 2.5-fold. Photosynthetic pigments, i.e., Chl a, Chl b and xanthophylls, and phenolics in the transgenic lines were found significantly (two–fourfold) enhanced in comparison to wild-type (WT) plants. The transgenic lines were also shown capturing 5–10 times more CO2 from the environment, which presumably gets accumulated as biomass. However, ratio of dry weight to fresh weight was slightly in favor of the WTs. Cellulose, hemi-cellulose and lignin contents in stem and leaves of each of the transgenic lines varied, and overlapped with the lignocellulosic contents of the WT plants. In conclusion, LlaNAC gene shows promise for exploitation in design of the future crops with various end uses.