Over‐expression of bael quinolone synthase in tobacco improves plant vigor under favorable conditions, drought, or salt stress

Abstract

a b s t r a c tType III polyketide synthases (PKSs) catalyze the biosynthesis of various medicinally important secondary metabolites in plants, but their role in growth and stress response is unclear. Here, we overexpressed quinolone synthase (QNS) from bael in tobacco. QNS-overexpressing plants showed an overall increase in growth, photosynthetic efficiency and chlorophyll content compared to wild type plants. Second-generation (T 2 ) transgenic plants grew to maturity, flowered early and set viable seeds under favorable conditions without yield penalty. An increased accumulation of flavonoids, phenols and alkaloids was associated with higher tolerance to drought and salinity stress in transgenic plants. Thus, bael QNS seems to function as a positive regulator of plant growth and stress response, and could be potentially used for engineering plants tolerant to abiotic stress.

Overexpression of the ChVDE gene, encoding a violaxanthin de-epoxidase, improves tolerance to drought and salt stress in transgenic Arabidopsis

“…Gas exchange was measured with an open gas-exchange system (LI-6400, Li-Cor, Lincoln, NE, USA). Measurements of net photosynthetic rate (Pn), transpiration rate, and respiration rate were performed as previously described (Resmi et al 2015).…”

Genome-wide characterization of chalcone synthase genes in sweet cherry and functional characterization of CpCHS1 under drought stress

“…Overexpression in tobacco of a quinolone synthase gene, a participant in the flavonoid synthesis pathway, of bael increased the root length of the transgenic plants and improved drought tolerance (Resmi et al, 2015). In the present study, the growth of OE lines and WT tobacco seedlings under nature drought stress was evaluated (Figure 4A).…”

“…With regard to the salt tolerance of Populus euphratica, genes associated with the flavonoid synthesis pathway are differentially expressed, illustrating the importance of flavonoidrelated genes in participating in stress responses to abiotic stress (Zhang et al, 2019). The improvement of plant tolerance to drought and salt stress is related to the increase of flavonoids, phenolics, and alkaloids (Resmi et al, 2015). Similarly, overexpression of CpCHS1 increased the germination frequency of tobacco under experimentally induced drought stress, possibly by increasing flavonoid or alkaloid biosynthesis (Gu et al, 2020;Yang et al, 2020).…”

Spatiotemporal Metabolic Responses to Water Deficit Stress in Distinct Leaf Cell-types of Poplar

“…An increase in the degree of unsaturation of membrane lipids was associated with improved drought resistance and ROS neutralization (He and Ding, 2020a, Ullah et al, 2022, Zi et al, 2022), which highlights the potential role of fatty acid composition in poplar leaf palisade cells to help mitigate the L-WD stress-related consequences. Looking at leaf physiological parameters during WD stress (Supplementary Figure S1B), compared to E-WD, photosynthesis, leaf conductance, and transpiration rates were improved during L-WD, signifying the possible roles of flavonoids and fatty acids in neutralizing ROS (Jia et al, 2021, Resmi et al, 2015), leading to the observed improved leaf performance during L-WD stress.…”