Simultaneous Over-Expression of PaSOD and RaAPX in Transgenic Arabidopsis thaliana Confers Cold Stress Tolerance through Increase in Vascular Lignifications

Abstract

Antioxidant enzymes play a significant role in eliminating toxic levels of reactive oxygen species (ROS), generated during stress from living cells. In the present study, two different antioxidant enzymes namely copper-zinc superoxide dismutase derived from Potentilla astrisanguinea (PaSOD) and ascorbate peroxidase (RaAPX) from Rheum austral both of which are high altitude cold niche area plants of Himalaya were cloned and simultaneously over-expressed in Arabidopsis thaliana to alleviate cold stress. It was found that the transgenic plants over-expressing both the genes were more tolerant to cold stress than either of the single gene expressing transgenic plants during growth and development. In both single (PaSOD, RaAPX) and double (PaSOD + RaAPX) transgenic plants higher levels of total antioxidant enzyme activities, chlorophyll content, total soluble sugars, proline content and lower levels of ROS, ion leakage were recorded when compared to the WT during cold stress (4°C), besides increase in yield. In the present study, Confocal and SEM analysis in conjunction with qPCR data on the expression pattern of lignin biosynthetic pathway genes revealed that the cold stress tolerance of the transgenic plants might be because of the peroxide induced up-regulation of lignin by antioxidant genes mediated triggering.

Overexpression of OsTF1L, a rice HD‐Zip transcription factor, promotes lignin biosynthesis and stomatal closure that improves drought tolerance

“…Cavitation occurs when the xylem conduits break and a void is created. The void is initially filled with water vapour, but air can diffuse into it, forming an embolism (Stiller et al, 2005). Resistance to cavitation is known to be directly related to drought tolerance (Urli et al, 2013).…”

“…Many kinds of literature suggest that abiotic stress tolerance is connected to plant lignification. In A. thaliana, overexpression of PaSOD from Potentilla atrosanguinea and/or RaAPX from Rheum austral induces high lignification in inflorescence stems, conferring tolerance to salt and cold stress through upregulation of the lignin biosynthetic genes, PAL1 and PRXR9GE (Gill et al, 2010;Shafi et al, 2014). In maize (Zea mays), drought-tolerant inbred lines with high expression levels of lignin biosynthetic genes such as cinnamyl alcohol dehydrogenase (CAD), cytochrome protein 96A8 (COMT) or S-adenosyl-Lmethionine synthase (SAMS; Hu et al, 2009) show highly lignified shoots, suggesting a correlation between drought tolerance and shoot lignification.…”

Overexpression ofCaAPXInduces Orchestrated Reactive Oxygen Scavenging and Enhances Cold and Heat Tolerances in Tobacco

“…Previous studies demonstrated that ROS is one of the main factors causing oxidative damage to plants exposed to environmental stresses [29]. Antioxidant enzymes play a significant role in eliminating toxic levels of ROS, generated during stress from living cells [44]. In stressful conditions, plants generally increased the APX activity and the elevated activity level usually correlates with increased stress tolerance [3].…”

Transcriptome Analysis of the Biosynthesis of Anthocyanins in Begonia semperflorens under Low-Temperature and High-Light Conditions

“…In our research, the HL condition upregulated CAD and PER, which is expected to increase the lignin content; the expression of HCT and C3 H were also enhanced by the HL condition, which might indicate a change in the lignin composition from H lignin to G lignin. Lignin deposition in vascular bundles has been found to improve stress tolerance in Arabidopsis thaliana (L.) Heynh [44].…”