Field assessment of CaMsrB2 transgenic lines in a drought stress environment

Abstract

Two drought-tolerant transgenic rice lines, L-8 (single copy) and L-23 (two copy), expressing the Capsicum annuum methionine sulfoxide reductase B2 (CaMsrB2) gene were selected for stress tolerance phenotyping under drought stress conditions. The two transgenic lines were selected on the basis of laboratory experiments and for performing well against drought. Field assessment of CaMsrB2 transgenic lines L-23 and L-8 in a drought stress environment was conducted. For the assessments, small plots were prepared at the Department of Botany of the University of Karachi to test the physiological response of transgenic lines. Relative water content, quantum yield (Fv/Fm ratio), photochemical quenching (qP) photosynthetic pigments, and performance index were high in transgenic lines compared to the wild type (WT). Antioxidant enzymes as represented by catalase and superoxide dismutase activities were increased while H 2 O 2 production was decreased in transgenic lines compared to the WT. The results are discussed with special reference to physiological response of the transgenic lines against drought in field conditions.

Physiological Aspects of Germination and Early Seedling Establishment of Pleurotus sajor-caju Glyceraldehyde-3-Phosphate Dehydrogenase Expressing Transgenic Rice in Saline Environment

“… Thermal images were taken by FLIR camera model SC620. An autogenerated model for the comparison of temperature and moisture content of the PsGPD expressing transgenic rice (T5) is also presented (Siddiqui et al, 2015 ). LMC, leaf moisture content.…”

“…Most transgenic lines that exhibit salt tolerance genes have been tested during plant growth stage. However, plants during germination and early seedling are more sensitive to abiotic stress than those during growth (Cho et al, 2014 ; Siddiqui et al, 2015 ). In this study, PsGPD expressing transgenic rice (T5) produced a substantially better final percent germination and seedling growth than WT in a salt stress environment.…”

“…After germination, as the growth of young seedlings proceeds, chlorophyll biosynthesis is the primary and mandatory physiological mechanism which can be significantly inhibited by a saline environment (Kwon et al, 2009 ; Cho et al, 2014 ; Siddiqui et al, 2015 ). PsGPD expressing transgenic rice responded to salt stress by less drastically scavenging porphyrin intermediates, resulting in increased chlorophyll content compared with WT against salt stress ( Figure 4 ).…”

“…Downregulation of chlorophyll biosynthesis during the greening process by salt stress is due to decreased activity of enzymes involved in the pathway. Reduced enzymatic activity is attributed to the downregulation of gene expression in salt-stressed seedlings (Siddiqui et al, 2015 ). Against such environmental extremes, transforming rice with salt-resistant genes effectively meets present and future food security needs.…”