Overexpression of AtDREB1D transcription factor improves drought tolerance in soybean

Abstract

Drought is one of the major abiotic stresses that affect productivity in soybean (Glycine max L.) Several genes induced by drought stress include functional genes and regulatory transcription factors. The Arabidopsis thaliana DREB1D transcription factor driven by the constitutive and ABA-inducible promoters was introduced into soybean through Agrobacterium tumefaciens-mediated gene transfer. Several transgenic lines were generated and molecular analysis was performed to confirm transgene integration. Transgenic plants with an ABA-inducible promoter showed a 1.5- to two-fold increase of transgene expression under severe stress conditions. Under well-watered conditions, transgenic plants with constitutive and ABA-inducible promoters showed reduced total leaf area and shoot biomass compared to non-transgenic plants. No significant differences in root length or root biomass were observed between transgenic and non-transgenic plants under non-stress conditions. When subjected to gradual water deficit, transgenic plants maintained higher relative water content because the transgenic lines used water more slowly as a result of reduced total leaf area. This caused them to wilt slower than non-transgenic plants. Transgenic plants showed differential drought tolerance responses with a significantly higher survival rate compared to non-transgenic plants when subjected to comparable severe water-deficit conditions. Moreover, the transgenic plants also showed improved drought tolerance by maintaining 17-24 % greater leaf cell membrane stability compared to non-transgenic plants. The results demonstrate the feasibility of engineering soybean for enhanced drought tolerance by expressing stress-responsive genes.

GmWRKY54 improves drought tolerance through activating genes in abscisic acid and Ca2+ signaling pathways in transgenic soybean

“…DREB1, also known as CBF (C‐repeat binding factor), is responsible for cold tolerance (Gehan et al ., ). Recent research has indicated that DREB1D/CBF4 also enhances drought tolerance in plants (Haake et al ., ; Guttikonda et al ., ). However, the two DREB1Ds may not be the direct targets of GmWRKY54, as GmWRKY54 could not bind to their promoter regions.…”

Salt tolerance conferred by expression of a global regulator IrrE from Deinococcus radiodurans in oilseed rape

“…For example, overexpression of DREB1A resulted in severe growth retardation under normal growing conditions (Guttikonda et al 2014). However, no adverse effects on growth and agronomic characteristics were found in transgenic PMI corn and wheat (Wright et al 2001;Negrotto et al 2000;Wang et al 2000), sugar beet (Joersbo et al 1998) and rice (Lucca et al 2001;He et al 2006).…”

Correlation between differential drought tolerability of two contrasting drought-responsive chickpea cultivars and differential expression of a subset of CaNAC genes under normal and dehydration conditions

“…In addition, leaf-related traits, such as stomata aperture and leaf cell membrane stability, have been also well-known traits that influence drought tolerance (Kaiser, 2009; Manavalan et al, 2009; Guttikonda et al, 2014; Ha et al, 2014). Overexpression of SNAC1 gene in rice was shown to enhance stomatal closure, thereby contributing to improved drought tolerance of transgenic plants (Hu et al, 2006).…”