Stress-Inducible Overexpression of SlDDF2 Gene Improves Tolerance against Multiple Abiotic Stresses in Tomato Plant

Abstract

Dehydration-responsive element-binding protein 1 (DREB1)/C-repeat binding factor (CBF) family plays a key role in plant tolerance against different abiotic stresses. In this study, an orthologous gene of the DWARF AND DELAYED FLOWERING (DDF) members in Arabidopsis, SlDDF2, was identified in tomato plants. The SlDDF2 gene expression was analyzed, and a clear induction in response to ABA treatment, cold, salinity, and drought stresses was observed. Furthermore, two transgenic lines (SlDDF2-IOE#6 and SlDDF2-IOE#9) with stress-inducible overexpression of SlDDF2 under Rd29a promoter were generated. Under stress conditions, the gene expression of SlDDF2 was significantly higher in both transgenic lines. The growth performance, as well as physiological parameters, were evaluated in wild-type and transgenic plants. The transgenic lines showed growth retardation phenotypes and had higher chlorophyll content under stress conditions in plants. However, the relative decrease in growth performance (plant height, leaf number, and leaf area) in stressed transgenic lines was lower than that in stressed wild-type plants, compared with nonstressed conditions. The reduction in the relative water content and water loss rate was also lower in the transgenic lines. Compared with wild-type plants, transgenic lines showed enhanced tolerance to different abiotic stresses including water deficit, salinity, and cold. In conclusion, stress-inducible expression of SlDDF2 can be a useful tool to improve tolerance against multiple abiotic stresses in tomato plants.

Genomic and Transcriptomic Approaches to Developing Abiotic Stress-Resilient Crops

“…Interestingly, this gene rendered plants highly insensitive to ABA and proposed to regulate abiotic stress tolerance possibly in an ABA-independent manner [53]. Similarly, tomato overexpression of the transgenic line of dwarf and delayed flowering 2 (SlDDF2) under stress-inducible RD29a promoter showed better growth performance and tolerance under abiotic stresses including salinity and drought [54]. Overall, these studies suggested that identification of the key gene inducible under multiple stresses, and its overexpression in plants, is an effective strategy for developing multi-stress resilient crops.…”

The Promising B−Type Response Regulator hst1 Gene Provides Multiple High Temperature and Drought Stress Tolerance in Rice

“…Recently, some favorable genes were found to overcome multiple stress tolerances (salinity, drought, high temperature, and osmotic stress) in several species, such as Arabidopsis, beans, tomatoes, and wheat [25][26][27][28]. Although those genes offer crucial insights into multiple stress tolerance mechanisms, legal restrictions prevent these genetically modified plants from progressing beyond laboratory and/or greenhouse experiments [29].…”