Drought stress stunt tomato plant growth and up-regulate expression of SlAREB, SlNCED3, and SlERF024 genes

- Drought stress response in tomato is associated with many physiological and genetic traits.
- The research was designed to understand the physiological and molecular mechanisms in tomato plants' resistance to drought stress.
- The molecular analysis of the important drought stress related genes in varieties 17905 and Nagina revealed that these were differentially expressed at different drought stress levels.
- These molecular results are strongly supported by the phenotypic parameters studied in this research.
- It is important to clone one or more of these critical genes and later transform the drought sensitive commercially important tomato varieties for an enhanced drought stress resistance.

Tomato is an important agricultural crop and facing severe drought stress. PEG-6000 in five different concentrations was used to artificially induced drought stress in two tomato varieties; Nagina and 17905.The results demonstrated that seed germination significantly reduced upto 60% for variety Nagina at 8% PEG-6000. Other phenotypic traits such as shoot length, leaf length, leaves number and leaf area also reduced with increasing concentration of PEG-6000, however, root length increased with increasing PEG-6000 concentration. Fresh biomass for both varieties was found maximum as 1.51 g and 2.50 g at 2% PEG-6000 and minimum as 1.20 g and 1.14 g at 8% PEG-6000, respectively. However, Nagina variety showed more tolerance than variety 17,905 at different PEG-6000 concentrations. At molecular level, the three selected genes i.e. SlAREB, SlNCED3, and SlERF024 were found to be over expressed with increasing concentration of PEG-6000. In silico characterization of these genes revealed important conserved protein domains, involved in the drought stress. These results concurred to conclude that the different concentrations of PEG-6000 induced drought stress in tomato plant and SlAREB, SlNCED3, SlERF024 could be used to produce drought tolerant tomato varieties through plant transformation.