Tomato plants may be exposed to different hazardous conditions such as heavy metals or wastewater mixed with water of irrigation. In this study, two-month old tomato plants were irrigated for two weeks using water, wastewater, 1mM copper acetate solution and 1mM or mercuric acetate solution. Tomato plants were then subjected to physiological and molecular analyses. Dry weight, proline, protein, total phenols, soluble sugars and photosynthetic pigments were determined. In addition, the start codon targeted (SCoT) molecular analysis using nine primers (SCoT7, SCoT9, SCoT10, SCoT11, SCoT24, SCoT28, SCoT32, SCoT35 and SCoT46) was conducted to explore differential gene expression under stress irrigation. Data revealed general decrease in dry weight except under wastewater treatment. All copper acetate, wastewater and mercuric acetate treatments triggered the production of proline and total phenols. Protein, chl a and chl b were significantly initiated by copper acetate treatment, whereas soluble sugars were superior in control along with mercuric acetate treatment. The photosynthetic pigments varied significantly under copper acetate treatment as compared to the other treatments. SCoT analysis revealed conspicuous monomorphic profile and high polymorphic pattern; the percent of polymorphism ranged from 81.8% to 100% in treated plants. Out of the nine SCoT primers only SCoT32 primer that produced no polymorphism. The 500 bp amplicon generated by SCoT24 primer was not produced in the control plants and produced in all other treatments. Thus, this 500 pb amplicon may be related to the production of antioxidative compounds e.g. phenols, proline to cope with the adverse irrigation. Molecular results of SCoT technique can be used to clarify and explain some physiological and genetic variations occurred in tomato plants under hazardous irrigation conditions.
Key words: copper acetate, mercuric acetate, phenol, proline, protein, SCoT, tomato, wastewater
|
