The changes in metabolite content of <i>iaa9</i> tomato mutants under salinity and drought stress

The iaa9-3 and iaa9-5 tomato mutants were initially developed to address low productivity caused by environmental factors. Those mutants can grow well under heat conditions. In tomatoes, antioxidant content is associated with secondary metabolites in the fruit, has potential for health applications, and can be increased by environmental modifications. However, the environmental conditions that improve secondary metabolite content in iaa9-3 and iaa9-5 tomatoes have not been identified. The objective of this study was to determine the effects of different environmental conditions on increasing metabolite content in iaa9-3 and iaa9-5. Both tomato mutants, iaa9-3 and iaa9-5, and WT-MT as a control were cultivated and treated with 10% Polyethylene Glycol (PEG) to represent drought stress and with 2.5% Sodium Chloride (NaCl) to represent salinity stress. The results showed that NaCl significantly increased lycopene and β-carotene contents in iaa9-3, whereas total phenolic and total flavonoid contents were not significantly affected. In contrast, PEG treatment significantly affected total phenolic and flavonoid contents in iaa9-5 and WT-MT. PEG treatment did not significantly affect plant height and leaf number in iaa9-3 and iaa9-5 compared with the control, although genotype-dependent responses were observed under salinity and osmotic stress conditions.