Polyamine accumulation in transgenic eggplant enhances tolerance to multiple abiotic stresses and fungal resistance

Polyamines (putrescine, spermidine and spermine) have been shown to be important in stress tolerance. Thus, the present study was undertaken with the aim to enhance stress tolerance in eggplant by introduction of a key polyamine biosynthetic gene arginine decarboxylase, adc under the control of a constitutive promoter of cauliflower mosaic virus, CaMV35S through Agrobacterium-mediated transformation. Several putative transgenic plants were generated and the transgene integration and expression was confirmed by PCR and Southern blot analyses, and RT-PCR analysis, respectively. These transgenic plants have shown an enhanced level of polyamines due to the increase in ADC enzyme activity. The diamine oxidase (an enzyme involved in putrescine and spermidine degradation) activity was also increased in these transgenic plants. Polyamine-accumulating transgenic plants exhibited an increased tolerance levels to multiple abiotic stresses such as salinity, drought, low and high temperature, and heavy-metal and resistance against fungal wilt disease caused by Fusarium oxysporium.