Figure 6

Abiotic stress response of selected genes at the whole plant level. Three-week-old N. benthamiana plants were inoculated with respective TRV derivatives, TRV::GFP and maintained in the greenhouse along with wild-type non-inoculated plants. A) Photosynthetic rates of NbP5CS1- and NtEDS1-silenced plants under water deficit stress. Stress was imposed on plants at 20 days after silencing by gradually bringing down the water level to 50% FC over a period of 15 days. Another batch of plants was maintained under non-stress conditions. Photosynthetic rates were measured in the third newly formed and fully expanded leaf. B) Effect of salt stress on NbSOS1-silenced plants. NbSOS1-silenced plants were irrigated with NaCl solution at 20 dpi while gradually exposing plants to higher NaCl concentration from 100 mM for 5 days, then 200 mM for 5 days and subsequently to 300 mM for 5 days. Another batch of plants was maintained under non-stress conditions. Photographs were taken at the end of the stress period. C) Leaf from NbSOS1-silenced plant showing salt pustules in the adaxial surface due to higher salt accumulation. D) Photosynthetic rates were measured at the end of the stress period. E) Effect of heat stress on cell membrane stability of NbHSP101-silenced plants. Wild-type, vector control and NbHSP101-silenced whole plants were initially acclimated with mild temperatures (35°C for 6 h) and subsequently exposed to high temperature stress (45°C for 1 h). Another batch of plants was maintained under non-stress conditions. Leaf disks were collected from these plants at the end of stress, and ion leakage was measured as described in the Materials and Methods section. Each bar value represents mean ± sd (n = 5) of three independent experiments. ‘*’ suggests values were significantly different from wild-type and vector control plants (Student’s t-test, P < 0.05).