Abstract
It is considered that some osmolites are accumulated in plants to acquire tolerance to environmental stresses. Proline accumulation is observed in many plants, and it plays a role as an osmoprotectant. We isolated a barley proline transporter (HvProT) gene from salt-stressed roots and identified its function and substrate specificity. To study contributions of HvProT to stress tolerance, we introduced HvProT gene in Arabidopsis and evaluated its tolerance under stress conditions and high concentration of proline conditions. As a result, enhancing of stress tolerance was clearly observed in transgenic plants. Especially, effects on initial growth stage were significantly. On the other hand, it was shown that high concentration of L-proline inhibited growth of transgenic plants. Similarly, transgenic plants showed more sensitive to D-proline than control plants. These results indicated regulation of proline concentration is quite important for acquisition of stress tolerance and suppression of plant growth.
