Improving Cold Tolerance of Rice by Increasing Antioxidative Capacity.(2)

Abstract

Rice plant is quite sensitive to low temperature at its seedling stage. Bleaching (discoloration) of the leaves is one of the typical symptom of chilling stress. This is mainly caused by the generation of active oxygen species (AOS) in chloroplasts. Thus, reinforcement of the scavenging system of AOS by introducing genes coding for stable scavenging enzymes would be a good remedy for the improvement of the chilling-stress tolerance of rice plants. From this point of view, we introduced the plastidal ascorbate peroxidase gene (apx) from Chlamydomonas sp. W80 into rice plants. Transgenic plants had 2-5 fold higher APX activity. These transgenic lines were more tolerant to 10 microM of methylviologen. Improvement of the tolerance to low temperature-stress of these transgenic plants was also confirmed.