ROS metabolism are affected in OEmiR399 transgenic Arabidopsis
plants under freezing stress
To verify the effect of tae-miR399 on oxidative tolerance induced by
freezing in Arabidopsis plants, we determined ROS including hydrogen
peroxide (H2O2) and super-oxygen ion
(O2.−) levels in different Arabidopsis
lines after freezing stress by histochemical staining and ROS content
determination. Nitroblue tetrazolium (NBT) staining for
O2.− and 3, 3′-diaminobenzidine (DAB)
staining for H2O2 showed ROS accumulated
to higher levels in WT than that in OEmiR399 transgenic Arabidopsis
plants under freezing stress (Fig.
11). These results indicated that OEmiR399 transgenic Arabidopsis plants
exhibited stronger ability to scavenge ROS and lesser symptoms in
response to freezing stress. The activities of
SOD, POD and CAT in OEmiR399
transgenic Arabidopsis plants were higher than that in WT under freezing
stress (Fig. 12). However, the
expression of SOD, POD and CAT encoding genes in OEmiR399 transgenic
Arabidopsis were not up-regulated under freezing stress. Moreover, the
expression of some SOD, POD and CAT encoding genes in OEmiR399
transgenic Arabidopsis was significantly lower than that in WT (Fig.
12).