| Citrus is the second largest fruit crops planted in China, whose planting distribution and production are severely affected by drought stress. Therefore, it is of great importance to create drought-tolerant citrus germplasms. In order to achieve this goal, PtrABF2 and PtrCDPK1, two drought-related genes cloned by our laboratory, were introduced into normal and precocious Poncirus trifoliata (L.) Raf. via Agrobacterium-mediated method, respectively. The main results were as follows:1. The PCR amplification demonstrated that 15 transgenic precocious Poncirus trifoliata shoots overexpressing PtrABF2,32 normal Poncirus trifoliata shoots overexpressing PtrCDPK1 and 16 precocious Poncirus trifoliata shoots overexpressing PtrCDPK1 were obtained.2. Using citrus Actin as the inner control, RT-PCR results showed that the expression levels of the target genes were higher in transgenic lines than in the control.3. The analysis of relative water loss, relative electrolyte leakage in two transgenic precocious Poncirus trifoliata lines overexpressing PtrABF2 showed that the untransformed (WT) leaves suffered from severer water loss and higher relative electrolyte leakage than the transgenic ones. (PtrABF2), which may be explained by the overexpression of PtrABF2 leading to better performance of the transgenic plants during drought stress.4. Histochemical staining of WT and one transgenic line by trypan blue/NBT/DAB clearly suggested that under dehydration conditions the transgenic line exhibited less accumulation of ROS and cell death. These results further proved that overexpression of PtrABF2 may greatly improve dehydration tolerance in Poncirus trifoliata (L.) Raf.. |
