Overexpression of CfPIP1 - 1 , CfPIP1 - 2 , and CfPIP1 - 4 genes of Catalpa fargesii in transgenic Arabidopsis thaliana under drought stress

Catalpa fargesii is an important economic tree species used for furniture and timber production because of its high density and hardness. Its survival and growth are severely affected and primarily limited by drought stress. Thus, to better understand the mechanism of drought resistance in C. fargesii , we used qRT-PCR to reveal significantly different expression of three plasma membrane intrinsic protein genes: CfPIP1 - 1 , CfPIP1 - 2 and CfPIP1 - 4 . We then cloned their full-length cDNA sequences and characterized the encoded proteins. We analyzed the genes phylogenetically and predicted conserved motifs, domains, and secondary and tertiary structures. To verify the function of the CfPIP1 genes further, we ectopically expressed CfPIP1 transgenes in Arabidopsis thaliana . The results showed that CfPIP1-1, CfPIP1-2 and CfPIP1-4 had several characteristics of aquaporins. The transgenic plants grew better than the WT plants did under drought stress, and overexpression of the CfPIP1 genes increased the plant water content and resistance to drought. Thus, CfPIP1-1, CfPIP1-2 and CfPIP1-4 of C. fargesii play key roles in regulating the intracellular and extracellular water balance and in mediating the plant response to drought.