Overexpression of the stress-associated protein (SAP) SAP MR219 in Oryza sativa (var. MR219) increases salt tolerance in transformed Arabidopsis thaliana plants

摘要

The stress-associated protein (SAP) family provides salinity stress tolerance in plants. We performed functional studies of SAP MR219, which is a member of the SAP family that is induced after salinity stresses. Computational analysis of the SAP MR219 cDNA clone that was isolated from rice root and shoot revealed significant homology with the SAP gene families from rice (89% to 36% ) and Arabidopsis (44% to 32%). This clone has a 516-bp coding region encoding a 171 amino acid protein with a predicted molecular mass of 18.31 kDa. In silico analysis demonstrated that the SAP MR219 gene product encoded a cytoplasmic zinc finger protein that might perform its functions via protein–protein interactions aided by its AN1 and A20 zinc finger domains. The SAP MR219 gene was isolated, cloned and introduced into Arabidopsis thaliana under the control of the CaMV35S promoter. Five transgenic Arabidopsis lines were obtained by the floral-dip transformation method using Agrobacterium tumefaciens strain GV3101. The survivability of the transgenic lines under salinity stress was evaluated at 100, 150, 200 and 250 mM NaCl. At 250 mM NaCl, the germination rates of transgenic lines were approximately 50%, whereas the wild-type plants did not grow. Our results indicate that SAP MR219 may play a significant role in the response to salt stress tolerance in plants.