Overexpression of ZmAFB2, the maize homologue of AFB2 gene, enhances salt tolerance in transgenic tobacco

The TIR1/AFB F-box proteins act as auxin receptors and play an important role in auxin mediated plant development. In the present study, a homologue of AFB2 gene, ZmAFB2, has been cloned from maize (Zea mays L.). Expression of ZmAFB2 is induced by NaCl and salicylic acid treatment and reduced by indole-3-acetic acid (IAA) treatment. To identify the function of the ZmAFB2 gene under stress conditions, a binary vector containing ZmAFB2 driven by CaMV 35S promoter was constructed and transformed into tobacco (Nicotiana tabacum) by Agrobacterium-mediated transformation. The transgenic tobacco lines overexpressing ZmAFB2 exhibit increased tolerance to salt treatment. Furthermore, overexpression of ZmAFB2 enhances the transcription levels of stress responsive genes Ascorbate peroxidase and Catalase. These results indicate that ZmAFB2 is involved in abiotic stress response and overexpression of ZmAFB2 enhances salt tolerance in transgenic tobacco.