Isolation, characterization and expression analysis of the GDP dissociation inhibitor protein gene MiRab-GDI from Mangifera indica L

Abstract

Rab guanosine nucleotide dissociation inhibitor (Rab-GDI) proteins are important Rab GTPase effectors, which control the cycling of small GTPases between membrane and cytosol byinteracting with the prenylated GDP bound small GTPases. However, little is known about the function of Rab-GDIs in fruit plants. In this study, we present the cloning and characterisation of a putative MiRab-GDI (GenBank accession no. KF768565) from Mangifera indica. The gene encoded a 444 amino acid protein with a molecular weight of 49.75kDa and a theoretical isoelectric point of 5.48. The deduced amino acid sequence exhibited high homology with Nicotiana tabacum (92% similarity) and contained five structurally and functionally defined sequence conserved residues (SCRs). SDS–PAGE and Western blot analysis indicated that recombinant MiRab-GDI was successfully expressed in E. coli and the molecular weight of the solute protein was the same as the predicted value. Real-time RT–PCR analysis demonstrated that MiRab-GDI was ubiquitously expressed in various plant tissues and organs at different levels. The expression of MiRab-GDI was down-regulated in the early stages of fruit development and up-regulated during later stages of fruit ripening. In addition, it could be induced by various treatments such as cold, NaCl, drought, abscisic acid (ABA), salicylic acid (SA), and hydrogenperoxide (H2O2). These results provide insights into the role of the MiRab-GDI gene in fruit ripening and abiotic stresses in the mango plants.