Isolation, characterization and functional analysis of StRab, a cDNA clone from potato encoding a small GTP-binding protein

Rab-related small GTP-binding proteins are known to be involved in regulation of the vesicular secretory pathway in eukaryotic cell. Here we described the isolation of the cDNA clone StRab from potato (Solanum tuberosum L.). StRab contains conservative regions of small GTP-binding proteins and Rab family specific motifs. Phylogenetic analysis indicated that StRab gene belongs to the Rab subfamily. StRab has a C-terminal motif (CCSS) which is considered as subcellular localization by post-translational modification. The late blight resistance assay showed that 4 StRab over-expression transgenic potato lines significantly reduced the lesion area when plants were inoculated with mixture races of Phytophthora infestans, suggesting that the StRab may contribute to potato resistance against P. infestans. Twenty-six target proteins potentially interact with StRab were identified. Many of them are related to plant defense responses. Our results provided some initial indications that StRab might play roles via regulating the secretary pathway of interaction proteins.

► A new gene was cloned from potato.
► It was designed StRab according to the alignment and conserved domains analysis.
► It supplied a resistance against P. infestans.
► A possible mechanism was inferred on how Rab protein could involve in plant defense responses.