Characterization of Snakin/GASA gene family in Solanum tuberosum and functional analysis of Snakin-1

NAHIRÑAK, V; GONZALEZ DE URRETA, M; ALMASIA, NI; HOPP, HE; VAZQUEZ ROVERE, C

Bruselas

Congreso; 19th Triennial Conference of the European Association for Potato Research; 2014

Introduction Snakin/GASA proteins are widely distributed among plant species. They have been implicated in diverse biological activities: cell elongation/division, root formation, stem growth, flowering time, fruit ripening, and stress tolerance [1-4]. Interestingly, all of them maintain 12 cysteines of the C-terminus in highly conserved positions that are probably responsible for their protein structure and were shown to be essential for their biochemical activity as antioxidants [5, 6]. Snakin-1 is a member of the Snakin/GASA family isolated from Solanum tuberosum that was found to be active against pathogens in vitro and we demonstrated that its overexpression in potato enhances resistance to Rhizoctonia solani and Erwinia carotovora [7, 8]. We recently showed that Snakin-1 silencing resulted in an abnormal phenotype affecting cell division, leaf primary metabolism and cell wall composition demonstrating that it has additional roles in growth and development [9]. Materials and Methods Snakin/GASA genes were in silico screened in the Potato Genome Sequencing Consortium database using the InterPro GASA domain annotation (IPR003854) as query. For functional analysis, Snakin-1 transgenic potato lines and conventional protocols were used [9]. Results In this work, we carried out a genome-wide search and 14 novel Snakin/GASA genes were identified in the potato genome in addition to the previously reported genes (Snakin-1, Snakin-2 and Snakin-3). Chromosome localization studies of Snakin/GASA genes indicated that they correspond to different loci and are distributed on nine of the 12 potato chromosomes. In silico analyses revealed that Snakin/GASA gene upstream sequences carry a variety of potential hormone and stress responsive cis-regulatory elements. Expression analyses showed a tissue specific expression pattern for each family member and also some differences from the previously reported data. Further analyses of transgenic potato lines suggested that the mechanism of action possibly involves the participation of Snakin-1 in redox homeostasis. Conclusion and perspectives Snakin/GASA family in potato consist of 17 members and phylogenetic analysis based on sequence alignments of the full-length proteins resulted in three major groups. Expression studies indicated that the spatial regulation of these novel Snakin/GASA genes is highly specific suggesting distinct functions. And as it was described for others Snakin/GASA genes, Snakin-1 may play its role by modulating reactive oxygen species.