Genomic cloning and characterization of a Pto-like gene SsPto-2 from Solanum surattense

A Pto-like gene (designated as SsPto-2) was isolated from Solanum surattense by using genomic walker technology which encoded a cytoplasmically localized serine-threonine protein kinase. Analysis of the 2365 bp segment revealed a gene including a 905 bp 5' flanking region, a 924 bp open reading frame (ORF) and a 536 bp 3' flanking region. The deduced amino acid sequence of the SsPto-2 gene shared high homology with other known Ptos. The deduced SsPto-2 protein contained no signal peptide with a calculated molecular weight of 34.61 kDa. The analysis of SsPto-2 promoter region and terminator region was also presented. Semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis revealed that SsPto-2 transcripts were up-regulated by defense-related factors such as gibberellic acid (GA(3)), salicylic acid (SA) and down-regulated by darkness. The cloning of the SsPto-2 gene will allow us to further study its potential role in disease resistance.