Characterization of two poplar homologs of the GRAS/SCL gene, which encodes a transcription factor putatively associated with salt tolerance

Abstract

To cope with soil salinity, which is one of the most severe forms of abiotic stress, efforts are being undertaken to enhance the salt tolerance of economically important poplar clones in the Vojvodina region of Serbia. One approach is to screen nucleotide diversity in candidate genes (CG) in several poplar clones of high economic importance to Serbia to search for associations with salt stress tolerance. As plant-specific GRAS/SCL transcription factors (TFs) play diverse roles in abiotic stress resistance, two poplar homologs of GRAS/SCL TFs were chosen to differentiate the species background with respect to salt tolerance. A BLAST search of the Populus trichocarpa genome using the P. euphratica gene GRAS/SCL TF_GH611858 sequence identified two putative orthologs, Scaf_5 and Scaf_7, with identities of 100% and 94%, respectively. Primers were designed in identical sequences of Scaf_5 and Scaf_7 to amplify fragments of GRAS/SCL TF orthologs in four poplar clones that are economically important to Serbia. The primers spanned regions where, at least in P. trichocarpa, single nucleotide polymorphisms (SNPs) are present, thereby increasing the probability of distinguishing Scaf_5 and Scaf_7 orthologs in the four clones. Alignments and analyses of the gene fragments revealed that both orthologs were representative of the genetic diversity between different poplar clones, and the identified SNP markers differentiated the four poplar clones with respect to salt tolerance.