Abstract:

In this study, a set of new polymorphic nuclear SSR markers were developed and characterized in Populus simonii by directly sequencing transcription factor genes expressed under abiotic stresses. A total of 31 polymorphic SSR loci were identified in 21 genes of 3 transcription factor families from 36 unrelated individuals of P. simonii. In the polymorphic SSR loci, there were di-, tri-, tetra-, and penta-nucleotide repeats, and 3-20 motifs repeats, with dinucleotide SSRs being the most frequent, accounting for 51.6% of the total loci in the natural population of P. simonii. Thirty-one primer pairs for PCR amplification SSR loci were designed according to the conservative flanking sequences of SSR loci. The utility and conservation of SSR loci were tested with 22 genotypic individuals in genus Populus. The PCR amplification exhibited an average of 93.5% conservation within at least four Sections under genus Populus, and the number of the detected polymorphic alleles ranged from 3 to 12, with an average of 6.0 alleles per locus. The developed gene-based SSR markers of the abiotic stress resistant transcription factor could provide a powerful tool for marker-assisted breeding of new germplasms with desirable abiotic stress resistance in P. simonii, and would have theoretical and practical significance in tree breeding.

Key words: Populus, traits with abiotic stress resistance, transcription factor, SSR marker within genes