Investigation of molecular variability in some Aegilops species using Start Codon Targeted Polymorphism (SCoT) and CAAT-Box Derived Polymorphism (CBDP) markers

Abstract

Among wild relatives of wheat, Aegilops species are ideal genetic resources for the discovery of new characteristics such as resistance to environmental stresses and even grain quality for wheat improvement. Hence, knowledge of the population structure and genetic diversity of this germplasm is very important for their conservation and further utilization. In the present study, 80 accessions of the Aegilops including Ae. tauschii, Ae. cylindrica and Ae. triuncialis were investigated for genetic diversity using SCoT and CBDP markers. Eight SCOT and twelve CBDP primers amplified a total of 84 and 94 fragments with a mean of 10.50 and 7.83 fragments per primer, respectively. Resolving power (Rp) for SCoT and CBDP primers varied between 6.04 and 11.65, and 13.08 and 28.02, with the polymorphic information content (PIC) from 0.40 to 0.49 and 0.35 to 0.48, respectively. The results of analysis of molecular variance (AMOVA) indicated that the highest proportion of genetic variance referred to between species. SCoT primers indicated high values for all informativeness parameter (except resolving power) than CBDP primers across all tested accessions. However, CBDP primers indicated higher values of the genetic parameters than using SCoT primers. As a result, the maximum values for genetic parameters such as number of effective alleles (Ne), Nei?s gene diversity (H) and Shannon?s information index (I) were detected in Ae. cylindrica and Ae. triuncialis using SCoT and CBDP markers, respectively. Cluster analysis based on those molecular system grouped all accessions into three main clusters. The grouping pattern observed by CBDP primers indicated more clear phylogenetic relationship among some Aegilops species, so that PCoA?s results confirmed the grouping pattern. In conclusion, it was observed that SCoT and CBDP displayed good efficiency in depicting polymorphism among the tested accessions, however, CBDP markers provided a clear grouping pattern of evaluated accessions. Hence, the use of CBDP markers in determining population structure and estimating genetic diversity in other plant species is recommended.