Genetic relationship analysis and molecular identification of Magnolia wufengensis cultivars based on SSR and SRAP markers

ObjectiveGenetic diversity and genetic variation of Magnolia wufengensis cultivars were examined by simple sequence repeats (SSR) and sequence-related amplified polymorphism (SRAP) molecular markers for establishing its molecular marker system.

MethodThirty-five simples of M.wufengensis cultivars were applied to PCR amplification for SSR and SRAP markers. The genetic similarity coefficient of each cultivar was calculated by NTSYS-pc2.1 and cluster analysis was carried out using UPGMA.The locus data of combination of primer pairs that can discriminate all cultivars were screened by R language.

ResultA total of 18 pairs of SSR primers with polymorphism and clear bands were obtained. With the genome DNA of 35 M. wufengensis cultivars as the PCR template, a total of 128 polymorphic bands were generated. The number of polymorphic bands at each polymorphic primer ranged from 2 to 15, with mean band number of 7.1, mean pattern number of 10.6, mean effective pattern number of 5.4 and mean D of 0.72.The mean value of the percentage of polymorphic loci was 0.730 2, ranging from 0.142 9 ~ 1.000 0. The mean Shannon's index was 0.304 2, ranging from 0.086 4 to 0.433 7. The mean expected heterozygosity among cultivars was 0.248 8, ranging from 0.059 2 to 0.282 3.Eleven pairs of effective SRAP primers were acquired through screening. A total of 156 polymorphic bands were produced with the genome DNA of 35 M.wufengensis cultivars as the template. The number of polymorphic bands at each polymorphic primer ranged from 7 to 18, with mean band number of 14.2, mean pattern number of 22.7, mean effective pattern number of 13.2 and mean D of 0.93. The mean value of the percentage of polymorphic loci was 0.815 6, ranging from 0.657 1 ~ 1.000 0. The mean Shannon’s index was 0.375 9, ranging from 0.287 2 to 0.455 3. The mean expected heterozygosity among cultivars was 0.240 4, ranging from 0.180 2 to 0.311 6.

ConclusionM. wufengensis has relatively high genetic diversity. The analysis of molecular variation of both SSR and SRAP marker systems indicates that most genetic diversity is within M. wufengensis cultivars. The locus data of combination of primer pairs can discriminate all cultivars for identifying M. wufengensis cultivars efficiently and accurately.These results provide important references for the protection and breeding of M. wufengensis.