RESUMO
Objective::Sixty-nine germplasm samples of Picria felterrae collected from the main producing areas in Guangxi were subject to genetic diversity and genetic relationship analyses using the simple seguence repeat(SSR) molecular marker technology and good germplasm genes associated with the content of picfeltarraenins were screened so as to provide references for germplasm resource evaluation, phylogenetic analysis, and molecular mark assisted breeding of that species. Method::20 pairs of randomly selected primers were amplified based on the transcriptome sequencing technology. The genetic diversity of and genetic relationship between the 69 samples were analyzed using the genetic polymorphic information for each marker locus, and one-variable linear regression and multiple stepwise regression analyses were performed to screen molecular markers associated with the content of picfeltarraenins. Result::The amplification using the 20 pairs of SSR primers produced 76 alleles, 3.8 alleles for each locus on average, higher than effective alleles (1.969 2), and the rare allele rate was 38.2%, suggesting that the alleles distributed unequally. The polymorphism rates of alleles varied between 0-59%, with an average of 38.24%, showing a great difference among loci. The polymorphic information content (PIC) varied between 0-0.621 1, with an average of 0.378 0.Shannon polymorphic information index varied between 0-1.240 1, with an average of 0.759.Nei's gene diversity index (Nei) varied between 0-0.682 3, with an average of 0.440 9.P21 had the highest level accompanied with the lowest P7 for the above three indexes, and significant genetic diversity differences were identified among the loci. For all loci, the mean observed heterozygosity was 0.382 4, lower than the average expected heterozygosity of 0.442 5, suggesting the loss of heterozygosity, the average genetic differentiation coefficient (Fst) was 0.365 9 and the average gene flow Nm was 0.433 2, suggesting a high genetic divergence and a low gene flow. The results of one-variable linear regression and multiple stepwise regression showed that there were 5 loci related to each of the picfeltarraenin IA and IB, and only 1 loci was associated with the content of both. Conclusion::There were significant differences in the genetic diversity of 20 SSR marker sites, and the 69 germplasm samples were greatly genetically differentiated and had low gene flow. From the selected 20 SSR markers 9 marker loci associated with the content of picfeltarraenin IA and IB were selected. The results can be used as a reference for phylogenetic analysis and selective breeding of Picria felterrae.
RESUMO
Objective To explore genetic diversity of and genetic relationships among 18 Picria felterrae populations to provide references for the resource assessment and utilization. Methods The genetic diversity of 18 P. felterrae populations were analyzed using the EST-SSR primer development technology and SSR molecular markers, and cluster analysis was performed based on genetic distances to determine the relationships among those populations. Results A total of 48 pairs of polymorphic primers were selected from 100 pairs of EST-SSR markers, of which 20 pairs were randomly selected and used for amplification of 18 populations. A total of 71 alleles were amplified, 3.55 alleles per primer. Among the primers, the percentage of polymorphic loci (P) varied from 0 to 40.7%, with an average of 19.9%; The polymorphism information content (PIC) varied from 0 to 0.794 1, 0.397 7 on average; The Shannon diversity information index (I) varied from 0 to 1.814 3, with an average of 0.808 4; Obs_Het varied from 0 to 0.442 3, with an average of 0.212 7; And the Exp_Het varied from 0 to 0.826 9, with an average of 0.455 8. For the 18 populations, the Inbreeding Coefficient (Fis) varied from -0.095 3 to 0.663 9, with an average of 0.159 2; The inbreeding coefficient of subgroups (Fit) varied from 0.062 6 to 0.858 7, with an average of 0.537 2; The genetic differentiation coefficient (Fst) varied from 0 to 0.686, with an average of 0.449 6; The gene flow (Nm) varied from 0.114 4 to 0.759 4, with an average of 0.306 1. For the 18 samples tested, the gene diversity index (Nei) varied from 0 to 0.401 6, the I varied from 0 to 0.620 9, Wuzhou Guangxi having the maximum value and Longtan Yunnan the minimum value. Menglong and Jingha, two towns in Yunnan, had the shortest genetic distance (0.031 9), whereas Longzhou Guangxi and Menghai Yunnan had the maximum genetic distance (0.963 8). The 18 populations could be divided into four groups at the location where genetic distance was 0.321 3. The three populations in Guangxi belonged to the same group, populations from Menglong, Menglun and Mengzhe of Yunnan belonged in the same group, populations from Mengsong Yunnan became an independent group, and the rest belonged in the fourth group. Conclusion The genetic differentiation levels of 18 populations were not consistent, and the heterogeneity difference was significant. The gene flow among populations was small, which indicated that the population gene exchange was low. A certain inbreeding rate exists among the populations. The relationship among populations was influenced by geographical isolation and environmental factors. Key words: