The Population Genetic Structure Of Camellia Flavida Chang

Camellia flavida Chang belonging to Camellia the genus of Theaceae includes C.flavida var.flavida and C.flavida var. patens. It is distributed in depression or valley of the evergreen broad-leaved forest limestone mountain region in the southern and southwestern Guangxi. C. flavida is one of the Camellia chrysantha which the colors of petals of are reddish, yellow to pale yellow. As we all know that C. flavida is also the precious germplasm resources with important ornamental and medicinal value.In this study, we are using microsatellite molecular marker method to overall reveal the population genetic structure of C. flavida. Focus on revealing its genetic diversity and population genetic structure, then discuss the impact of habitat heterogeneity and habitat fragmentation on C.flavida. It will provide the basis for the effective protection and use of the precious germplasm resources. The main results are showing as follows:(1)We have successfully developed twenty one polymorphic microsatellite primers for C. pingguoensis using 454 sequencing and isolated thirty eight microsatellite loci for C. flavida by transcriptome sequencing. Of which, twenty one effective sequences for C. pingguoensis (TER1～TER21) in the GenBank accession number are:KJ670125～KJ670145. For C. pingguoensis, all of these loci showed polymorphism, and the number of alleles per locus ranged from 3 to 9. The observed and expected heterozygosities ranged from 0.200 to 0.963 and from 0.246 to 0.868, respectively. Microsatellite primers developing by the above two methods will provides a solid foundation for further study on genetic diversity and population genetic structure of C. Flavida.(2) The results of genetic diversity show as follows:Total 112 alleles were detected from 601 individuals in 19 populations of C.flavida by 14 microsatellite loci. The number of alleles per locus ranged from 7 to 20, with the mean of 8. Among it, locus TER4 had the highest alleles (20), and loci FLA12 and FLA16 got the lowest alleles (7). The observed and expected heterozygosities ranged from 0.411 to 0.672 and from 0.350 to 0.657, with an average of 0.563 and 0.555, respectively.(3)The study results of population genetic structure on C. flavida indicate that genetic differentiation (Fst=0.276) among populations locate at higher differentiation level. Gene flow ranged from 0.565 to 5.036, with the value of 0.732 among the populations, which indicated that the related low level gene flow among populations; AMOVA analysis revealed that most of the genetic variability detected was between individuals within populations on the two species (C. flavida var. flavida and C. flavida var. patens), and variation between populations was also showing certain proportions. Of which, the variation of the two spices, C. flavida var. flavida and C. flavida var. patens between populations was 24.84%,25.49% and 27.66%, respectively. It indicated that there is a relative high genetic differentiation between populations; Mantle test showed extremely significant positive correlation between genetic distance based on Fst and geographical distance (r=0.4383 p=0.0030); BOTTLENECK analysis might infer that the NF national population in the C. flavida may have experienced a bottleneck effect; STRUCTURE analysis indicated that 19 national populations of C. flavida could strictly divide into two large clusters, cluster I including 12 populations of C. flavida var. flavida such as LS, NZ and LL, and cluster II containing the specie of C. flavida var. patens and tow populations of C. flavida var. flavida (LN and LZ).In summary, this study reveal that C. flavida maintain a high level of the genetic diversity. It indicated that it is a good time to protect the C. flavida at the present stage. According to the STUCTURE analysis, it is a guidance to divide C. flavida into three protection unit for reasonable protection. In view of the higher population genetic differentiation and the low level of gene flow, it need to carried on the ex situ conservation policy. It will provide a scientific foundation for the effective protecting and exploiting of C. flavida.