Background: Gerbera delavayi Franch., a perennial herb native to southwest China, is of important and special value in textile and culture. Its abaxial leaves have a layer of soft fibers, which can be manually peeled, twisted into a yarn, and applied in textiles for hand-made clothes. The particular craftsmanship, unique all over the world, is a part of the intangible cultural heritage in Yunnan and Sichuan Province. To date, the wild species has become endangered because its leaves are excessively harvested for textile applications. Estimating the genetic variation of plant species is crucial for plant conservation and breeding. So, the aim of this study was to (1) provide an accurate outline of the genetic diversity and population structure of G. delavayi and (2) propose targeted conservation strategies for these wild resources.
Methods: Simple sequence repeats (SSR) markers were developed from the G. delavayi transcriptome for its genetic analysis. A total of 5,179 genic-SSR markers were identified and 350 primer pairs were selected for PCR validation. After primary screening , 19 polymorphic and neutral primer pairs were used to analyze the genetic diversity and population structure of nine wild fireweed populations (a total of 204 individuals) collected from Southwest China.
Results: Moderate genetic diversity (allelic richness (Ar)=3.436, Shannon’s information index (I)=0.789 , observed heterozygosity (Ho)=0.304 , and expected heterozygosity (He)=0.415) and moderate differentiation (FST=0.110, P=0.000) were found among nine populations. The lowest genetic diversity (Ar=2.351, I=0.497, Ho=0.178, and He=0.284) and highest inbreeding (inbreeding coefficient (FIS)=0.365) were both detected within the isolated population PE. Furthermore, high genetic differentiation, limited gene flow, and clear genetic barrier were detected between PE and other populations, showing the significant effects of habitat fragmentation on the genetic differentiation of these G. delavayi populations.
Conclusions: Our results showed that human overexploitation has led to moderate genetic diversity in G.delavayi populations. Furthermore, habitat fragmentation has resulted in clear genetic barrier and high differentiation between the isolated and concentrated populations. Upon the genetic features of wild G. delavayi populations, we proposed several strategies for protecting and utilizing the current wild resources.
Genetic diversity and population structure of castor (Ricinus communis L.) germplasm within the US collection assessed with EST-SSR markers
