Genetic diversity and structure of wild Rosa roxburghii in Southwest China

Abstract

In order to study genetic diversity and the origin of wild Rosa roxburghii in Southwest China and provide some bases for its utilization and protection. A survey was based on the splicing sequences of two single-copy nuclear genes (GAPDH and ncpGS) and three chloroplast genes (atpF-trnH, trnL-trnF and trnG-trnS). The individuals of 320 wild R. roxburghii from 27 wild populations in China were amplified, sequenced by PCR. After that, the sequencing results were analyzed with relevant software. The results were as follows: (1) Low genetic diversity levels were found in R. roxburghii of single-copy nuclear gene (Hd=0.469 2, π=0.000 49) and chloroplast gene (Hd=0.653 4, π=0.000 65). But there were significant differences among different populations. (2) Analysis of molecular variance (AMOVA) showed that the genetic variation almost occured within populations, which indicated that population variation was the main source of genetic variation in wild R. roxburghii. It existed obvious genetic differentiation among populations (cpDNA: FST=0.336 47, GST=0.273, NST=0.308; scnDNA: FST=0.094 87, NST=0.076, GST=0.056). The distribution of R. roxburghii did not have obvious phylogeographical structure (P>0.05). (3) Tajima’s D value of neutral test was insignificantly negative value, indicating that R. roxburghii populations conformed to neutral evolution model. Fu's Fs value was significantly negative, combining the result of mismatch analysis curve, deducing that R. roxburghii populations had an expansion within a small range before. But generally, they remained stable. (4) According to the haplotype network, the populations of the Bijie region not only presented higher genetic diversity, but also had a lot of haplotypes. Therefore, the Bijie region was speculated to be one of the refuges of ice age. Therefore, they were supposed to be carried out the strategy of local protection, and the populations with special traits and unique haplotypes shall be protected to adopt a priority protection approach. The study provides a reference for wild R. roxburghii of the resource protection and genetic breeding.

Keywords

• rosa roxburghii
• single-copy nuclear gene
• chloroplast gene
• genetic diversity
• genetic structure