SSR molecular marker developments and genetic diversity analysis of Zanthoxylum nitidum (Roxb.) DC

Zanthoxylum nitidum (Roxb.) is a commonly used traditional Chinese medicine. However, the collection and protection of wild germplasm resources of Z. nitidum are still insufficient, and there is limited research on its genetic diversity and fingerprint. In the present study, 15 simple sequence repeat (SSR) markers were developed by genotyping based on multiplexed shotgun sequencing. The genetic diversity of 51 populations (142 individuals) of Z. nitidum was evaluated using these 15 SSRs. A total of 245 alleles (Na) were detected, with an average value of 16.333, and the average polymorphism information content was 0.756. The genetic distance among 51 populations was 0.164~1.000, with an average of 0.659. Analysis of molecular variance showed low genetic differentiation (40%) and high genetic differentiation (60%) between populations and individuals, respectively. The genetic differentiation coefficient (Fst) of the population was 0.338, indicating that 66.2% of the genetic variation occurred within the population, and the gene flow (Nm) was 0.636, demonstrating that the gene exchange between populations was low. Clustering analysis revealed that the genetic similarity coefficient was 0.30, dividing the 51 populations into 4 groups of 2, 17, 3, and 29 populations. There was no specific relationship between geographical location differences and genetic distance. The genetic diversity level of Z. nitidum is relatively high, and our results provide a theoretical basis for the rapid identification of Z. nitidum germplasm resources and variety selection.