Genetic Diversity Analysis Of Nai Plum (Prunus Salicina) Resources And Genetic Identification Of Superior Varieties Based On SCoT And SRAP Markers

Nai plum（Prunus salicina）is a species of Prunus,one of the most traditional and excellent fruit trees in Fujian Province,China.However,the origin and classification of Nai plum has always been controversial,its germplasm resources are chaotic,and the complex genetic background brings some challenges to breeding work.In this study,SCoT and SRAP molecular markers and DNA barcode techniques were used to analyze the genetic diversity and genetic relationship of Nai plum germplasm.In addition,molecular identification of new Nai plum varieties based on molecular marker technology.In order to provide reference value for the collection,utilization and popularization of Nai plum germplasm and breeding of novel plum varieties.The main results are as follows:1.In this experiment,SCoT-PCR and SRAP-PCR reaction systems of Nai plum were optimized using a single factor and orthogonal design.The optimal PCR reaction mixture of SCoT-PCR system was 10ng template DNA,0.8μmol/L primer and 9μL 2×Taq Plus Master Mix in20μL mixtures.The optimal PCR reaction mixture of SRAP-PCR system was 20 ng template DNA,0.8μmol/L primer and 11μL 2×Taq Plus Master Mix in 20μL mixtures.21 SCoT primers and 17 pairs of SRAP primers with clear bands and rich polymorphism were screened,these primers can be used for genetic diversity analysis and genetic relationship studies of Nai plum germplasm.2.SCoT and SRAP markers were used to analyze 40 samples’genetic diversity and genetic relationships.A total of 361 polymorphic bands were amplified by the two markers,all with a high polymorphism ratio(Pi _SCoT=87.4%,Pi _SRAP=95.34%).The average values of effective number of alleles（Ne）,Nei’s genetic diversity index（H）and Shannon’s information index（I）obtained by SCoT and SRAP markers were 1.363,0.227,0.357 and 1.403,0.255,0.401,respectively.The results showed that the Prunus plant had high heterozygosity and genetic diversity.SCoT and SRAP primers can amplify Prunus materials.SCoT and SRAP markers can be used to determine Nai plum’s genetic background and genetic relationship.In the UPGMA cluster map,both SCoT and SRAP markers can clearly distinguish‘Jintaiyang’from other samples,European plum germplasm and Nai plum germplasm were clustered into one group.This result indicated that the genetic relationship between‘Jintaiyang’and Nai plum is distant,and the genetic relationship between European plum and Nai plum is close.3.The amplification rates of MatK and psbA-trun H DNA sequences in Prunus plants were 100%,and the success rate of sequencing was100%and 97.5%respectively.The sequence characteristics of the two chloroplast gene fragments in Prunus were comprehensively analyzed and a phylogenetic tree was constructed.The results showed that MatK and psbA-trun H sequences were very conservative in Prunus,and there were only 2 and 6 sequence variation sites.These two hot barcodes are not suitable for identifying the Nai plum plant.4.The genetic relationship between a new late-maturing Nai plum variety‘Wanhuangjin’and‘Wanshuyounai’（yellow meat）was studied using SCoT and SRAP markers.The results showed that 77 and 66 bands were amplified by 16 SCoT primers and 14 pairs of SRAP primers.The percentage of polymorphism was 16.98%and 18.28%,respectively.With the cluster map,we identified that‘Wanhuangjin’and‘Wanshuyounai’had the highest similarity genetic background,although there were some differences.This suggests that the genetic relationship between‘Wanhuangjin’and‘Wanshuyounai’（yellow meat）is close,belongs to two varieties,and has the same source.