关键词: 油梨, 转录组, SSR, 多态性引物, 聚类分析

Abstract: The‘Fuerte’（Persea americana Mill.）avocado flowers and small fruits from the avocado germplasm resource nursery of Hainan University were selected for transcriptome sequencing，and 18 010 sequences were obtained，with a total length of 29 422 056 bp. MISA software was used to retrieve the transcriptome sequences data of avocado‘Fuerte’ to obtain 6 312 SSR loci distributed in 4 687 sequences. The frequency of these SSRs was 35.05%. Analysis of SSR locus characteristics showed that the average length of SSRs was 18.90 bp and the average distance between SSRs was 4.66 kb in the unigenes. The major types of SSR repeated motifs were dinucleotide and trinucleotide，which accounted for 87.15% of all the SSRs. AG/CT，AAG/CTT，and AAAT/ATTT were the predominant motifs in dinucleotide，trinucleotide and tetranucleotide groups，respectively. A total of 13 398 primers were designed with Primer 3.0 software for the SSR sequences. Thirty-two avocado germplasm resources were used as experimental subjects to verify the validity of 100 randomly chosen primers，and the genetic relationship of these avocado germplasm was also analyzed. Forty primers showed polymorphism with the He and PIC mean values as 0.529 and 0.456，respectively. A total of 219 bands and 171 polymorphic bands were amplified. On average，each pair of primers produced 4.275 polymorphic fragments. Consistent results were obtanned with the UPGMA clustering and PCA analysis，respectively. When the coefficient was set to 0.74，these avocado germplasms can be divided into 4 groups，which has certain correlation with geographical distribution.

Key words: Persea americana, avocado, transcriptome, SSR, polymorphic primer, cluster analysis