Exploring the Relationship between Genomic Variation and Phenotype in Ornamental Pomegranate: A Study of Single and Double-Petal Varieties

Abstract

The double-petal varieties of ornamental pomegranate have higher ornamental value and garden development potential than the single-petal varieties but there has been no study on the genomic variation between them. This study aimed to determine the genomic variation between the two kinds of varieties and the relationship between the variation and phenotype by identifying the DNA variation of three single-petal varieties and three double-petal varieties using re-sequencing technology. The results showed that the variation number of each variety was in the order of single nucleotide polymorphisms (SNPs) > insertions and deletions (InDels) > structural variations (SVs) > copy number variations (CNVs). The number of SNPs and InDels in the double-petal varieties was significantly higher than that in the single-petal varieties, and there was no significant difference in the number of SVs and CNVs. The number of non-synonymous SNPs in the coding region (Nonsyn_CDS_SNPs) and InDels with a 3X length in the coding region (3X_shiftMutation_CDS_InDel) was significantly higher in the double-petal varieties than that in the single-petal varieties. The number of the two variants was strongly positively correlated with each morphological index that was related to the phenotypic difference between the two varieties. Nonsyn_CDS_SNPs and 3X_shiftMutation_CDS_InDel were enriched in the cell membrane system, cell periphery, and signal transduction, from which 15 candidate genes were screened. Our results provide genomic data for the study of the formation mechanism of the double-petal flower and lay a theoretical foundation for new variety breeding of ornamental pomegranate.