Project description:Hoya is a remarkable genus with high horticultural ornamental value. In this study, we report and characterize the complete plastid genome sequence of Hoya carnosa. The complete chloroplast genome was 176,340 bp in length, which includes a pair of inverted repeat regions (IRs) of 41,381 bp separated by a large single copy region (LSC) 91,281 bp and a small single copy region (SSC) 2,297 bp. Interestingly, IRs expanded into SSC, with the result that most of the genes in SSC were duplicated. This chloroplast genome contained 110 genes, including 76 protein-coding genes, 30 tRNA genes, and 4 rRNA genes. The complete plastome sequence of H. carnosa will provide some useful information for future phylogenetic study of Hoya and its horticultural application.
Project description:Fragaria iinumae, a diploid progenitor species of octoploid strawberries, likely occupies a basal position within the genus Fragaria. In this study, we report a near-complete genome assembly of F. iinumae v2.0, totaling 241.14 Mb with a contig N50 of 33.31 Mb. We identified 14 telomeric and 7 centromeric regions across its seven chromosomes. Compared to previous assemblies, F. iinumae v2.0 demonstrates substantial improvements in both genome continuity (gaps reduced from 29 to 0) and annotation completeness, including the annotation of 4,144 new genes and 395 new gene clusters. Notably, several large structural variants were identified between the F. iinumae v1.0 and F. iinumae v2.0 genomes, with most gaps in the v1.0 assembly overlapping with structural variant breakpoints. Additionally, we found a significant expansion of telomeric repeats in the B subgenome of octoploid strawberries compared to F. iinumae. Interestingly, two telomeres consistently exhibited low repeat abundance in both the diploid and octoploid B subgenomes, suggesting significant contraction early in the evolution of F. iinumae. Furthermore, through multiple lines of genomic evidence-including phylogenetic analyses, genetic distance matrices, a burst of LTR insertions, and the distribution of NLR resistance genes, we conclude that F. iinumae may represent an early-diverging lineage within the strawberry genus. This updated assembly provides a crucial genomic resource for understanding of the origin and structural dynamics of the strawberry genus and facilitates further exploration of genome-wide consequences of polyploidy.