Camellia oleifera is a widely planted woody oil crop with economic significance because it does not occupy cultivated land. The sugar-derived acetyl-CoA is the basic building block in fatty acid synthesis and oil synthesis in C. oleifera fruit; however, sugar metabolism in this species is uncharacterized. Herein, the changes in sugar content and metabolic enzyme activity and the transcriptomic changes during C. oleifera fruit development were determined in four developmental stages (CR6: young fruit formation; CR7: expansion; CR9: oil transformation; CR10: ripening). CR7 was the key period of sugar metabolism since it had the highest amount of soluble sugar, sucrose, and glucose with a high expression of genes related to sugar transport (four sucrose transporters (SUTs) or and one SWEET-like gene, also known as a sugar, will eventually be exported transporters) and metabolism. The significant positive correlation between their expression and sucrose content suggests that they may be the key genes responsible for sucrose transport and content maintenance. Significantly differentially expressed genes enriched in the starch and sucrose metabolism pathway were observed in the CR6 versus CR10 stages according to KEGG annotation. The 26 enriched candidate genes related to sucrose metabolism provide a molecular basis for further sugar metabolism studies in C. oleifera fruit.

Michelia shiluensis is a rare and endangered magnolia species found in South China. This species produces beautiful flowers and is thus widely used in landscape gardening. Additionally, its timber is also used for furniture production. As a result of low rates of natural reproduction and increasing levels of human impact, wild M. shiluensis populations have become fragmented. This species is now classified as endangered by the IUCN. In the present study, we characterized the complete chloroplast genome of M. shiluensis and found it to be 160,075 bp in length with two inverted repeat regions (26,587 bp each), a large single-copy region (88,105 bp), and a small copy region (18,796 bp). The genome contained 131 genes, including 86 protein-coding genes, 37 tRNAs, and 8 rRNAs. The guanine-cytosine content represented 39.26% of the overall genome. Comparative analysis revealed high similarity between the M. shiluensis chloroplast genome and those of four closely related species: Michelia odora, Magnolia laevifolia, Magnolia insignis, and Magnolia cathcartii. Phylogenetic analysis shows that M. shiluensis is most closely related to M. odora. The genomic information presented in this study is valuable for further classification, phylogenetic studies, and to support ongoing conservation efforts.