Pectins are major components of cell walls in plants. Pectin methylesterases (PMEs) and pectin methylesterase inhibitors (PMEIs) play crucial roles in pectin synthesis and metabolism. Overall, 28 putative DkPMEs and 29 putative DkPMEIs were identified from the D. kaki genome. According to phylogenetic analysis, DkPME/DkPMEI proteins can be classified into four and five clades, respectively. Motif and gene structure analysis showed that DkPME/DkPMEI are highly conserved in the same clades, which indicates that the function of these DkPME/DkPMEI were similar. Besides, DkPME/DkPMEI genes were distributed unevenly on their corresponding chromosomes. Synteny analysis showed that PME or PMEI gene usually matched with more than one DkPME/DkPMEI in D. oleifera, D. lotus, and A. thaliana, implying that the function of these genes in D. kaki may be diverse. Expression analysis showed that DkPME/DkPMEI from the same clade exhibited diverse expression patterns, indicating that these genes might have diverse functions. Functional protein–protein interaction network analysis showed that DkPMEI21 and DkPMEI15 were core nodes and were, respectively, positive and negative regulators for carbohydrate metabolism, stress responses, and sugar signaling. This study provides a theoretical basis for the functional characteristics, evolutionary relationship, and role of these gene families in developing persimmon fruit.

Lilac (Syringa oblata Lindl.) is an important eco-economic aromatic shrub in northern China; however, the key volatile organic compounds (VOCs) responsible for its floral aroma and their origin remain largely unexplored. In this study, we conducted an integrated analysis of volatile metabolomics and transcriptomics to elucidate the composition, dynamic changes, and potential regulatory network of VOCs across different floral organs and petal developmental stages. A total of 1440 VOCs were identified in the stamens, pistils, and petals, with petals being the primary contributors to the overall floral aroma. Analysis of different petal developmental stages revealed that the full-bloom stage (S3) is critical for VOCs emission. The floral aroma of S. oblata is primarily composed of terpenoids, alcohols, and aldehydes. By relative odor activity value (rOAV) with multivariate statistical screening, seven key VOCs with high contributions to the floral aroma were identified. Transcriptome analysis identified 69,935 differentially expressed genes (DEGs) across petal developmental stages, which were predominantly enriched in metabolic pathways and the biosynthesis of secondary metabolites. The expression patterns of these DEGs were highly consistent with the accumulation trends of VOCs, increasing at stages S2 and S3 and subsequently declining at stage S4. Integrative analysis of VOCs and gene expression further identified candidate genes significantly correlated with the key aroma volatiles. Specifically, the carotenoid pathway-related genes CYP97A3 and LYC may influence the formation of carotenoid-derived volatiles and floral aroma. Additionally, genes associated with the fatty acid-lipoxygenase pathway, transport-related genes, and transcription factors are potentially involved in the formation and regulation of aldehyde and alcohol volatiles. These findings advance our understanding of the floral aroma formation in S. oblata and provide metabolic basis, candidate gene resources and a theoretical foundation for the genetic improvement of aroma traits and the breeding of new cultivars.

Rubus sachalinensis, a Mongolian medicinal plant, serves as a valuable raspberry breeding resource due to its high value and stress resistance. Global climate change and human logging have contributed to its gradual decline in population. In this study, we utilized MaxEnt modeling to forecast the potential distribution of suitable habitat for R. sachalinensis under changing climatic conditions, aiming to facilitate controlled cultivation to lessen dependence on wild populations and support conservation efforts. In this study, by integrating 573 global distribution records of R. sachalinensis with 22 environmental variables related to climate and terrain, we developed the MaxEnt model and selected 11 variables based on the correlation (correlation threshold r < 0.8) for analysis. Through the jackknife method, we found that the distribution of R. sachalinensis is primarily influenced by precipitation during the warmest quarter (bio18, 43%), mean temperature of the coldest quarter (bio11, 20.5%), temperature seasonality (bio4, 17.1%), and slope (12.2%). The habitat of R. sachalinensis reached its maximum extent during the Last Interglacial period, subsequently decreased, and then expanded to 4726.25 × 10³ km² during the Mid-Holocene period, and currently stands at 5293.45 × 10³ km² in northeastern China, eastern Mongolia, and southeastern Russia, with a smaller distribution in North America, particularly in western Canada. Future projections indicated a declining trend in SSP1_2.6 and SSP5_8.5, with the centroid expected to shift eastward. Consequently, due to environmental changes, the suitable habitat distribution of R. sachalinensis will shift eastward, leading to a reduction in habitat area, and human logging will further exacerbate the reduction in wild resources. The resources within the area that remain constant from the ancient climate period to the future suitable habitat should be strengthened for protection, as well as the resources in the shrinking areas. These findings provide potential distribution information and dynamic changes in R. sachalinensis, which will provide vital data for identifying important conservation areas and sustainable harvesting.

Lilac flowers emit diverse volatile organic compounds (VOCs) that contribute to their characteristic fragrance. However, limited research has been conducted on the characteristics of VOCs emitted by naturally grown lilac flowers from the bud to withering stages. To investigate the variations in the VOCs of lilacs across different developmental stages, dynamic headspace sampling combined with gas chromatography-mass spectrometry (GC-MS) detection was adopted to collect and identify VOCs emitted by Syringa oblata, Syringa meyeri and Syringa vulgaris at various developmental stages, and statistical methods were applied to screen key differential compounds. A total of 73 VOCs belonging to 7 categories were emitted by the three lilac species across all developmental stages, and the VOCs content differed significantly among developmental stages. For Syringa oblata, 2-butenal and octanal peaked at the full flowering stage. While 2-ethyl-2-hexenal and (Z)-3,7-dimethyl-1,3,6-octatriene were the most abundant substances in Syringa meyeri at the flowering stage, most VOCs in Syringa vulgaris exhibited a U-shaped trend, which is opposite to the development of the other two lilacs. Terpenoids, including camphene, Limonene, and β-pinene, were observed to change considerably during flower development. These results revealed the dynamic distribution of VOCs in lilacs at different developmental stages.