Male Idesia polycarpa, which display distinct morphological and physiological traits, exhibit greater adaptability to stressful environments than females. However, the connection between this adaptability and rhizosphere processes remains unclear. Here, we investigate the differences in root bacterial community structures between male and female plants at different developmental stages, identifying bacterial strains associated with plant sex through functional predictions. This study aims to inform the optimal allocation of male and female plants during cultivation and provide a theoretical basis for sex identification and breeding. Samples from seven-year-old male and female plants were collected during the flowering (May) and fruit ripening (October) stages. Rhizosphere nutrient content and bacterial diversity were analyzed using Illumina high-throughput sequencing technology. The results demonstrate that total nitrogen (TN), total carbon (TC), and available potassium (AK) varied between sexes at different times. No significant differences between male and female plants were observed in the Shannon, Simpson, and Chao1 indexes during the flowering period. However, the Chao1 and Shannon indexes were significantly higher at fruit maturity in male rather than female plants. The predominant phyla of rhizosphere bacteria were Pseudomonadota, Acidobacteriota, and Actinomycetes. Interestingly, from flowering to fruit ripening, the dominant phyla in both male and female plants shifted from Actinomycetes to Pseudomonadota. A significant correlation was observed between pH and AK and rhizosphere bacteria (p < 0.05), with metabolism being the main functional difference. This study provides preliminary insights into the functional predictions and analyses of bacteria associated with Idesia polycarpa. The above findings lay the groundwork for further investigation into the sex-specific differences in microbial flora across different developmental stages, elucidating the mechanisms underlying flora changes and offering theoretical support for the high-quality management of Idesia polycarpa.

To explore the differences in the fine root characteristics and rhizosphere environment of male and female Idesia polycarpa Maxim at different stages, 7-year-old male and female I. polycarpa were used as plant materials. The fine root characteristics were measured with a root scanner, and rhizosphere soil was collected at the flowering stage (May), fruit accumulation stage (July), and fruit maturity stage (October). In addition, this study analyzed the soil nutrient characteristics of these conditions at different stages. At the same time, Illumine high-throughput sequencing technology and gas chromatography–tandem mass spectrometry (GC–MS) technology were used to analyze the rhizosphere microbes and metabolites of male and female plants at different stages. The results showed that the total root length, surface area, total volume, root tip number, and total average diameter of the fine root of female plants were larger than those of male plants, and the difference reached its maximum in the fruit material accumulation stage. Total carbon (TC) and total nitrogen (TN) content in the rhizosphere soil of male and female plants significantly differed over multiple stages, while available soil nitrogen and potassium content significantly differed during fruit ripening. The rhizosphere microbial composition of male and female plants was similar, and the dominant bacteria in the rhizosphere soil of each stage were Proteobacteria, Acidobacteria, Ascomycota, and Mortierellomycota. The relative abundance of Bacillus, Arthrobacter, Volutella, and Neocosmospora in rhizosphere soil at different stages differed between male and female plants. Combined with the OPLS-DA model and database retrieval, 29 significantly different metabolites, most of which were carbohydrates, were detected in the rhizosphere soil of male and female plants. Moreover, there were more significant metabolites in the rhizosphere soil at the flowering stage than in the fruit ripening stage. Through RDA analysis, available potassium (AK), Pedomicrobium, Chaetomium, and Glucose 1 had the greatest influence on fine root traits of I. polycarpa. The results indicated that the fine root traits were negatively correlated with AK and rhizosphere metabolites. Moreover, positive correlations were found with rhizosphere microorganism traits. The above results laid a foundation for the field management of I. polycarpa and the screening and application of rhizosphere growth-promoting bacteria resources.

Idesia polycarpa Maxim is described as a dioecious species, in which flowers are female or male, but we have also found individuals with bisexual flowers. The study aimed to provide the theoretical basis for the artificial control on flowering, fruiting, and floral initiation of Idesia polycarpa Maxim species. The morphological and anatomical structure of female, male, and bisexual flowers of I. polycarpa was studied. In this study, the routine paraffin section and morphological observation methods were used. The flowering of I. polycarpa began in late July. Results showed that the short-branch terminal bud was the highest percentage of floral bud position both in the female and male plants compared to the other bud types, and the proportion was 68.6% and 76.3%, respectively. Evidence from floral structural analysis suggests that the female and male flowers of I. polycarpa are unisexual by abortion. The ovary of the male flower stops developing after the ovule primordium initiation. The female, male, and bisexual flowers of I. polycarpa had the same anatomical structure at the beginning of development, but differences emerge in the differentiation stage of the female and male. In the bisexual flowers, females and males develop normally and may produce fruits. The study suggests that the bisexual, male, and female flowers were produced on the separate plants of the same species; therefore, the species is trioecious.

Key message: The dioeciousIdesia polycarpaall that males and females do not invest in the same way in growth and branching in quantity, type of axes and in time (annual growth and sequence of these events over time). The annual growth of plants is an important indicator for growth and development, especially for younger trees. The aim of this study was to decide the physiological basis for vegetative growth effects on the trunk and crown development in Idesia polycarpa by assessing the effects on variations in bud growth, leaf, and canopy size. This study focused on the annual vegetative growth of young (3-year old) female and male I. polycarpa Maxim trees and their functions are separate. The phenology provides a challenge in the production of resources (seed, oil) and to investigate the effect of sexual specialization. Here we describe the variations between two sexes in terms of vegetative growth in our field studies. The study began in the sprouting season with observations of the gradual growth of the newly sprouting buds. The length of expansion, diameter growth, and leaf production from the terminal bud (TB), lateral terminal bud (LTB) of the first tier of branches (1Y), second tier of branches (2Y), and third tier of branches (3Y) of the trees were measured. The results showed growth differences between female and male groups in the growing year. The length of shoot expansion, diameter, and leaf production were higher for female trees than for male trees. Male trees grew more long and short branches (SB) than the female trees, with large numbers of short branches on the 1Y and 2Y of the male trees. Further investigation needed to analyze factors of annual fluctuation of the shoot expansion of the tree, with more studies investigating complex branching phenomenon, flowering, and fruit production in I. polycarpa Maxim.

Idesia polycarpa Maxim is an emerging oil plant species. Understanding its microecological characteristics and internal mechanisms can serve as a basis for field management and the screening and application of growth-promoting bacteria during the growth phase of young trees. This study used three-year-old young I. polycarpa to analyze the tree’s root morphology, soil, and leaf nutrient status variations from May to October. In addition, differences in the rhizosphere soil, leaf metabolites, and microorganisms were observed. The results showed that, from May to October, the total nitrogen (TN) in the soil significantly decreased, whereas the TN, total potassium (TK), and total phosphorus (TP) in the leaves differed (p < 0.05). The leaf-dominant bacteria changed from Pseudomonadota to Firmicutes phylum. In addition, the relative abundance of soil and leaf-dominant bacteria decreased. The study found that the soil and leaf differential metabolites were mainly sugars and phenolic acids. The soil bacterial community showed a significant correlation with soil pH, available potassium (AK), available phosphorus (AP), and TN (p < 0.05). Further, the soil fungal community was significantly correlated with pH and AK (p < 0.001). TP, pH, and TK were the main factors influencing the leaf bacterial community, while the leaf fungal community was significantly correlated with five factors, including pH, TC, and TN. The root morphology was also mainly affected by pH, Pedomicrobium sp., Talaromyces sp., Penicillium sp., and D-Mannitol 2.

Volatiles are essential substances that determine distinct fruit flavors and user preferences. However, the metabolic dynamic and molecular modulation models that regulate the overall flavor generation during fruit growth and ripening are still largely unclear for most fruit species. To comprehensively analyze the molecular mechanism and regulation mechanism of aroma accumulation and aroma component formation in Pyrus spp. ‘Panguxiang’ (‘Panguxiang’pear), this study compared pear phenotype, sugars, organic acid content, and the expression of related genes and metabolites amid pear growth and development in Pyrus spp. ‘Panguxiang’. A total of 417 VOCs (4 amines, 19 aromatics, 29 aldehydes, 31 alcohols, 38 ketones, 64 heterocyclic compounds, 89 terpenoids, 94 esters, and 49 others) were found. The potential gene expression patterns were explored by combining transcriptomics and metabolomics, and VOC-associated metabolism and transcriptome data from all samples were integrated during the growth and development period. On this basis, we constructed a colorful model depicting changes in the VOCs and genes throughout pear growth and development. Our findings reveal that terpenoid biosynthesis pathways are the main aroma production pathways during pear growth and development. In addition to providing novel insights into the metabolic control of fruit flavor during growth and development, this study also provides a new theoretical basis for studying aroma metabolites in pears.