Search

Assisted gene flow can restore genetic diversity when genetic drift has driven deleterious alleles to high frequencies in small, isolated populations. Previous crosses among 20 populations of Gymnadenia conopsea documented the strongest heterosis and the weakest inbreeding depression in sparse and small populations, consistent with fixation of mildly deleterious alleles by genetic drift. We genotyped the populations used for crosses, and used 1200–1728 SNPs to test the following predictions: (1) heterosis increases with genetic differentiation (FST) to donor populations and decreases with genetic diversity in the recipient population, (2) inbreeding depression increases with genetic diversity, and (3) genetic diversity increases, and mean FST to other populations decreases, with population size and density. Pairwise FST ranged from very low to moderate (0.005–0.20) and genetic diversity varied moderately among populations (proportion of polymorphic loci = 0.52–0.75). However, neither FST between populations, nor genetic diversity in the recipient population, were related to the strength of heterosis. There was also no association between genetic diversity and the strength of inbreeding depression. Genetic diversity increased and mean FST decreased with population size, consistent with reduced diversity and increased differentiation of small populations by genetic drift. The results indicate that the loci conferring heterosis are not mirrored by overall population differentiation, and limited additional information on potential source populations for genetic rescue is gained by the genetic data. Instead, the use of controlled crosses can directly reveal positive effects of introducing new genetic material, and is a simple method with high potential in conservation. [ABSTRACT FROM AUTHOR]

A bioactivity-guided separation strategy was used to identify novel antistroke compounds from Gymnadenia conopsea (L.) R. Br., a medicinal plant. As a result, 4 undescribed compounds (1–2, 13, and 17) and 13 known compounds, including 1 new natural product (3), were isolated from G. conopsea. The structures of these compounds were elucidated through comprehensive spectroscopic techniques, such as 1D/2D nuclear magnetic resonance (NMR) spectroscopy, high-resolution electrospray ionization mass spectrometry (HRESIMS), and quantum chemical calculations. An oxygen–glucose deprivation/reoxygenation (OGD/R)-injured rat pheochromocytoma (PC12) cell model was used to evaluate the antistroke effects of the isolates. Compounds 1–2, 10–11, 13–15, and 17 provided varying degrees of protection against OGD/R injury in the PC12 cells at concentrations of 12.5, 25, and 50 µM. Among the tested compounds, compound 17 demonstrated the most potent neuroprotective effect, which was equivalent to that of the positive control drug (edaravone). Then, transcriptomic and bioinformatics analyses were conducted to reveal the regulatory effect of compound 17 on gene expression. In addition, quantitative real-time PCR (qPCR) was performed to verify the results of the transcriptomic and bioinformatics analyses. These results suggest that the in vitro antistroke effect of compound 17 may be associated with the regulation of the Col27a1 gene. Thus, compound 17 is a promising candidate for the development of novel antistroke drugs derived from natural products, and this topic should be further studied. [ABSTRACT FROM AUTHOR]

ABSTRACT Fungi and bacteria often occupy very similar niches; they interact closely with each other, and bacteria can provide direct or indirect benefits to plants that form mutualistic interactions with fungi. In orchids, successful seed germination largely depends on compatible mycorrhizal fungi, but whether and how bacteria contribute to seed germination and protocorm development remains largely unknown. Here, we performed field and laboratory experiments to assess the potential role of bacteria in mediating seed germination and protocorm development in the terrestrial orchid Gymnadenia conopsea. Our results suggested that bacterial and fungal communities differ between developmental stages in the germination process. The diversity of bacterial and fungal communities and their interaction network in germinating seeds (Stage 1) differed significantly from those in later developmental stages (Stages 2–5). Pseudomonas gradually became the dominant bacterial group as the protocorms matured and showed a positive association with Ceratobasidiaceae fungi. Seed germination tests in vitro demonstrated that co-inoculation of Ceratobasidium sp. GS2 with Pseudomonas isolates significantly improved protocorm growth and development, suggesting that the observed increase in Pseudomonas abundance during protocorm development directly or indirectly improves the growth of germinating seeds. Overall, our findings indicate that bacteria may exert non-negligible effects on seed germination of orchids and, therefore, offer valuable perspectives for future strategies for conservation and cultivating orchid species.IMPORTANCEIt is well known that orchid seeds depend on mycorrhizal fungi to supply the necessary nutrients that support germination in natural environments. Apart from fungi, bacteria may also be involved in the germination process of orchid seeds, but so far, their role has not been intensively studied. This research provides evidence that bacterial community composition changes during seed germination of the terrestrial orchid Gymnadenia conopsea. Interestingly, in vitro experiments showed that Pseudomonas spp., which were the most dominant bacteria in the later germination stages, improved protocorm growth. These results suggest that bacteria contribute to the germination of orchid seeds, which may open new perspectives to apply bacteria as a biofertilizer in the introduction and restoration of G. conopsea populations.

[Objective] The present paper aimed to explore the effects of environmental factors on bacterial community structure in rhizosphere soil of wild Gymnadenia conopsea in Tibet. (Method) Therefore, four sampling sites were selected to collect soil samples, including the abandoned timber factory (FM), Linzhi viewing station (LZ), Linhai viewing station (LH), and the radar station (LD), and the high-throughput sequencing technology was used to analyze the diversity and structure of bacterial community in rhizosphere soil of G. conopsea at different altitudes, and the effects of different environmental factors on the diversity and structure of bacterial community were analyzed. [Result] The total of 32 phyla, 90 classes, 224 orders, 378 families, and 693 genera were detected in all samples. Proteobacteria, Actinobacteria and Acidobacteria were the dominant phyla, Bradyrhizobium and Chryseobacterium were the dominant genera. With the increase of altitude, the diversity and richness of rhizosphere soil bacterial community increased, and the difference between groups was greater than the difference within groups. [Conclusion] Altitude, TK, pH and EC significantly affected the bacterial community composition in rhizosphere soil at phylum level. Three environmental factors, namely TK, TP and altitude, had more obvious effects on bacterial community composition at genus level. Key words: Gymnadenia conopsea; Environmental factor; Rhizosphere soil bacteria; Community diversity; Community structure [ABSTRACT FROM AUTHOR]

ABSTRACTAlmost all orchids rely on mycorrhizal fungus to support their seed germination. To date, the effect of active components in mycorrhizal fungus on orchid seed germination largely remains unknown. In this study, we aimed to investigate the impact of active components found in mycorrhizal fungus on orchid seed germination. Specifically, we focused on a terrestrial orchid Gymnadenia conopsea and its host-specific seed germination supporting fungus Ceratobasidium GS2. In total, several steroids (1–7) were isolated from this fungus. Notably, compounds 1, 2, 4, and 5 exhibited significant enhancements in protocorm volume. Moreover, compounds 1–6 demonstrated strong promotion of protocorm differentiation. These findings suggest that steroids may play a crucial role in the symbiotic germination of G. conopsea seeds. Future studies should continue to explore the specific mechanisms through which these steroids exert their effects, contributing to our understanding of orchid biology and mycorrhizal interaction.

[Objective] The study aimed to analyze the diversity of fungi community in the rhizosphere soil of Gymnadenia conopsea and its correlation with soil environmental factors, so as to provide reference for exploring the work of resource protection and sustainable utilization such as artificial cultivation and ecological planting of G. conopsea. [Method] High-flux sequencing and comparative analysis were carried out on the diversity of rhizosphere soil fungal communities of G. conopsea in Aruhorqin Banner, Dongwuzhumuqin Banner and Ongniud Banner of Inner Mongolia by using Illumina Miseq high-throughput sequencing technology, and the physical and chemical properties and correlation of plant rhizosphere soil were analyzed. [Result] The rhizosphere soil of G. conopsea was acidic, rich in organic matter and available potassium, but low in nitrogen and phosphorus, and the soil physical and chemical properties in different distribution areas were significantly different. A total of 5125 OTUs were obtained from soil samples from three distribution areas, belonging to 11 phyla, 31 classes, 65 orders, 161 families and 158 genera. At the phylum level, the dominant phyla of fungi in the rhizosphere soil of the three distribution areas were Ascomycota and Basidiomycota. At the genus level, Trichoglossum, Hygrocybe and Mortierella were the dominant groups of G. conopsea rhizosphere soil fungi. Alpha diversity index showed that the general trend of diversity and richness of rhizosphere soil fungal community in G. conopsea in the three distribution areas was Al > D3 > W2; Beta diversity index showed that there were some differences in the composition of true communities in rhizosphere soil of G. conopsea in the three distribution areas. The contents of total potassium, total phosphorus, total nitrogen and water in the soil may be the key factors affecting the composition of the fungal community in the rhizosphere soil of G. conopsea distributed in Inner Mongolia. Among them, Hygrocybe and Clavulinosis had significant positive correlation with the key factors of soil environment; However, there was a significantly negative correlation between the key factors of soil environment and the pathogenic species of Hyphomycea and Fusarium. [Conclusion] Through the results of the study, we have a preliminary understanding of the growth soil conditions and characteristics of the rhizosphere soil fungal community of G. conopsea distributed in Inner Mongolia. Among the three different distribution areas, the diversity and richness of the rhizosphere soil fungal community of G. conopsea in Aruhorqin Banner are the highest. Soil physical and chemical properties have a great impact on the diversity of fungi in the rhizosphere soil of G. conopsea, and other influencing factors need to be further studied. [ABSTRACT FROM AUTHOR]

Almost all orchids rely on mycorrhizal fungus to support their seed germination. To date, the effect of active components in mycorrhizal fungus on orchid seed germination largely remains unknown. In this study, we aimed to investigate the impact of active components found in mycorrhizal fungus on orchid seed germination. Specifically, we focused on a terrestrial orchid Gymnadenia conopsea and its host-specific seed germination supporting fungus Ceratobasidium GS2. In total, several steroids (1–7) were isolated from this fungus. Notably, compounds 1, 2, 4, and 5 exhibited significant enhancements in protocorm volume. Moreover, compounds 1–6 demonstrated strong promotion of protocorm differentiation. These findings suggest that steroids may play a crucial role in the symbiotic germination of G. conopsea seeds. Future studies should continue to explore the specific mechanisms through which these steroids exert their effects, contributing to our understanding of orchid biology and mycorrhizal interaction. [ABSTRACT FROM AUTHOR]