Bioactive steroids from seed germination supporting fungus (Ceratobasidium GS2) of the terrestrial orchid Gymnadenia conopsea

ABSTRACT

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.

KEYWORDS:

• Gymnadenia conopsea
• orchid mycorrhizal fungi
• Ceratobasidium sp.
• steroids
• biologic activity
• protocorm differentiation

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/21501203.2023.2254893.

Additional information

Funding

The work was supported by the National Natural Science Foundation of China (32170013) and CAMS Initiative for Innovative Medicine (2021-I2M-1-031).