An exploration of mechanism of high quality and yield of Gastrodia elata Bl. f. glauca by the isolation, identification, and evaluation of Mycena

Abstract

<i>Gastrodia elata</i> Bl. <i>f. glauca</i> is an important traditional Chinese medicinal plant. The yield and quality of <i>Gastrodia elata</i> Bl. have significantly decreased due to multigenerational asexual reproduction. Therefore, it is necessary to have sexual reproduction of <i>Gastrodia elata</i> Bl. to supplement the market supply. Seeds of <i>G. elata</i> Bl. have no endosperm, and their sexual reproduction depends on the nutrients provided by the embryo cells infected by <i>Mycena</i> fungi to complete seed germination. However, <i>Mycena</i> fungi are small and have many species, and not all <i>Mycena</i> fungi can promote the germination of <i>G. elata</i> Bl. seeds. Therefore, it is of great significance to isolate and identify suitable germination fungi and explore the mechanism for improving the production performance and yield, and quality of <i>G. elata</i> Bl. Six closely related <i>Mycena</i> isolates, JFGL-01, JFGL-02, JFGL-03, JFGL-04, JFGL-05, and JFGL-06, were isolated from the leaves and protocorms of <i>G. elata</i> Bl. <i>f. glauca</i> and were identified as <i>Mycena purpureofusca</i>. The mycelial state and number of germinating protocorms were used as indicators to preferentially select <i>Mycena</i> fungi, and it was concluded that JFGL-06 had the best mycelial state and ability to germinate <i>G. elata</i> Bl. seeds. Finally, a mechanism to increase the yield of <i>G. elata</i> Bl. was explored by comparing the changes in nutrient elements and microbial diversity in the soil around <i>G. elata</i> Bl. with different strains. JFGL-06 proved to be an excellent <i>Mycena</i> fungal strain suitable for <i>G. elata</i> Bl. <i>f. glauca</i>. Compared with the commercial strain, JFGL-06 significantly increased the C, N, Na, Mg, S, Cl, K, Ca, and Fe contents of the soil surrounding the protocorms of <i>G. elata</i> Bl. <i>f. glauca</i>. JFGL-06 improved the composition, diversity, and metabolic function of the surrounding soil microbial community of <i>G. elata</i> Bl. <i>f. glauca</i> protocorms at the phylum, class, and genus levels, significantly increased the relative abundance of bacteria such as <i>Acidobacteria</i> and fungi such as <i>Trichoderma</i> among the dominant groups, and increased the abundance of functional genes in metabolic pathways such as nucleotide metabolism and energy metabolism. There was a significant reduction in the relative abundance of bacteria, such as <i>Actinomycetes,</i> and fungi, such as <i>Fusarium,</i> in the dominant flora, and a reduced abundance of functional genes, such as amino acid metabolism and xenobiotic biodegradation and metabolism. This is the main reason why the JFGL-06 strain promoted high-quality and high-yield <i>G. elata</i> Bl. <i>f. glauca</i> in Changbai Mountain.