Diversity of Endophytic Microbes in Taxus yunnanensis and Their Potential for Plant Growth Promotion and Taxane Accumulation

Abstract

Taxus spp. are ancient tree species that have survived from the Quaternary glacier period, and their metabolites, such as taxol, have been used as anticancer drugs globally. Plant–endophytic microbial interaction plays a crucial role in exerting a profound impact on host growth and secondary metabolite synthesis. In this study, high-throughput sequencing was employed to explore endophytic microbial diversity in the roots, stems, and leaves of the Taxus yunnanensis (T. yunnanensis). The analysis revealed some dominant genera of endophytic bacteria, such as Pseudomonas, Neorhizobium, Acidovorax, and Flavobacterium, with Cladosporium, Phyllosticta, Fusarium, and Codinaeopsis as prominent endophytic fungi genera. We isolated 108 endophytic bacteria and 27 endophytic fungi from roots, stems, and leaves. In vitro assays were utilized to screen for endophytic bacteria with growth-promoting capabilities, including IAA production, cellulase, siderophore production, protease and ACC deaminase activity, inorganic phosphate solubilization, and nitrogen fixation. Three promising strains, Kocuria sp. TRI2-1, Micromonospora sp. TSI4-1, and Sphingomonas sp. MG-2, were selected based on their superior growth-promotion characteristics. These strains exhibited preferable plant growth promotion when applied to Arabidopsis thaliana growth. Fermentation broths of these three strains were also found to significantly promote the accumulation of taxanes in T. yunnanensis stem cells, among which strain TSI4-1 demonstrated outstanding increase potentials, with an effective induction of taxol, baccatin III, and 10-DAB contents. After six days of treatment, the contents of these metabolites were 3.28 times, 2.23 times, and 2.17 times the initial amounts, reaching 8720, 331, and 371 ng/g of dry weight of stem cells, respectively. These findings present new insight into the industrialization of taxol production through Taxus stem cell fermentation, thereby promoting the conservation of wild Taxus resources by maximizing their potential economic benefits.

Optimization of the fermentation media, mathematical modeling, and enhancement of paclitaxel production by Alternaria alternata after elicitation with pectin

“…Endophytic fungi offer several advantages, including rapid growth, ease of cultivation, and potential genetic manipulation, making them attractive candidates for paclitaxel production 21 . Extensive research has been devoted to isolating and characterizing a diverse array of endophytic fungi capable of paclitaxel biosynthesis 22 , with the ultimate goal of developing sustainable and scalable production methods 23 .…”

Endophytic Bacterium Flexivirga meconopsidis sp. nov. with Plant Growth-Promoting Function, Isolated from the Seeds of Meconopsis integrifolia

“…TSI4-1, and Sphingomonas sp. MG-2 [15], exhibit the ability to fix nitrogen, dissolve phosphate, produce IAA, and promote plant growth.…”