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The vegetative propagation of ectomycorrhizal truffle fungi is limited by their slow mycelial growth. Many factors including media, isolate genotypes and environmental conditions can alter fungal mycelial growth rates. This study aimed to improve the in vitro growth rate of Tuber brumale by determining the optimal carbohydrate and nitrogen sources, temperature and pH. After 8 weeks, the highest level of growth and densest hyphal branching were recorded in the medium containing glucose as the main carbohydrate. For nitrogen, glutamine (200 mg N l-1) provided the greatest hyphal growth and density compared to the other amino acid treatments. Regarding temperature, 16?C proved to be optimal for T. brumale growth and branching. Media of pH 6 and pH 7 were most favourable for the growth of T. brumale. The results from this research provide baseline data on the vegetative nutrition of T. brumale and have implications for the in vitro culture of winter truffle hyphae.
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Effects of Field Fumigation and Inoculation With the Pecan Truffle (Tuber lyonii) on the Fungal Community of Pecan (Carya illinoinensis) Seedlings Over 5 Years
Truffle fungi are esteemed for their aromatic qualities and are among the most widely cultivated edible ectomycorrhizal fungi. Here we document a successful method for establishing Tuber lyonii , the pecan truffle, on pecan ( Carya illinoinensis ) seedlings in a field setting. We assessed the impacts of soil fumigation and varying concentrations of truffle spore inoculum on the ectomycorrhizal fungal and the complete fungal communities as well as the colonization of T. lyonii on pecan roots at three nurseries in Georgia, United States. To identify fungal communities on pecan seedlings, we performed high-throughput amplicon sequencing of the fungal ITS1 rDNA region. Our 5-year long field experiment demonstrates that fumigation and inoculation together resulted in the highest persistence of T. lyonii on pecan roots. While fungal OTU numbers fluctuated over the years of our experiments, there was no statistical support to demonstrate diversification of communities when Shannon diversity metrics were used. However, we did find that older seedlings were less likely to be dominated by T. lyonii compared to younger ones, suggesting successional changes in the fungal community over time. This suggests that transplanting inoculated seedlings after 2 or 3 years post-inoculation is optimal for future truffle propagation efforts. Our results demonstrate that T. lyonii can be established in situ with methods that are compatible with current pecan nursery industry practices and that fungal communities on pecan seedlings vary depending on the experimental treatments used during planting. While the pecan truffle is not yet widely cultivated, our results provide insights for future large-scale cultivation of this and perhaps other Tuber species.
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- Award ID(s):
- 1946445
- PAR ID:
- 10314647
- Date Published:
- Journal Name:
- Frontiers in Microbiology
- Volume:
- 12
- ISSN:
- 1664-302X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3389/fmicb.2021.661515
