As a member of ectomycorrhizal fungi, Tricholoma matsutake has a symbiotic relationship with its host, Pinus densiflora. To cultivate T. matsutake artificially, the co-cultivation of T. matsutake mycelia and bacteria from shiro was introduced. In this study, bacteria were isolated from soil samples in Bonghwa-gun, and seven bacterial isolates (B22_7_B05, B22_7_B06, B22_7_B07, B22_7_B08, B22_7_B10, B22_7_B13, and B22_7_B14) promoted the growth of T. matsutake mycelia (147.48, 232.11, 266.72, 211.43, 175.17, 154.62, and 177.92%, respectively). Sequencing of the 16S rRNA region of the isolated bacteria was performed. B22_7_B05 and B22_7_B10 were identified as Bacillus toyonensis, B22_7_B06 and B22_7_B08 as Paenibacillus taichungensis, B22_7_B07 and B22_7_B14 as P. gorilla, and B22_7_B13 as P. odorifer. These bacterial isolates were associated with the shiro community and are expected to contribute to the cultivation of T. matsutake.

Tricholoma matsutake is a traditional favorite food in East Asia, cultivated in fairy rings called “shiro,” which are found near Pinus densiflora. For effective artificial cultivation of Tri. matsutake, microorganisms from symbiotic fairy rings are co-cultivated. In this study, one bacterial isolate (Y22_B35) and two fungal isolates (Y22_F64 and Y22_F68) displayed growth-promoting effects on Tri. matsutake mycelium (158.47, 125.00, and 122.26% enhanced growth, respectively). For identification, 16S rRNA or ITS regions from the microorganisms¡¯ genomes were sequenced. Other sequences, including BenA, CaM, and RPB2 were sequenced in the fungal isolates. The bacterial isolate Y22_B35 was identified as Bacillus cereus. Y22_F64 and Y22_F68 were identified as Umbelopsis nana and Aspergillus parvulus, respectively. To identify the effects of the dominant microorganisms on Tri. Matsutake cultivation, metagenomic analyses were performed. Discovery of these Tri. matsutake mycelium growth-promoting microorganisms and metagenomics analyses are expected to contribute to our understanding of Tri. matsutake fruiting body growth and construction of biomimicry.

가송이(Tricholoma bakamatsutake Hongo)는 주름버섯목(Agaricales), 송이과(Tricholomataceae)에 속 하는 외생균근성 버섯류의 하나로, 송이(T. matsutake)와 일반적인 외형이 거의 비슷하며, 송이향과 맛이 강하게 나기 때문에 이 두 균종은 쉽게 혼동되며, 실제 분류 및 계통발생학적으로도 가송이와 송이는 유연 관계가 있는 것으로 밝혀졌다. 가송이는 한국, 일본, 대만, 중국의 신갈나무 등과 같은 활엽수림에 분포하는 것으로 알려져 있으며, 최근에는 제주도 구실잣밤나무림에서 발견되었다. 가송이는 균사생장이 매우 느려 연구에 어려움이 많아 균사배양 최적 조건을 구명하고자 본 연구를 실시하였다. 온도에 따른 가송이 균주 별 균사생장 특성을 조사한 결과, 모든 균주에서 25℃에서 가장 균사생장속도가 가장 빨랐으며, 특히 3833 균주가 다른 균주에 비해 약 1.5배 빠른 것으로 조사되었다.

To cultivate pine mushroom (Tricholoma matsutake) artificially, co-cultivation with microorganisms has been introduced. Here, experiments were performed to assess the growth-promoting effect of bacteria on T. matsutake mycelia. Bacteria were isolated from soil samples collected in Yangyang County, Korea. Four of the bacterial isolates (Y22_B06, Y22_B11, Y22_B18, and Y22_B22) exhibited a growth-promoting effect on T. matsutake mycelia (154.67%, 125.91%, 134.06%, and 158.28%, respectively). To analyze the characteristics of the bacteria, especially the antifungal activity, -amylase and cellulase activity assays were performed. In comparison with the controls, the isolated bacteria exhibited low -amylase and cellulase activity. 16S rRNA gene sequencing was performed to identify the four bacterial isolates. The isolates belonged to the Terrabacteria group and were identified as Microbacterium paraoxydans, Paenibacillus castaneae, Peribacillus frigoritolerans, and P. butanolivorans. These bacterial isolates are expected to have contributed to the growth promotion of T. matsutake mycelia and the artificial cultivation of T. matsutake.

In this study, we aimed to compare the mycelial growth of Pleurotus ostreatus after medium supplementation with various amino acids at different concentrations to select the optimal medium nutrient composition for mycelial growth. The mycelial growth of P. ostreatus was investigated after adding four amino acids (tryptophan, threonine, methionine, and lysine) at 0.5% or 1% to the medium.The rate of P. ostreatus mycelial growthwas faster in the potato dextrose agar (PDA) medium supplemented with threonine at 0.5% or 1% than that of the control, whereas it was inhibited by tryptophan treatment. Supplementation of sawdust mediumwith all amino acids, except tryptophan, at 0.5% did not alter the mycelial growth, compared to the controls. However, addition of any amino acid to sawdust medium at a higher concentration (1%) inhibited the mycelial growth. The laccase acitivity of P. ostreatus mycelium cultured in PDA medium was the highest when threonine was added, and the lowest when tryptophane was added, consistent with the results of the mycelial growth. Therefore, the addition of threonine, methionine, or lysine to PDA medium at a concentration of 0.5-1%was effective for increasing the mycelial growth of P. ostreatus; however, it inhibited mycelial growth insawdust medium, suggesting that the effects of amino acids dependedon the medium nutrient composition.

This study was conducted to investigate the growth and antioxidant activity of Pleurotus ostreatus mycelia grown in medium supplemented with Aronia. The diameter and dry weight of the mycelia were increased in the medium supplemented with Aronia compared with the untreated medium. The total polyphenol content of mycelia grown in medium supplemented with Aronia and untreated medium was 6.54 mg GAE/g and 5.77 mg GAE/g, respectively. The 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity of mycelia grown in medium supplemented with Aronia and untreated medium was 61.81% and 49.65%, respectively. Moreover, the 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity of mycelia grown in medium supplemented with Aronia and untreated medium was 59.83% and 52.66%, respectively. These results confirmed that P. ostreatus mycelial growth and antioxidant activity were increased when Aronia was added to the culture medium.

In this study, we determined the effect of different concentrations of Cd on the growth of Pleurotus ostreatus mycelia, which was confirmed using PDA, PDB, and a column test. The efficacy of treatment was evaluated using Cd at two concentrations, 10 ppm and 100 ppm. The extent of mycelial growth on PDA and PDB was similar to that observed in the untreated groups and those treated with 10 ppm Cd. However, it was found that the mycelial growth was suppressed in a system treated with Cd at concentrations of 100 ppm. Moreover, the extent of mycelial growth observed upon conducting a column test was similar to that obtained using PDA and PDB. When the composition of free amino acids in PDB was determined, their levels in the group treated with 100 ppm Cd were found to be similar to those of the control. However, the amounts of 15 amino acids in the group treated with 10 ppm of Cd had increased compared to those detected in the control.