Department of Microbiology, Faculty of Science, Kasetsart University, Bangkok, Thailand.
Academy of Science, The Royal Society of Thailand, Bangkok, Thailand.
PLoS One. 2020 Mar 16;15(3):e0230269. doi: 10.1371/journal.pone.0230269. eCollection 2020.
Secondary peat swamp forest (PSF) arise by degradation of primary PSF as a result of fire and human activities. Yeasts diversity of Kuan Kreng (KK) and Rayong Botanical Garden (RBG) PSF, which are two secondary PSF in southern and in eastern Thailand, respectively, were investigated. Yeasts were isolated from soil and peat soil by the dilution plate and enrichment techniques. From six samples collected from KK PSF, 35 strains were obtained, and they were identified based on the sequence analysis of the D1/D2 region of the large subunit (LSU) rRNA gene 13 species in 12 genera, and one potential new species of the genus Galactomyces were detected. Thirty-two strains were obtained from six samples collected from RBG PSF and 26 strains were identified as 13 known yeast species in 11 genera, whereas six strains were found to represent two potential new species of the genera Papiliotrema and Moesziomyces. Among yeast strains isolated from KK PSF, the number of strains in the phylum Ascomycota and Basidiomycota were equal, whereas there were slightly fewer strains in Ascomycota than in Basidiomycota among the strains obtained from RBG PSF. The yeast strains were evaluated for their antagonistic activities against fungal pathogens which cause rice diseases (Fusarium moniliforme, Helminthosporium oryzae, Rhizoctonia solani, Curvularia lunata and Pyricularia grisea) and postharvest disease of fruits (Phytophthora palmivora, Lasiodiplodia theobromae and Colletotrichum gloeosporioides). Twelve strains of seven species were found to be antagonistic yeast strains. Starmerella kuoi DMKU-SPS13-6, Hanseniaspora lindneri DMKU ESS10-9 and Piskurozyma taiwanensis DMKU-SPS12-2 capable to inhibit R. solani by 70.1-76.2%, Wickerhamomyces anomalus DMKU SPS6-1 and three Rhodotorula taiwanensis strains (DMKU SPS8-1, DMKU ESS9-3, DMKU SPS9-2) inhibited C. lunata by 69.8-71.9%, Hanseniaspora lindneri DMKU ESS10-9 and Scheffersomyces spartinae DMKU SPS9-3 inhibited P. grisea by 81.9-84.4% and four Papiliotrema laurentii strains (DMKU-SPS15-1, DMKU-ESS11-2, DMKU-ESS8-2, DMKU-ESS6-4) inhibited P. palmivora by 53.2-59.5%.
次生泥炭沼泽森林（PSF）是由于火灾和人类活动导致原生 PSF 退化而产生的。本研究调查了分别位于泰国南部和东部的两个次生 PSF，即关敬（KK）和罗勇植物园（RBG）PSF 的酵母多样性。通过稀释平板和富集技术从六个 KK PSF 样本中分离出酵母，从六个 RBG PSF 样本中获得了 32 株酵母，根据 LSU rRNA 基因 D1/D2 区序列分析，它们被鉴定为 12 属中的 13 种酵母，还检测到一种属于 Galactomyces 的潜在新种。从 KK PSF 中分离出的 35 株酵母中，有 13 种属于 11 个属，而从 RBG PSF 中分离出的 32 株酵母中，有 26 种属于 11 个属，有 6 株属于 Papiliotrema 和 Moesziomyces 两个属的潜在新种。在从 KK PSF 中分离出的酵母菌株中，子囊菌门和担子菌门的菌株数量相等，而从 RBG PSF 中分离出的菌株中，子囊菌门的菌株数量略少于担子菌门。对这些酵母菌株进行了抗真菌病原体（引起水稻病害的稻瘟病菌、稻曲病菌、立枯丝核菌、新月弯孢霉和稻瘟病菌）和水果采后病害（棕榈疫霉、胶孢炭疽菌和可可球二孢菌）的拮抗活性评估。从七个种的 12 个菌株中发现了具有拮抗活性的酵母菌株。Starmerella kuoi DMKU-SPS13-6、Hanseniaspora lindneri DMKU ESS10-9 和 Piskurozyma taiwanensis DMKU-SPS12-2 对 R. solani 的抑制率为 70.1-76.2%，Wickerhamomyces anomalus DMKU SPS6-1 和三个 Rhodotorula taiwanensis 菌株（DMKU SPS8-1、DMKU ESS9-3、DMKU SPS9-2）对 C. lunata 的抑制率为 69.8-71.9%，Hanseniaspora lindneri DMKU ESS10-9 和 Scheffersomyces spartinae DMKU SPS9-3 对 P. grisea 的抑制率为 81.9-84.4%，四个 Papiliotrema laurentii 菌株（DMKU-SPS15-1、DMKU-ESS11-2、DMKU-ESS8-2、DMKU-ESS6-4）对 P. palmivora 的抑制率为 53.2-59.5%。
