Kajadpai Napapohn, Angchuan Jirameth, Khunnamwong Pannida, Srisuk Nantana
Department of Microbiology, Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand.
Biodiversity Center Kasetsart University (BDCKU), Bangkok 10900, Thailand.
AIMS Microbiol. 2023 May 16;9(3):486-517. doi: 10.3934/microbiol.2023026. eCollection 2023.
The diversity of duckweed () associated yeasts was studied using a culture-dependent method. A total of 252 yeast strains were isolated from 53 duckweed samples out of the 72 samples collected from 16 provinces in Thailand. Yeast identification was conducted based on the D1/D2 region of the large subunit (LSU) rRNA gene sequence analysis. It revealed that 55.2% and 44.8% yeast species were Ascomycota and Basidiomycota duckweed associated yeasts, respectively. Among all, , a basidiomycetous yeast, was found as the most prevalent species showing a relative of frequency and frequency of occurrence of 21.8% and 25%, respectively. In this study, high diversity index values were shown, indicated by the Shannon-Wiener index (), Shannon equitability index () and Simpson diversity index () values of 3.48, 0.86 and 0.96, respectively. The present results revealed that the yeast community on duckweed had increased species diversity, with evenness among species. Principal coordinate analysis (PCoA) revealed no marked differences in yeast communities among duckweed genera. The species accumulation curve showed that the observed species richness was lower than expected. Investigation of the plant growth promoting traits of the isolated yeast on duckweed revealed that 178 yeast strains produced indole-3-acetic acid (IAA) at levels ranging from 0.08-688.93 mg/L. Moreover, siderophore production and phosphate solubilization were also studied. One hundred and seventy-three yeast strains produced siderophores and exhibited siderophores that showed 0.94-2.55 activity units (AU). One hundred six yeast strains showed phosphate solubilization activity, expressed as solubilization efficiency (SE) units, in the range of 0.32-2.13 SE. This work indicates that duckweed associated yeast is a potential microbial resource that can be used for plant growth promotion.
采用依赖培养的方法研究了浮萍相关酵母的多样性。从泰国16个省份采集的72个样本中的53个浮萍样本中，共分离出252株酵母菌株。基于大亚基（LSU）rRNA基因序列分析的D1/D2区域进行酵母鉴定。结果表明，浮萍相关酵母中，子囊菌门和担子菌门的酵母种类分别占55.2%和44.8%。其中，担子菌酵母是最常见的种类，相对频率和出现频率分别为21.8%和25%。在本研究中，香农-维纳指数（ ）、香农均匀度指数（ ）和辛普森多样性指数（ ）值分别为3.48、0.86和0.96，表明多样性指数较高。目前的结果表明，浮萍上的酵母群落物种多样性增加，物种间均匀度良好。主坐标分析（PCoA）表明，浮萍属间的酵母群落没有显著差异。物种积累曲线表明，观察到的物种丰富度低于预期。对分离自浮萍的酵母促进植物生长特性的研究表明，178株酵母菌株产生吲哚-3-乙酸（IAA）的水平在0.08-688.93 mg/L之间。此外，还研究了铁载体的产生和磷的溶解情况。173株酵母菌株产生铁载体，其活性单位（AU）为0.94-2.55。106株酵母菌株表现出磷溶解活性，溶解效率（SE）单位在0.32-2.13 SE范围内。这项工作表明，浮萍相关酵母是一种可用于促进植物生长的潜在微生物资源。
