Xiao Jia-Lei, Sun Jian-Guang, Pang Bo, Zhou Xin, Gong Yuan, Jiang Lichao, Zhang Luan, Ding Xiaodong, Yin Jing
College of Life Science, Northeast Agriculture University, Harbin, 150030, China.
Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education (Northeast Forestry University), Harbin, 150040, China.
Appl Microbiol Biotechnol. 2021 Jan;105(2):755-768. doi: 10.1007/s00253-020-11048-2. Epub 2021 Jan 6.
In this study, we firstly reported the large-scale screening and isolation of endophytic fungi from nine wild and six cultivated soybeans in the cold regions of China. We totally isolated 302 endophytic fungal strains, of which 215 strains are isolated from the wild soybeans and 87 are identified from cultivated soybeans. Among these endophytic fungal strains, in the roots, stems, and leaves, 24.17% were isolated from roots, 28.8% were isolated from stems, and 47.01% were isolated from leaves, respectively. Most endophytic fungal strains isolated from the wild soybean roots were the species of Fusarium genus, and the fungal strains in the stems were the species of ascomycetes and Fusarium fungi, whereas most strains in the leaves were Alternaria fungi. To analyze the taxonomy of the obtained samples, we sequenced and compared their rDNA internal transcribed spacer (ITS) sequences. The data showed that 6 strains are putatively novel strains exhibiting ≤ 97% homology with the known strains. We next measured the secondary metabolites produced by the different strains and we found 11 strains exhibited high-performance synthesis of triterpenoids, phenols, and polysaccharides. Furthermore, we characterized their tolerance to abiotic stresses. The results indicated that 4 strains exhibited high tolerance to cadmium, and some strains exhibited resistance to acid, and alkali. The results of the study could facilitate the further exploration of the diversity of plant endophytic fungi and the potential applications of the fungi to practical agriculture and medicine industries. KEY POINTS: • 302 endophytic fungal strains isolated from wild soybean and cultivated soybean • 11 strains had high contents of triterpenoids, phenols, and polysaccharides • 4 strains exhibited high Cd tolerance, and a few strains with strong tolerance to acid and alkali solution.
在本研究中，我们首次报道了对中国寒冷地区9种野生大豆和6种栽培大豆进行内生真菌的大规模筛选与分离。我们共分离出302株内生真菌菌株，其中215株从野生大豆中分离得到，87株从栽培大豆中鉴定得到。在这些内生真菌菌株中，根、茎、叶中分别有24.17%、28.8%和47.01%的菌株被分离得到。从野生大豆根部分离出的大多数内生真菌菌株为镰刀菌属，茎中的真菌菌株为子囊菌和镰刀菌，而叶中的大多数菌株为链格孢属真菌。为了分析所获样本的分类学，我们对其核糖体DNA内转录间隔区（ITS）序列进行了测序和比较。数据显示，有6株菌株被推测为新菌株，与已知菌株的同源性≤97%。接下来，我们测定了不同菌株产生的次生代谢产物，发现有11株菌株表现出三萜类、酚类和多糖的高效合成。此外，我们还对它们对非生物胁迫的耐受性进行了表征。结果表明，有4株菌株对镉具有高耐受性，一些菌株对酸和碱具有抗性。该研究结果有助于进一步探索植物内生真菌的多样性以及这些真菌在实际农业和医药行业中的潜在应用。要点：• 从野生大豆和栽培大豆中分离出302株内生真菌菌株 • 11株菌株的三萜类、酚类和多糖含量较高 • 4株菌株对镉具有高耐受性，少数菌株对酸碱溶液具有较强耐受性
