Department of Plant Protection, College of Agriculture, Razi University, Kermanshah, Iran.
Department of Soil Science, College of Agriculture, Razi University, Kermanshah, Iran.
Braz J Microbiol. 2021 Sep;52(3):1097-1106. doi: 10.1007/s42770-021-00493-4. Epub 2021 Apr 19.
Four hundred endophytic fungi isolates with different colony morphologies were isolated from roots of Hordeum vulgare L. collected from un-engineered landfills (the measured cadmium was 0.9 mg kg) of Kermanshah province in West Iran. Based on morphology and phylogeny of DNA sequence data for the internal transcribed spacer (ITS) rDNA and comparing the sequences with that available in NCBI database, 11 isolates are identified as dark septate endophytes (DSE) including Alternaria alternata, Microdochium bolleyi, Bipolaris zeicola, Alternaria sp., and Pleosporales sp., and the other nine are not dark septate endophytes (non-DSE) including Fusarium redolens, Fusarium tricinctum, Fusarium monliforme, Clonostachys rosea, and Epicoccum nigrum. Tolerance of DSE and non-DSE strains for Cd were investigated in potato dextrose agar medium. Minimum inhibitory concentrations (MIC) of Cd from nitrate salt source (Cd (NO)) and EC were determined. The means of MIC and EC values for DSE fungi species were 1254.5 and 209.74 mg/kg, compared to 800 and 150.3 mg/kg for non-DSEs. Among the endophytic fungi isolated, Alternaria sp. (TBR5) and Bipolaris zeicola (Tw26) showed the highest tolerance to Cd with a MIC value of 2000 mg/L and 1800 mg/L, respectively. Barley plants were inoculated with TBR5 and Tw26 in Cd-added sands (0, 10, 30, 60 mg Cd/kg sand). In terms of Cd accumulation, our results showed that TBR5 and Tw26 inoculation increased the amount of Cd in the barley roots. TBR5 and Tw26 significantly improved (p < 0.05) plant growth in the presence of Cd by enhancing plant growth attributes such as chlorophyll content, root weight, plant length, fresh weight, and dry weight of plants. This is the first study on the abundance and identification of endophytic root fungi of barley in a cadmium-contaminated soil in Iran. The results of this study showed that DSE and non-DSE have the potential to improve the efficiency of phytoremediation.
从伊朗西部克尔曼沙阿省未受工程干扰的垃圾填埋场（测量的镉含量为 0.9 毫克/千克）采集的大麦根部分离出 400 株具有不同菌落形态的内生真菌。根据 DNA 序列数据的内部转录间隔区（ITS）rDNA 的形态和系统发育，并将序列与 NCBI 数据库中的序列进行比较，11 株被鉴定为深色隔丝内生真菌（DSE），包括链格孢Alternaria alternata、麦长蠕孢 Microdochium bolleyi、玉米旋孢腔菌 Bipolaris zeicola、链格孢属 Alternaria sp. 和假球腔菌属 Pleosporales sp.，而另外 9 株不是深色隔丝内生真菌（非-DSE），包括红色镰刀菌 Fusarium redolens、三隔镰刀菌 Fusarium tricinctum、单轮镰孢菌 Fusarium monliforme、玫瑰色丛赤壳 Clonostachys rosea 和黑曲霉 Epicoccum nigrum。在马铃薯葡萄糖琼脂培养基中研究了 DSE 和非-DSE 菌株对 Cd 的耐受性。从硝酸盐盐源（Cd（NO3））和 EC 确定 Cd 的最小抑制浓度（MIC）。与非-DSE 相比，DSE 真菌的 MIC 和 EC 值平均值分别为 1254.5 和 209.74 mg/kg，而非-DSE 为 800 和 150.3 mg/kg。在所分离的内生真菌中，链格孢属（TBR5）和玉米旋孢腔菌（Tw26）对 Cd 的耐受性最高，MIC 值分别为 2000 mg/L 和 1800 mg/L。在添加 Cd 的沙中（0、10、30、60 mg Cd/kg 沙）用 TBR5 和 Tw26 接种大麦植物。就 Cd 积累而言，我们的结果表明，TBR5 和 Tw26 的接种增加了大麦根中的 Cd 量。TBR5 和 Tw26 通过增强植物叶绿素含量、根重、植物长度、鲜重和干重等植物生长属性，显著提高（p<0.05）Cd 存在下的植物生长。这是伊朗受 Cd 污染土壤中大麦内生根真菌丰度和鉴定的首次研究。本研究结果表明，DSE 和非-DSE 具有提高植物修复效率的潜力。
