Fouda Amr, Eid Ahmed M, Elsaied Albaraa, El-Belely Ehab F, Barghoth Mohammed G, Azab Ehab, Gobouri Adil A, Hassan Saad El-Din
Department of Botany and Microbiology, Faculty of Science, Al-Azhar University, Nasr City, Cairo 11884, Egypt.
Department of Biotechnology, College of Science, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia.
Plants (Basel). 2021 Jan 1;10(1):76. doi: 10.3390/plants10010076.
In this study, 15 bacterial endophytes linked with the leaves of the native medicinal plant were isolated and identified as , , , , , , and These isolates exhibited variant tolerances to salt stress and showed high efficacy in indole-3-acetic acid (IAA) production in the absence/presence of tryptophan. The maximum productivity of IAA was recorded for BI-8 and BI-10 with values of 117 ± 6 and 108 ± 4.6 μg mL, respectively, in the presence of 5 mg mL tryptophan after 10 days. These two isolates had a high potential in phosphate solubilization and ammonia production, and they showed enzymatic activities for amylase, protease, xylanase, cellulase, chitinase, and catalase. In vitro antagonistic investigation showed their high efficacy against the three phytopathogens , , and , with inhibition percentages ranging from 20% ± 0.2% to 52.6% ± 0.2% ( ≤ 0.05). Therefore, these two endophytic bacteria were used as bio-inoculants for maize seeds, and the results showed that bacterial inoculations significantly increased the root length as well as the fresh and dry weights of the roots compared to the control plants. The plant inoculated with the two endophytic strains BI-8 and BI-10 significantly improved ( ≤ 0.05) the growth performance as well as the nutrient uptake compared with an un-inoculated plant.
在本研究中，从本地药用植物叶片中分离出15种细菌内生菌，鉴定为 、 、 、 、 、 、 。这些分离株对盐胁迫表现出不同的耐受性，并且在有无色氨酸的情况下，在吲哚 - 3 - 乙酸（IAA）产生方面显示出高效性。在10天后，在存在5 mg/mL色氨酸的情况下，BI - 8和BI - 10的IAA最大产量分别记录为117±6和108±4.6 μg/mL。这两个分离株在磷溶解和氨产生方面具有很高的潜力，并且它们显示出淀粉酶、蛋白酶、木聚糖酶、纤维素酶、几丁质酶和过氧化氢酶的酶活性。体外拮抗研究表明它们对三种植物病原体 、 和 具有高效性，抑制率范围为20%±0.2%至52.6%±0.2%（P≤0.05）。因此，这两种内生细菌被用作玉米种子的生物接种剂，结果表明与对照植物相比，细菌接种显著增加了根长以及根的鲜重和干重。与未接种的植物相比，接种了两种内生菌株BI - 8和BI - 10的植物显著改善（P≤0.05）了生长性能以及养分吸收。
