El-Nahas Gehad A, Ibrahim Mohsen E, Baka Zakaria A M, Ibrahim Ali H
Department of Botany, Faculty of Science, Port Said University, Port Said, Egypt.
Department of Botany and Microbiology, Faculty of Science, University of Damietta, New Damietta, Egypt.
Int Microbiol. 2024 Nov 14. doi: 10.1007/s10123-024-00609-4.
Drought constitutes a significant abiotic stressor that hinders plant growth and productivity in many countries. Habitat-adapted endophytic fungi offer an environmentally sustainable approach to address this issue by promoting plant development and enhancing resilience against abiotic stresses. In this study, 30 endophytic fungal isolates were recovered from some wild plants in the extreme habitats of Port Said Governorate, Egypt, and evaluated for their drought tolerance using polyethylene glycol (PEG-6000). Only eight isolates demonstrated drought tolerance properties and were further evaluated for their plant growth-promoting biochemical activities and ability to improve maize germination under simulated drought conditions. All eight isolates exhibited enzyme activity for endo-1,4-β-glucanase, amylase, and pectinase, and most displayed significant nutrient mobilization, with siderophores production ranging from 4 to 89%, ammonia production from 1 to 7 μmol/ml, and phosphate solubilization from 129 to 256 µg/ml. Additionally, all isolates showed strong antioxidant activity and high total phenolic content, with some also producing notable levels of indole acetic acid (IAA) and gibberellic acid (GA) as plant growth hormones. Coating maize grains with spore suspensions of the eight fungal isolates, in general, significantly increased their germination parameters and seedling vigor in vitro under 8% PEG-6000. This enhancement was particularly pronounced with Neurospora sitophila (P8L4M1) and Penicillium tardochrysogenum (P15L4M1), which increased the vigor of maize seedlings by approximately 308% compared to untreated control. Molecular identification of P8L4M1 and P15L4M1 was performed by amplifying the 28S rRNA gene. This study disclosed unique endophytic fungal isolates with promising potential for enhancing drought resistance in maize.
干旱是一种严重的非生物胁迫因素，在许多国家阻碍了植物生长和生产力。适应栖息地的内生真菌提供了一种环境可持续的方法来解决这个问题，即通过促进植物发育和增强对非生物胁迫的恢复力。在本研究中，从埃及塞得港省极端栖息地的一些野生植物中分离出30株内生真菌，并使用聚乙二醇（PEG - 6000）评估它们的耐旱性。只有8株分离物表现出耐旱特性，并进一步评估它们促进植物生长的生化活性以及在模拟干旱条件下改善玉米发芽的能力。所有8株分离物均表现出内切 - 1,4 - β - 葡聚糖酶、淀粉酶和果胶酶的酶活性，并且大多数表现出显著的养分活化能力，铁载体产量在4%至89%之间，氨产量在1至7 μmol/ml之间，磷溶解量在129至256 μg/ml之间。此外，所有分离物均表现出较强的抗氧化活性和较高的总酚含量，一些还产生了显著水平的吲哚乙酸（IAA）和赤霉素（GA）作为植物生长激素。用这8株真菌分离物的孢子悬浮液包衣玉米种子，总体上在8% PEG - 6000条件下显著提高了它们在体外的发芽参数和幼苗活力。嗜热栖 Neurospora sitophila（P8L4M1）和迟缓青霉 Penicillium tardochrysogenum（P15L4M1）的这种增强尤为明显，与未处理的对照相比，它们使玉米幼苗活力提高了约308%。通过扩增28S rRNA基因对P8L4M1和P15L4M1进行了分子鉴定。本研究揭示了具有增强玉米抗旱潜力的独特内生真菌分离物。
