Dilawar Naveen, Hamayun Muhammad, Iqbal Amjad, Lee Bokyung, Ali Sajid, Ahmad Ayaz, Alrefaei Abdulwahed Fahad, Faraj Turki Kh, Kim Ho-Youn, Hussain Anwar
Department of Botany, Abdul Wali Khan University Mardan, Mardan 23200, Pakistan.
Department of Food Science and Technology, Abdul Wali Khan University Mardan, Mardan 23200, Pakistan.
Plants (Basel). 2024 Sep 21;13(18):2643. doi: 10.3390/plants13182643.
Industrial waste and sewage deposit heavy metals into the soil, where they can remain for long periods. Although there are several methods to manage heavy metals in agricultural soil, microorganisms present a promising and effective solution for their detoxification. We isolated a rhizofungus, (GenBank Acc. No. KT310979.1), from L., and investigated its growth-promoting and metal detoxification capabilities. The isolated fungus was evaluated for its ability to mitigate lead (25 and 75 ppm) and copper (100 and 200 ppm) toxicity in L. seedlings. The experiment utilized a completely randomized design with three replicates for each treatment. successfully colonized the roots of wheat seedlings, even in the presence of heavy metals, and significantly enhanced plant growth. The isolate effectively alleviates lead and copper stress in wheat seedlings, as evidenced by increases in shoot length (142%), root length (98%), fresh weight (24%), dry weight (73%), protein content (31%), and sugar content (40%). It was observed that wheat seedlings possess a basic defense system against stress, but it was insufficient to support normal growth. Fungal inoculation strengthened the host's defense system and reduced its exposure to toxic heavy metals. In treated seedlings, exposure to heavy metals significantly upregulated MT1 gene expression, which aided in metal detoxification, enhanced antioxidant defenses, and maintained metal homeostasis. A reduction in metal exposure was observed in several areas, including normalizing the activities of antioxidant enzymes that had been elevated by up to 67% following exposure to Pb (75 mg/kg) and Cu (200 mg/kg). Heavy metal exposure elevated antioxidant levels but also increased ROS levels by 86%. However, with colonization, ROS levels stayed within normal ranges. This decrease in ROS was associated with reduced malondialdehyde (MDA) levels, enhanced membrane stability, and restored root architecture. In conclusion, rhizofungal colonization improved metal tolerance in seedlings by decreasing metal uptake and increasing the levels of metal-binding metallothionein proteins.
工业废物和污水将重金属沉积到土壤中，这些重金属可在土壤中长时间留存。尽管有多种方法可处理农业土壤中的重金属，但微生物为其解毒提供了一种有前景且有效的解决方案。我们从黑麦草中分离出一种根际真菌（GenBank登录号：KT310979.1），并研究了其促进生长和金属解毒能力。评估了分离出的真菌减轻黑麦草幼苗中铅（25 ppm和75 ppm）和铜（100 ppm和200 ppm）毒性的能力。该实验采用完全随机设计，每个处理重复三次。该真菌成功定殖在小麦幼苗根部，即使在存在重金属的情况下，也显著促进了植物生长。该分离物有效缓解了小麦幼苗中的铅和铜胁迫，表现为地上部长度增加（142%）、根长度增加（98%）、鲜重增加（24%）、干重增加（73%）、蛋白质含量增加（31%）和糖分含量增加（40%）。观察到小麦幼苗具有针对胁迫的基本防御系统，但不足以支持正常生长。真菌接种增强了宿主的防御系统并减少了其对有毒重金属的暴露。在处理过的幼苗中，暴露于重金属显著上调了MT1基因表达，这有助于金属解毒、增强抗氧化防御并维持金属稳态。在几个方面观察到金属暴露的减少，包括使因暴露于铅（75 mg/kg）和铜（200 mg/kg）后升高高达67%的抗氧化酶活性恢复正常。重金属暴露提高了抗氧化水平，但也使活性氧水平增加了86%。然而，随着该真菌定殖，活性氧水平保持在正常范围内。活性氧的这种减少与丙二醛（MDA）水平降低、膜稳定性增强和根系结构恢复有关。总之，根际真菌定殖通过减少金属吸收和增加金属结合金属硫蛋白的水平提高了幼苗对金属的耐受性。
