China
Africa
Explore chapters and articles related to this topic
Multi-Disciplinary Nature of Microbes in Agricultural Research
Published in Gustavo Molina, Zeba Usmani, Minaxi Sharma, Abdelaziz Yasri, Vijai Kumar Gupta, Microbes in Agri-Forestry Biotechnology, 2023
Zengwei Feng, Honghui Zhu, Qing Yao
Mycorrhizal fungi, which are ubiquitous and multifunctional fungi of the plant rhizospheric microbiome, can enhance their host plant access to soil nutrients (e.g., N and P) and water, improving the tolerance of their host plants to a variety of biotic and abiotic stresses, and improving ambient soil structure and properties (Smith and Read 2008; van der Heijden et al. 2015). By far, four major types of mycorrhizal fungi have been reported in terrestrial ecosystems based on their structure and/or the identity of their host plant, namely arbuscular mycorrhizal (AM) fungi, ectomycorrhizal (EcM) fungi, orchid mycorrhizal fungi, and ericoid mycorrhizal fungi. However, two predominant functional groups, AM fungi and EcM fungi, are potentially applied and function in agricultural ecosystems.
Agro-ecosystemBioremediation Mediated by Plant-microbe Associations
Published in Vivek Kumar, Rhizomicrobiome Dynamics in Bioremediation, 2021
Maryam Bello-Akinosho, Busiswa Ndaba, Ashira Roopnarain, Emomotimi Bamuza-Pemu, Rosina Nkuna, Haripriya Rama, Rasheed Adeleke
It is generally recognized that plant fitness would only be characterized and understood within the plant holobiont concept, where plant plus its intimately associated microbiota is considered a functional whole (Zilber-Rosenberg and Rosenberg 2008, Vandenkoornhuyse et al. 2015). A holistic discussion of phytoremediation would, therefore, be within the context of microbe-assisted phytoremediation, also referred to as rhizoremediation, which is the remediation of contaminants by metabolically active microorganisms through their association with plant roots within the rhizosphere. During rhizoremediation, plant roots exude several organic compounds useable by microbes as nutrient sources of carbon, nitrogen, phosphorous or sulphur in order to multiply in the rhizosphere. These root exudates can also act as inducers of catabolic pathways for biodegradation of different contaminants (Kuiper et al. 2004, El Amrani et al. 2015). The presence of the root exudates is responsible for enhancing the density and activity of rhizospheric microbial communities as well as potentially enhancing the breakdown of hydrocarbons (Correa-Garcia et al. 2018) (Fig. 1). In addition, some root exudates assist in separating organic contaminants from the organic matter in soil, increasing their availability for microbial degradation (Gao et al. 2010). Therefore, biodegradation of contaminants through plant–microbe interactions is more effective in the presence of roots and the effectiveness of rhizoremediation is reduced in compacted soils where roots cannot penetrate contaminated zones (Manschadi et al. 2006).
Rhizosphere Bioremediation: Green Technology to Clean Up the Environment
Published in M.H. Fulekar, Bhawana Pathak, Bioremediation Technology, 2020
In the present study, the rhizosphere of the host plant grown in mycorrhizal soil formed a mycorrhizosphere encompassing the plant roots, the root symbiotic mycorrhizal fungi, bacteria actinomycetes and soil in the immediate vicinity of the mycorrhizal roots (Anderson et al., 1993). In the plant-assisted bioremediation, the rhizosphere helps increase soil organic carbon bacteria and mycorrhizal fungi, all factors that encourage degradation of organic compounds and pesticides in soil (Schnoor, 1997). The study observed that plants release exudates in soil that help to stimulate the degradation of organic chemicals by inducing enzyme systems of existing bacterial populations, stimulating growth of the new species that are able to degrade the waste and/or increasing substrate concentrations for all microorganisms. Exudates include short-chain organic acids, sugars, alcohols, phenolics and small concentrations of high-molecular-weight compounds (enzymes and proteins, Schnoor, 1997).
Elevated atmospheric CO2 enhances the phytoremediation efficiency of tall fescue (Festuca arundinacea) in Cd-polluted soil
Published in International Journal of Phytoremediation, 2022
Xiaoying Yang, Yueping Gao, Tian Gan, Pan Yang, Min Cao, Jie Luo
The rhizosphere, a dynamic micro-environment in which the soil, plant roots, and microorganisms interact with each other, plays a significant role in controlling the uptake and accumulation of metals by plants (Wang and Chen 2009). It has been reported that the combination of elevated atmospheric CO2 and heavy metal pollution could lower pH and increase dissolved organic matter levels in the rhizosphere of Triticum aestivum and S. alfredii, accelerating transformation of the stable residual form of metals to their soluble forms, and subsequently increasing the metal accumulation capacity of the species (Li et al.2013; Jia et al.2014). It has also been reported that elevated atmospheric CO2 levels can alleviate the toxicity of Cd to Lolium multiflorum and L. perenne; in this experiment, plants treated with three Cd levels (0, 4, and 16 mg L−1), showed significantly improved morphological parameters such as root length, surface area, volume, and tip numbers when subjected to CO2 treatments up to 1,000 ppm, compared with controls (Jia et al.2011).
Rhizosphere mediated biodegradation of benzo(A)pyrene by surfactin producing soil bacilli applied through Melia azedarach rhizosphere
Published in International Journal of Phytoremediation, 2020
Pot trial experiment was done to determine the efficiency of the plant-microbe association to remove BaP from the non-sterile rhizospheric soil of plant M. azedarach and compared with the degradation in bulk soil. The rhizosphere soil is the narrow region of soil near the roots of plants that is directly influenced by associated soil microorganisms and root secretions, while the soil outside the rhizosphere is considered as the bulk-soil where no penetration by plant roots occurs or no plants are growing. The M. azedarach seeds were washed with water and surface sterilized with 0.1% HgCl2 for 2–3 min followed by washing with ethanol and distilled water. The seeds were soaked in sterile water and kept in a rotary shaker for 48 h before transferring to pot. Then the seedling of 20 days old, were grown in pots of different sets, BaP (C), BaP + Plant (P), and BaP + Plant + Isolate S1I26/S1I8 (P26/P8), where cell suspension (5 ml, O.D. 600 = 0.5) of the isolates were applied to the soil. The total residual amount of BaP was measured after 60 days of growth of the plant in the pots.
Study on removal of pyrene by Agropyron cristatum L. in pyrene–Ni co-contaminated soil
Published in International Journal of Phytoremediation, 2020
Xinying Zhang, Jing Chen, Xiaoyan Liu, Yanming Zhang, Yuqi Zou, Jingxi Yuan
It is generally believed that plants play a favorable role in the treatment of HMs and PAHs co-contaminated soil (Zhang et al. 2017). Carbon deposition in plant rhizosphere could increase the activity and abundance of microorganisms in the soil (Chen et al. 2003). The biostimulation caused by plant roots could effectively improve the biodegradation of PAHs (Wu et al. 2018). The results of Liu et al. (2018) also suggested that the plants' cultivation could promote the dissipation of pyrene. The promoting effect of plants enhanced the biodegradation of pyrene by stimulating the activity of microorganisms in the soil (Figure 1(b)). Chen et al. (2017) also showed that the increase activity of soil microbial was the reason for the higher removal of pyrene. In addition, the toxic effects of heavy metals on soil microbes could result in lower soil microbial activity (Maliszewska-Kordybach and Smreczak 2003), which could explain that microbial activity in combined contaminated soil was lower than that of single contaminated soils, especially in the case of unplanted. The presence of heavy metals have a negative impact on the catabolism of microbial communities (Colombo et al. 2011), it was also detrimental to the decomposition of PAHs.