Natural Fungal Endophytes From Noccaea caerulescens Mediate Neutral to Positive Effects on Plant Biomass, Mineral Nutrition and Zn Phytoextraction

Abstract

Phytoextraction using hyperaccumulating plants is a method for the remediation of soils contaminated with trace elements (TEs). As a strategy for improvement, the concept of fungal-assisted phytoextraction has emerged in the last decade. However, the role played by fungal endophytes of hyperaccumulating plants in phytoextraction is poorly studied. Here, fungal endophytes isolated from calamine or non-metalliferous populations of the Cd/Zn hyperaccumulator Noccaea caerulescens were tested for their growth promotion abilities affecting the host plant. Plants were inoculated with seven different isolates and grown for 2 months in trace element (TE)-contaminated soil. The outcomes of the interactions between N. caerulescens and its native strains ranged from neutral to beneficial. Among the strains, Alternaria thlaspis and Metapochonia rubescens, respectively, isolated from the roots of a non-metallicolous and a calamine population of N. caerulescens, respectively, exhibited the most promising abilities to enhance the Zn phytoextraction potential of N. caerulescens related to a significant increase of the plant biomass. These strains significantly increased the root elemental composition, particularly in the case of K, P, and S, suggesting an improvement of the plant nutrition. Results obtained in this study provide new insights into the relevance of microbial-assisted phytoextraction approaches in the case of hyperaccumulating plants.

Application of Multi-Plant Symbiotic Systems in Phytoremediation: A Bibliometric Review

“…Therefore, future phytoremediation mechanisms must be examined from multiple perspectives in both the above and belowground portions. (3) Future trends include the use of additives [e.g., plant growth regulators (PGR) [122], organic improvers [123], inorganic improvers [124], chelating agents [125], microorganisms [arbuscular mycorrhizal fungi (AMF), plant-growth-promoting rhizobacteria (PGPR)] [126][127][128], and other means to assist multi-plant combination restoration techniques. (4) Molecular, breeding, and biotechnology are also important ways to improve the efficiency of multiplant assemblages for remediation, reduce remediation time, and speed up ecosystem recovery by targeting transgenic plants that improve plant-microbe interactions or rhizosphere microbial activity, thereby promoting positive plant-plant benefits.…”

Fungal Endophytes to Combat Biotic and Abiotic Stresses for Climate-Smart and Sustainable Agriculture

“…Recently, many fungal endophytes have been identified which solubilize and mobilize phosphorus ( Penicillium , Aspergillus , Curvularia , Trichoderma , Mesorhizobium , etc.) ( Mehta et al, 2019 ), potassium ( Aspergillus fumigatus and A. niger ) ( Haro and Benito, 2019 ), and zinc salts ( Alternaria thlaspis and Metapochonia rubescens ) ( Yung et al, 2021 ), boosting plant metabolic activity, plant growth resulting in high crop production. They execute phytostimulation via lowering plant hormone ethylene levels by 1-aminocyclopropane-1-carboxylate deaminase (ACC), escalating plant growth ( Nascimento et al, 2014 ; Singh et al, 2015 ); they may biodegrade biomass and recycle them in the environment, enhancing nitrogen availability, Zinc and phosphorus uptake for the host resulting in phytoimmobilization ( Yung et al, 2021 ).…”

“…( Mehta et al, 2019 ), potassium ( Aspergillus fumigatus and A. niger ) ( Haro and Benito, 2019 ), and zinc salts ( Alternaria thlaspis and Metapochonia rubescens ) ( Yung et al, 2021 ), boosting plant metabolic activity, plant growth resulting in high crop production. They execute phytostimulation via lowering plant hormone ethylene levels by 1-aminocyclopropane-1-carboxylate deaminase (ACC), escalating plant growth ( Nascimento et al, 2014 ; Singh et al, 2015 ); they may biodegrade biomass and recycle them in the environment, enhancing nitrogen availability, Zinc and phosphorus uptake for the host resulting in phytoimmobilization ( Yung et al, 2021 ). Phytoimmobilization ultimately boosts plants to sustain abiotic stresses via immobilizing osmolytes and stabilizing membrane ion conductivity during stress conditions.…”

“…inhabiting Brassica campestris enhances Indole-3 amino acid (IAA), ACC deaminase and solubilize phosphate secretion resulting in plant growth promotion ( Sahoo et al, 2017 ). Fungal endophytes perform phosphate solubilization, siderophores production, antibiotic production, phytohormone production, nutrient mineralization, etc., functions for plant growth promotion during stress conditions ( Yung et al, 2021 ). Due to abiotic stress stimuli, abscisic acid, jasmonic acid, and salicylic acid are produced and act as defense signaling substances.…”

Response of Poplar and Associated Fungal Endophytic Communities to a PAH Contamination Gradient

“…Endophytes thrive from a protected and nutrient-rich environment conferred by the plant. In return, they produce a wide range of molecules improving plant growth and development by facilitating nutrient accessibility, producing phytohormones or exerting biocontrol activity [ 14 , 15 , 16 , 17 , 18 ]. Most studies focused on bacterial endophytes mitigating the role that fungi could play in these complex relationships between plants and their microbiota, especially in contaminated environments.…”