Showing their mettle: extraradical mycelia of arbuscular mycorrhizae form a metal filter to improve host Al tolerance and P nutrition
Showing their mettle: extraradical mycelia of arbuscular mycorrhizae form a metal filter to improve host Al tolerance and P nutrition
Authors
Seguel, Alex
Meier, Felix
Azcon, Rosario
Valentine, Alex
Merino Gergichevich, Cristian
Cornejo, Pablo
Aguilera, Paula
Borie, Fernando
Meier, Felix
Azcon, Rosario
Valentine, Alex
Merino Gergichevich, Cristian
Cornejo, Pablo
Aguilera, Paula
Borie, Fernando
Authors
Date
Datos de publicaciĆ³n:
JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE,Vol.100,803-810,2020
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Abstract
BACKGROUND New evidence has shown that arbuscular mycorrhizal (AM) fungi can contribute to the aluminum (Al3+) tolerance of host plants growing in acidic soils with phytotoxic levels of Al3+. The aim of this study was to investigate the role of AM fungi isolated from naturally occurring Al3+ acidic soils in conferring host tolerance to Al3+ toxicity in three wheat cultivars differing in Al3+ sensitivity. The experiment was conducted in a soilless substrate (vermiculite/perlite, 2:1 v/v) using two Al3+-tolerant wheat genotypes and one Al3+-sensitive wheat genotype. The wheat was colonized with a consortium of AM fungi isolated from an Andisol, with or without Al3+ at a concentration of 200 mu mol L-1. RESULTS The response of wheat to Al3+ in the medium was dependent on both the plant genotype and AM colonization. The benefits of the AM fungi to the wheat cultivars included an increased P concentration and relatively low Al3+ accumulation in the plants. This was achieved through two mechanisms. First, the metal-chelating capacity of the AM fungi was clear in two of the cultivars ('Tukan' and 'Porfiado'), in which the enhanced extraradical mycelium development was able to retain Al3+ in the glomalin and hyphae. Second, the increased AM-induced acid phosphatase activity in the rhizosphere of the other cultivar ('Atlas 66') increased host nutrition possibly by hyphae-mediated nutrient uptake and glomalin-related soil protein. CONCLUSION The results suggest that the role of AM fungi in cultivar-specific Al3+ detoxification can be achieved by increased extraradical mycelial filters and enhanced bioavailability of P in the host rhizosphere. (c) 2019 Society of Chemical Industry