Phosphate solubilization and synergism between P-solubilizing and arbuscular mycorrhizal fungi

Abstract

-The objective of this work was to evaluate the ability of several P-solubilizing fungi to solubilize aluminum phosphate and Araxá apatite as well as the synergism between the P-solubilizing fungus, PSF 7, and arbuscular mycorrhizal fungi to promote clover growth amended with aluminum phosphate. Two experiments were carried out, the first under laboratory conditions and the second in a controlled environmental chamber. In the first experiment, PSF 7, PSF 9, PSF 21 and PSF 22 isolates plus control were incubated in liquid medium at 28ºC for eight days. On the 2 nd , 4 th and 8 th day of incubation, pH and soluble P were determined. In the second experiment, clover was sowed in plastic pots containing 300 g of sterilized substrate amended with aluminum phosphate, 3 g L -1, in presence and absence of PSF 7 isolate and arbuscular mycorrhizal fungi. A completely randomized design, in factorial outline 2x2 (presence and absence of PSF 7 and arbuscular mycorrhizal fungi) and five replicates were used. In the first experiment, higher P content was detected in the medium containing aluminum phosphate. PSF 7 is the best fungi isolate which increases aluminum solubilization with major tolerance to Al 3+ . Clover growth was stimulated by presence of PSF 7 and arbuscular mycorrhizal fungi. There is synergism between microorganisms utilized to improve plant nutrition.Index terms: Aspergillus, Trifolium pratense, Araxá apatite, aluminum phosphate, symbiosis, Glomus. Solubilização de fosfatos e sinergismo entre fungos solubilizadores de fosfato e micorrízicos arbuscularesResumo -O objetivo deste trabalho foi avaliar a capacidade de solubilização de fosfato de alumínio e apatita de Araxá por diversos isolados de fungos solubilizadores de fosfato e o sinergismo entre o fungo solubilizador de fosfato, FSF 7, e fungos micorrízicos arbusculares, na promoção do crescimento de trevo fertilizado com fosfato de alumínio. Dois experimentos foram conduzidos, o primeiro em laboratório e o segundo em câmaras de cultivo. No primeiro experimento, os isolados FSF 7, FSF 9, FSF 21 e FSF 22, mais controle foram incubados em meio líquido, sob agitação, a 28ºC, por oito dias. Avaliou-se o pH e P solúvel no segundo, quarto e oitavo dia de incubação. No segundo experimento, semeou-se trevo em copos de plástico contendo 300 g de substrato esterilizado, fertilizado com fosfato de alumínio, 3 g L -1, com e sem FSF 7 e fungos micorrízicos. O delineamento foi inteiramente casualizado, esquema fatorial 2x2 (presença e ausência de FSF 7 e fungos micorrízicos), com cinco repetições. No primeiro experimento, foram encontradas maiores quantidades de P solúvel no meio contendo fosfato de alumínio. O FSF 7 aumentou a solubilização desse fosfato. O crescimento do trevo foi favorecido pela presença do FSF 7 e fungos micorrízicos arbusculares, o que evidencia sinergismo entre esses microrganismos.Termos para indexação: Aspergillus, Trifolium pratense, apatita de Araxá, fosfato de alumínio, simbiose, Glomus.

Effect of plant species on P cycle-related microorganisms associated with litter decomposition and P soil availability: implications for agroforestry management

“…However, not only were the PSM dominant in the rhizosphere of the noninoculated AMF plants, but the PSM population was also inhibited in the Carrasco soil where AMF was dominant. These results suggest that AMF and PSM show the same functional behavior but worked independently from each other, although synergic actions have been reported to occur in others case (Souchie et al 2006). Furthermore, both ectomycorrhizal fungi and PSM produce acid phosphatases (Conn & Dighton 2000), which explains the increase of these enzymes in single and mixed Eucalyptus plantations, as well as the accelerated mass and nutrient losses in the litter bags.…”

Improving Activity of Native Arbuscular Mycorrhizal Fungi (AMF) for Mycorrhizal Benefits in Agriculture: Status and Prospect

“…Coinoculation of multifunctional microorganisms combinations like (i) AMF + PGPR + PSB in lettuce [76], (ii) AMF + PGPR (Azospirillum, Azotobacter, Pseudomonas etc.) in Rhodes grass (Chloris gayana Kunth) [77], (iii) AMF + PSB in clover [78] and in English mint (Mentha piperita L.) [79] not only expressed individual beneficial effects, also resulted in additive or synergistic effects on plant growth promotion. Such results prompted the researchers to develop microbial consortium inoculum.…”

Efecto de diferentes niveles de fósforo en aguacate (Persea americana) inoculado con hongos micorrízicos arbusculares

“…El fósforo (P) es uno de los nutrientes limitantes en el suelo, debido a su baja disponibilidad y por presentar una baja tasa de movilidad entre los macro nutrientes (Souchie et al, 2006). En la planta, el fósforo es requerido en la formación de ácidos nucleicos, fosfatos de azúcares y membranas, síntesis de proteínas y formación del nuevo protoplasma, por lo que es necesario un adecuado abastecimiento de este elemento en el suelo (Condron y Tiessen, 2005).…”

“…The phosphorus (P) is one of the limiting nutrients in the soil due to its low availability and low mobility among macro nutrients (Souchie et al, 2006). In the plant, phosphorus is required in the formation of nucleic acids, phosphates of sugars and membranes, protein synthesis and formation of the new protoplasm, so an adequate supply of this element in the soil is necessary (Condron and Tiessen, 2005).…”