Enhancement of clover growth by inoculation of P-solubilizing fungi and arbuscular mycorrhizal fungi

This study evaluated the synergism between several P-solubilizing fungi isolates and arbuscular mycorrhizal fungi to improve clover ( Trifolium pratense) growth in the presence of Araxá apatite. Clover was sown directly in plastic pots with 300g of sterilized washed sand, vermiculite and sepiolite 1:1:1 (v:v:v) as substrate, and grown in a controlled environment chamber. The substrate was fertilized with 3 g L-1 of Araxá apatite. A completely randomized design, in 8×2 factorial scheme (eight P-solubilizing fungi treatments with or without arbuscular mycorrhizal fungi)and four replicates were used. The P-solubilizing fungi treatments consisted of five Brazilian P-solubilizing fungi isolates (PSF 7, 9, 20, 21 and 22), two Spanish isolates ( Aspergillus niger and the yeast Yarowia lipolytica) and control (non-inoculated treatment). The greatest clover growth rate was recorded when Aspergillus niger and PSF 21 were co-inoculated with arbuscular mycorrhizal fungi. Aspergillus niger, PSF 7 and PSF 21 were the most effective isolates on increasing clover growth in the presence of arbuscular mycorrhizal fungi. Greater mycorrhizal colonization resulted in greater clover growth rate in most PSF treatments. PSF 7 was the best isolate to improve the establishment of mycorrhizal and rhizobia symbiosis.

Este estudo avaliou o sinergismo entre diversos isolados defungos solubilizadores de fosfato e micorrízicos arbusculares para beneficiar o crescimento de trevo ( Trifolium pratense) na presença de apatita de Araxá. A cultura foi semeada diretamente em potes plásticos com 300 g de substrato esterilizado formado por areia lavada, vermiculita e sepiolita 1:1:1 (v:v:v) e cultivada em câmara climática. O substrato foi fertilizado com 3 g L-1 de apatita de Araxá. O experimento foi instalado em delineamento completamente casualizado, esquema fatorial 8×2 (oito tratamentos de inoculação de fungos solubilizadores de fosfato com ou sem fungos micorrízicos arbusculares) e quatro repetições. Os tratamentos de fungos solubilizadores de fosfato consistiram em cinco isolados brasileiros de fungos solubilizadores de fosfato (FSF 7, 9, 20, 21 e 22), dois isolados procedentes da Espanha ( Aspergillus niger e a levedura Yarowia lipolytica) e o controle (tratamento não inoculado). A maior taxa de crescimento da cultura foi obtida quando Aspergillus niger e FSF 21 foram co-inoculados com fungos micorrízicos arbusculares. Aspergillus niger, FSF 7 e o FSF 21 foram os isolados mais efetivos para incrementar o crescimento de trevo na presença de fungos micorrízicosarbusculares. A maior taxa de colonização micorrízica resultou em alta taxa de crescimento de trevo na maioria dos tratamentos com fungos solubilizadores de fosfato. O isolado FSF 7 foi o melhor para favorecer o estabelecimento das simbioses com fungos micorrízicos e com rizóbio.

Enhancement of clover growth by inoculation of P-solubilizing fungi and arbuscular mycorrhizal fungi.

This study evaluated the synergism between several P-solubilizing fungi isolates and arbuscular mycorrhizal fungi to improve clover ( Trifolium pratense) growth in the presence of Araxá apatite. Clover was sown directly in plastic pots with 300g of sterilized washed sand, vermiculite and sepiolite 1:1:1 (v:v:v) as substrate, and grown in a controlled environment chamber. The substrate was fertilized with 3 g L(-1) of Araxá apatite. A completely randomized design, in 8×2 factorial scheme (eight P-solubilizing fungi treatments with or without arbuscular mycorrhizal fungi)and four replicates were used. The P-solubilizing fungi treatments consisted of five Brazilian P-solubilizing fungi isolates (PSF 7, 9, 20, 21 and 22), two Spanish isolates ( Aspergillus niger and the yeast Yarowia lipolytica) and control (non-inoculated treatment). The greatest clover growth rate was recorded when Aspergillus niger and PSF 21 were co-inoculated with arbuscular mycorrhizal fungi. Aspergillus niger, PSF 7 and PSF 21 were the most effective isolates on increasing clover growth in the presence of arbuscular mycorrhizal fungi. Greater mycorrhizal colonization resulted in greater clover growth rate in most PSF treatments. PSF 7 was the best isolate to improve the establishment of mycorrhizal and rhizobia symbiosis.

Communities of P-solubilizing bacteria, fungi and arbuscular mycorrhizal fungi in grass pasture and secondary forest of Paraty, RJ--Brazil.

Communities of P-solubilizing bacteria, fungi and arbuscular mycorrhizal fungi, were evaluated in two different ecosystems. Samplings taken from two areas of Atlantic forest, in Paraty-RJ, Brazil, one with a secondary forest and the other with a grass pasture were studied. Four growth media: GL (glucose and yeast extract), GES (glucose, soil extract, KNO3, CaCl2, MgSO4, NaCl, FeEDTA and micronutrients solution), GAGES (glucose, soil extract, arabinose, glycerol, CaCl2, MgSO4 and NaCl) and GELP (glucose, soil extract, yeast extract, peptone, CaCl2, MgSO4 and NaCl) were evaluated for the isolation of P-solubilizing microorganisms. The identification of P-solubilizing bacteria was based on 16 S rDNA sequence analysis, while the identification of P-solubilizing fungi and arbuscular mycorrhizal fungi was based on morphology. The greatest number of P-solubilizing bacteria was isolated using GL and GELP growth media. The greatest number of P-solubilizing fungi was isolated using GAGES and GES. The bacteria were identified as Enterobacteriaceae and Bacillus sp., while the P-solubilizing fungi were identified as Aspergillus sp. Glomus macrocarpum and Glomus etunicatum were the dominant mycorrhizal fungi in the secondary forest and grass pasture area, respectively.

Communities of P-solubilizing bacteria, fungi and arbuscular mycorrhizal fungi in grass pasture and secondary forest of Paraty, RJ - Brazil

Avaliaram-se as comunidades de bactérias, fungos solubilizadores de fosfato e fungos micorrízicos arbusculares em dois diferentes ecossistemas. Foram feitas amostragens em duas áreas de Mata Atlântica, em Paraty - RJ, Brasil, uma de floresta secundária e outra de pastagem. Foram avaliados quatro meios de cultura: GL (glicose e extrato de levedura), GES (glicose, extrato de solo, KNO3, CaCl2, MgSO4, NaCl, FeEDTA solução de micronutrientes), GAGES (glicose, extrato de solo, arabinose, glicerol, CaCl2, MgSO4 e NaCl) e GELP (glicose, extrato de solo, extrato de levedura, peptona, CaCl2, MgSO4 e NaCl) para isolamento de microrganismos solubilizadores de fosfato. A identificação das bactérias solubilizadoras foi baseada na análise do 16 S rDNA, enquanto que os fungos solubilizadores e os micorrízicos arbusculares foram identificados pela sua morfologia. O maior número de bactérias solubilizadoras foi obtido usando os meios GL e GELP. O maior número de fungos solubilizadores foi obtido com os meios GAGES e GES. As bactérias solubilizadoras foram identificadas como Enterobacteriaceae e Bacillus sp., e os fungos como Aspergillus sp. Glomus macrocarpum e Glomus etunicatum foram as espécies de fungos micorrízicos dominantes nas áreas de floresta secundária e pastagem, respectivamente.