Interaction with soil bacteria affects the growth and amino acid content of piriformospora indica
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Fecha
2020-01
Autores
Leyva-Rojas, Jorge A.
Coy-Barrera, Ericsson
Hampp, Rüdiger
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Editor
MDPI
Resumen
Exploration of the e ect of soil bacteria on growth and metabolism of beneficial root
endophytic fungi is relevant to promote favorable associations between microorganisms of the plant
rhizosphere. Hence, the interaction between the plant-growth-promoting fungus Piriformospora indica
and di erent soil bacteria was investigated. The parameters studied were fungal growth and its
amino acid composition during the interaction. Fungus and bacteria were confronted in dual
cultures in Petri dishes, either through agar or separated by a Perspex wall that only allowed the
bacterial volatiles to be e ective. Fungal growth was stimulated by Azotobacter chroococcum, whereas
Streptomyces anulatus AcH 1003 inhibited it and Streptomyces sp. Nov AcH 505 had no e ect. To analyze
amino acid concentration data, targeted metabolomics was implemented under supervised analysis
according to fungal-bacteria interaction and time. Orthogonal partial least squares-discriminant
analysis (OPLS-DA) model clearly discriminated P. indica–A. chroococcum and P. indica–S. anulatus
interactions, according to the respective score plot in comparison to the control. The most observable
responses were in the glutamine and alanine size groups: While Streptomyces AcH 1003 increased the
amount of glutamine, A. chroococcum decreased it. The fungal growth and the increase of alanine
content might be associated with the assimilation of nitrogen in the presence of glucose as a carbon
source. The N-fixing bacterium A. chroococcum should stimulate fungal amino acid metabolism via
glutamine synthetase-glutamate synthase (GS-GOGAT). The data pointed to a stimulated glycolytic
activity in the fungus observed by the accumulation of alanine, possibly via alanine aminotransferase.
The responses toward the growth-inhibiting Streptomyces AcH 1003 suggest an (oxidative) stress
response of the fungus.
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Palabras clave
Piriformospora indica, Endophytic fungi, Mycorrhiza helper bacteria, Amino acid content