CINDEFI   05381
CENTRO DE INVESTIGACION Y DESARROLLO EN FERMENTACIONES INDUSTRIALES
Unidad Ejecutora - UE
artículos
Título:
Mineral phosphate solubilization activity of gluconacetobacter diazotrophicus under P-limitation and plant root environment
Autor/es:
CRESPO JUAN MANUEL; LUNA M:F:; BOIARDI JOSE LUIS
Revista:
Agricultural Sciences
Editorial:
Scientific Research Publishing
Referencias:
Lugar: Irvine (CA); Año: 2011 vol. 2 p. 16 - 22
ISSN:
2156-8553
Resumen:
The ability to solubilize insoluble inorganic phosphate
compounds by Gluconacetobacter diazotrophicus
was studied using different culture
approaches. Qualitative plate assays using
tricalcium phosphate as the sole P-source
showed that G. diazotrophicus produced solubilization
only when aldoses were used as the
C-source. Extracellular aldose oxidation via a
pyrroloquinoline quinone-linked glucose dehydrogenase
(PQQ-GDH) is the main pathway for
glucose metabolism in G. diazotrophicus. In
batch cultures with 5 g l-1 of hydroxyapatite as
the P-source and glucose as the C-source, more
than 98% of insoluble P was solubilized. No
solubilization was observed neither using glycerol
nor culturing a PQQ-GDH mutant of G. diazotrophicus.
Solubilizaton was not affected by
adding 100 mmol l-1 of MES buffer. Continuous
cultures of G. diazotrophicus showed significant
activities of PQQ-GDH either under C or P limitation.
An intense acidification in the root environment
of tomato and wheat seedlings inoculated
with a G. diazotrophicus PAL5 was observed.
Seedlings inoculated with a PQQ-GDH
mutant strain of G. diazotrophicus showed no
acidification. Our results suggest that G. diazotrophicus
is an excellent candidate to be
used as biofertilizer because in addition to the
already described plant growth-promoting abilities
of this organism, it shows a significant
mineral phosphate solubilization capacity.