218
P. T. Lacava et al.
bacteria with the potential for phosphate solubilization. Janarthine and Eganathan
(2012) isolated endophytic bacteria from surface-sterilized pneumatophores of
Avicennia marina, a plant common to all mangroves of India. Among 13 endophytic
bacteria, four isolates were genotypically identified as Bacillus spp., B. cereus, Enterobacter sp., and Sporosarcina aquimarina. The potential of the endophytic strain S.
aquimarina SjAM16103 to promote plant growth was analyzed in vitro and in vivo.
The results indicated that SjAM16103 produced 2.37 µmol/mL IAA, siderophores
and was able to solubilize insoluble phosphate. Gayathri and Muralikrishnan (2013),
observed that 24 endophytic bacteria exhibited phosphate solubilization in vitro
according to the method described by Pandey et al. (2008).
Tam et al. (2018) reported the isolation of P- solubilizing endophytic bacteria associated with Rhizophora mucronate and Avicennia alba, naturally growing mangrove
species. The inorganic phosphate solubilizing ability by endophytes was tested on
the National Botanical Research Institute’s phosphate (NBRIP) medium and the
P 2 O 5 concentration was measured by the ammonium molybdate method (Nautiyal
et al. 2000). All 86 endophytic isolates grew well on the NBRIP medium showed
phosphate solubilization abilities.
Brazilian mangroves are primarily made up of three tree species, Rhizophora
mangle, Laguncularia racemosa, and Avicennia sp. (Dias et al. 2009b), from which
several diverse endophytic bacteria (Castro et al. 2014) have been isolated. Our
research group evaluated a large number of endophytic bacterial strains, from three
different plant species, namely, R. mangle, L. racemosa, and Avicennia sp., to examine
phosphate solubilization (Castro et al. 2018). All 115 strains examined produced a
halo during the phosphate solubilization test in vitro. The endophytic strain MCR1.48
(Enterobacter sp.), which has a high P solubilization index, was selected for in vivo
assays in Acacia polyphylla. We selected the commonly used reforestation tree A.
polyphylla, which has few published studies involving inoculation by bacteria of
agronomic interest and used for the reforestation of degraded areas in Brazil and
reflects the ability of this leguminous tree species to recover degraded soils, thereby
decreasing costs and increasing benefits to the environment (Rao et al. 2007). Inoculation with Enterobacter sp. strain MCR1.48 increased the dry mass of A. polyphylla
shoots and roots, suggesting that the presence of the endophyte generates important benefits that promote the growth and fitness of this plant. In this context, Castro
et al. (2018) reported that the inoculation of a highly P-solubilizing strain, MCR1.48,
increased the shoot dry mass of A. polyphylla. This result indicates that phosphorous
solubilization plays a key role in plant growth in trees.
9.4.4 The Agronomic Potential of Phosphate Solubilization
by Endophytic Fungi from the Tropical Savanna
Sustainable agriculture requires the use of strategies to increase or maintain the
current rate of food production while reducing damage to the environment and human
P. T. Lacava et al.
bacteria with the potential for phosphate solubilization. Janarthine and Eganathan
(2012) isolated endophytic bacteria from surface-sterilized pneumatophores of
Avicennia marina, a plant common to all mangroves of India. Among 13 endophytic
bacteria, four isolates were genotypically identified as Bacillus spp., B. cereus, Enterobacter sp., and Sporosarcina aquimarina. The potential of the endophytic strain S.
aquimarina SjAM16103 to promote plant growth was analyzed in vitro and in vivo.
The results indicated that SjAM16103 produced 2.37 µmol/mL IAA, siderophores
and was able to solubilize insoluble phosphate. Gayathri and Muralikrishnan (2013),
observed that 24 endophytic bacteria exhibited phosphate solubilization in vitro
according to the method described by Pandey et al. (2008).
Tam et al. (2018) reported the isolation of P- solubilizing endophytic bacteria associated with Rhizophora mucronate and Avicennia alba, naturally growing mangrove
species. The inorganic phosphate solubilizing ability by endophytes was tested on
the National Botanical Research Institute’s phosphate (NBRIP) medium and the
P 2 O 5 concentration was measured by the ammonium molybdate method (Nautiyal
et al. 2000). All 86 endophytic isolates grew well on the NBRIP medium showed
phosphate solubilization abilities.
Brazilian mangroves are primarily made up of three tree species, Rhizophora
mangle, Laguncularia racemosa, and Avicennia sp. (Dias et al. 2009b), from which
several diverse endophytic bacteria (Castro et al. 2014) have been isolated. Our
research group evaluated a large number of endophytic bacterial strains, from three
different plant species, namely, R. mangle, L. racemosa, and Avicennia sp., to examine
phosphate solubilization (Castro et al. 2018). All 115 strains examined produced a
halo during the phosphate solubilization test in vitro. The endophytic strain MCR1.48
(Enterobacter sp.), which has a high P solubilization index, was selected for in vivo
assays in Acacia polyphylla. We selected the commonly used reforestation tree A.
polyphylla, which has few published studies involving inoculation by bacteria of
agronomic interest and used for the reforestation of degraded areas in Brazil and
reflects the ability of this leguminous tree species to recover degraded soils, thereby
decreasing costs and increasing benefits to the environment (Rao et al. 2007). Inoculation with Enterobacter sp. strain MCR1.48 increased the dry mass of A. polyphylla
shoots and roots, suggesting that the presence of the endophyte generates important benefits that promote the growth and fitness of this plant. In this context, Castro
et al. (2018) reported that the inoculation of a highly P-solubilizing strain, MCR1.48,
increased the shoot dry mass of A. polyphylla. This result indicates that phosphorous
solubilization plays a key role in plant growth in trees.
9.4.4 The Agronomic Potential of Phosphate Solubilization
by Endophytic Fungi from the Tropical Savanna
Sustainable agriculture requires the use of strategies to increase or maintain the
current rate of food production while reducing damage to the environment and human