CIHIDECAR   12529
CENTRO DE INVESTIGACIONES EN HIDRATOS DE CARBONO
Unidad Ejecutora - UE
artículos
Título:
Effects of N-starvation and C-source on Bradyrhizobium japonicum exopolysaccharide production and composition, and bacterial infectivity to soybean roots
Autor/es:
J. I. QUELAS; S. L. LOPEZ-GARCÝA; A. CASABUONO; M. J.ALTHABEGOITI; E. J. MONGIARDINI; J. PEREZ-GIMENEZ; A. S. COUTO; A. R. LODEIRO
Revista:
ARCHIVES OF MICROBIOLOGY
Editorial:
Springer-Verlag
Referencias:
Lugar: Germany; Año: 2006 vol. 186 p. 119 - 128
ISSN:
0302-8933
Resumen:
The exopolysaccharide (EPS) is an extracellular
molecule that in Bradyrhizobium japonicumThe exopolysaccharide (EPS) is an extracellular
molecule that in Bradyrhizobium japonicumBradyrhizobium japonicum
affects bacterial efficiency to nodulate soybean. Culture
conditions such as N availability, type of C-source,
or culture age can modify the amount and composition
of EPS. To better understand the relationship among
these conditions for EPS production, we analyzed their
influence on EPS in B. japonicum USDA 110 and its
derived mutant DP22. This mutant has a deletion
including the 3¢ region of exoP, exoT, and the 5¢ region
of exoB, and produces a shorter EPS devoid of galactose.
The studies were carried out in minimal media
with the N-source at starving or sufficient levels, and
mannitol or malate as the only C-source. Under
N-starvation there was a net EPS accumulation, the
levels being similar in the wild type and the mutant
with malate as the C-source. By contrast, the amount
of EPS diminished in N-sufficient conditions, being
poyhydroxybutyrate accumulated with culture age.
Hexoses composition was the same in both N-situations,
either with mannitol or malate as the only
C-source, in contrast to previous observations made
with different strains. This result suggests that the
change in EPS composition in response to the environment
is not general in B. japonicum. The wild type
EPS composition was 1 glucose:0.5 galactose:0.5
galacturonic acid:0.17 mannose. In DP22 the EPS had
no galactose but had galacturonic acid, thus indicating
that it was not produced from oxidation of UDPgalactose.
Infectivity was lower in DP22 than in USDA
110. When the mutant infectivity was compared between
N-starved or N-sufficient cultures, the N-starved
were not less infective, despite the fact that the
amounts of altered EPS produced by this mutant under
N-starvation were higher than in N-sufficiency. Since
this altered EPS does not bind soybean lectin, the
interaction of EPS with this protein was not involved in
increasing DP22 infectivity under N-starvation.B. japonicum USDA 110 and its
derived mutant DP22. This mutant has a deletion
including the 3¢ region of exoP, exoT, and the 5¢ region
of exoB, and produces a shorter EPS devoid of galactose.
The studies were carried out in minimal media
with the N-source at starving or sufficient levels, and
mannitol or malate as the only C-source. Under
N-starvation there was a net EPS accumulation, the
levels being similar in the wild type and the mutant
with malate as the C-source. By contrast, the amount
of EPS diminished in N-sufficient conditions, being
poyhydroxybutyrate accumulated with culture age.
Hexoses composition was the same in both N-situations,
either with mannitol or malate as the only
C-source, in contrast to previous observations made
with different strains. This result suggests that the
change in EPS composition in response to the environment
is not general in B. japonicum. The wild type
EPS composition was 1 glucose:0.5 galactose:0.5
galacturonic acid:0.17 mannose. In DP22 the EPS had
no galactose but had galacturonic acid, thus indicating
that it was not produced from oxidation of UDPgalactose.
Infectivity was lower in DP22 than in USDA
110. When the mutant infectivity was compared between
N-starved or N-sufficient cultures, the N-starved
were not less infective, despite the fact that the
amounts of altered EPS produced by this mutant under
N-starvation were higher than in N-sufficiency. Since
this altered EPS does not bind soybean lectin, the
interaction of EPS with this protein was not involved in
increasing DP22 infectivity under N-starvation.DP22. This mutant has a deletion
including the 3¢ region of exoP, exoT, and the 5¢ region
of exoB, and produces a shorter EPS devoid of galactose.
The studies were carried out in minimal media
with the N-source at starving or sufficient levels, and
mannitol or malate as the only C-source. Under
N-starvation there was a net EPS accumulation, the
levels being similar in the wild type and the mutant
with malate as the C-source. By contrast, the amount
of EPS diminished in N-sufficient conditions, being
poyhydroxybutyrate accumulated with culture age.
Hexoses composition was the same in both N-situations,
either with mannitol or malate as the only
C-source, in contrast to previous observations made
with different strains. This result suggests that the
change in EPS composition in response to the environment
is not general in B. japonicum. The wild type
EPS composition was 1 glucose:0.5 galactose:0.5
galacturonic acid:0.17 mannose. In DP22 the EPS had
no galactose but had galacturonic acid, thus indicating
that it was not produced from oxidation of UDPgalactose.
Infectivity was lower in DP22 than in USDA
110. When the mutant infectivity was compared between
N-starved or N-sufficient cultures, the N-starved
were not less infective, despite the fact that the
amounts of altered EPS produced by this mutant under
N-starvation were higher than in N-sufficiency. Since
this altered EPS does not bind soybean lectin, the
interaction of EPS with this protein was not involved in
increasing DP22 infectivity under N-starvation.¢ region of exoP, exoT, and the 5¢ region
of exoB, and produces a shorter EPS devoid of galactose.
The studies were carried out in minimal media
with the N-source at starving or sufficient levels, and
mannitol or malate as the only C-source. Under
N-starvation there was a net EPS accumulation, the
levels being similar in the wild type and the mutant
with malate as the C-source. By contrast, the amount
of EPS diminished in N-sufficient conditions, being
poyhydroxybutyrate accumulated with culture age.
Hexoses composition was the same in both N-situations,
either with mannitol or malate as the only
C-source, in contrast to previous observations made
with different strains. This result suggests that the
change in EPS composition in response to the environment
is not general in B. japonicum. The wild type
EPS composition was 1 glucose:0.5 galactose:0.5
galacturonic acid:0.17 mannose. In DP22 the EPS had
no galactose but had galacturonic acid, thus indicating
that it was not produced from oxidation of UDPgalactose.
Infectivity was lower in DP22 than in USDA
110. When the mutant infectivity was compared between
N-starved or N-sufficient cultures, the N-starved
were not less infective, despite the fact that the
amounts of altered EPS produced by this mutant under
N-starvation were higher than in N-sufficiency. Since
this altered EPS does not bind soybean lectin, the
interaction of EPS with this protein was not involved in
increasing DP22 infectivity under N-starvation.exoB, and produces a shorter EPS devoid of galactose.
The studies were carried out in minimal media
with the N-source at starving or sufficient levels, and
mannitol or malate as the only C-source. Under
N-starvation there was a net EPS accumulation, the
levels being similar in the wild type and the mutant
with malate as the C-source. By contrast, the amount
of EPS diminished in N-sufficient conditions, being
poyhydroxybutyrate accumulated with culture age.
Hexoses composition was the same in both N-situations,
either with mannitol or malate as the only
C-source, in contrast to previous observations made
with different strains. This result suggests that the
change in EPS composition in response to the environment
is not general in B. japonicum. The wild type
EPS composition was 1 glucose:0.5 galactose:0.5
galacturonic acid:0.17 mannose. In DP22 the EPS had
no galactose but had galacturonic acid, thus indicating
that it was not produced from oxidation of UDPgalactose.
Infectivity was lower in DP22 than in USDA
110. When the mutant infectivity was compared between
N-starved or N-sufficient cultures, the N-starved
were not less infective, despite the fact that the
amounts of altered EPS produced by this mutant under
N-starvation were higher than in N-sufficiency. Since
this altered EPS does not bind soybean lectin, the
interaction of EPS with this protein was not involved in
increasing DP22 infectivity under N-starvation.B. japonicum. The wild type
EPS composition was 1 glucose:0.5 galactose:0.5
galacturonic acid:0.17 mannose. In DP22 the EPS had
no galactose but had galacturonic acid, thus indicating
that it was not produced from oxidation of UDPgalactose.
Infectivity was lower in DP22 than in USDA
110. When the mutant infectivity was compared between
N-starved or N-sufficient cultures, the N-starved
were not less infective, despite the fact that the
amounts of altered EPS produced by this mutant under
N-starvation were higher than in N-sufficiency. Since
this altered EPS does not bind soybean lectin, the
interaction of EPS with this protein was not involved in
increasing DP22 infectivity under N-starvation.DP22 the EPS had
no galactose but had galacturonic acid, thus indicating
that it was not produced from oxidation of UDPgalactose.
Infectivity was lower in DP22 than in USDA
110. When the mutant infectivity was compared between
N-starved or N-sufficient cultures, the N-starved
were not less infective, despite the fact that the
amounts of altered EPS produced by this mutant under
N-starvation were higher than in N-sufficiency. Since
this altered EPS does not bind soybean lectin, the
interaction of EPS with this protein was not involved in
increasing DP22 infectivity under N-starvation.DP22 than in USDA
110. When the mutant infectivity was compared between
N-starved or N-sufficient cultures, the N-starved
were not less infective, despite the fact that the
amounts of altered EPS produced by this mutant under
N-starvation were higher than in N-sufficiency. Since
this altered EPS does not bind soybean lectin, the
interaction of EPS with this protein was not involved in
increasing DP22 infectivity under N-starvation.DP22 infectivity under N-starvation.