147
species; therefore, more scientific researches are required to understand the mechanisms undertaken by the plant defense system.
The bacterial siderophores are observed with antagonistic activity for the fungal
pyoverdin siderophore of Pseudomonas putida which effectively controlled the
Fusarium wilt in radish through the mechanism called induced systemic resistance
(ISR) in plants (De Boer et al. 2003). Bacterial siderophores have the capacity to
reduce the ferric ions of rhizosphere which indirectly affect the growth of fungus
(Sulochana et al. 2014). Siderophores treated spores of Aspergillus sp. lacks the
germination and mycelial growth (Sulochana et al. 2014). Siderophores being utilized for antagonizing plant pathogens might also possess multiple activities toward
host plant and the other microbial niches (Thomashow and Bakker 2015). In wide
variety of plants, these siderophores might result in priming which is said to be plant
defense regulator (Conrath et al. 2002). The iron competition in the soil portrayed
the mechanism in biological control of soil-borne diseases (Thomashow and
Bakker 2015).
Plants utilize the bacterial siderophores in controlling pathogenesis of diseasecausing fungi. The siderophore pyoverdine from Pseudomonas controls the wilt
diseases of potato caused by Fusarium oxysporum (Schippers et al. 1987), fungus
Gaeumannomyces graminis which is the basis for growth deficiency of wheat and
barley (Voisard et al. 1989), phytopathogens of peanuts, maize (Pal et al. 2001), etc.
Recent study by Maindad et al. (2014) reported the capability of acinetobactin-like
siderophore produced by Acinetobacter calcoaceticus (common niche of wheat rhizosphere) in inhibiting the plant pathogen F. oxysporum.
9.4.2 Environment Impacts
Siderophore applications in the benefit of agriculture sector are even considered as
worthy under the environmental impacts. The contribution of siderophores for the
environmental welfare is quite enormous. Extracellular siderophores on the way of
sequestering iron make the mobility of other metal ions (divalent, trivalent, and
actinides) (Renshaw et al. 2002; Dahlheimer et al. 2007) in addition to its role of
plant and microbial nutrition. Siderophores apart from binding iron have the ability
to complex with essential elements like molybdenum, manganese, cobalt, and
nickel facilitating their availability for microbial cells. Siderophores based on their
ligand functionalities are able to solubilize and increase the mobility of wide range
of metals (Cd, Cu, Ni, Pb, Zn and actinides such as Th(IV), U(IV), and Pu(IV)),
which could be useful as an environmentally friendly, cost-effective tool in bioremediation (Rajkumar et al. 2010). This might be able to solve the metal pollution
caused by manufacturing industry, sludge applications, nuclear power stations, and
mining (Wasi et al. 2013). The siderophore molecule desferrioxamine B chelates
Co(III) with greater affinity than Fe(III) especially under high pH conditions
(Neubauer et al. 2000). For example, siderophore produced by Fusarium solani
contributes in mobilizing Cu and Zn (Hong et al. 2010). Siderophore-mediated iron
9 Fungal Siderophores: Prospects and Applications
species; therefore, more scientific researches are required to understand the mechanisms undertaken by the plant defense system.
The bacterial siderophores are observed with antagonistic activity for the fungal
pyoverdin siderophore of Pseudomonas putida which effectively controlled the
Fusarium wilt in radish through the mechanism called induced systemic resistance
(ISR) in plants (De Boer et al. 2003). Bacterial siderophores have the capacity to
reduce the ferric ions of rhizosphere which indirectly affect the growth of fungus
(Sulochana et al. 2014). Siderophores treated spores of Aspergillus sp. lacks the
germination and mycelial growth (Sulochana et al. 2014). Siderophores being utilized for antagonizing plant pathogens might also possess multiple activities toward
host plant and the other microbial niches (Thomashow and Bakker 2015). In wide
variety of plants, these siderophores might result in priming which is said to be plant
defense regulator (Conrath et al. 2002). The iron competition in the soil portrayed
the mechanism in biological control of soil-borne diseases (Thomashow and
Bakker 2015).
Plants utilize the bacterial siderophores in controlling pathogenesis of diseasecausing fungi. The siderophore pyoverdine from Pseudomonas controls the wilt
diseases of potato caused by Fusarium oxysporum (Schippers et al. 1987), fungus
Gaeumannomyces graminis which is the basis for growth deficiency of wheat and
barley (Voisard et al. 1989), phytopathogens of peanuts, maize (Pal et al. 2001), etc.
Recent study by Maindad et al. (2014) reported the capability of acinetobactin-like
siderophore produced by Acinetobacter calcoaceticus (common niche of wheat rhizosphere) in inhibiting the plant pathogen F. oxysporum.
9.4.2 Environment Impacts
Siderophore applications in the benefit of agriculture sector are even considered as
worthy under the environmental impacts. The contribution of siderophores for the
environmental welfare is quite enormous. Extracellular siderophores on the way of
sequestering iron make the mobility of other metal ions (divalent, trivalent, and
actinides) (Renshaw et al. 2002; Dahlheimer et al. 2007) in addition to its role of
plant and microbial nutrition. Siderophores apart from binding iron have the ability
to complex with essential elements like molybdenum, manganese, cobalt, and
nickel facilitating their availability for microbial cells. Siderophores based on their
ligand functionalities are able to solubilize and increase the mobility of wide range
of metals (Cd, Cu, Ni, Pb, Zn and actinides such as Th(IV), U(IV), and Pu(IV)),
which could be useful as an environmentally friendly, cost-effective tool in bioremediation (Rajkumar et al. 2010). This might be able to solve the metal pollution
caused by manufacturing industry, sludge applications, nuclear power stations, and
mining (Wasi et al. 2013). The siderophore molecule desferrioxamine B chelates
Co(III) with greater affinity than Fe(III) especially under high pH conditions
(Neubauer et al. 2000). For example, siderophore produced by Fusarium solani
contributes in mobilizing Cu and Zn (Hong et al. 2010). Siderophore-mediated iron
9 Fungal Siderophores: Prospects and Applications