Differential cross-utilization of heterologous siderophores by nodule bacteria of Cajanus cajan and its possible role in growth under iron-limited conditions

Khan, Mukhtar A.; Geetha, R; Akolkar, Aparna V.; Pandya, Ami; Archana, G.; Desai, Anjana J.

doi:10.1016/j.apsoil.2005.12.001

Cited by 45 publications

(34 citation statements)

References 34 publications

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“…Coinoculation of ferrichrome producing U. maydis did not have any antagonistic effect on plant growth, however transconjugant ST1pFJ12 co-inoculated with U. maydis do show better survival and hence increased nodule occupancy, as compared to parent ST1, co-inoculated with U. maydis. The results obtained here in association with other similar reports from our laboratory [26][27][28][29]47] support the fact that iron sufficiency of any organism largely depends on its ability to utilize the siderophore present in large concentrations in its vicinity [29,48] . Survival under iron limiting soil conditions is an important quality which every biofertilizer strain must possess.…”

Section: Resultssupporting

confidence: 80%

“…IC3169 were found to produce only catecholate type of siderophores (Table 3) and failed to utilize hydroxamate siderophores, mainly ferrichrome and rhodotorulic acid (Table 3). Since rhizobia generally lack the ability to produce and utilize hydroxamates [26][27][28][29] , it is hypothesized that imparting upon them the ability to utilize hydroxamate siderophores would lead to increase in their rhizosperic competence. Ferrichrome constitutes one of the major hydroxamate siderophores in the soil [24] .…”

Section: Resultsmentioning

confidence: 99%

“…The iron acquisition problem is more pronounced in rhizobia because nitrogen fixation involves iron rich proteins like nitrogenase, leghemoglobin and cytochromes, with nitrogenase and leghemoglobin constituting up to 12 and 30% of total protein in the bacterial and infected plant cells, respectively [43] . Earlier studies from our lab have demonstrated that Arachis hypogea and Cajanus cajan root nodule isolates of rhizobia are poor producers and utilizers of hydroxamate-type siderophores [26][27][28][29]47] . Recent study from our laboratory has shown that the expression of Bradyrhizobium japonicum 61A152 fegA gene in peanut rhizobia, not only supports the growth of the fegA transconjugants under iron limited laboratory conditions, but also increases its survivability under natural soil conditions, leading to higher nodulation on peanut plant [31] .…”

Section: Discussionmentioning

confidence: 99%

“…The concentration of hydroxamate type siderophore in soil is reported to be as high as 10 µM [23] , ferrichrome, constituting the major fraction amongst these [24] . Most of the rhizobial isolates and other nodule bacteria tested in our laboratory produced mainly catecholate type of siderophores and failed to utilize iron complexed with ferrichrome, a hydroxamate siderophore known to be present in abundance in the soil [26][27][28][29] . Many studies indicate that efficient utilization of hydroxamate siderophores by rhizobia is a positive fitness factor with respect to its soil survival [22,45] .…”

Section: Introductionmentioning

confidence: 99%

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Enhanced Survival and Nodule Occupancy of Pigeon pea Nodulating Rhizobium sp. ST1 expressing fegA Gene of Bradyrhizobium japonicum 61A152

Joshi¹,

Desai²,

Archana³

et al. 2009

OnLine J. of Biological Sciences

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Problem statement: Rhizobial isolates belonging to genera (Rhizobium sp. and Mesorhizobium sp.) in our laboratory produced only catecholate type of siderophores. Although FhuA and FegA (ferrichrome receptors) homologs were found to be present in the sequenced genomes of few rhizobia (e.g., 1 in R. etli and 2 in Mesorhizobium sp. BNC1), laboratory isolates of the corresponding genera failed to utilize ferrichrome, a siderophore which is present in nanomolar concentrations in the soil. This inability was considered as a negative fitness factor with respect to rhizospheric colonization by these rhizobia. Approach: The 2.4 kb fegA gene (encoding ferrichrome receptor) was amplified along with its native promoter from Bradyrhizobium japonicum 61A152 and cloned in a broad host range plasmid vector pUCPM18. The plasmid construct pFJ was transferred by conjugation into Rhizobium sp. ST1 to give transconjugant ST1pFJ12. The consequence of FegA expression on the transconjugant was tested under lab and soil conditions, using physiological experiments. Results: Ability of the transconjugant ST1pFJ12 to utilize ferrichrome and expression of a 79 kD protein band on the outer membrane of the transconjugant confirmed FegA expression. Transconjugant ST1pFJ12 exhibited increased growth rate as compared to the parent strain ST1, in minimal media containing ferrichrome as the sole iron source, confirming the positive effect of FegA expression. Inoculation of pigeon pea seedlings with transconjugant ST1pFJ12 led to a marked increase in plant growth parameters as compared to plants inoculated with the parent strain ST1, the effect being more pronounced when Ustilago maydis, a ferrichrome producer was co-inoculated in the systems. Nodule occupancy on pigeon pea plant when inoculated with the transconjugant ST1pFJ12 alone was 57% which increased to 66% when co-inoculated with U. maydis as compared with 37 and 30% respectively, seen with parental strain ST1 inoculation. Conclusion: The clear increase in nodule occupancy and higher rhizospheric colonization by the fegA transconjugants, presented in this study together with the previous research reported from our laboratory, led us to conclude that ferrichrome utilization ability played an important role in the rhizospheric colonization of the bioinoculant strains. Testing the ability to utilize hydroxamate siderophores therefore, holds prime importance in selecting an efficient biofertilizer strain.

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Section: Resultssupporting

confidence: 80%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Enhanced Survival and Nodule Occupancy of Pigeon pea Nodulating Rhizobium sp. ST1 expressing fegA Gene of Bradyrhizobium japonicum 61A152

Joshi¹,

Desai²,

Archana³

et al. 2009

OnLine J. of Biological Sciences

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“…Microbial siderophores are excreted into the environment and bind Fe outside the cell for uptake through specific cell membrane receptors (Budzikiewicz 2005). Recent studies on siderophore cross-utilization have established that many organisms are capable of siderophore uptake and utilization regardless of their own ability to biosynthesize these molecules (Indiragandhi et al 2008;Khan et al 2006;Joshi et al 2006). Additionally, the presence of exogenous siderophores may positively stimulate indigenous organisms to increase Fe uptake and synthesize their own native siderophores (Guan et al 2001).…”

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confidence: 98%

Siderophore production of African dust microorganisms over Trinidad and Tobago

et al. 2012

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Iron (Fe) deposition from African dust has been implicated in a variety of environmental impacts on downwind terrestrial and marine ecosystems throughout the Caribbean. The most abundant form of Fe in African dust is Fe III , which is often not bioavailable. The objective of this study was to determine to what degree microorganisms isolated from African dust collected in Trinidad and Tobago are capable of producing siderophores that mobilize bioavailable Fe into the environment. Aerosol samples were collected for microbial analyses during African dust conditions in the source region (Mali) and downwind sites (Trinidad and Tobago). Microbial community fingerprints, obtained by means of terminal restriction fragment length polymorphism analysis, were compared among aerosol samples and possible Trinidadian sources of locally aerosolized microorganisms (sea water and soils). Ordination of the fingerprint data revealed similarities between aerosols from the source region and the aerosols and soils of downwind regions. Aerosol isolates from the downwind sites were screened for siderophore production using a modified chrome azurol-S (CAS) assay. Twenty-five percent of isolates tested that were sampled under non-dust conditions and 65% of African dust isolates produced at least one type of siderophore; among African dust isolates, all known classes of siderophores were produced. These data support African dust microorganism siderophore production as a viable mechanism by which Fe bioavailability may be increased in downwind locations, given appropriate conditions for microbial proliferation.

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Involvement of Trichoderma asperellum strain T6 in regulating iron acquisition in plants

Zhao

Wang

Zhang

et al. 2014

J. Basic Microbiol.

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Iron (Fe) deficiency is a major plant nutritional disorder in many parts of the world, particularly in areas with saline soils. Among the numerous root-associated microbes that are beneficial for plant nutrient uptake, Trichoderma spp. are the most effective rhizosphere fungi for enhancing plant growth and plant resistance to biotic and abiotic stresses. To investigate the potential mechanisms of action of Trichoderma on insoluble Fe in the soil, which is difficult for plants to absorb and utilize, a high siderophore-producing strain of Trichoderma T6, was isolated from the rhizosphere of cucumber plants. The strain was identified as T. asperellum based on the morphological features and molecular phylogenetic analyses. Applying strain T6 to sterile soil could increase soil levels of Fe(2+) and siderophores, as well as increase Fe(2+) and Fe(3+)-chelate reductase (FCR) activity in cucumber tissues. Purified siderophore eluent (PSE) increased plant growth, thus confirming its role in plant growth promotion. Moreover, extracellular Fe(3+) reducing activity and three kinds of organic acids were detected in the culture filtrate of strain T6. These results indicate that strain T6 influences plant Fe absorption in several ways. Siderophore-based Fe chelation is effective in providing Fe to plants, organic acids, and Fe(3+) reducing enzymes may participate in the solubilization and reduction of insoluble Fe(3+) to Fe(2+).

show abstract

Differential cross-utilization of heterologous siderophores by nodule bacteria of Cajanus cajan and its possible role in growth under iron-limited conditions

Cited by 45 publications

References 34 publications

Enhanced Survival and Nodule Occupancy of Pigeon pea Nodulating Rhizobium sp. ST1 expressing fegA Gene of Bradyrhizobium japonicum 61A152

Enhanced Survival and Nodule Occupancy of Pigeon pea Nodulating Rhizobium sp. ST1 expressing fegA Gene of Bradyrhizobium japonicum 61A152

Siderophore production of African dust microorganisms over Trinidad and Tobago

Involvement of Trichoderma asperellum strain T6 in regulating iron acquisition in plants

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