Coordination Chemistry of Siderophores: The Intersection of Bacterial Iron Acquisition and Host Defense

Bacterial pathogens acquire the iron they need for survival and growth in a host by using siderophores. The structures of siderophores are specialized for binding ferric ion with high affinity. Siderophore structures are also specialized to specifically interact with the proteins that mediate siderophore function. These proteins include the bacterial proteins involved in siderophore uptake and utilization, as well as host proteins that inhibit bacterial iron acquisition by intercepting siderophores. The interactions between siderophores and iron underlie biological function. The fundamental coordination chemistry of catecholate and hydroxamate siderophores affects protein interactions during siderophore uptake and host defense.

Siderophores carry iron into a bacterial cell through specific transport systems. Once inside the cell, the iron must be removed from the siderophore. Bacteria that use ferric enterobactin remove the iron by hydrolyzing the backbone with an esterase followed by reduction of the ferric ion. Hydrolysis is necessary because the high stability of intact ferric enterobactin prevents biological reduction and iron release. V. cholerae had been reported to use ferric enterobactin, but it does not have an esterase to hydrolyze the backbone. 

Uptake of ferric siderophores relies on specific cell membrane receptors. Many

siderophore receptors recognize the apo-siderophores as well as the ferric complexes. Binding apo-siderophores does not directly deliver iron to the bacteria, but it plays a role in the uptake mechanism.  YxeB transports the siderophores using a Gram-positive siderophore-shuttle in which metal exchange between a ferric siderophore and the bound apo-siderophore is facilitated by the receptor. Metal exchange is not required for uptake, but the siderophore-shuttle is faster than transport without metal exchange. Metal exchange, iron release, and the sterics and electronics of the metal center are coordination chemistry principles that influence the interactions between siderophores and proteins. Proteins usher siderophores through the biological functions of removing iron from the host, passing through the bacterial membrane, and releasing iron to the cell. Therefore, siderophores act as the intermediaries between ferric ion and the biology of bacterial iron uptake

Great job

Thanks Allawi and Abhishek for appreciation.  Some fascinating literature , you have attached Abhishek..i appreciate your wholehearted efforts in bringing the real quality literature...

great project

Thank  you Ali..appreciate your remarks..

Thanks Abhishek for some mind blowing stuff , the classical reading materials for all of us. Can we have some literature focusing role of siderophores beyond Fe-nutrition ....

Coordination Chemistry of Siderophores: The Intersection of Bacterial Iron Acquisition and Host Defense

Bacterial pathogens acquire the iron they need for survival and growth in a host by using siderophores. The structures of siderophores are specialized for binding ferric ion with high affinity. Siderophore structures are also specialized to specifically interact with the proteins that mediate siderophore function. These proteins include the bacterial proteins involved in siderophore uptake and utilization, as well as host proteins that inhibit bacterial iron acquisition by intercepting siderophores. The interactions between siderophores and iron underlie biological function. The fundamental coordination chemistry of catecholate and hydroxamate siderophores affects protein interactions during siderophore uptake and host defense.

Siderophores carry iron into a bacterial cell through specific transport systems. Once inside the cell, the iron must be removed from the siderophore. Bacteria that use ferric enterobactin remove the iron by hydrolyzing the backbone with an esterase followed by reduction of the ferric ion. Hydrolysis is necessary because the high stability of intact ferric enterobactin prevents biological reduction and iron release. V. cholerae had been reported to use ferric enterobactin, but it does not have an esterase to hydrolyze the backbone. 

Uptake of ferric siderophores relies on specific cell membrane receptors. Many

siderophore receptors recognize the apo-siderophores as well as the ferric complexes. Binding apo-siderophores does not directly deliver iron to the bacteria, but it plays a role in the uptake mechanism.  YxeB transports the siderophores using a Gram-positive siderophore-shuttle in which metal exchange between a ferric siderophore and the bound apo-siderophore is facilitated by the receptor. Metal exchange is not required for uptake, but the siderophore-shuttle is faster than transport without metal exchange. Metal exchange, iron release, and the sterics and electronics of the metal center are coordination chemistry principles that influence the interactions between siderophores and proteins. Proteins usher siderophores through the biological functions of removing iron from the host, passing through the bacterial membrane, and releasing iron to the cell. Therefore, siderophores act as the intermediaries between ferric ion and the biology of bacterial iron uptake

So interesting 

great work

Thanks Abhishek for your addition ..i agree with your concern...Find some interesting issue for further debate..

Influence of phytosiderophore on iron and zinc uptake and rhizospheric microbial activity ( Source ; African J. Microbiol.Vol. 7(51), pp. 5781-5788, 29 December, 2013 DOI: 10.5897/AJMR2013.6461)

Micronutrients play a vital role in crop production and sustainable crop yield. High crop yield varieties make soil micronutrients deficient, without incorporating external inputs. Due to deficiency of micronutrients such as iron (Fe) and zinc (Zn), yield decline drastically. It limits more than macronutrients, but requirements of these plant nutrients are very less, but plants have self regulated mechanism, which secrete the phytosiderophore (PS) and mobilize the lower concentration of these

metals to soil solution for easy uptake by plants. Phytosiderophore production is a general response of plants to Fe and Zn deficiency in particular. The uptake rate of PS-chelated Fe and Zn is 100 and 5 to 10 times higher than that of free Fe and Zn, respectively. Higher amount of carbon containing organic compounds enhanced the microbial activities in rhizosphere and alter the plant nutrient chemistry in

soil. This article discussed the importance of PS in microbial activity in soil and nutrient uptake mechanism in plants. PDF enclosed for further reading..

Find below another very good manuscript entitled Siderophores: Biochemical Ecology and Mechanism of Iron Transport in Enterobacteria...PDF enclosed for further reference..

Well formulated set of questions Dr Srivastava. I feel, siderophore synthesis is such a issue, that should be discussed with the possibility of expanding this concept to other nutrients. 

Dear Abhishek..it will be good if you can pick some salient points for our friends who are so closely following the discussion , that will help everyone to get something in a shortest possible time..

 Prod Rep. 2010 May;27(5):637-57. doi: 10.1039/b906679a.

Chemistry and biology of siderophores.

Hider RC1, Kong X.

Abstract : Siderophores are compounds produced by bacteria, fungi and graminaceous plants for scavenging iron from the environment. They are low-molecular-weight compounds (500-1500 daltons) possessing a high affinity for iron(III) (Kf > 1030), the biosynthesis of which is regulated by iron levels and the function of which is to supply iron to the cell. This article briefly describes the classification and chemical properties of siderophores, before outlining research on siderophore biosynthesis and transport. Clinically important siderophores and the therapeutic potential of siderophore design are described. Appendix 1 provides a comprehensive list of siderophore structures.

What is the biochemistry of siderophores functioning.

Very good attachment , Abhishek...

Siderophores are common products of aerobic and facultative anaerobic bacteria and of fungi. Elucidation of the molecular genetics of siderophore synthesis, and the regulation of this process by iron, has been facilitated by the fact that E. coli uses its own siderophores as well as those derived from other species, including fungi. Overproduction of the siderophore and its transport system at low iron is in this species well established to be the result of negative transcriptional repression, but the detailed mechanism may be positive in other organisms. Siderophores are transported across the double membrane enveMinireview: Siderophores 26725 by guest on May 3, 2017 http://www.jbc.org/ Downloaded from  lope of E. coli via a gating mechanism linking the inner and outer membranes. 

The siderophore for which we have the greatest inventory of information with regard to its anabolism is aerobactin , first isolated from Aerobacter aerogenes . Subsequently, it was detected as a product of pColV-K30, a plasmid commonly

borne by clinical isolates of Escherichia coli. The aerobactin determinants from the latter source have been cloned and shown to occur in an operon preceded by a regulatory element . Aerobactin, which consists of citrate substituted on the distal carboxyls with residues of N6 -hydroxyacetyl lysine, is fabricated in sequence by oxidation of  L-lysine, followed by acetylation and condensation, in a particular order, of two of these side chains with citrate.

PDF enclosed for further reading..

We have discussed enough about the role of siderophores, their structure , biosynthesis and other functioning..What determines the nature and properties of siderophores..?

Find some interesting work...entitled  Eubacterial Siderophores and Factors Modulating Their Production ..PDF enclosed for further reference..

The effectiveness of siderophores depend upon iron level of soil, carbon and nitrogen sourced.

some good attachments Abhishek ...

I was wondering , is it a possibility , composition of siderphores will vary according to nature and properties of soils..Whet really determines the effectiveness of siderophores..

Elhafid , appreciate your response. Do we have any study , where such siderophores function equally effective in acquisition of other nutrients as well...

Study the Effects of Siderophore-Producing Bacteria on Zinc and Phosphorous Nutrition of Canola and Maize Plants..very interesting 

ABSTRACT : Plant growth-promoting rhizobacteria (PGPR) are soil bacteria that are able to colonize rhizosphere and to enhance plant growth by means of a wide variety of mechanisms. In the present study, Myristica yunnanensis and Stenotrophomonas chelatiphaga strains were recognized as new records in Iran flora. According to the results, these strains significantly affected plants’ zinc and phosphorous contents which could be due to the production of phytosiderophore. Siderophore-producing bacteria increased canola zinc (Zn) content as strategy-I plant, while in maize, it can be said that probably the effect of phytosiderophore produced by plant on increasing root and shoot Zn content was more than siderophore produced by bacteria. These isolates could be used as bio-input for improving the plant productivity as a substitute to chemical fertilizers and also to correct the nutrient deficiencies in canola and maize for sustainable agriculture. Source :http://dx.doi.org/10.1080/00103624.2016.1194991, Coomun. Soil Science and  Pl.Anal.

Very useful work , full of quality content..

Effects of two new siderophore-producing rhizobacteria on growth and iron content of maize and canola plants

ABSTRACT

Siderophore-producing rhizobacteria beneficially affect plant growth by providing available iron to plants. In this study, bacteria were isolated from the rhizosphere of canola (Brassica napus L.) plants grown in the central fields in Iran, for the presence of siderophore-producing bacteria. A total of 45 distinct isolates were found to produce siderophore using qualitative chrome azurol sulfonate (CAS)-agar assay. Of them, ten isolates, based on the highest halo diameter/colony diameter ratios, were selected to quantify the rate of siderophore production using CAS-liquid assay. A variety of biochemical assays was used to determine the type(s) of siderophores produced by each of the ten isolates. The best isolates, based on production of the highest rates of either hydroxamates or carboxylates, were identified and used in further studies. Based on 16S ribosomal ribonucleic acid (rRNA) sequence analysis and a variety of phenotypic properties, the isolates were identified as Micrococcus yunnanensisYIM 65004 (T) and Stenotrophomonas chelatiphaga LPM-5 (T). We also studied the plant growth-promoting effect of the most promising isolates (YIM 65004 and LPM-5) on canola and maize plants under greenhouse conditions. The results of this study showed that M. yunnanensis and S. chelatiphagaincreased gain weight and iron (Fe) content of roots and shoots significantly, in comparison with control, indicating beneficial effects of these rhizobacteria on plant growth and development. This study reports M. yunnanensis and S. chelatiphaga, as new records for Iran. The latter is reported for the first time from plant (canola) rhizosphere. Besides, the ability of both M. yunnanensis and S. chelatiphaga to produce siderophores is documented for the first time. Source ; J.Pl. Nutrition,http://dx.doi.org/10.1080/01904167.2016.1262409

We found very little work in role of siderophores on transformation of other nutrients.

Find below an interesting PDF about siderophores characterization...

Very interesting PDF Dr Srivastava. There is no doubt about the importance of the siderophores in soil fertility and plant nutrition. It will be interesting to observe the siderophore producing microorganisms as one of the criteria for their PGPR activity. 

Bacteria and fungi are two most predominating soil microbial communities , engaged in siderophores production , however latter is anticipated to produce much stronger siderophores. Can we take concentration siderophores as an indication of soil fertility..?

 Plants use two strategies to acquire iron. Strategy I involves acidification of the rhizosphere followed by reduction of Fe3+ ions by membrane-bound Fe(III)-chelate reductase and subsequent uptake of Fe2+ into root cells. Strategy II refers to the plants which secrete low molecular weight phytosiderophores in order to solubilise and bind iron which is then transported into root cells via membrane proteins. However, these strategies are often not efficient enough to meet the needs of the plants growing especially in calcareous and alkaline soils. Therefore, providing plants with accessible forms of iron is necessary when it is scant or unavailable in soils. 

For details see: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3739868/

Can we synthesize siderophores artificially and use them as chelating  agents?

Interesting attachment , Abhishek to open up the whole discussion further...

A new route to trihydroxamate-containing artificial siderophores and ...

www.sciencedirect.com/science/article/pii/S0968089604009538 

A new route to trihydroxamate-containing artificial siderophores and synthesis of a new fluorescent probe

Abstract—A fluorescent labelled artificial siderophore 1 was synthesized by coupling a 7-nitrobenz-2-oxa-1,3-diazole (NBD) derivative to the terminal amino group of a new trihydroxamate-containing amine 2, a ferrichrome-type siderophore that was obtained

from tris(hydroxymethyl)aminomethane. Compound 1 was shown to be a suitable tool for experiments on siderophore transport and uptake processes in various organisms cells and particularly in Candida albicans cells. Source ; Bioorganic & Medicinal Chemistry 13 (2005) 1799–1803

Interesting attachment Abhishek...How siderophores influence soil fertility and ultimate crop response..

EFFECT OF SIDEROPHORE ON PLANT GROWTH PROMOTION

Abstract

At present fertilizer has become essential to modern agriculture to feed the growing population. Though chemical fertilizers increase crop production; their overuse has hardened the soil, decreased fertility, strengthened pesticides, polluted air and water, and released greenhouse gases, thereby bringing hazards to human health and environment as well. Due to the adverse effect of chemical fertilizers and the presence of plant pathogens, apart from using chemically based methods present study provides a biological platform to increase plant productivity. It has been

reported that many siderophore producing bacterial and fungal strains have their potentials in plant growth promotions because although iron is abundant in the soil it is unavailable to plants because of its low solubility. Thus siderophore produce will chelate iron and make it available to the plant. Pseudomonas fluorescens was able to produce extracellular water soluble yellow green siderophore of pyoverdine type in succinate medium. Siderophore produced was also proved to be

useful for plant growth promotion due to increase in root length, shoot length and number of leaves of leguminous plants like Lens Culinaris and Phaseolus lunatus when grown under iron limiting conditions with siderophore supplements. Thus siderophore can be used in combination with other biofertilizers to increase crop productivity.

We need in-depth discussion on these lines, friends.. 

Friends , find another very interesting work..The Role of Siderophores on Plants under Heavy Meal Stress: A View from the Rhizosphere

Abstract

At present fertilizer has become essential to modern agriculture to feed the growing population. Though chemical fertilizers increase crop production; their overuse has hardened the soil, decreased fertility, strengthened pesticides, polluted air and water, and released greenhouse gases, thereby bringing hazards to human health and environment as well. Due to the adverse effect of chemical fertilizers and the presence of plant pathogens, apart from using chemically based methods present study provides a biological platform to increase plant productivity. It has been reported that many siderophore producing bacterial and fungal strains have their potentials in plant growth promotions because although iron is abundant in the soil it is unavailable to plants because of its low solubility. Thus siderophore produce will chelate iron and make it available to the plant. Pseudomonas fluorescens was able to produce extracellular water soluble yellow green siderophore of pyoverdine type in succinate medium. Siderophore produced was also proved to be

useful for plant growth promotion due to increase in root length, shoot length and number of leaves of leguminous plants like Lens Culinaris and Phaseolus lunatus when grown under iron limiting conditions with siderophore supplements. Thus siderophore can be used in combination with other biofertilizers to increase crop productivity. Source ; Journal of  Botanical  Science e-ISSN:2320-0189

p-ISSN:2347-2308, PDF enclosed for further reading..

Research  on synthesis of siderophores artificially has to go a long way , before their use like synthesized fertilizers/biofertilizers start finding wide acceptance . But , certainly some breakthroughs have already been made which indicate strong prospects about use of siderophores in this direction..

Synthetic siderophores are still not a reality in plant nutrition.

sir please the attachment

Yes, other than iron binding siderophores are known to occur. Ability of siderophores to function as zincophores, chalkophores, and metallophores for a variety of other metals, sequester heavy metal toxins, transport boron, act as signalling molecules, regulate oxidative stress, and provide antibacterial activity have been reported. But fundamental research on many such aspects is needed to establish firm facts.

Nice piece of information Dr Malhotra, it would be more scintillating , if you can some information for the benefit of  all of us...

Thanks Abhishek as well  for so actively participating in such fruitful discussion..

Find here some classical work on ..

Fungal zinc metabolism and its connections to virulence.

Staats CC1, Kmetzsch L, Schrank A, Vainstein MH.

Abstract: Zinc is a ubiquitous metal in all life forms, as it is a structural component of the almost 10% of eukaryotic proteins, which are called zinc-binding proteins. In zinc-limiting conditions such as those found during infection, pathogenic fungi activate the expression of several systems to enhance the uptake of zinc. These systems include ZIP transporters (solute carrier 39 family) and secreted zincophores, which are proteins that are able to chelate zinc. The expression of some fungal zinc uptake systems are regulated by a master regulator (Zap1), first characterized in the yeast Saccharomyces cerevisiae. In this review, we highlight features of zinc uptake and metabolism in human fungal pathogens and aspects of the relationship between proper zinc metabolism and the expression of virulence factors and adaptation to the host habitat. Source :Front Cell Infect Microbiol. 2013 Oct 14;3:65. doi: 10.3389/fcimb.2013.00065. eCollection 2013. PDF enclosed fro further reading..

Another classical work..

Beyond iron: non-classical biological functions of bacterial siderophores.

Abstract:: Bacteria secrete small molecules known as siderophores to acquire iron from their surroundings. For over 60 years, investigations into the bioinorganic chemistry of these molecules, including fundamental coordination chemistry studies, have provided insight into the crucial role that siderophores play in bacterial iron homeostasis. The importance of understanding the fundamental chemistry underlying bacterial life has been highlighted evermore in recent years because of the emergence of antibiotic-resistant bacteria and the need to prevent the global rise of these superbugs. Increasing reports of siderophores functioning in capacities other than iron transport have appeared recently, but reports of "non-classical" siderophore functions have long paralleled those of iron transport. One particular non-classical function of these iron chelators, namely antibiotic activity, was documented before the role of siderophores in iron transport was established. In this Perspective, we present an exposition of past and current work into non-classical functions of siderophores and highlight the directions in which we anticipate that this research is headed. Examples include the ability of siderophores to function as zincophores, chalkophores, and metallophores for a variety of other metals, sequester heavy metal toxins, transport boron, act as signalling molecules, regulate oxidative stress, and provide antibacterial activity.Source :..Dalton Trans. 2015 Apr 14;44(14):6320-39. doi: 10.1039/c4dt03559c. ,DOI:10.1039/c4dt03559c..PDF enclosed for further reading..

Another worth reading work..friends..

Zinc Starvation Response in a Cyanobacterium Revealed.. Some excerpts..

Complicated and large molecules such as siderophores and cobalamin, however, cannot be transported efficiently across the outer membrane of Gram-negative bacteria by facilitated diffusion through porins. Such a process needs active transport across this membrane. The energy needed here stems from the proton motive force, which is transformed into conformational energy by the ExbB and ExbD proteins of the inner cytoplasmic membrane and is transmitted across the periplasm by the TonB protein. Therefore, TonB-dependent outer membrane proteins are a group of proteins that catalyze active transport of substances across this barrier...PDF enclosed for further reading..

Big thanks to Dr Malhotra for floating some conceptual words fro siderophores..

An excellent link to refer more about the subject which is so under-exploited , but so useful in soil fertility and plant nutrition , regardless of soils and crops...Here are some  links..

Metallomics: A Primer of Integrated Biometal Sciences

https://books.google.co.in/books?isbn=1783268301

Wolfgang Maret - 2016 - ‎Science

... the metal ions into cells. Siderophores carry Fe, chalcophores Cu, and zincophores Zn. Ionophores 134 Metallomics: A Primer of Intergrated Biometal Sciences.

Metal economy in host-microbe interactions:

https://books.google.co.in/books?isbn=2889194973

Frédéric Veyrier, ‎ Mathieu Cellier - 2015 - ‎Infectious and parasitic diseases

These systems include ZIP transporters (solute carrier 39 family) and secreted zincophores, which are proteins that are able to chelate zinc. The expression of .

Handbook of Metal-Microbe Interactions and Bioremediation

https://books.google.co.in/books?isbn=1498762433

Surajit Das, ‎Hirak Ranjan Dash - 2017 - ‎Science

One can find a few examples, indicating that bacterial siderophores could play a role as zinc chelators, termed zincophores or tsinkophores, which could be ..

We all would be grateful to you ..if you can please help out in procuring electronic copy and attach to this question..my  big thanks in advance...

Some good work..

Structural Analysis of Cytochrome P450 105N1 Involved in the Biosynthesis of the Zincophore, Coelibactin

Abstract: Coelibactin is a putative non-ribosomally synthesized peptide with predicted zincophore activity and which has been implicated in antibiotic regulation in Streptomyces coelicolor A3(2). The coelibactin biosynthetic pathway contains a stereo- and regio-specific monooxygenation step catalyzed by a cytochrome P450 enzyme (CYP105N1). We have determined the X-ray crystal structure of CYP105N1 at 2.9 Å and analyzed it in the context of the bacterial CYP105 family as a whole. The crystal structure reveals a channel between the α-helical domain and the β-sheet domain exposing the heme pocket and the long helix I to the solvent. This wide-open conformation of CYP105N1 may be related to the bulky substrate coelibactin. The ligand-free CYP105N1 structure has enough room in the substrate access channel to allow the coelibactin to enter into the active site. Analysis of typical siderophore ligands suggests that CYP105N1 may produce derivatives of coelibactin, which would then be able to chelate the zinc divalent cation.Int. J. Mol. Sci. 2012, 13, 8500-8513; doi:10.3390/ijms13078500

Great stuff on siderophores , friends, worth reading ...

THE SIGNIFICANCE OF SIDEROPHORES IN SOIL

Abstract: Sideropores are defined as relatively low molecular weight iron ion specific chelating agents, which existence is dependent on the amount of iron in the soil. Iron is known to be a very important microelement influencing metabolic processes of bacteria, fungi and plants. There are numerous factors influencing the production of siderophores by soil microorganisms, for instance pH. Due to the fact that the existence of different iron forms in the soil is strictly connected with pH, the absorption of iron by bacteria or fungi differs. Siderophores have very special function, especially when they are produced by bacteria living in the root zone, which are known as PGPR (Plant Growth Promoting Rhizobacteria) on the basis of the fact that their metabolites influence the growth and development of green plants in case of iron deficiency. One of the most important examples of PGPR, and the best known one, is Pseudomonas fluorescence, which contribution to plant growth has been tested in various research. These chelating nagents also cause the absorption of heavy metals from the soil, which can be very positive

when it comes to bioaugmentation of soils contaminated with heavy metals. PDF enclosed for further reading..

well said Abhishek , i agree with you . Lets try to debate on these issues...

Role of Microbial Siderophores in Improving Crop Productivity in Wheat (DOI10.1007/978-3-642-37241-4_12)

Iron is an important trace metal for all aerobic microbes, plants, animals and human beings. Although it is the second-most abundant metal on earth, biologically it is unavailable in ecological habitats. The poor solubility of iron in the soil is the cause of major plant nutritional disorders, leading to decreased productivity. Graminaceous plants like wheat under iron-limiting conditions secrete iron-chelating ligands (i.e. phytosiderophores) that solubilize iron and transport it across the root plasma membrane. This chapter focuses on iron solubilization by microbial siderophores in conjunction with phytosiderophores secreted by wheat and its effect on plant growth, productivity and value-addition of iron. Understanding the mechanisms of iron nutrition by phytosiderophores in coordination with microbial siderophores and siderophoregenic microbes will contribute to efforts to increase the productivity of wheat.

Role of Microbial Siderophores in Improving Crop Productivity ...

link.springer › chapter › ... › 978-3-642-37241-4_12

Role of Microbial Siderophores in Improving Crop ... by microbial siderophores in conjunction with ... part of the adaptive Fe-stress response.

Excellent piece of discussion Dr Srivastav and Abhishek. I hardly find any discussion on Siderophores response on crop yield and quality. 

Any study on crop response of synthesized siderophores..

Let me add another question. How can we quantify siderophores ? What are the siderophores types ? Which type of siderophore is most effective /

Excellent feedbacks Abhishek...worth reading by all of us

Thanks Abhishek for very good response.This is the reason why siderophores produced by fungi are far more effective in dimension than siderophores produced by any other soil microbial community..

Let us discuss the role of Siderophores as a plant growth promoters. 

Good insight we got about siderophores that how they regulate soil fertility and plant nutrition via changes in soil biology. What kind of microclimate is needed for siderophores promoting bacteria for high efficiency.

Excellent piece of information Abhishek , i am yet to get the appropriate response for my quarry , why the siderophores produced by fungi are much more stronger and effective  than any other soil microbial communities...?

Interesting to learn that siderophores are not limited to iron binding but also play other roles of cell signaling, to cooperative element scavenging, to oxidative stress protectors or even producers. Good abhishek

http://www.sciencedirect.com/science/article/pii/S0944501315300288    

This link may help you

It's interesting. However, before inject chemicals into the soil, it's better to watch https://www.youtube.com/watch?v=ShaaasGMQW8. It's in English speaking. All solutions are in nature. So, everyone is better to find solutions from natural to avoid using chemicals to pollute the earth. Thanks.

It's interesting. Therefore, control fungus, should control the iron supplements.

Abstract

Siderophores are organic compounds with low molecular masses that are produced by microorganisms and plants growing under low iron conditions. The primary function of these compounds is to chelate the ferric iron [Fe(III)] from different terrestrial and aquatic habitats and thereby make it available for microbial and plant cells. Siderophores have received much attention in recent years because of their potential roles and applications in various areas of environmental research. Their significance in these applications is because siderophores have the ability to bind a variety of metals in addition to iron, and they have a wide range of chemical structures and specific properties. For instance, siderophores function as biocontrols, biosensors, and bioremediation and chelation agents, in addition to their important role in weathering soil minerals and enhancing plant growth. The aim of this literature review is to outline and discuss the important roles and functions of siderophores in different environmental habitats and emphasize the significant roles that these small organic molecules could play in applied environmental processes.

[Ahmed E, Holmström SJM. Siderophores in environmental research: roles and applications. Microbial Biotechnology. 2014;7(3):196-208. doi:10.1111/1751-7915.12117.]

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3992016/

very nice and interesting discussion. I was totally blank in this area and now I have got much info. Thanks to all of the teachers and scientists. 

Dear Abhishek and Adijailton,

Thanks for sharing. Microbiology is fun. The discovery of the siderophores has a broad application. Besides the application to the agriculture, it also can be applied in the industry and the medical field for treating human, animal, plants, farm, and the environment.

Do you know what is the best and the worst environment for the siderophores keeping alive besides pH6, such as temperature, oxygen supply, etc.? Thanks.

It brings the hope of eliminating many chemical applications. You guys should have a very bright future!

Good Luck!

Frieda

Thanks, dear Frieda Mah.

Dear Adijailton,

You are welcome. You are one of our hopes. Before I retired, I would like to see we handed the world to the people who can make the world better without harm the world.

Think out of the box and have broader knowledge, siderophores has very broader applications. You can have a high demand new business in the near future. Get your partner now to work together for your future.

Best Regards,

Frieda