Role of siderophores in the biocontrol of Pseudomonas tolaasii by fluorescent pseudomonad antagonists (original) (raw)
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Siderophore producing Pseudomonas as pathogenic Rhisoctonia solani and Botrytis cinerea antagonists
Pseudomonas aeruginosa, Pseudomonas putida biovar B, Pseudomonas marginalis y Burkholderia cepacia, aisladas de rizosfera y filosfera de plantas de rosa y alstroemeria, identificadas por ensayos bioquímicos y cultivadas en medio King B, mostraron propiedades antagónicas contra los patógenos (se usó medio PDA agar par el cultivo) Rhizoctonia solani y Botrytis cinerea. Estas propiedades coincidieron con la presencia de un sideróforo, sustancia polar con bandas de absorción en 260 nm y 402 nm. Se observó incremento del crecimiento longitudinal de las plantas, medido sobre el tallo central, por influencia de P. putida biovar B, P. aeruginosa y P. marginalis. El crecimiento de rizomas (a: 0.05) fue notorio bajo la influencia de P. marginalis.
Siderophore Production from Fluorescent PSEUDOMONAS and Its Application for Plant Growth Promotion
Pseudomonas fluorescensare themajor rhizobacteria whichproduces siderophoreandimproves ferric ion uptake and plant growth.Iron deficiency impairs chlorophyll biosynthesis and chloroplast development in monocots and dicots.As the consequences of iron dificiency are profound and alarming for plants and human health.Therefore,present research aims to produce siderophores from fluorescent Pseudomonasand its applicationfor plant growth promotion. Coconut rhizosphic soil sampleswere collected from Nashik, India. All the isolated bacterial species were labeled as B1 to B10 and cultivated in iron deficient medium for detection of siderophore production by CAS assay.It was observed that onlyisolate B3 hadshown positive test and from the morphological and biochemical characterization it was confirmedthat isolate B-3 wasPseudomonas spp.with fluorescence characterastics.Detection of siderophores by chemical as well as spectrophotometric assay showed presence of ferric hydroxamate (pyoveridine) andArnow's positive test showed possibility of presense of catecholate type of siderophore (pyochelin). The pot culture study of Vignaradiata and Sorghum bicolor,showed significant increase in the length of root and shoot of both plants by treatment with 5%, 10% and 15% supernatant .Result of chlorophyll estimation revealedthat there was significant increase in total chlorophyll content of both plants. Maximum chlorophyll content was found in the plants treated with 15% supernatant and it was also found that Sorghum bicolor showed higher chlorophyll content as compared to Vignaradiata.Thus, it can be concluded that siderophore produced by fluorescent Pseudomonascan be aneffective solution toimprove the crop yield by plant growth promotionof monocot and dicot plants in the iron deficient regions
Applied Biochemistry and Biotechnology, 2004
A marine isolate of fluorescent Pseudomonas sp. having the ability to produce the pyoverdine type of siderophores under low iron stress (up to 10 µM iron in the succinate medium) was identified as Pseudomonas aeruginosa by using BIOLOG Breathprint and siderotyping. Pyoverdine production was optimum at 0.2% (w/v) succinate, pH 6.0, in an iron-deficient medium. Studies carried out in vitro revealed that purified siderophores and Pseudomonas culture have good antifungal activity against the plant deleterious fungi, namely, Aspergillus niger, Aspergillus flavus, Aspergillus oryzae, Fusarium oxysporum, and Sclerotium rolfsii. Siderophore-based maximum inhibition was observed against A. niger. These in vitro antagonistic actions of marine Pseudomonas against phytopathogens suggest the potential of the organism to serve as a biocontrol agent.
Siderophore as a Potential Plant Growth-Promoting Agent Produced by Pseudomonas aeruginosa JAS-25
Siderophores scavenges Fe +3 from the vicinity of the roots of plants, and thus limit the amount of iron required for the growth of pathogens such as Fusarium oxysporum, Pythium ultimum, and Fusarium udum, which cause wilt and root rot disease in crops. The ability of Pseudomonas to grow and to produce siderophore depends upon the iron content, pH, and temperature. Maximum yield of siderophore of 130 μM was observed at pH 7.0±0.2 and temperature of 30°C at 30 h. The threshold level of iron was 50 μM, which increases up to 150 μM, favoring growth but drastically affecting the production of siderophore by Pseudomonas aeruginosa JAS-25. The seeds of agricultural crops like Cicer arietinum (chick pea), Cajanus cajan (pigeon pea), and Arachis hypogaea (ground nut) were treated with P. aeruginosa JAS-25, which enhanced the seed germination, root length, shoot length, and dry weight of chick pea, pigeon pea, and ground nut plants under pot studies. The efficient growth of the plants was not only due to the biocontrol activity of the siderophore produced by P. aeruginosa JAS-25 but also may be by the production of indole acetic acid (IAA), which influences the growth of the plants as phytohormones.
Biocontrol Mechanisms of Siderophores against Bacterial Plant Pathogens
Siderophore is an iron-healing compound that has an immense role in micro-bial interaction, especially in the rhizosphere. Siderophore is present in one of the major mechanisms of bacteria that is involved in the biological control of plant diseases. Both plant pathogenic fungi and bacteria are reported to be inhibited by siderophore-producing biocon-trol agents. These siderophores are produced in iron-limited conditions to sequester the CONTENTS 8.1 Iron Importance ....................................................................................................................168 8.2 Siderophore ...........................................................................................................................168 8.2.1 Siderophores: Structures and Binding Sites .............................................................169 8.2.2 Hydroxymate Siderophore ........................................................................................169 8.2.3 Catecholate Siderophores .........................................................................................170 8.2.4 Carboxylate (Complexion) Siderophore ....................................................................170 8.2.5 Mixed Siderophores ..................................................................................................170 8.2.6 Pyoverdin ..................................................................................................................170 8.2.7 Siderophore Biosynthesis ..........................................................................................171 8.2.8 Mechanism of Siderophore Export ...........................................................................171 8.2.9 Transport of Iron-Siderophore Complex ..................................................................172 8.2.10 Metabolism of Iron ...................................................................................................173 8.2.11 Iron Regulation in Bacteria ......................................................................................173 8.3 Applications of Siderophore .................................................................................................174 8.4 Mechanisms of Siderophore in Biocontrol: Overview .........................................................175 8.5 Phytopathology .....................................................................................................................176 8.6 Bacteria–Pathogen Interactions ............................................................................................177 8.6.1 Bacterial Soft Rot of Potato ......................................................................................177 8.6.2 Tomato Bacterial Wilt ...............................................................................................177 8.6.3 Rice Bacterial Blight ................................................................................................178 8.6.4 Bacterial Canker of Tomato ......................................................................................179 8.6.5 Bacterial Blight of Cotton .........................................................................................179 8.6.6 Bacterial Leaf Spot of Mungbean.............................................................................180 8.6.7 Fire Blight Disease ...................................................................................................180 8.7 Conclusion ............................................................................................................................181 Acknowledgments ..........................................................................................................................181 References ......................................................................................................................................181 168 Sustainable Approaches to Controlling Plant Pathogenic Bacteria less-available iron from the environment and thereby deprive the pathogen of iron, which ulti-mately leads to inhibition. Three main groups of siderophores have been reported: hydroxy-mate siderophore, catecholate siderophore, and mixed siderophore. Siderophores are synthesized through two different biosynthetic pathways: NRPSs-dependent and non-NRPSs-dependent. The ABC-type transporter proteins are also involved in the delivery of iron-sider-ophore complex into the cytosol of the producing organism, where it can be utilized. Some pathogenic bacteria capable of producing siderophores are highly virulent. Siderophore inter-acts with the H2O2 and peroxidases in the affected tissue either to enhance oxidative stress induced by harpin, coded by an hrpNgene, or to protect bacterial cells by inhibiting the generation of reactive oxygen species. In this chapter we discuss control of bacterial plant pathogens with the production of siderophore by antagonistic rhizobacterium. Emphasis is given to the most economically important bacterial plant diseases such as bacterial soft rot of potato, tomato bacterial wilt, bacterial canker of tomato, rice bacterial blight, bacterial blight of cotton, bacterial leaf spot of mungbean, and fire blight disease in apple. An overview is included of the significance of siderophores in the context of the inhibition of plant pathogenic bacteria.
Agriculture and Natural Resources, 2016
Siderophores are compounds secreted under low iron stress, which act as specific ferric iron chelating agents. Owing to their potential in the biological control of fungal phytopathogens, they may be used as an alternative strategy to chemical control. Pseudomonas aeruginosa FP6, previously isolated from rhizospheric soil samples was screened for its siderophore production on a chrome-azurol S agar plate. Change in the colour of the chrome-azurol S agar from blue to orange red confirmed the siderophore producing ability of P. aeruginosa FP6. The effects of various physicochemical parameters on siderophore production were studied. The maximum siderophore production was obtained in succinate medium (125 mM) followed by King's B medium (105 mM). The presence of sucrose and mannitol increased the siderophore production. Yeast extract proved to be the most suitable nitrogen source. Media supplemented with Pb 2þ , Mn 2þ and Mg 2þ showed appreciable siderophore production as well as growth of cultures. An increase in the iron concentration favoured growth but substantially reduced siderophore production. The strain when tested for its in-vitro antagonistic activity against Rhizoctonia solani and Colletotrichum gloeosporioides on King's B media, with and without FeCl 3 , showed a significant reduction in R. solani growth with FeCl 3 supplementation compared to the control (without FeCl 3), suggesting the role of siderophore mediated antagonism of R. solani. Antifungal activity was not influenced by FeCl 3 in the case of C. gloeosporioides, suggesting the presence of other antagonistic mechanisms.
Siderophore isolation and its Biocontrol action against Rice Fungal Pathogens
Rice blast caused by Magnaporthe grisea and sheath blight caused by Rhizoctonia solani are the major diseases affecting the rice production. Application of beneficial bacteria as seed or seedling root dip to protect these diseases may be an alternative strategies to chemical control. In this study, fluorescent Pseudomonads isolated from rice seedlings were used to screen for their antagonistic ability and siderophore mediated antibiosis under in-vitro conditions against these pathogens. Among 10 isolates, strain P.f 003 gave significantly higher inhibition of mycelial growth of M. grisea and R. solani. Strains of P.f 001, P.f 003, P.f 005 and P.f 007 produced siderophores when grown on Fe deficient and Fe fortified King's B medium. These strains again tested for their in-vitro antagonistic activity against M. grisea and R. solani on King's B media with or without FeCl3. Our results showed that all these strains significantly reduced the growth of M. grisea and R. solani with FeCl3 in the media compared to without FeCl3. Strain P.f 003 activity was superior compared to other strains evaluated.
Processes
Twenty fluorescent Pseudomonas isolates were tested for their ability to produce siderophores on chrome azurol S (CAS) agar plates and their antagonistic activity against six plant pathogenic fungal isolates was assessed. Scaling-up production of siderophores from the promising isolates, P. aeruginosa F2 and P. fluorescens JY3 was performed using batch and exponential fed-batch fermentation. Finally, culture broth of the investigated bacterial isolates was used for the preparation of two economical bioformulations for controlling Fusarium oxysporum and Rhizoctonia solani. The results showed that both isolates yielded high siderophore production and they were more effective in inhibiting the mycelial growth of the tested fungi compared to the other bacterial isolates. Exponential fed-batch fermentation gave higher siderophore concentrations (estimated in 10 µL), which reached 67.05% at 46 h and 45.59% at 48 h for isolates F2 and JY3, respectively, than batch fermentation. Formulated ...
Fifteen rhizobacterial fluorescent pseudomonas isolates obtained from rice in the region of Andhra Pradesh, India In all 10 strains of Pseudomonas fluorescens were selected based on preliminary screening of all these isolates for antifungal activity against rice fungal pathogens (P.oryzae and R.solani)., inhibited the growth of rice fungal pathogens in Fe deficient King's B medium that varied from (3 to 58 % inhibition). Among these Pf 003 strain completely inhibited the mycelial growth of two rice pathogens (P.oryzae and R.solani) both in presence and absence of FeCl 3 which indicated the siderophore mediation along with antifungal metabolites.
Concomitant Ability of Siderophore Against Iron Paucity and Fusarium wilt in Lycopersicon esculentum
Biosciences, Biotechnology Research Asia, 2017
Insoluble iron present in soil severely restricts its bioavailability for plant growth. Microorganisms present in the rhizosphere release siderophore to make it available to the plants. Among others, fluorescent pseudomonads are known to exert extensive biocontrol action against soil and root borne phytopathogens through release of siderophores. A total of 172 rhizobacterial isolates were obtained from two different ecosystems viz. forests and agricultural soils, among these 34 were found to produce siderophore with an apparent decrease in siderophore production when supplemented with 20 µM iron. With the aim of utilizing siderophore production as an antagonist against Fusarium oxysporium, isolates, four Pseudomonas isolates namely RSP7 (KR051487), RSP8 (KR051488), RSP3 (KR051489) and RSP5 (KR051490) were selected. Paired t-test analysis resulted in showing antagonism of RSP5 as 48.5% on plate, and the paired t-test value as 14with a significance of P< 0.01. RSP showed an antagonism of 20% on plate with t value of 31.1 and P< 0.01. Paired t-test analysis proved a highly significant antagonism with isolate RSP7 (t = 37.37, P < 0.001). The results among the four isolates are comparable with RSP3 as best enhancer and antagonist followed by RSP5 > RSP7 > RSP8. Siderophore mediated antagonism when iron d" 20 µM and maximum shoot and root length and dry weight were observed with Pseudomonas as inoculants suggesting application of siderophore producing plant growth promoting rhizobacterial strains in crop productivity.