Coffee production has decreased due to environmental and management factors. The current plantations are old and unproductive, also due to the rust problem, caused by the fungus Hemileia vastatrix Berk & Br. Furth...Coffee production has decreased due to environmental and management factors. The current plantations are old and unproductive, also due to the rust problem, caused by the fungus Hemileia vastatrix Berk & Br. Furthermore, the shade in the production systems has decreased with the consequent increase in soil erosion, in addition to the increase in agrochemicals. Currently, the planting of new varieties with resistance to the fungus is increasing. Furthermore, it has been shown that various biofertilized perennial crops in nursery favor their growth. In this study, the effect of applying two beneficial microorganisms, Rhizophagus intraradices and/or Azospirillum brasilense, to the planting of four varieties of Coffea arabica L. was evaluated. The coffee varieties marseillase, geisha, sarchimor and costa rica 95 were established in bags with the following treatments: 1) control, 2) R. intraradices, 3) A. brasilense, 4) R. intraradices + A. brasilense. Morphological and physiological yield components were recorded 168 days after transplanting. Data was analyzed statistically and differences between treatments were compared according to Tukey (p ≤ 0.05). The results indicate that individual or combined biofertilization of microorganisms favors dry matter allocation compared to the control and the same is differentially assigned to the stem and root. The Specific Leaf Area (SLA) also showed differential response between applications of the microorganisms, in two varieties it increased when they were applied alone and in the others when they were applied together.展开更多
Plasmid pVK1001 which carried the gfp gene of GFPmut2, a mutant of GFP, was introduced into Azospirillum brasilense Yu62 by electroporation. Maize seedlings were inoculated with the GFP-labelled baeteria and grown gno...Plasmid pVK1001 which carried the gfp gene of GFPmut2, a mutant of GFP, was introduced into Azospirillum brasilense Yu62 by electroporation. Maize seedlings were inoculated with the GFP-labelled baeteria and grown gnotobiotically in flask with semi-solid agar medium. Observations were performed with confocal laser scanning microscopy (CLSM) and electron microscopy, respectively, at 8 d and 12 d after inoculation. Confocal laser scanning microscopy showed that A. brasilense Yu62 could penetrate into the cortex tissue, colonizing in the intercellular spaces of the parenchyma cells of the cortex tissue. Transmission and scanning electron microscopy (TEM) showed that the majority of the bacteria colonized on the root surface and only a minority of them resided in the root interior.展开更多
The potential of Plant Growth Promoting Rhizobacteria(PGPR)has been demonstrated in the case of plant inoculation with bacteria of the genus Azospirillum which improves yield.A.brasilense produces a wide variety of mo...The potential of Plant Growth Promoting Rhizobacteria(PGPR)has been demonstrated in the case of plant inoculation with bacteria of the genus Azospirillum which improves yield.A.brasilense produces a wide variety of molecules,including the natural auxin indole-3-acetic acid(IAA),as well as other phytoregulators.However,several studies have suggested that auxin induces changes in plant development during their interaction with the bacteria.The effects of A.brasilense Sp245 on the development of Arabidopsis thaliana root were investigated to help explain the molecular basis of the interaction.The results obtained showed a decrease in primary root length from the first day and remained so throughout the exposure,accompanied by a stimulation of initiation and maturation of lateral root primordia and an increase of lateral roots.An enhanced auxin response was evident in the vascular tissue and lateral root meristems of inoculated plants.However,after five days of bacterization,the response disappeared in the primary root meristems.The role of polar auxin transport(PAT)in auxins relocation involved the PGP1,AXR4-1,and BEN2 proteins,which apparently mediated A.brasilense-induced root branching of Arabidopsis seedlings.展开更多
The interactive effect of different Cu++ concentrations (5 mM, 10 mM, 20 mM and 25 mM) and treatments with biofertilizers Azospirillum brasilense on growth, metabolites, minerals and osmotic pressure of wheat plants w...The interactive effect of different Cu++ concentrations (5 mM, 10 mM, 20 mM and 25 mM) and treatments with biofertilizers Azospirillum brasilense on growth, metabolites, minerals and osmotic pressure of wheat plants was investigated. Shoots and roots of wheat plant were differentially response to Cu++ treatments, while shoot organ response positively to this treatment, root response negatively. The positive effect of Cu++ in shoot organ was concomitant with the increase in the production of fresh, dry matter, length and water content and this related with the accumulation of soluble sugar, soluble protein and mineral as a result of increasing osmotic pressure. On the other side, the negative effect of Cu++ on root organ was concomitant with the decrease in production of fresh, dry matter, length and water content that related with the reduction in the accumulation of soluble sugar and mineral with the insignificant change in osmotic pressure. Azospirillum brasilense inoculation increased the accumulation of soluble sugar and soluble protein which reflected an increase in the production of fresh, dry matter and water content with increasing values of osmotic pressure of the tested plants under Cu++ treatment. Finally, wheat plants response differentially to Cu++ treatment according to its organ and Azospirillum brasilense treatment improved wheat plant efficiency to tolerate the effect of Cu++ stress.展开更多
NifA in Azospirillum brasilense plays a key role in regulating the synthesis and activity of nitrogenase in re- sponse to ammonia and oxygen available. In this work we used the yeast two-hybrid system to identify the ...NifA in Azospirillum brasilense plays a key role in regulating the synthesis and activity of nitrogenase in re- sponse to ammonia and oxygen available. In this work we used the yeast two-hybrid system to identify the proteins that interact with NifA. The nifA gene was fused to the yeast two-hybrid vector pGBD-C2, and three A. brasilense Sp7 genomic libraries for use in yeast two-hybrid studies were constructed. Screening of the libraries identified four clones encoding proteins that interact with NifA. The confirmation of the interactions of each gene product of the four clones and NifA were carried out by exchanging the vectors for nifA and the four clones and by mutageneses of the four clones with shift reading frame experiments in yeast two-hybrid studies. DNA sequence analyses showed that two clones en- code proteins containing PAS domains that play an impor- tant role in signal transduction. One clone has high similarity with the fhuE gene of Escherichia coli, whose gene product is involved in iron uptake and transportation, and the other clone encodes an unknown protein.展开更多
A flagellar gene cluster fragment includingflbD of Azospirillum brasilense was cloned and sequenced. TheflbD mutant strain was found to be nonmotile——losingboth polar and lateral flagella (Fla-Laf-). Motility and fl...A flagellar gene cluster fragment includingflbD of Azospirillum brasilense was cloned and sequenced. TheflbD mutant strain was found to be nonmotile——losingboth polar and lateral flagella (Fla-Laf-). Motility and fla-gella were regained by complementation with plasmid-borne multicopy flbD, but altered with larger swarming circle and fewer lateral flagella on the semisolid plate. This result indicated that FlbD plays an important role in the regulation of both polar and lateral flagellar biosynthesis in A. brasilense.展开更多
The objective of this work was to verify the responses in agronomic and physiological characters of lettuce seedlings when submitted to different doses of humic acids and the presence or absence of inoculation of the ...The objective of this work was to verify the responses in agronomic and physiological characters of lettuce seedlings when submitted to different doses of humic acids and the presence or absence of inoculation of the bacterium Azospirillum brasilense. The experiment was carried out at the Protected Cultivation Station and Biological Control Teacher Mário César Lopes, belonging to the Experimental Stations Nucleus of the State University of the West of Paraná. The experimental design was a randomized block design, in a 5 × 2 factorial scheme, with four repetitions, totaling 40 plots. The first factor consisted of five solutions containing humic acid (100%, 75%, 50%, 25% and 0%) and the second factor was the presence or absence of the diazotrophic bacterium Azospirillum brasilense obtained by commercial product. Germination tests were carried out in addition to the determination of agronomic characters such as the number of fully expanded leaves, plant height, stem diameter, main root length, shoot dry mass, root dry mass, total dry mass, and Dickson quality index. The association of diazotrophic bacteria and humic acids did not influence the emergency rate, mean emergence time, mean speed of emergency, emergence speed index, plant height, and root length of lettuce seedlings. The dilutions of humic acids, regardless of inoculation with bacteria diazotrophic favored the development of the number of leaves, stem diameter and Dickson quality index. Inoculation of lettuce seeds with diazotrophic bacteria associated with the addition of humic acids, favored the development of the dry mass of root and total dry matter.展开更多
The most widely used method of olive propagation is cutting,although for some cultivars the technique is still limited.The objective of this work was to evaluate the use of plant growth promoter bacteria and arbuscula...The most widely used method of olive propagation is cutting,although for some cultivars the technique is still limited.The objective of this work was to evaluate the use of plant growth promoter bacteria and arbuscular mycorrhizal fungi in the rooting of olive cuttings.Two experiments were conducted from October 2017 to January 2018 with cuttings from 4 olive cultivars(Ascolano 315,Koroneiki,Maria da Féand Picual)from four-year-old plants.The first experiment consisted of 4 olive cultivars and 3 mycorrhizal species plus the control and the second experiment of 3 concentrations of commercial inoculant(Nitro1000®),containing Azospirillum brasilense plus control.The cuttings were treated with 3000 mg/L of indolebutyric acid(IBA).The experimental design used in the two experiments was randomized blocks,in a 4×4 factorial scheme,containing 25 stakes per replicate and 3 replicates.The cuttings were kept under weaver conditions and within a low rooting tunnel.After 75 d,the percentage of rooted cuttings,callus and sprouts,length of the largest root,number and length of shoots were evaluated.The use of FMA in Maria da Féand Picual has a positive response to cutting rooting and the fungi benefit the quality of the seedlings by the higher number of shoots and larger root length.The relation of Azospirillum brasilense cultivar is specific,being that,the cultivar Picual does not respond to inoculation of the bacterium having less viability in the propagation by cutting.Maria da Féand Koroneiki have the best percentages of rooting with the use of 75.00 and 52.00 mL/L of inoculant,respectively.展开更多
文摘Coffee production has decreased due to environmental and management factors. The current plantations are old and unproductive, also due to the rust problem, caused by the fungus Hemileia vastatrix Berk & Br. Furthermore, the shade in the production systems has decreased with the consequent increase in soil erosion, in addition to the increase in agrochemicals. Currently, the planting of new varieties with resistance to the fungus is increasing. Furthermore, it has been shown that various biofertilized perennial crops in nursery favor their growth. In this study, the effect of applying two beneficial microorganisms, Rhizophagus intraradices and/or Azospirillum brasilense, to the planting of four varieties of Coffea arabica L. was evaluated. The coffee varieties marseillase, geisha, sarchimor and costa rica 95 were established in bags with the following treatments: 1) control, 2) R. intraradices, 3) A. brasilense, 4) R. intraradices + A. brasilense. Morphological and physiological yield components were recorded 168 days after transplanting. Data was analyzed statistically and differences between treatments were compared according to Tukey (p ≤ 0.05). The results indicate that individual or combined biofertilization of microorganisms favors dry matter allocation compared to the control and the same is differentially assigned to the stem and root. The Specific Leaf Area (SLA) also showed differential response between applications of the microorganisms, in two varieties it increased when they were applied alone and in the others when they were applied together.
文摘Plasmid pVK1001 which carried the gfp gene of GFPmut2, a mutant of GFP, was introduced into Azospirillum brasilense Yu62 by electroporation. Maize seedlings were inoculated with the GFP-labelled baeteria and grown gnotobiotically in flask with semi-solid agar medium. Observations were performed with confocal laser scanning microscopy (CLSM) and electron microscopy, respectively, at 8 d and 12 d after inoculation. Confocal laser scanning microscopy showed that A. brasilense Yu62 could penetrate into the cortex tissue, colonizing in the intercellular spaces of the parenchyma cells of the cortex tissue. Transmission and scanning electron microscopy (TEM) showed that the majority of the bacteria colonized on the root surface and only a minority of them resided in the root interior.
基金supported by the Coordinación de la Investigación Científica UMSNH.E.C.-F.and J.A.-R.were fellows of CONACYT-México.
文摘The potential of Plant Growth Promoting Rhizobacteria(PGPR)has been demonstrated in the case of plant inoculation with bacteria of the genus Azospirillum which improves yield.A.brasilense produces a wide variety of molecules,including the natural auxin indole-3-acetic acid(IAA),as well as other phytoregulators.However,several studies have suggested that auxin induces changes in plant development during their interaction with the bacteria.The effects of A.brasilense Sp245 on the development of Arabidopsis thaliana root were investigated to help explain the molecular basis of the interaction.The results obtained showed a decrease in primary root length from the first day and remained so throughout the exposure,accompanied by a stimulation of initiation and maturation of lateral root primordia and an increase of lateral roots.An enhanced auxin response was evident in the vascular tissue and lateral root meristems of inoculated plants.However,after five days of bacterization,the response disappeared in the primary root meristems.The role of polar auxin transport(PAT)in auxins relocation involved the PGP1,AXR4-1,and BEN2 proteins,which apparently mediated A.brasilense-induced root branching of Arabidopsis seedlings.
文摘The interactive effect of different Cu++ concentrations (5 mM, 10 mM, 20 mM and 25 mM) and treatments with biofertilizers Azospirillum brasilense on growth, metabolites, minerals and osmotic pressure of wheat plants was investigated. Shoots and roots of wheat plant were differentially response to Cu++ treatments, while shoot organ response positively to this treatment, root response negatively. The positive effect of Cu++ in shoot organ was concomitant with the increase in the production of fresh, dry matter, length and water content and this related with the accumulation of soluble sugar, soluble protein and mineral as a result of increasing osmotic pressure. On the other side, the negative effect of Cu++ on root organ was concomitant with the decrease in production of fresh, dry matter, length and water content that related with the reduction in the accumulation of soluble sugar and mineral with the insignificant change in osmotic pressure. Azospirillum brasilense inoculation increased the accumulation of soluble sugar and soluble protein which reflected an increase in the production of fresh, dry matter and water content with increasing values of osmotic pressure of the tested plants under Cu++ treatment. Finally, wheat plants response differentially to Cu++ treatment according to its organ and Azospirillum brasilense treatment improved wheat plant efficiency to tolerate the effect of Cu++ stress.
基金supported by the National Natural Science Foundation of China(Grant No.30170020)by the Doctoral Fellowship of the Education Ministry of China(Grant No.20010019002).
文摘NifA in Azospirillum brasilense plays a key role in regulating the synthesis and activity of nitrogenase in re- sponse to ammonia and oxygen available. In this work we used the yeast two-hybrid system to identify the proteins that interact with NifA. The nifA gene was fused to the yeast two-hybrid vector pGBD-C2, and three A. brasilense Sp7 genomic libraries for use in yeast two-hybrid studies were constructed. Screening of the libraries identified four clones encoding proteins that interact with NifA. The confirmation of the interactions of each gene product of the four clones and NifA were carried out by exchanging the vectors for nifA and the four clones and by mutageneses of the four clones with shift reading frame experiments in yeast two-hybrid studies. DNA sequence analyses showed that two clones en- code proteins containing PAS domains that play an impor- tant role in signal transduction. One clone has high similarity with the fhuE gene of Escherichia coli, whose gene product is involved in iron uptake and transportation, and the other clone encodes an unknown protein.
基金This work was supported by the National "863" High-tech Project (Grant No. 863-101-03-04-02).
文摘A flagellar gene cluster fragment includingflbD of Azospirillum brasilense was cloned and sequenced. TheflbD mutant strain was found to be nonmotile——losingboth polar and lateral flagella (Fla-Laf-). Motility and fla-gella were regained by complementation with plasmid-borne multicopy flbD, but altered with larger swarming circle and fewer lateral flagella on the semisolid plate. This result indicated that FlbD plays an important role in the regulation of both polar and lateral flagellar biosynthesis in A. brasilense.
基金Coordination for the Improvement of Higher Education Personnel(CAPES)by the scholarship of the master’s degree and resources for conducting the research.
文摘The objective of this work was to verify the responses in agronomic and physiological characters of lettuce seedlings when submitted to different doses of humic acids and the presence or absence of inoculation of the bacterium Azospirillum brasilense. The experiment was carried out at the Protected Cultivation Station and Biological Control Teacher Mário César Lopes, belonging to the Experimental Stations Nucleus of the State University of the West of Paraná. The experimental design was a randomized block design, in a 5 × 2 factorial scheme, with four repetitions, totaling 40 plots. The first factor consisted of five solutions containing humic acid (100%, 75%, 50%, 25% and 0%) and the second factor was the presence or absence of the diazotrophic bacterium Azospirillum brasilense obtained by commercial product. Germination tests were carried out in addition to the determination of agronomic characters such as the number of fully expanded leaves, plant height, stem diameter, main root length, shoot dry mass, root dry mass, total dry mass, and Dickson quality index. The association of diazotrophic bacteria and humic acids did not influence the emergency rate, mean emergence time, mean speed of emergency, emergence speed index, plant height, and root length of lettuce seedlings. The dilutions of humic acids, regardless of inoculation with bacteria diazotrophic favored the development of the number of leaves, stem diameter and Dickson quality index. Inoculation of lettuce seeds with diazotrophic bacteria associated with the addition of humic acids, favored the development of the dry mass of root and total dry matter.
文摘The most widely used method of olive propagation is cutting,although for some cultivars the technique is still limited.The objective of this work was to evaluate the use of plant growth promoter bacteria and arbuscular mycorrhizal fungi in the rooting of olive cuttings.Two experiments were conducted from October 2017 to January 2018 with cuttings from 4 olive cultivars(Ascolano 315,Koroneiki,Maria da Féand Picual)from four-year-old plants.The first experiment consisted of 4 olive cultivars and 3 mycorrhizal species plus the control and the second experiment of 3 concentrations of commercial inoculant(Nitro1000®),containing Azospirillum brasilense plus control.The cuttings were treated with 3000 mg/L of indolebutyric acid(IBA).The experimental design used in the two experiments was randomized blocks,in a 4×4 factorial scheme,containing 25 stakes per replicate and 3 replicates.The cuttings were kept under weaver conditions and within a low rooting tunnel.After 75 d,the percentage of rooted cuttings,callus and sprouts,length of the largest root,number and length of shoots were evaluated.The use of FMA in Maria da Féand Picual has a positive response to cutting rooting and the fungi benefit the quality of the seedlings by the higher number of shoots and larger root length.The relation of Azospirillum brasilense cultivar is specific,being that,the cultivar Picual does not respond to inoculation of the bacterium having less viability in the propagation by cutting.Maria da Féand Koroneiki have the best percentages of rooting with the use of 75.00 and 52.00 mL/L of inoculant,respectively.
