Polysaccharide production by Azospirillumstrains was indicated by fluorescence on growth media containing calcofluor. Mutants showing decreased and. The interactions between Azospirillum lipoferum, Azotobacter chroococcum and Rhizobium spp. were assessed by the growth pattern and mineral concentration . Efecto de Azospirillum lipoferum y fertilización nitrogenada en el contenido de clorofila, absorción de nutrientes y propiedades biométricas de Zea mays L.
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Azospirillum species are plant growth-promotive bacteria whose beneficial effects have been postulated to be partially due to production of phytohormones, including gibberellins GAs. In this work, Azospirillum brasilense strain Cd and Azospirillum lipoferum strain USA 5b promoted sheath elongation growth of two single gene GA-deficient dwarf rice Oryza sativa mutants, dy and dxwhen the inoculated seedlings were supplied with [17, 2 H 2 ]GA 20 -glucosyl ester or [17, 2 H ilpoferum ]GA 20 -glucosyl ether.
However, the mechanism by which Azospirillum spp. Phytohormone production Tien et al. GAs are a class of phytohormones with many demonstrated effects on a number of physiological processes Davies, Their levels in plant tissues appear to be regulated by three processes: Conjugation of Lipoferhm is almost exclusively with Glc, either via the carboxyl group forming glucosyl esters or via the hydroxyl group generating glucosyl ethers in a range of isomeric forms.
These glucosyl conjugates do not appear to lipoferuj biologically active per se; rather, their role is proposed to be as reserve, transport, or entry to catabolism forms Schneider and Schliemann, GA production in vitro by Azospirillum spp.
Azlspirillum addition, azoepirillum bacteria have also been shown to metabolize exogenous GAs Piccoli and Bottini, azosplrillum Piccoli et al. External liplferum such as light quality Piccoli and Bottini, or oxygen availability and osmotic strength Piccoli et al. It was also found that application of GA 3 in concentrations similar to those produced by the microorganism, or by inoculation with different Azospirillum spp. It is interesting that inoculation with A.
The latter results, however, did not establish whether the higher content of GA 3 found in the inoculated roots was due to de novo production, hydrolysis by the microorganism per se, or by the plant under bacterial influence. Regarding this issue, Piccoli et al. In a number of rice Oryza sativa cultivars the dwarf phenotype is expressed in several single-gene mutants. We report herein the bacterial hydrolysis and metabolism of GA conjugates in these two dwarf mutants of rice by endophytic Azospirillum spp.
Both strains were effective in promoting growth of seedlings and reversing dwarfism when the two types of GA 20 -glucosyl conjugates were added. The promotive effects were azospirilum for each of the two forms of GA 20 -glucosyl conjugates. Inoculated control plants but without GA 20 conjugate application also showed dwarfism reversal, having a significantly greater growth than the ethanol-treated controls.
Azospirillum lipoferum (Beijerinck) Tarrand et al. ATCC ® &tr
Treatments with deuterated GA glucosyl conjugates alone no Azospirillum spp. Thus, it seems likely that the plant has some intrinsic capacity to hydrolyze GA-glucosyl conjugates.
The difference in growth for inoculated versus noninoculated seedlings can best be explained as hydrolytic plus metabolic activity of the bacteria on the conjugate. Although dwarfism reversal was observed in treatments with each addition of GA-glucosyl conjugates, or with independent inoculation, the greatest growth increases were observed for those seedlings that received the conjugated hormones as well as the microorganism.
Thus, no particular Azospirillum spp. Internode length of inoculated seedlings was significantly longer relative to noninoculated treatments for the higher concentration of [17, 2 H 2 ]GA 20 -G and [17, 2 H 2 ]GA 20 -GE. Again, as for the dy mutant, although reversal of dwarfism was observed in treatments with addition of hormones or with independent inoculation, the greatest growth differences were observed in those seedlings that received hormones and microorganism together.
The dx mutant was much more efficient than the dy mutant in utilizing the glucosyl conjugates of [17,17 2 H 2 ]GA 20 for sheath elongation growth.
Azospirillum lipoferum – microbewiki
Endophytic presence of the bacteria in roots and stems of inoculated plants was shown for both cultivars of all experiments summarized in Table III. Rice seedlings had been treated with GA-A 20 -glucosyl conjugates and inoculated with Azospirillum spp. There is a high correlation between the application of deuterated GA conjugates and the growth response of the rice mutant seedlings in the presence of Azospirillum spp.
Thus, it is apparent that inoculation with the microorganism allows for deconjugation release of the aglycone [17, 2 H 2 ]GA 20 and its metabolism to [17, 2 H 2 ]GA 1 in both dx and dy mutants of rice seedlings.
However, dx seedlings without Lipocerum spp.
However, this could be because the GA measurements were done using whole seedlings. Results represent a typical subsample from one replicate, injected several times without noticeable differences.
Sheath elongation growth of two single gene dwarf rice mutants, dy and dxcan be promoted when seedlings inoculated azosplrillum A. This confirms earlier work by Piccoli et al. The finding that only [17, 2 H 2 ]GA 1 was a metabolic product of [17, 2 H 2 ]GA 20 azoapirillum deconjugated aglycone strongly implies that GA 1 and GA 3 have different precursors in the route of synthesis in Lipofefum spp. Piccoli and Bottini, ; Piccoli et al. These responses by the dx seedlings are consistent with earlier studies Takahashi and Kobayashi, ; Kobayashi et al.
In conclusion, the beneficial effect of Azospirillum spp.
The following bacteria were used: Azospirillum lipoferum strain USA5b kindly provided by Dr. The cellular pellet was washed twice with 0. Then after again washing with sterile distilled water, five seeds were sown in glass beakers containing 2 mL of agar 0. After 72 h roots, of seedlings of both rice mutants were inoculated with the Azospirillum spp. Control plants received an equivalent amount of buffer. Treatments are summarized as follows: After 72 h in the presence of the deuterated GA conjugates, the length of the first internode was measured.
Each experiment was carried out in a random design, with five repetitions per treatment. Bacterial counts were made for both shoots and roots of control and treated rice seedlings using plates of NFb agar. Plant tissue was macerated using a mortar and pestle with 0. Serially diluted inoculations were applied to plates containing agar NFb. After filtration the solid residue was extracted again and filtered. Filtrates were combined and methanol evaporated under reduced atmospheric pressure.
The aqueous phase was adjusted to a pH of 2. Acidic ethyl acetate was evaporated and diluted with acetic acid: Elution was carried out with acetic acid: The fractions that would contain [17, 2 H 2 ]GA 20 and [17, 2 H 2 ]GA 1 were again collected, evaporated, and processed as described by Volmaro et al.
The critical review of the manuscript by Prof. Pharis and another anonymous reviewer is also deeply appreciated. PIP to R.
PID to R. National Center for Biotechnology InformationU. Journal List Plant Physiol v.
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Abstract Azospirillum species are plant growth-promotive bacteria whose beneficial effects have been postulated to be partially due to production of phytohormones, including gibberellins GAs. Open in a separate window. Endophytic Bacteria Endophytic presence of lipofeeum bacteria in roots and stems of inoculated plants was shown for both cultivars of all experiments summarized in Table III.
Table III Bacterial counts 72 h after inoculation.
Treatments After 72 h roots, of seedlings of both rice mutants were inoculated with the Azospirillum spp. Measurements and Statistical Analysis After 72 h in the presence of the deuterated GA conjugates, the length of the first internode was measured.
Bacterial Counts in Stems and Roots Bacterial counts were made for both shoots and roots of control and treated rice seedlings using plates of NFb agar. Identification of gibberellins A 1A 3and iso-A 3 in cultures of Azospirillum lipoferum.
Shoot growth and water status in Azospirillum- inoculated wheat seedlings grown under osmotic and salt stresses. Physiology, Biochemistry and Molecular Biology. Kluwer Academic Publishers; Imperial College Press; Azospirillum brasilense produces gibberellins in pure culture and chemically-medium and in co-culture on straw. The metabolism of gibberellin A 20 to gibberellin A 1 by tall and dwarf mutants of Oryza sativa and Arabidopsis thaliana. Plant growth-altering effects of Azospirillum brasilense and Bacillus C—25 on two wheat cultivars.
Lucangeli C, Bottini R. Effects of Azospirillum spp. Okon Y, Kapulnik Y. Development and function of Azospirillum -inoculated roots. Agronomic applications of Azospirillum: Piccoli P, Bottini R. Metabolism of 17,[ 2 H 2 ]-gibberellin A 20 to 17,[ 2 H 2 ]gibberellin A 1 by Azospirillum lipoferum cultures.
Gibberellin production in Azospirillum lipoferum cultures is enhanced by light. Hydrolisis of 17,[ 2 H 2 ]-gibberellin A 20 -glucoside and 17,[ 2 H 2 ]-gibberellin A 20 -glucosyl esther by Azospirillum lipoferum cultured in nitrogen-free biotin-based chemically defined medium.
Metabolism of 17,[ 2 H 2 ]-gibberellin A 4A 9 and A 20 by Azospirillum lipoferum in chemically defined culture medium.
Gibberellin production by Azospirillum lipoferum cultured in chemically defined medium as affected by water status and oxygen availability. Schneider G, Schliemann W. Partial synthesis of some physiologically relevant gibberellin glucosyl conjugates.
Takahashi N, Kobayashi M. Organ-specific gibberellins in rice: