Polygalacturonic acid transeliminase production by <i>Azospirillum</i> species

Tien, Turmuktini; Diem, Hoang Gia; Gaskins, M. H.; Hubbell, D. H.

doi:10.1139/m81-065

Cited by 54 publications

(15 citation statements)

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“…A species of rhizotrophic bacteria, Azospirillum sp., can produce the growth promoting factor auxin such as indol-3-acetic acid. 21) We also investigated high auxin producing bacteria. As shown in Fig.…”

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confidence: 99%

Development of a New Biofertilizer with a High Capacity for N₂Fixation, Phosphate and Potassium Solubilization and Auxin Production

Leaungvutiviroj

Ruangphisarn

Hansanimitkul

et al. 2010

Bioscience, Biotechnology, and Biochemistry

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confidence: 99%

Development of a New Biofertilizer with a High Capacity for N₂Fixation, Phosphate and Potassium Solubilization and Auxin Production

Leaungvutiviroj

Ruangphisarn

Hansanimitkul

et al. 2010

Bioscience, Biotechnology, and Biochemistry

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“…In the legume-Rhizobium symbiosis, ultrastructural studies provided evidence that rhizobial cellulases may be involved in various steps of the infection process (8,9). The grass-associated diazotroph Azospirillulm brasilense, although able to colonize the interior of grass roots (35,51), is pectinolytic (55), but so far no cellulolytic activity has been reported to be present. Cellulose only supported growth of Azospirillum cells in coculture with cellulolytic bacteria (22).…”

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Cloning, expression in Escherichia coli, and characterization of cellulolytic enzymes of Azoarcus sp., a root-invading diazotroph

et al. 1993

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We screened members of a new genus of grass-associated diazotrophs (Azoarcus spp.) for the presence of cellulolytic enzymes. Out of five Azoarcus strains representing different species, only in the endorhizosphere isolate BH72, which is also capable of invading grass roots, was significant endoglucanase activity, in addition to 13-glucosidase and cellobiohydrolase activity, present. Reducing sugars were readily released from medium-viscosity carboxymethylcellulose (CMC), but neither CMC, cellulose filter strips, Avicel, cellobiose, nor D-glucose served as the sole carbon source for growth of Azoarcus spp. Clones from a plasmid library of strain BH72 expressed all three enzymes in Escherichia coli, apparently not from their own promoter. According to restriction endonuclease mapping and subclone analysis, ,-glucosidase and cellobiohydrolase activities were localized on a single 2.6-kb fragment not physically linked to a 1.45-kb fragment from which endoglucanase (egl) was expressed. Two isoenzymes of endoglucanase probably resulting from proteolytic cleavage had pl values of 6.4 and 6.1 and an apparent molecular mass of approximately 36 kDa. Cellobiohydrolase and ,I-glucosidase activity were conferred by one enzyme 41 kDa in size with a pl of 5.4, which we classified as an unspecific exoglycanase (exg) according to substrate utilization and specificity mapping; hydrolysis of various oligomeric substrates differentiated it from endoglucanase, which degraded substituted soluble cellulose derivatives but not microcrystalline cellulose. Both enzymes were not excreted but were associated with the surface of Azoarcus cells. Both activities were only slightly influenced by the presence of CMC or D-glucose in the growth medium but were enhanced by ethanol. egl was located on a large transcript 15 kb in size, which was detectable only in cells grown under microaerobic conditions on N2. Surface-bound exo-and endoglucanases with some unusual regulatory features, detected in this study in a strain which is unable to metabolize cellulose or sugars, might assist Azoarcus sp. strain BH72 in infection of grass roots.

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“…There is no obvious evidence for producing cellulase by Azospirillum and the reports of pectinolytic activity of Azospirillum brasilense are contradictory. Several authors (Plazinski and Rolfe 1985;Tien et al 1981) have reported pectinolytic activity but others (Khammas and Kaiser 1991;Myers and Hubbell 1987) have found no evidence of pectin breakdown by A. irakens. However, it is also possible that Azospirillum does not produce the complete enzyme set required for the infection but induces plant to produce these enzymes by e.g.…”

Section: Discussionmentioning

confidence: 99%

“…Polygalacturonic acid and pectin are utilized by Azospirillum brasilense Sp7 in broth culture and on agar plates (Umali-Garcia et al 1980). Polygalactacturonic acid transeliminase (pectic lyase) activity has been detected in strain Sp7 culture (Tien et al 1981). It has been suggested that the ability of Azospirillum spp to degrade pectin could assist in the penetration of the middle lamellae of grass roots (Umali-Garcia et al 1980).…”

Section: Introductionmentioning

confidence: 99%

The participation of the cell wall hydrolytic enzymes in the initial colonization of Azospirillum brasilense on wheat roots

2007

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The effect of cellulase and pectinase on bacterial colonization of wheat was studied by three different experiments. In the first experiment, the root colonization of 3 wheat cultivars (Ghods, Roshan and Omid) by two A. brasilense strains (Sp7 and Dol) was compared using pretreated roots with cellulase and pectinase, and non-treated with these enzymes (control). Although the root colonization varied greatly among strain-plant combinations in controls, the pre-treatment of roots with polysaccharide degrading enzymes significantly increased the bacterial count in roots, regardless of the strainplant combination. This might be an indication that cell wall may act as an important factor in plant-Azospirillum interaction. In the second experiment, the root cellulase activity of the same wheat cultivars treated with and without the two Azospirillum brasilense, strains (Sp7 and Dol) was compared. The pre-treatment of wheat roots with Azospirillum enhanced the cellulase activity of wheat root extracts. Thus, the cellulase activity might participate in the initial colonization of wheat roots by Azospirillum. The comparison of the cellulase activity of root extracts within inoculated and non-inoculated seedlings showed that the inoculation had enhanced the cellulase activity in root extracts, but this effect was directly dependent on the strain-plant combination. Strain Sp7 stimulated the highest cellulase activity in cv. Roshan, but strain Dol induced the highest enzyme activity in cv. Ghods. In the third experiment, several growth parameters of those 3 wheat cultivars treated with and without those two bacterial strains (Sp7 and Dol) were compared. The highest magnitude of growth responses caused by Sp7 strain was in the cv Roshan, but Dol strain stimulated the highest growth in cv Ghods. Therefore, effective colonization may contribute to more growth responses.

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Polygalacturonic acid transeliminase production by Azospirillum species

Cited by 54 publications

References 9 publications

Development of a New Biofertilizer with a High Capacity for N₂Fixation, Phosphate and Potassium Solubilization and Auxin Production

Development of a New Biofertilizer with a High Capacity for N₂Fixation, Phosphate and Potassium Solubilization and Auxin Production

Cloning, expression in Escherichia coli, and characterization of cellulolytic enzymes of Azoarcus sp., a root-invading diazotroph

The participation of the cell wall hydrolytic enzymes in the initial colonization of Azospirillum brasilense on wheat roots

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Polygalacturonic acid transeliminase production by Azospirillum species

Cited by 54 publications

References 9 publications

Development of a New Biofertilizer with a High Capacity for N2Fixation, Phosphate and Potassium Solubilization and Auxin Production

Development of a New Biofertilizer with a High Capacity for N2Fixation, Phosphate and Potassium Solubilization and Auxin Production

Cloning, expression in Escherichia coli, and characterization of cellulolytic enzymes of Azoarcus sp., a root-invading diazotroph

The participation of the cell wall hydrolytic enzymes in the initial colonization of Azospirillum brasilense on wheat roots

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Development of a New Biofertilizer with a High Capacity for N₂Fixation, Phosphate and Potassium Solubilization and Auxin Production

Development of a New Biofertilizer with a High Capacity for N₂Fixation, Phosphate and Potassium Solubilization and Auxin Production