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Abstract

This is the first report documenting the presence of 1-aminocyclopropane-1-carboxylate (ACC) deaminase in Rhizobium. This enzyme, previously found in free-living bacteria, yeast and fungi, degrades ACC, the immediate precursor of ethylene in higher plants. Thirteen different rhizobial strains were examined by Southern hybridization, Western blots and ACC deaminase enzyme assay. Five of them tested positive for ACC deaminase. Induction of the expression of ACC deaminase was examined in one of the positively tested strains, Rhizobium leguminosarum bv. viciae 128C53K. This rhizobial ACC deaminase had a trace basal level of expression without ACC, but could be induced by a concentration of ACC as low as 1 microM. The more ACC added to this Rhizobium the higher the expression level of the ACC deaminase.

Isolation and characterization of ACC deaminase-producing fluorescent pseudomonads, to alleviate salinity stress on canola (Brassica napus L.) growth

“…Screening the isolates, based on the activity of ACC deaminase, revealed that 14% of the isolates (16% of Pseudomonas putida and 12% of Pseudomonas fluorescence) were able to produce ACC deaminase, and hence, utilize ACC as the sole N-source, which is similar to the results of Ma et al (2003). With increase in the salinity level in the LB medium from 5 to 10 g/L, bacterial growth did not decrease.…”

Properties of Astragalus sp. microsymbionts and their putative role in plant growth promotion

“…It was found that many bacteria of the genus Mesorhizobium have the ACC deaminase-coding acdS gene, which plays an important role in the growth and nodulation of fabacean legume plants (Ma et al 2003, 2004; Glick et al 2007; Conforte et al 2010; Nascimento et al 2012a, b). …”

“…The bacterial cells were centrifuged and washed twice with 0.1 M Tris–HCl (pH 7.5). Next, the bacteria were suspended in 2 ml of M9 minimal medium supplemented with ACC (final concentration of 5 mM) and incubated at 30 °C with shaking for 36 h. ACC deaminase activity was determined according to the method described before (Ma et al 2003; Penrose and Glick 2003). ACC deaminase activity was determined by measuring the production of α-ketobutyrate (Honma and Shimomura 1978).…”

Azospirillum lipoferum strain AZm5 containing 1-aminocyclopropane-1-carboxylic acid deaminase improves early growth of tomato seedlings under nitrogen deficiency

“…Therefore, the production of indole pyruvic acid, indole lactic acid, indole acetamide, indole acetaldehyde, indole ethanol and indole methanol, which are similar to IAA (Crozier et al 1988), needs to be tested. AZm5 produced high concentrations of ACC deaminase 2.68±0.16 (in μmol α keto-butyrate mg protein per h), in relation to those produced by Enterobacter cloacae UW4 (2.43±0.04), Escherichia coli pRKACC (1.74±0.06), Rhizobium leguminosarum 128C53K Biovar viciae (1.06±0.17) and Acidovorax facilis AY197008 (0.7±0.1) (Holguin and Glick 2001;Ma et al 2003, Belimov et al 2005. This finding coincides with the presence of the acdS gene, which encodes ACC deaminase, in AZm5 and also with the root elongation observed in tomato seedlings grown under 1.2 μmol m −2 s −1 of light; root elongation is promoted by the interruption of ethylene synthesis from ACC .…”

“…In these bacteria, the acdS gene has been associated with the presence of the enzyme ACC deaminase (Glick et al 1995;Belimov et al 2001;Penrose and Glick 2001;Babalola et al 2003;Ma et al 2003;Mayak et al 2004;Belimov et al 2005;Madhaiyan et al 2006). It has been previously documented that some members of Azospirillum sp.…”