Cloning and Characterization of a Plasmid Encoded ACC Deaminase from an Indigenous Pseudomonas fluorescens FY32

Abstract

In addition to the characterized mechanisms responsible for many direct effects of plant growth promoting bacteria (PGPB) on plants, it has been suggested that a number of PGPB contain the enzyme ACC deaminase that catalyzes degradation of 1-aminocyclopropane-1-carboxylic acid (ACC), the immediate precursor of ethylene, into alpha-ketobutyrate and ammonia. As part of an effort to obtain an ACC deaminase encoding gene from a collection of soil samples, only one bacterial isolate, Pseudomonas fluorescens FY32 was capable of growing on ACC as a sole source of nitrogen. The ACC deaminase gene was amplified from the above isolate by polymerase chain reaction (PCR) giving an expected DNA fragment, 1017 bp. Sequence analysis of the fragment showed that it was highly homologous (94% and 98% identities at nucleotide and amino acid levels, respectively) to the previously characterized acdS gene from Pseudomonas sp. 6G5. Furthermore, fusion of the ACC deaminase ORF with lacZ gene resulted in the expression of active enzyme in Escherichia coli. In addition, further analyses revealed that the acdS gene was plasmid-encoded so that a large plasmid (pFY32) with almost 50 kb in size was identified from this bacterium. Furthermore, transfer of pFY32 into E. coli DH5alpha proved its ACC deaminase activity. This result was in accordance with previous reports suggesting horizontal transfer of the acdS gene. However, it needs more investigation to identify whether this pFY32 plasmid has undergone lateral gene transfer during the evolutionary process.

Characterization of the antifungal and plant growth-promoting effects of diffusible and volatile organic compounds produced by Pseudomonas fluorescens strains

“…For the HCNsynthase gene (hcnCB), we used the primers Fhcn, 5´-CTCAAGCTGCACGGCATT-3´ and Rhcn 5´-ATCCGGCAACGTCGGTTTT-3´. For detection of the ACC deaminase gene, we used the specific primers AzbAc F and AzbAc R previously reported by Farajzadeh et al (2010) and…”

Stress-tolerant antagonistic rhizobacteria isolated from the medicinal plant Tinospora cordifolia

“…Several plant growth-promoting bacteria produce 1-aminocyclopropane-1-carboxylate (ACC) deaminase, which cleaves the plant ethylene precursor ACC to α-ketobutyrate and ammonia, thereby lowering the level of ethylene in the rhizosphere (Glick, 2014). The bacteria producing ACC-deaminase are known to promote root elongation and plant growth by hydrolyzing ACC from germinating seeds, thereby lowering ethylene levels and increasing the active rhizosphere zone (Glick, 2014;Farajzadeh et al, 2010). Several researchers have exploited the ability of bacteria to utilize ACC as sole source of nitrogen in the screening of ACC-deaminase producing bacteria (Penrose and Glick, 2003;Dey et al, 2004;Glick, 2014).…”

Comprehensive proteomic analysis of canola leaf inoculated with a plant growth-promoting bacterium, Pseudomonas fluorescens, under salt stress

“…To enhance the detection of low-abundant proteins, PEG fractionation method was used to remove high-abundance proteins, such as RuBisCO. A proteomic technique was used to identify stress-responsive proteins in canola inoculated with the plant-growth promoting bacterium P. fluorescens FY32 (21). To better understand the role of the until protein extraction.…”