scholarly journals 1-Aminocyclopropane-1-Carboxylate: A Novel and Strong Chemoattractant for the Plant Beneficial Rhizobacterium Pseudomonas putida UW4

2019 ◽  
Vol 32 (6) ◽  
pp. 750-759 ◽  
Author(s):  
Tao Li ◽  
Jun Zhang ◽  
Chaohui Shen ◽  
Huiru Li ◽  
Liyou Qiu

Plant growth–promoting rhizobacteria (PGPR) and fungi-bacterial biofilms are both important biofertilizer inoculants for sustainable agriculture. However, the strongest chemoattractant for bacteria to colonize the rhizosphere and mycelia is not clear. Coincidentally, almost all the PGPRs possess 1-aminocyclopropane-1-carboxylate (ACC) deaminase (AcdS) and can utilize ACC as the sole nitrogen source. Here, we found that ACC was a novel, metabolic dependent and methyl-accepting chemoreceptor–involved chemoattractant for Pseudomonas putida UW4. The chemotactic response of UW4 to ACC is significantly greater than that to the amino acids and organic acids identified in the plant root and fungal hyphal exudates. The colonization counts of the UW4 acdS or cheR deletion mutants in the wheat rhizosphere and on Agaricus bisporus mycelia were reduced one magnitude compared with those of UW4. The colonization counts of UW4 on A. bisporus antisense ACC oxidase mycelia with a high ACC production significantly increased compared with A. bisporus, followed by the UW4 cheR complementary strain and the ethylene chemoreceptor gene–deletion mutant. The colonization counts of the UW4 strains on A. bisporus acdS+ mycelia with a low ACC production decreased significantly compared with A. bisporus wild type. These results suggested that ACC and not ethylene should be the strongest chemoattractant for the PGPR that contain AcdS.

Author(s):  
Shamal S. Kumar ◽  
Ananta G. Mahale ◽  
Md. Mifta Faizullah ◽  
J. Radha Krishna ◽  
Tharun K. Channa

Water scarcity is known as a major stumbling block towards crop development and its output all over the world. Certain free-living bacterial strains have been found near the plant root zones which have shown to improve resistance of plants towards water stress. Despite availability of basic nutrients, drought an abiotic factor substantially inhibits growth, development and yield of crops by causing an increase in ethylene levels. It is a good idea to incorporate the use of a management tool which is the utilization of plant growth-promoting rhizobacteria to help several crops manage drought conditions. Drought stress in crops can be alleviated by reducing ethylene synthesis, exopolysaccharide, osmoregulation, Indole-3-acetic acid and aggregation with the ACC deaminase-containing plant growth-promoting rhizobacteria. Inoculating pathogens like root rot (Macrophomina phaseolina) affected plant with Pseudomonas fluorescens strain TDK1 with ACC deaminase function improves drought stress. Using plant growth-promoting rhizobacteria to mitigate the negative imbibes of drought in most crops is a good idea. Several studies have been carried out on plant growth-promoting rhizobacteria, as its inoculation not only manages drought related conditions but increases root hair growth and lateral root, which assist in increased water and nutrient uptake. It limits ethylene supply, alternatively increases plant root growth by hydrolyzing 1-aminocyclopropane-1-carboxylic acid (ACC). This review will give us a perspective on the importance of plant growth-promoting rhizobacteria, as it is one of the efficient tools that helps manage drought stress on several crops.


1994 ◽  
Vol 40 (12) ◽  
pp. 1019-1025 ◽  
Author(s):  
Christian B. Jacobson ◽  
J. J. Pasternak ◽  
Bernard R. Glick

The plant growth promoting rhizobacterium Pseudomonas putida GR12-2 can utilize 1-aminocyclopropane-1-carboxylate (ACC) as a sole nitrogen source because it possess the unusual enzyme ACC deaminase, which hydrolyzes ACC to ammonia and α-ketobutyrate. This enzyme, which is thought to be intimately involved in the mechanism that the bacterium uses to promote root elongation in developing canola seedlings, was partially purified and characterized. The native form of the enzyme is a trimer with a molecular mass of 105 kDa and a subunit molecular mass of 35 kDa. ACC deaminase activity is found in the cytoplasm of the bacterium, is induced by low levels (i.e., 100 nM) of ACC, and has a temperature optimum at approximately 30 °C and a pH optimum of 8.5. These properties are very similar to those reported for ACC deaminase from another soil bacterium, Pseudomonas sp. strain APC.Key words: 1-aminocyclopropane-1-carboxylate, ACC, plant growth promoting rhizobacteria, PGPR, ACC deaminase, bacterial fertilizer.


1994 ◽  
Vol 40 (11) ◽  
pp. 911-915 ◽  
Author(s):  
Bernard R. Glick ◽  
Christian B. Jacobson ◽  
Melinda M. K. Schwarze ◽  
J. J. Pasternak

The plant growth promoting rhizobacterium Pseudomonas putida GR12-2 was mutagenized with nitrosoguanidine and three separate mutants that were unable to utilize 1-aminocyclopropane-1-carboxylic acid (ACC) as a sole nitrogen source were selected. These mutants are devoid of the ACC deaminase activity that is present in wild-type P. putida GR12-2 cells. Only wild-type cells, but not any of the ACC deaminase mutants, promoted root elongation of developing canola seedlings under gnotobiotic conditions. These results are interpreted in terms of a model in which P. putida GR12-2 promotes root elongation by binding to germinating seeds and sequesters and hydrolyzes some of the unbound ACC, thereby lowering the level of ACC and hence the endogenous ethylene concentration, allowing the roots to grow longer.Key words: 1-aminocyclopropane-1-carboxylate, ACC, plant growth promoting rhizobacteria, PGPR, ACC deaminase, bacterial fertilizer.


Author(s):  
Himanshi Verma ◽  
Meghna Jindal ◽  
Shabir A. Rather

The soil is a repository of microorganisms such as bacteria, fungi, algae, and protozoa. Among these, more bacteria are found, most of which are located in the rhizosphere region of the soil. The rhizosphere, under the direct control of plant root secretions, is the complex, narrow area of the soil. It is densely populated with microorganisms (mostly bacteria) that interact with the plants. These interactions influence the growth of the plant directly or indirectly. Plant growth-promoting rhizobacteria (PGPR) inhabiting the rhizosphere colonizes the plant roots and increases plant growth via different mechanisms. Iron is an essential micronutrient required by almost all life forms including plants. Oxidation of Fe2+ (soluble) to Fe3+ (insoluble) due to the soil's aerobic conditions limits its bioavailability. Siderophores are selective low molecular weight ferric ion chelators secreted by bacteria to acquire iron from the surrounding. They bind to iron (Fe3+) with high specificity as well as high affinity. By helping the insolubilisation of iron, it promotes the growth and yield.


2013 ◽  
Vol 1 (1) ◽  
pp. 11-15 ◽  
Author(s):  
Umesh P. Shrivastava ◽  
Ashok Kumar

A total of nine strains of plant growth promoting rhizobacteria were analyzed for ACC deaminase activity, where highest ACC deaminase activity was found in Klebsiella sp strain ECI-10A (539.1 nmol α-keto butyrate/ mg protein/ h) and lowest in Microbacterium sp strain ECI-12A (122.0 nmol α-keto butyrate/ mg protein/ h). Although Microbacterium sp strain ECI-12A showed lowest level of ACC deaminase activity, but, the species of Microbacterium isolated from rhizosphere is the first report. Microbacterium sp strain ECI-12A was also analyzed under varying conditions of time, amount of 1-Aminocyclopropane-1- carboxylate (ACC), and temperature for optimization of the ACC deaminase activity. The optimum activity was recorded with the supplementation of 5mM ACC at 30°C temperature after 24h of culture growth. All the nine strains showed acdS gene in the PCR amplification of that gene. No any rhizospheric Microbacterium species showing ACC deaminase activity have been reported earlier, therefore, we report here ACC deaminase activity in Microbacterium sp ECI-12A isolated from rice rhizosphere is a novel finding. DOI: http://dx.doi.org/10.3126/ijasbt.v1i1.7921 Int J Appl Sci Biotechnol, 2013, Vol. 1(1): 11-15


1995 ◽  
Vol 41 (9) ◽  
pp. 776-784 ◽  
Author(s):  
Xiuying Sun ◽  
Marilyn Griffith ◽  
J. J. Pasternak ◽  
Bernard R. Glick

The plant growth promoting rhizobacterium Pseudomonas putida GR12-2 was originally isolated from the rhizosphere of plants growing in the Canadian High Arctic. Here we report that this bacterium was able to grow and promote root elongation of both spring and winter canola at 5 °C, a temperature at which only a relatively small number of bacteria are able to proliferate and function. In addition, the bacterium survived exposure to freezing temperatures, i.e., −20 and −50 °C. In an effort to determine the mechanistic basis for this behaviour, it was discovered that following growth at 5 °C, P. putida GR12-2 synthesized and secreted to the growth medium a protein with antifreeze activity. Analysis of the spent growth medium, following concentration by ultrafiltration, by SDS-polyacrylamide gel electrophoresis revealed the presence of one major protein with a molecular mass of approximately 32–34 kDa and a number of minor proteins. However, at this point it is not known which of these proteins contains the antifreeze activity.Key words: plant growth promoting rhizobacteria, PGPR, bacterial fertilizer, soil bacteria, antifreeze protein.


2008 ◽  
Vol 57 (4) ◽  
pp. 312-317 ◽  
Author(s):  
Venkadasamy Govindasamy ◽  
Murugesan Senthilkumar ◽  
Kishore Gaikwad ◽  
Kannepalli Annapurna

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