Annals of Microbiology 

About: Annals of Microbiology is an academic journal published by Springer Science+Business Media. The journal publishes majorly in the area(s): Fermentation & Population. It has an ISSN identifier of 1590-4261. It is also open access. Over the lifetime, 2376 publications have been published receiving 42275 citations. The journal is also known as: An official journal of the University of Milan.

Soil beneficial bacteria and their role in plant growth promotion: a review

Abstract: Soil bacteria are very important in biogeochemical cycles and have been used for crop production for decades. Plant–bacterial interactions in the rhizosphere are the determinants of plant health and soil fertility. Free-living soil bacteria beneficial to plant growth, usually referred to as plant growth promoting rhizobacteria (PGPR), are capable of promoting plant growth by colonizing the plant root. PGPR are also termed plant health promoting rhizobacteria (PHPR) or nodule promoting rhizobacteria (NPR). These are associated with the rhizosphere, which is an important soil ecological environment for plant–microbe interactions. Symbiotic nitrogen-fixing bacteria include the cyanobacteria of the genera Rhizobium, Bradyrhizobium, Azorhizobium, Allorhizobium, Sinorhizobium and Mesorhizobium. Free-living nitrogen-fixing bacteria or associative nitrogen fixers, for example bacteria belonging to the species Azospirillum, Enterobacter, Klebsiella and Pseudomonas, have been shown to attach to the root and efficiently colonize root surfaces. PGPR have the potential to contribute to sustainable plant growth promotion. Generally, PGPR function in three different ways: synthesizing particular compounds for the plants, facilitating the uptake of certain nutrients from the soil, and lessening or preventing the plants from diseases. Plant growth promotion and development can be facilitated both directly and indirectly. Indirect plant growth promotion includes the prevention of the deleterious effects of phytopathogenic organisms. This can be achieved by the production of siderophores, i.e. small metal-binding molecules. Biological control of soil-borne plant pathogens and the synthesis of antibiotics have also been reported in several bacterial species. Another mechanism by which PGPR can inhibit phytopathogens is the production of hydrogen cyanide (HCN) and/or fungal cell wall degrading enzymes, e.g., chitinase and s-1,3-glucanase. Direct plant growth promotion includes symbiotic and non-symbiotic PGPR which function through production of plant hormones such as auxins, cytokinins, gibberellins, ethylene and abscisic acid. Production of indole-3-ethanol or indole-3-acetic acid (IAA), the compounds belonging to auxins, have been reported for several bacterial genera. Some PGPR function as a sink for 1-aminocyclopropane-1-carboxylate (ACC), the immediate precursor of ethylene in higher plants, by hydrolyzing it into α-ketobutyrate and ammonia, and in this way promote root growth by lowering indigenous ethylene levels in the micro-rhizo environment. PGPR also help in solubilization of mineral phosphates and other nutrients, enhance resistance to stress, stabilize soil aggregates, and improve soil structure and organic matter content. PGPR retain more soil organic N, and other nutrients in the plant–soil system, thus reducing the need for fertilizer N and P and enhancing release of the nutrients.

Investigations into the antibacterial behavior of copper nanoparticles against Escherichia coli

Abstract: Zerovalent copper nanoparticles (Cu0) of 12 nm size were synthesized using an inert gas condensation method in which bulk copper metal was evaporated into an inert environment of argon with subsequent cooling for nucleation and growth of nanoparticles Crystalline structure, morphology and estimation of size of nanoparticles were carried out by X-ray diffraction and transmission electron microscopy The antibacterial activity of these nanoparticles against the Gram-negative bacterium Escherichia coli was assessed in liquid as well as solid growth media It was observed from scanning electron microscopic analysis that the interaction of copper nanoparticles with E coli resulted in the formation of cavities/pits in the bacterial cell wall The antibacterial property of copper nanoparticles was attributed mainly to adhesion with bacteria because of their opposite electrical charges, resulting in a reduction reaction at the bacterial cell wall Nanoparticles with a larger surface-to-volume ratio provide more efficient means for antibacterial activity

A survey of bacteria and fungi occurring during composting and self-heating processes

Abstract: Composting is a controlled self-heating, aerobic solid phase biodegradative process of organic materials The process comprises mesophilic and thermophilic phases involving numerous microorganisms In several successive steps, microbial communities degrade organic substrates into more stable, humified forms and inorganic products, gener- ating heat as a metabolic waste product Due to the complexity of substrates and intermedi- ate products, microbial diversity and the succession of populations is a prerequisite to ensure complete biodegradation Due to the dynamic process, both in time and space (microhabi- tats), which is reflected by constantly changing pH, humidity, oxygen partial pressure and temperature it is extremely difficult to detect, albeit isolate, all the microorganisms involved Research on composts is also so difficult because the process can hardly be simulated in the laboratory since all major gas and temperature fluxes are to a large extent determined by the physical extension of the system In this comprehensive survey of literature an inventory of the mesophilic and thermophilic bacteria, actinomycetes and fungi isolated during several phases of composting (including also self-heating organic materials) is presented

Plant-growth-promoting rhizobacteria: drought stress alleviators to ameliorate crop production in drylands

Abstract: Drylands are known for being a drought stressed environment, which is an alarming constraint to crop productivity. To rescue plant growth in such stressful conditions, plant-growth-promoting rhizobacteria (PGPR) are a bulwark against drought stress and imperilled sustainability of agriculture in drylands. PGPR mitigates the impact of drought stress on plants through a process called rhizobacterial-induced drought endurance and resilience (RIDER), which includes physiological and biochemical changes. Various RIDER mechanisms include modification in phytohormonal levels, antioxidant defense, bacterial exopolysaccharides (EPS), and those associated with metabolic adjustments encompass accumulation of several compatible organic solutes like sugars, amino acids and polyamines. Production of heat-shock proteins (HSPs), dehydrins and volatile organic compounds (VOCs) also plays significant role in the acquisition of drought tolerance. Selection, screening and application of drought-stress-tolerant PGPRs to crops can help to overcome productivity limits in drylands.

Assessment of genetic diversity and plant growth promoting attributes of psychrotolerant bacteria allied with wheat ( Triticum aestivum ) from the northern hills zone of India

Abstract: The biodiversity of wheat-associated bacteria from the northern hills zone of India was deciphered. A total of 247 bacteria was isolated from five different sites. Analysis of these bacteria by amplified ribosomal DNA restriction analysis (ARDRA) using three restriction enzymes, AluI, MspI and HaeIII, led to the grouping of these isolates into 19–33 clusters for the different sites at 75 % similarity index. 16S rRNA gene based phylogenetic analysis revealed that 65 %, 26 %, 8 % and 1 % bacteria belonged to four phyla, namely Proteobacteria, Firmicutes, Actinobacteria and Bacteroidetes, respectively. Overall, 28 % of the total morphotypes belonged to Pseudomonas followed by Bacillus (20 %), Stenotrophomonas (9 %), Methylobacterium (8 %), Arthrobacter (7 %), Pantoea (4 %), Achromobacter, Acinetobacter, Exiguobacterium and Staphylococcus (3 %), Enterobacter, Providencia, Klebsiella and Leclercia (2 %), Brevundimonas, Flavobacterium, Kocuria, Kluyvera and Planococcus (1 %). Representative strains from each cluster were screened in vitro for plant growth promoting traits, which included solubilisation of phosphorus, potassium and zinc; production of ammonia, hydrogen cyanide, indole-3-acetic acid and siderophore; nitrogen fixation, 1-aminocyclopropane-1-carboxylate deaminase activity and biocontrol against Fusarium graminearum, Rhizoctonia solani and Macrophomina phaseolina. Cold-adapted isolates may have application as inoculants for plant growth promotion and biocontrol agents for crops growing under cold climatic conditions.