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The green revolution brought amazing consequences in food grain production but with insufficient concern for agricultural sustainability. The availability and affordability of fossil fuel based chemical fertilizers at farm level in India have been ensured only through imports and subsidies which are largely dependent on GDP of the country. Dependence on chemicals for future agricultural needs would result in further loss in soil health, possibilities of water contamination and calculated burden on the fiscal system. Indiscriminate synthetic fertilizer usage has polluted the soil, water basins, destroyed microorganisms and eco-friendly insects, made the crop more susceptible to diseases and depleted soil fertility at the primary levels as of today, which is the main concern of the write up. In this critical context Microorganisms have been emerged as the potential alternative for the productivity, reliability and sustainability of the global food chain. Carrier based biofertilzers has already proved to be the best over the agro chemicals and have been showing the tremendous effect on the global agriculture productivity since the past two decades. Rectifying the disadvantages of the carrier based biofertilizers, liquid biofertilizers have been developed which would be the only alternative for the cost effective sustainable agriculture. The article focuses on Liquid Biofertilizer Technology providing reliable reasons for their necessity, specificity and emphasizes that "Use of agriculturally important microorganisms in different combinations i.e. Liquid microbial consortium (LMC) is the only solution for restoration of soil health". Even though biofertilizers are being produced and distributed constantly by private agencies, NGO's, State and Central Government production units for the last three decades, their corresponding usage is not in the satisfactory proportions. To cope with the rising demands for food commodities, serious efforts are being made by the State and Central Governments (under the National Projects) for the sufficient agricultural production by popularizing biofertilizers and making them available to the farmer community. In spite of these efforts, the rate of consumption of biofertilizers is not to the optimum level in comparison with the agrochemicals. The reason attributed is the "non-availability of good and suitable carrier materials" that raises contamination problems and shorter shelf life. To cope with this alarming situation, Liquid formulations (LFs) are being developed that ensure more quality over the conventional carrier based biofertilizers inaugurating a new era in the Biological input technology. These liquid formulations facilitate long shelf life (up to 2 years), minimum contamination, carrier free activity, handling comfort, storage and transport convenience, easy quality control, enhanced export potentials and are preferred by the farmer community as well as manufacturers.

Transposon mutagenesis of Pseudomonas syringae Lz4W, a psychrophilic bacterium capable of growing at temperatures between 2 and 30°C, yielded 30 cold-sensitive mutants, and CSM1, one of these cold-sensitive mutants, was characterized. Growth of CSM1 was retarded when it was cultured at 4°C but not when it was cultured at 22°C and 28°C compared to the growth of wild-type cells, indicating that CSM1 is a cold-sensitive mutant of P. syringae Lz4W. The mutated gene in CSM1 was identified as trmE (coding for tRNA modification GTPase), and evidence is provided that this gene is induced at low temperatures. Further, the cold-inducible nature of the trmE promoter was demonstrated. In addition, the transcription start site and the various regulatory elements of the trmE promoter, such as the ؊10 region, ؊35 region, UP element, cold box, and DEAD box, were identified, and the importance of these regulatory elements in promoter activity were confirmed. The importance of trmE in rapid adaptation to growth at low temperatures was further highlighted by plasmid-mediated complementation that alleviated the cold-sensitive phenotype of CSM1.Psychrophilic bacteria (57) constitute a sizeable proportion of bacterial diversity because a large proportion of Earth's biosphere (75%) is either transiently or permanently cold (temperature, Ͻ5°C) (2). Studies have indicated that psychrophiles adapt to low temperatures by being able to sense changes in temperature (41,48,59), by modulating membrane fluidity (11-13, 28, 29), and because they possess enzymes and genes which are active at low temperatures (8,10,19,35,50,60,64). In psychrophilic bacteria pnp (encoding polynucleotide phosphorylase) (23), oppA (mediation of the transport of oligonucleotides) (5), and recD (51) have been identified as genes required for low-temperature growth. In contrast, in mesophilic bacteria many genes are induced following a downshift in temperature; these genes include genes for fatty acid desaturases and other enzymes (26,32,62), cold shock genes (33, 47), and genes involved in replication transcription and translation (3,9,26,33,69). The question is whether such genes are induced in psychrophiles, which, unlike mesophiles, are not cold stressed but are cold adapted. The present study investigated the role of trmE in low-temperature growth. MATERIALS AND METHODS Generation of cold-sensitive mutants. Psychrophilic Pseudomonas syringaeLz4W (referred to as P.syringae below) and Escherichia coli strains DH-5␣ and S-17-1 (Table 1) were grown in Antarctic bacterial medium (58) or Luria-Bertani medium (66). P. syringae was mutagenized with a Tn5 transposon-based suicide plasmid vector (pOT182) (35, 42), and cold-sensitive mutants were identified based on their inability to grow or their delayed growth on plates incubated at 4°C for 1 week. Growth characteristics were also analyzed using a UV-visible spectrophotometer (Shimadzu, Kyoto, Japan) (36, 37).Identification of the disrupted gene. Southern analysis using genomic DNA of CSM1 (one of the cold-sensitive mutan...

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The bacterial diversity of two soil samples collected from the periphery of the Roopkund glacial lake and one soil sample from the surface of the Roopkund Glacier in the Himalayan ranges was determined by constructing three 16S rRNA gene clone libraries. The three clone libraries yielded a total of 798 clones belonging to 25 classes. Actinobacteria was the most predominant class (>10% of the clones) in the three libraries. In the library from the glacial soil, class Betaproteobacteria (24.2%) was the most predominant. The rarefaction analysis indicated coverage of 43.4 and 41.2% in the samples collected from the periphery of the lake thus indicating a limited bacterial diversity covered; at the same time, the coverage of 98.4% in the glacier sample indicated most of the diversity was covered. Further, the bacterial diversity in the Roopkund glacier soil was low, but was comparable with the bacterial diversity of a few other glaciers. The results of principal component analysis based on the 16S rRNA gene clone library data, percentages of OTUs and biogeochemical data revealed that the lake soil samples were different from the glacier soil sample and the biogeochemical properties affected the diversity of microbial communities in the soil samples.

Two bacterial strains, designated BBH5 and BBH7 T , were isolated from a deep-sea sediment sample collected from the Chagos Trench of the Indian Ocean (116 069 S 726 319 E). Based on their 16S rRNA gene sequence similarity (99.9 %), level of DNA-DNA relatedness (93 %) and a number of similar phenotypic characteristics, the two strains are identified as representing the same species. Their phylogenetically nearest neighbours, based on 16S rRNA gene sequence similarity values (97.9-98.4 %), were identified as Brevibacterium iodinum, Brevibacterium epidermidis, Brevibacterium linens and Brevibacterium permense. However, strains BBH5 and BBH7T could be distinguished from the above four species by a number of phenotypic characteristics, and levels of DNA-DNA relatedness between the two new isolates and these Brevibacterium species were 35-42 %. Therefore, strains BBH5 and BBH7 T are considered to represent a novel species of the genus Brevibacterium, for which the name Brevibacterium oceani sp. nov. is proposed. The type strain is BBH7 T (5LMG 23457 T 5IAM 15353 T ).The genus Brevibacterium was first described by Breed (1953) with Brevibacterium linens as type species; the description was emended by Collins et al. (1980). Species of the genus Brevibacterium exhibit a rod-coccus cell cycle, are aerobic, possess meso-diaminopimelic acid in the peptidoglycan and have MK-8(H 2 ) as the major respiratory menaquinone, diphosphatidylglycerol, phosphatidylglycerol, dimannosidediacylglycerol and phosphatidylinositol as major polar lipids and anteiso-and iso-branched fatty acids as major cellular fatty acids (Collins et al., 1980;Jones & Keddie, 1986;Heyrman et al., 2004). Brevibacterium species have been isolated from diverse habitats such as milk products, clinical specimens, soil, sediment, brown algae, paintings and foot lesions of fowl (Wauters et al., 2004;Lee, 2006;Gavrish et al., 2004;Ivanova et al., 2004;Heyrman et al., 2004;Pascual & Collins, 1999). Here we describe two Brevibacterium-like strains, BBH5 and BBH7 T , isolated from a sediment sample collected at a water depth of 5904 m (from a 50-70-cm section of a deep sediment core of 4.6 m, approximately 50 000 years old) from the Chagos Trench in the Indian Ocean (11 u 069 S 72 u 319 E) (Raghukumar et al., 2004).Deep-sea sediment samples were collected as described by Raghukumar et al. (2004). Approximately 1.0 g of the sediment was suspended in 10 ml 2 % NaCl and vortexed for 1 min and the suspension was then allowed to settle for 2 min. Next, 100 ml of the top aqueous layer was spread on a plate of yeast extract/peptone (YP) agar (per litre distilled water: 5 g yeast extract, 10 g peptone, 30 g NaCl, 15 g agar) and incubated at 15 u C for 15 days. The number of colonyforming units per gram of sediment ranged from 4.4610 3 to 7.6610 3 . A total of 21 pale-orange-coloured colonies were purified and subjected to total protein analysis via SDS-PAGE (Laemmli, 1970). All 21 isolates showed similar protein banding patterns and were assumed to be representatives of a sin...

A bacterial strain, SPC26 T , was isolated from a sediment sample of the Southern Ocean off Antarctica. The strain was Gram-staining-and catalase-positive and contained lysine and alanine in the cell-wall peptidoglycan. The major cellular fatty acids were anteiso-C 15 : 0 (54.92 %), iso-C 15 : 0 (11.47 %), anteiso-C 17 : 0 (6.48 %) and anteiso-C 15 : 1 (6.38 %) and the major menaquinones were MK-8, MK-9 and MK-10. The major polar lipids were phosphatidylethanolamine and diphosphatidylglycerol. The G+C content was 68±0.5 mol%. Based on 16S rRNA gene sequence similarities, the nearest phylogenetic neighbours of strain SPC26 T were identified as Arthrobacter gangotriensis Lz1y T (98.8 %), A. sulfureus DSM 20167 T (98.6 %), A. psychrophenolicus DSM 15454 T (97.9 %) and A. kerguelensis KGN15 T (97.5). With these strains, strain SPC26 T exhibited DNA-DNA relatedness values of 36, 21, 12 and 10 %, respectively. Therefore, on the basis of 16S rRNA gene sequence comparisons, phylogenetic analysis, phenotypic characteristics and DNA-DNA relatedness, it is proposed that strain SPC26 T represents a novel species of Arthrobacter, for which the name Arthrobacter antarcticus sp. nov. is proposed, with strain SPC26 T (5LMG 24542 T 5NCCB 100228 T ) as the type strain.The genus Arthrobacter was first proposed by Conn & Dimmick (1947) with Arthrobacter globiformis as the type species. All Arthrobacter species are strictly aerobic, catalasepositive and sporogenous rod-shaped bacteria that display coryneform morphology and contain A-type (A3a or A4a) peptidoglycan with L-lysine as the dibasic amino acid (Schleifer & Kandler, 1972). The genus Arthrobacter is phenotypically heterogeneous, and over 52 species have so far been isolated from various sources such as soil (Reddy et al., 2002;Lee et al., 2003;Gupta et al., 2004;Chen et al., 2005), cheese (Irlinger et al., 2005), clinical specimens (Funke et al., 1996; Hou et al., 1998;Wauters et al., 2000;Huang et al., 2005), paintings (Heyrman et al., 2005), seals (Collins et al., 2002), an alpine ice cave (Margesin et al., 2004), fish (Osorio et al., 1999), wastewater reservoir sediment (Roh et al., 2008) and air (Li et al., 2004). In this paper, we report the characteristics of a novel Arthrobacter strain isolated from a sediment sample of the Southern Ocean off Antarctica. Sediment samples were collected from a depth of 400 m near the Larsemann Hills area (69 u 229 S 76 u 069 E) using a spade box corer and brought to the laboratory. The sample, after suspending 0.1 g in 1 ml sterile water by vortexing, plating on nutrient agar (NA) (l 21 : 10 g peptone, 10 g beef extract, 5 g NaCl and 20 g agar) and incubation at 22 u C for 7 days, yielded 7.9-15.2610 3 c.f.u. g 21 . Strain SPC26 T was isolated by repeated subcultivation on NA plates and subjected to a detailed polyphasic taxonomic analysis. Arthrobacter gangotriensis DSM 15796 T , A. sulfureus DSM 20167 T , A. psychrophenolicus DSM 154547 T and A. kerguelensis DSM 15797 T were used as reference strains.Tryptone soy broth (TSB) (M290;...

Nitrogen (N), phosphorus (P) and potassium (K) are the three important nutrients required by any plant for healthy growth. Among these, P stands as the second limiting nutrient next to nitrogen. Even though different forms of P are abundantly present in soil, its availability in plant-utilizable form is limited. This defi ciency is usually compensated by adding chemical fertilizers. However, the chemical fertilizers are expensive and are not eco-friendly. Nonjudicious and irregular usage for a long time leads to decreased soil activity and soil microfl ora leading to imbalance in equilibrium. Usage of microorganisms to augment the P availability is the best alternative. Phosphate-solubilizing microorganisms (PSMs) when applied in appropriate numbers into the rhizosphere help the plant by supplementing P in plant-utilizable form by several mechanisms. In addition, few PSMs also possess added features as plant growth-promoting rhizobacteria (PGPR) and biocontrol agents conferring protection from phytopathogens. Improvement in soil characters by PSMs is an added advantage. Recent advances in technology paved the way for modifying PSMs with desired qualities. In spite of these, several areas in this area of research suffer different lacunae. Efforts are being made to discuss all major areas pertaining to PSMs in the present review.