Studies on nutrient solubilization, biocontrol and plant growth promoting traits of Burkholderia cepacia from tea soil

A study was undertaken to isolate a novel indigenous bacterial strain namely Burkholderia cepacia from tea soils to solubilize potassium (K) and phosphorus (P) sources respectively. The isolated strain was screened based on its solubilization potential in both broth and agarized medium amended with various K and P sources. Plant growth promoting traits and biocontrol activity of the purified strain against tea pathogens such as Pestalotiopsis theae, Glomerella cingulata, Poria hypolateritia, Phomopsis theae and Hypoxylon serpens were studied. Results revealed a significant solubilizing zone in agar medium blended with muriate of potash (MOP) (2.0 cm), sulphate of potash (SOP) (1.2 cm), rock phosphate (1.6 cm) and single super phosphate (0.8 cm). The release of available K was quantified in liquid medium supplemented with MOP and was found to be higher (41.5 mg L-1) than SOP. Among different P sources, rock phosphate (35.2 mg L-1) showed higher solubilization than single super phosphate (30.2 mg L-1) by the test organism on 5th day of incubation. B. cepacia was found to produce a large amount of bioactive compounds like siderophore (12.3 μg mL-1), IAA (263.3 μg mL-1) and GA3 (14.9 μg mL-1) including exo-polysaccharides (46.8 ppm). The test organism also showed a remarkable biocontrol activity against P. theae (52.5%), G. cingulata (42.5%), H. serpens (47.5%), Phomopsis theae (32.7%) and P. hypolateritia (30.9%). The secondary metabolites production by an efficient strain B. cepacia revealed that the strain could produce a wide range of volatile compounds

Antimicrobial activity of important Indian medicinal plants against Pyogenic infection

The antimicrobial activity of crude extracts of five medicinal plants used in traditional Indian medicine was tested against five   important  pyogenic bacteria.They are Streptococcus pyogenes, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa.Streptococcus pneumoniae. Of the five medicinal plants used only three were showed considerable antimicrobial activity against one or more species of microorganisms tested. Among the three solvents used the most effective extract was found to be methanol extraction. The most effective antimicrobial plant was identified as Glycyrriza glabra followed by Dathura metal, Coccinia grandis. Least activity was observed in  Sida spinosa, and Lab lab purpureus.       ÂÂ

Characterization, hemolysis and multidrug resistance among Aeromonas spp. isolated from Bhavani river, Erode, South India

A total of 87 strains of Aeromonas spp. were identified biochemically. The strains were isolated from 50 samples of water from Bhavani river Erode, Tamil Nadu, India. In the present study among 87 Aeromonas spp. the prevalence strain was identified as A.hydrophila (60.9%), while the other strains belonged to the species A. sobria (20.7%), A. caviae (11.5%) and A.salmonicida (6.9%). The virulence factors like hemolysin, lipase, and serine protease were present in 96%, 93% and 94% of the strains respectively. Antibiotic susceptibility of Aeromonas spp. was determined by disc diffusion method. All Aeromonas spp. were examined for resistance against 16 antibiotics. All strains showed 100% of resistance to Ampicillin,Carbenicillin and Cephalothin. The highest resistances encountered were 91.9% to streptomycin,90.8% to polymyxin-B, 85% to rifampicin while the rest were under 50%.In contrast all the strains were sensitive to cefotaxime.The present work highlights the important incidence of Aeromonas spp., with virulence potential and antimicrobial resistance, isolated from river bhavani

Effects of biofertilizer containing N-fixer, P and K solubilizers and AM fungi on maize growth: A greenhouse trial.

An in vitro study was undertaken to evaluate the compatibility of indigenous plant growth promoting rhizobacteria (PGPR) with commonly used inorganic and organic sources of fertilizers in tea plantations. The nitrogenous, phosphatic and potash fertilizers used for this study were urea, rock phosphate and muriate of potash, respectively. The organic sources of fertilizers neem cake, composted coir pith and vermicompost were also used. PGPRs such as nitrogen fixer; Azospirillum lipoferum, Phosphate Solubilizing Bacteria (PSB); Pseudomonas putida, Potassium Solubilizing Bacteria (KSB); Burkholderia cepacia and Pseudomonas putida were used for compatibility study. Results were indicated that PGPRs preferred the coir pith and they proved their higher colony establishment in the formulation except Azospirillum spp. that preferred vermicompost for their establishment. The optimum dose of neem cake powder

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Not AvailableSugarcane mosaic virus (SCMV) one of the causative viruses of mosaic disease in sugarcane occurs in sugarcane growing countries worldwide. India is the second largest sugarcane producing country and genome of SCMV from India has not been characterized so far. Hence detailed studies were carried out to characterize the virus isolates based on its complete genome. Comparative genome analyses of five new isolates were performed with previously reported SCMV full genome sequences of isolates infecting sugarcane, maize, sorghum and canna. Sequence identity matrix and phylogenetic analyses clearly represented that Indian isolates are closely related to sugarcane infecting isolates reported from Australia, Argentina, China and Iran and they are diverged as a separate subgroup from other reported maize infecting isolates from Mexico, China, Ohio, Spain, Germany, Iran, Ethiopia, Kenya and Eucador. Selection pressure analysis clearly depicted the predomination of strong purifying selection throughout the viral genome, and strongest in CI and HC-Pro gene. Evidence for few positively selected sites was identified in all the cistrons except in 6K1 and Nib rep. Among the genomic region, CI gene has exhibited comparatively more recombination hotspots followed by HC-Pro unlike other reported isolates. As the cultivation of sugarcane was first originated in India, our results from the recombination events strongly suggest that Indian SCMV populations contribute for the emergence of upcoming new recombinant SCMV isolates not only within the sugarcane isolates but also with maize infection isolates of SCMV in other countries irrespective of geographic origin and host type.Not Availabl

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Not AvailableThe Potyviridae family is one of the largest and economically most significant families of plant viruses, owing to their effects on crops globally. Sugarcane streak mosaic virus (SCSMV), a member of the genus Poacevirus, of this family, an important viral pathogen affects the sugarcane production in India. The genome has a single open reading frame that is translated in to a large polypeptide and consequently cleaved into functional proteins. This virus causes mosaic of sugarcane along with the Sugarcane mosaic virus (SCMV) which is a serious disease causing varietal degeneration reported from India in 1999 and later has been reported from geographically different Asian countries. The coding region for P1 peptidase is located at the very beginning of the viral genome of the family Potyviridae. P1 was thought of as serine peptidase with RNA-binding activity and with possible influence in cell-to-cell viral spreading. In order to unveil its mechanism of evolution we initiated the study by characterizing 10 P1 gene of Indian isolates and the sequences were compared with previously reported SCSMV isolates from different countries. Comparison of all of the sequenced virus isolates revealed a high level of diversity in the P1 gene (83–98% nt sequence identity; 87–100% aa sequence identity), and the Indian isolates were found to be the most divergent (up to 9% variation at the amino acid level). Phylogenetic analysis revealed clustering of 17 SCSMV isolates into two groups. Group I included isolates from India (except SCSMV-TPT) and Pakistan, and group II consisted of isolates from Japan, Indonesia, Thailand and SCSMV-TPT. The results obtained from phylogenetic study were further supported with the SNPs (single nucleotide polymorphism), INDELs (insertion and deletion) and evolutionary distance analysis. A significant proportion of recombination sites were found at the N terminal region of P1 gene of Indian isolates. Analysis of selection pressure indicated that the P1 gene of Indian SCSMV isolates is under strong negative selection. It is likely that recombination, along with strong negative selection, enhances the speed of elimination of lethal mutations in the P1 gene of Indian SCSMV isolates.Not Availabl

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Not AvailableFor the first time we determined complete nucleotide sequence of SCMV-IND from infecting popular variety CoC 671 from India. From the same variety complete genome sequence of SCSMV has already been reported by Parameswari et al. (2013) which is also the first study in India. Nine overlapping primer pairs were designed from the reference sequences collected from the genbank covering the whole genome of SCMV. cDNA was synthesized from the total RNA extracted from the variety CoC 671 and PCR conditions were optimized for each primer sets. The products were purified using GenElute Gel Extraction kit and the resulting fragments were cloned into the pTZ57R/T vector After the recombinant DNA was introduced into E. coli DH5α by transformation, positive clones were identified by colony PCR and two clones from each of the nine amplified fragments were sequenced in both directions to eliminate potential sequence heterogeneity introduced by Taq DNA polymerase. The nt and amino acid sequences of other known SCMV isolates were retrieved from the GenBank and used for comparison The overlapping sequences of the nine fragments were assembled using the BioEdit software.The linearly assembled single strand positive sense RNA genome of SCMV-IND was about 9573 nucleotides in length excluding the poly (A) tail. The genome encodes a polyprotein of about 3064 amino acid residues which is processed to form ten mature proteins (P1, HC-Pro, P3, 6K1, CI, 6K2, VPg, NIa-Pro, NIb, and CP). Based on this whole genome study, the Indian isolate showed close identity to the Australian isolate Brisbane of about 98.2% and 94.9% at the protein and nucleotide level, respectively. The Indian isolate shares the least identity with the American isolate Ohio of about 88.2% and 78.9% at the protein and nucleotide sequences respectively. This study supports the work done by Viswanathan et al. (2009) on SCMV coat protein gene analysis and its genetic variability where the Indian isolates shared a very close similarity with the Australian isolate sharing 99% nucleotide identity unlike other country isolates. Further, phylogenetic tree drawn using the software Bioedit through Neighbor joining method with 1000 bootstrap replications clearly depicted its close similarity with Australian and American isolate sharing a common progenitor whereas the other country isolates diverged to a different cluster. Within the monocot specific potyvirus, the Indian SCMV isolate shares close identity with Sorghum mosaic virus with 69.1% identity followed by Maize dwarf virus with 67.9% identity at the nucleotide level. Further study on recombination event among the SCMV complete genome sequences is in progress which will provide a good insight on SCMV evolutionary biology.Not Availabl

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Not AvailableSugarcane streak mosaic virus (SCSMV), a member of the genus Poacevirus is an important viral pathogen affecting sugarcane production in India. The P1 gene of ten Indian isolates was sequenced and compared with previously reported SCSMV isolates. Comparative sequence analysis revealed a high level of diversity in the P1 gene (83–98% nucleotide sequence identity; 87–100% amino acid sequence identity), and the Indian SCSMV isolates were found to be the most variable (up to 9% diversity at the amino acid level). Phylogenetic tree analysis showed clustering of 17 SCSMV isolates into two groups: group I included isolates from India (except SCSMV-TPT) and Pakistan, and group II consisted of isolates from Japan, Indonesia, Thailand and SCSMV-TPT. The results obtained from phylogenetic study were further supported by the different Insilco analysis viz. SNPS (single nucleotide polymorphism), INDELS (insertion and deletion) and evolutionary distance analysis. A significant proportion of recombination sites were observed at the N terminal region of P1 gene. Analysis of selection pressure indicated that the P1 gene of the Indian SCSMV isolates is under strong negative or purifying selection. It is likely that recombination identified in Indian SCSMV isolates, along with strong purifying selection, enhances the speed of elimination of deleterious mutations in the P1 gene. The evolutionary processes (recombination and selection pressure) together contributed to the observed genetic diversity and population structure of Indian SCSMV isolatesNot Availabl

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Not AvailableSugarcane streak mosaic virus (SCSMV), an unassigned member of the family Potyviridae is an important viral pathogen affecting sugarcane cultivation in India. The complete nucleotide sequence of a SCSMV isolate from India (SCSMV-IND) was determined. The linear, assembled, single stranded positive sense RNA genome of SCSMV-IND was 9786 nucleotides in length (excluding the poly (A) tail) and it comprises a large open reading frame encoding polyprotein of 3131 amino acid residues. The genome of SCSMV-IND shared high degree of sequence identity at nucleotide (93%) and amino acid (97%) levels with SCSMV-PAK and shared 81% and 94% nucleotide and amino acid identities respectively with all the three SCSMV isolates (SCSMV-JP1, -JP2 and -ID). Phylogenetic analysis of the complete genome sequences of SCSMV isolates revealed that they can be clustered into two groups: group I includes isolates from India (SCSMV-IND) and Pakistan (SCSMV-PAK), group II consists of isolates from Japan (SCSMV-JP1 and -JP2) and Indonesia (SCSMV-ID). SCSMV-IND and -AP isolates originating from the same geographical region (India) showed 18% divergence at nucleotide level within the highly conserved 3 half genome indicated existence of diversity among SCSMV isolates from India. Recombination analysis revealed one potentially significant intra-specific recombination in SCSMV-PAK. This work provided the first opportunity to establish the whole genome and polyprotein variability between SCSMV isolates from India and other Asian countries.Not Availabl