MAIZE RHIZOSPHERE MICROBIAL POPULATION IN SOILS OF JHARKHAND

Objective: The main objective of the present investigation is to isolate plant growth promoting rhizobacteria (PGPR) strains from three different zone of rhizosphere and arhizosphere soil, observing bacterial density and exploring rhizosphere effect on the bacterial community.Methods: Maize rhizosphere soils were collected from twelve different locations of Jharkhand. Various microbial populations (like Pseudomonas spp., Azotobacter spp., phosphate solubilizing bacterial spp. and Azospirillum spp.) were isolated from the different variety of maize rhizosphere. These strains were obtained through pour plate technique by using PGPR specific medium. To explore rhizosphere effects on the bacterial community, some physicochemical properties of arhizosphere soil and rhizosphere soil were measured and the soil bacterial community which helps in plant growth through direct and indirect mechanisms called plant growth promoting rhizobacteria (PGPR) detected by morphological and biochemical characterization. PGPR was purified and subcultured in their respective medium and stored at 40C to maintain throughout the experiment.Results: Total 65 isolates of Pseudomonas strain, 34 isolates of Azotobacter strain, 49 isolates of phosphate solubilizing bacterial strain and 34 isolates of Azospirillum strain were isolated from maize rhizosphere. The pH of rhizosphere soil was lower than arhizosphere soil and rhizosphere soils contain more moisture than arhizosphere soil. Highest moisture % was found in Deoghar (26.90%) followed by Dhurwa (21.73%) and Tamar (21.21%) rhizosphere soils. Microbial population was highest in rhizoplane zone. Organic carbon, available nitrogen, phosphorus, potassium and sulphur were found more in rhizosphere soil than arhizosphere soil. High quantity of organic matter (1.52%), available nitrogen (272.83 kg ha-1), available phosphorus (73.64 kg ha-1), potassium (317.42 kg ha-1) and sulphur (66.60 kg ha-1) were present in rhizosphere soil.Conclusion: This study reveals that rhizosphere soil characterized by greater microbial population and their activity which enhance soil fertility through increasing moisture, pH and available nutrients in soil to promote the growth of plants.Â

Bioprospecting of plant growth promoting psychrotrophic Bacilli from the cold desert of north western Indian Himalayas

142-150<span style="font-size:11.0pt;font-family: " times="" new="" roman";mso-fareast-font-family:"times="" roman";mso-bidi-font-family:="" mangal;mso-ansi-language:en-gb;mso-fareast-language:en-in;mso-bidi-language:="" hi"="" lang="EN-GB">The plant growth promoting psychrotrophic<span style="font-size:11.0pt; font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" mso-bidi-font-family:mangal;mso-ansi-language:en-gb;mso-fareast-language:en-in;="" mso-bidi-language:hi"="" lang="EN-GB"> <span style="font-size:11.0pt; font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" mso-bidi-font-family:mangal;mso-ansi-language:en-gb;mso-fareast-language:en-in;="" mso-bidi-language:hi"="" lang="EN-GB">Bacilli were investigated from different sites in north<span style="font-size:11.0pt; font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" mso-bidi-font-family:mangal;mso-ansi-language:en-gb;mso-fareast-language:en-us;="" mso-bidi-language:hi"="" lang="EN-GB"> <span style="font-size:11.0pt; font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" mso-bidi-font-family:mangal;mso-ansi-language:en-gb;mso-fareast-language:en-us;="" mso-bidi-language:hi"="" lang="EN-GB">western Indian Himalayas. A total of 247 morphotypes were obtained from different soil and water samples and were grouped into 43 clusters based on 16S rDNA-RFLP analysis with three restriction endonucleases. Sequencing of representative isolates has revealed that these 43 Bacilli belonged to different species of 11 genera viz.<span style="mso-bidi-font-style: italic">, Desemzia, Exiguobacterium,<i style="mso-bidi-font-style: normal"> Jeotgalicoccus, Lysinibacillus, Paenibacillus, Planococcus,<i style="mso-bidi-font-style: normal"> Pontibacillus, Sinobaca, Sporosarcina,<i style="mso-bidi-font-style: normal"> Staphylococcus and Virgibacillus. With an aim to develop microbial inoculants that can perform efficiently at low temperatures, all representative isolates were screened for different plant growth promoting traits at low temperatures (5-15<span style="font-size:11.0pt; font-family:Symbol;mso-ascii-font-family:" times="" new="" roman";mso-fareast-font-family:="" "times="" roman";mso-hansi-font-family:"times="" roman";mso-bidi-font-family:="" mangal;mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:="" hi;mso-char-type:symbol;mso-symbol-font-family:symbol"="" lang="EN-GB">°C). Among the strains, variations were observed for production (%) of indole-3-acetic acid (20), ammonia (19), siderophores (11), gibberellic acid (4) and hydrogen cyanide (2); <span style="font-size: 11.0pt;font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" mso-bidi-font-family:mangal;mso-ansi-language:en-gb;mso-fareast-language:en-us;="" mso-bidi-language:hi"="" lang="EN-GB">solubilisation (%) of zinc (14), phosphate (13) and potassium (7); 1-aminocyclopropane-1-carboxylate deaminase activity (6%) and biocontrol activity (4%) against <span style="font-size:11.0pt; font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" mso-bidi-font-family:mangal;mso-ansi-language:en-gb;mso-fareast-language:en-us;="" mso-bidi-language:hi;mso-bidi-font-weight:bold"="" lang="EN-GB">Rhizoctonia solani and Macrophomina phaseolina. Among all the strains, <span style="font-size:11.0pt; font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" mso-bidi-font-family:mangal;mso-ansi-language:en-gb;mso-fareast-language:en-us;="" mso-bidi-language:hi"="" lang="EN-GB">Bacillus licheniformis,<i style="mso-bidi-font-style: normal"> Bacillus muralis, Desemzia incerta, <span style="mso-bidi-font-weight: bold;mso-bidi-font-style:italic">Paenibacillus tylopili and Sporosarcina globispora were found to be potent candidates to be developed as inoculants as they exhibited multiple PGP traits at low temperature.</span