Isolation and Characterization of Plant Growth Promoting Rhizobacteria for Growth Promotion of Rice (Oryza sativa L.) and Wheat (Triticum aestivum)

The use of rhizobacteria for plant growth enhancement is decades old. Still, in this era of the 21st century, biofertilizers have become the need of the day due to the health and environmental concerns associated with chemical fertilizers and pesticides. Rhizobacteria strains were isolated from the rhizosphere of rice and wheat. The selected bacterial strains' nitrogen fixation, indole acetic acid (IAA) production, phosphorus solubilization, and antifungal activity were determined on morphological, biochemical, and molecular levels. Production of IAA ranged from 6 µg/ml to 29.33 µg/ml. Ethylene production (C2H4/hr) varied from 2 µmoles to 9.8 µmoles. Maximum Phosphorus Solubilization index (7), decrease in pH (4) and Solubilization % age (0.49) was observed in WM-2 (wheat microbe). Promising results were obtained concerning antifungal activity against Rhizoctonia solani and Fusarium sp. The effect of the potential PGPR strains on the germination of rice and wheat was significantly positive in Petri plates. In the case of rice, the highest shoot length (29.27 cm) was observed by inoculation with RPR-33 (Rice isolate), and the most increased root length (9.33 cm) was observed in the treatment inoculated with RPR-42. The highest shoot fresh weight (476.67 mg/plant) was recorded in the treatment inoculated with RPR-42. The maximum root weight was 170 mg/plant in the same treatment. For wheat, all recorded growth parameters were improved significantly by wheat microbe WM-5. All the PGPR isolates showed positive results for growth parameters of wheat and rice on inoculation. So, it is suggested that these PGPR isolates may be used in potential biofertilizers.

Characterization of rhizospheric bacteria isolated from soil cultivated with sugarcane in Tamaulipas state, Mexico

The state of Tamaulipas, Mexico, has two important sugar mills, with plantations of sugarcane (Saccharum officinarum L.) of more than 50 years, the objective of the study was the identification and bacterial characterization in the production of indole-3-acetic acid (IAA), the solubilization of phosphorus and plant growth of bacterial isolates from the rhizosphere of sugarcane. The isolation and morphological characterization were in 30 rhizosphere soil samples of the sugarcane variety CP 72-2086 using the Luria-Bertani media, Congo Red Agar and Potato Dextrose Agar. The molecular characterization was with the 16S rRNA gene and the bacterial inoculation consisted of seedlings of the variety CP 72-2086. 121 strains (38 species) were isolated, being Bacillus sp. most frequently, 14 species were positive for phosphorus solubilization: Bacillus sp. (6), Pseudomonas spp. (5), Paenibacillus (2) Streptomyces venezuelae (1) stand out. The greater phosphorus solubilization was Pseudomonas mediterranea (21.6 mm). Nine bacteria showed production close to 5 ppm IAA: Bacillus aryabhattai (6 ppm), Bacillus pumilus (5.8 ppm) and Ensifer adhaerens (5.6 ppm). Bacillus megaterium showed a higher percentage of chlorophyll and foliar nitrogen. In the present analysis, 38 bacterial species associated with the rhizosphere of the sugarcane variety CP 72-2086 were identified, so these results showed the potential to select native bacteria that have the ability to stimulate plant growth of the variety CP 72-2086.

Phosphorus solubilization in stormwater ponds: rapid field assessment to identify ponds with excessive total phosphorus concentrations

Wet stormwater ponds are sedimentation basins used for phosphorus (P) removal in urban watersheds.

Phosphorus Biosolubilization by Micro-Organisms

Phosphorus (P) is one of the essential macronutrients for the growth and reproduction of plants, the main source of which is phosphate rocks (PRs). In view of the extraction process of this mineral, major environmental impacts are characterized, with the generation of solid residues that represent great economic value when using appropriate techniques for using minerals in solid residues, representing an extractive process with better efficiency and utilization of the extracted amount. There are many possible techniques applicable to a better yield in the extractive process, for example, in particular biosolubilization, which makes use of different microorganisms in the solubilization of the phosphorus element. In this review article, different microorganisms will be presented in the phosphorus solubilization, as well as the knowledge of the chemical and biological characteristics of the microorganisms in the biosolubization process

Overproduction of Some Plant Growth Promoters by Rhizospheric Microorganisms on Natural Medium

Considering the nutritional values of Mentha viridis. L and Aloe veraplants, these plants can be utilized for the production of alternative cultivation media. The cost of artificial culture media is very high, and some components may be unavailable. Use of the plant-based culture media would drastically reduce the expense of the synthetic media. Fifteen bacterial isolates were isolated from Aloe vera rhizosphere, nine bacterial and nine actinomycetes isolates were isolated from Mentha viridis rhizosphere both cultivated in Sirs EL- Layan, El-Menoufia governorate, Egypt. In-vitroscreening was done for the production of indole acetic acid (IAA) and phosphorus solubilization. Results revealed that bacterial isolate No. MB4 produced a high amount of IAA(36.51 μg/ml) on the Mentha-based culture medium, No. A6 showed maximum IAA production (16.25μg/ml) on the Aloe vera-based culture medium and isolate No. MA6 was efficient in phosphorus solubilization (867.85μg/ml) that was isolated from the Mentha viridis. L rhizosphere.16s rRNA analysis of these isolates revealed they are (Pseudomonas monteilii strain CIP 104883, Streptomyces rochei strain DW3 and Kosakonia radicincitans strain DSM 16656 respectively.