scholarly journals In Vitro Screening for Abiotic Stress Tolerance in Potent Biocontrol and Plant Growth Promoting Strains of Pseudomonas and Bacillus spp.

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
G. Praveen Kumar ◽  
S. K. Mir Hassan Ahmed ◽  
Suseelendra Desai ◽  
E. Leo Daniel Amalraj ◽  
Abdul Rasul

Plant growth promoting rhizobacteria (PGPR) has been identified as a group of microbes that are used for plant growth enhancement and biocontrol for management of plant diseases. The inconsistency in performance of these bacteria from laboratory to field conditions is compounded due to the prevailing abiotic stresses in the field. Therefore, selection of bacterial strains with tolerance to abiotic stresses would benefit the end-user by successful establishment of the strain for showing desired effects. In this study we attempted to isolate and identify strains of Bacillus and Pseudomonas spp. with stress tolerance and proven ability to inhibit the growth of potential phytopathogenic fungi. Screening of bacterial strains for high temperature (50°C), salinity (7% NaCl), and drought (−1.2 MPa) showed that stress tolerance was pronounced less in Pseudomonas isolates than in Bacillus strains. The reason behind this could be the formation of endospores by Bacillus isolates. Tolerance to drought was high in Pseudomonas strains than the other two stresses. Three strains, P8, P20 and P21 showed both salinity and temperature tolerance. P59 strain possessed promising antagonistic activity and drought tolerance. The magnitude of antagonism shown by Bacillus isolates was also higher when compared to Pseudomonas strains. To conclude, identification of microbial candidate strains with stress tolerance and other added characteristic features would help the end-user obtain the desired beneficial effects.

2018 ◽  
Vol 15 (2) ◽  
pp. 485-494 ◽  
Author(s):  
K. Damodara Chari ◽  
R. Subhash Reddy ◽  
S. Triveni ◽  
N. Trimurtulu ◽  
CH. V. Durga Rani ◽  
...  

Present investigation was carried out to identify plant growth promoting rhizobacterial isolates for abiotic stress tolerance. To achieve this bacterial isolates were isolated from different rhizospheric soils of Telanagana and screened for plant growth promoting properties and tolerance to different abiotic stresses such as pH, temperature, salt, drought and heavy metals. Such PGPR will be helpful for efficient management of abiotic stresses in crop production. Rhizospheric soils from normal, salt affected, drought affected and bulk soils were collected from different places of Telangana state. From all soil samples, based on cultural, morphological and biochemical characterization it was found that forty four were of Bacillus spp. Among the forty four (44) Bacillus isolates, twenty eight (28) isolates were showing plant growth promoting properties. These positive isolates tested for abiotic stress tolerance to pH, temperature, salt, drought and heavy metals (As and Cd). Four isolates were showed growth at pH range from 4-12 (BS 1, BS 3, BS 14, BS 18), five isolates were showed tolerance to 1.5 to 20 % of NaCl concentration (BS 1, BS 3, BS 14, BS 18, BS 42, six isolates showed tolerance to temperature from 20ºC -50ºC (BS 10, BS 14, BS 18, BS 27, BS 37, BS 43), four isolates showed tolerance to water potential from - 0.05 Mpa to- 0.73 Mpa (BS 4, BS 10, BS 18, BS 33).


2019 ◽  
Author(s):  
G. Praveen Kumar ◽  
Suseelendra Desai ◽  
Bruno M. Moerschbacher ◽  
Nour Eddine-El Gueddari

AbstractInoculation of crop plants with PGPR has in a large number of investigations resulted in increased plant growth and yield both in the greenhouse and in the field. This plant growth promoting effect of bacteria could be due to net result of synergistic effect of various pgpr traits that they exert in the rhizosphere region of the plant. Four (04) bacterial strain of fluorescent Pseudomonas spp. viz. P1, P17, P22 and P28 were identified previously for their plant growth promoting nature and abiotic stress tolerance and selected further to assess their chitinolytic activity and growth promotion on sorghum in combination with chitosans of low and high degree of acetylation. It was found that P1 has no chitin degrading nature and rest of the three strains have this property. When studied for their ability to grow in presence of chitosans of DA 1.6, 11, 35 and 56% all the strains showed growth in presence of chitosans. Seed bacterization of sorghum seeds with 04 bacterial strains in the presence and absence of chitosans (both low and high DA) and assessment of plant growth promotion after 15 days of sowing showed that P17+DA 56% chitosan combination showed higher growth of seedlings in plant growth chamber with highest root length of 25.9 cm, highest shoot length of 32.1 cm and dry mass of 132.7 mg/ plant. In P17+DA 56% chitosan treated seedlings various defence enzymes and PR-proteins were found to be present in highest quantities as compared to P1 and un-inoculated controls. Since this strain showed highest growth promotion of sorghum seedlings chitin-chitosan modifying enzyme (CCME) of this strain was partially characterized using different proteomic tools and techniques. CCME of P17 had one active polypeptide with a Pi in the range of 3.0-4.0. The digestion pattern of acetylated and deacetylated chitosans showed that P17 enzyme has endochitinase activity. Substrate specificity assay showed that the enzyme had more specificity towards highly acetylated chitosans. Two dimensional PAGE and MS analysis of the protein revealed similarities of this enzyme with protein of Pseudomonas aeruginosa chitinase PA01 strain of GenBank. In conclusion, the study established the option of opening new possibilities for developing bacterial-chitosan (P17+DA 56% chitosan) product for plant growth promotion and induced systemic resistance in sorghum.


Metabolites ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 337
Author(s):  
Rafael J. L. Morcillo ◽  
Maximino Manzanera

Plant growth-promoting rhizobacteria (PGPR) are beneficial soil microorganisms that can stimulate plant growth and increase tolerance to biotic and abiotic stresses. Some PGPR are capable of secreting exopolysaccharides (EPS) to protect themselves and, consequently, their plant hosts against environmental fluctuations and other abiotic stresses such as drought, salinity, or heavy metal pollution. This review focuses on the enhancement of plant abiotic stress tolerance by bacterial EPS. We provide a comprehensive summary of the mechanisms through EPS to alleviate plant abiotic stress tolerance, including salinity, drought, temperature, and heavy metal toxicity. Finally, we discuss how these abiotic stresses may affect bacterial EPS production and its role during plant-microbe interactions.


2008 ◽  
Vol 54 (10) ◽  
pp. 861-867 ◽  
Author(s):  
Kanchalee Jetiyanon ◽  
Sakchai Wittaya-Areekul ◽  
Pinyupa Plianbangchang

The plant growth-promoting rhizobacterium Bacillus cereus RS87 was previously reported to promote plant growth in various crops in both greenhouse and field trials. To apply as a plant growth promoting agent with practical use, it is essential to ease the burden of routine preparation of a fresh suspension of strain RS87 in laboratory. The objectives of this study were to investigate the feasibility of film-coating seeds with B. cereus RS87 spores for early plant growth enhancement and to reveal the indoleacetic acid (IAA) production released from strain RS87. The experiment consisted of the following 5 treatments: nontreated seeds, water-soaked seeds, film-coated seeds, seeds soaked with vegetative cells of strain RS87, and film-coated seeds with strain RS87 spores. Three experiments were conducted separately to assess seed emergence, root length, and plant height. Results showed that both vegetative cells and spores of strain RS87 significantly promoted (P ≤ 0.05) seed emergence, root length and plant height over the control treatments. The strain RS87 also produced IAA. In conclusion, the film coating of seeds with spores of B. cereus RS87 demonstrated early plant growth enhancement as well as seeds using their vegetative cells. IAA released from strain RS87 would be one of the mechanisms for plant growth enhancement.


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