scholarly journals Isolation and Characterization of Cold-Tolerant Hyper-ACC-Degrading Bacteria from the Rhizosphere, Endosphere, and Phyllosphere of Antarctic Vascular Plants

2020 ◽  
Vol 8 (11) ◽  
pp. 1788
Author(s):  
Macarena A. Araya ◽  
Tamara Valenzuela ◽  
Nitza G. Inostroza ◽  
Fumito Maruyama ◽  
Milko A. Jorquera ◽  
...  

1-Aminociclopropane-1-carboxylate (ACC)-degrading bacteria having been widely studied for their use in alleviating abiotic stresses in plants. In the present study, we isolated and characterized ACC-degrading bacteria from the rhizosphere, phyllosphere, and endosphere of the Antarctic vascular plants Deschampsia antarctica and Colobanthus quitensis. One hundred and eighty of the 578 isolates (31%) were able to grow on minimal medium containing ACC, with 101 isolates (23, 37, and 41 endosphere-, phyllosphere- and rhizosphere-associated isolates, respectively) identified as being genetically unique by enterobacterial repetitive intergenic consensus (ERIC)-PCR. Subsequently, freeze/thaw treatments and ice-recrystallization-inhibition (IRI) activity assays were performed, the results of which revealed that 77 (13%) of cold-tolerant isolates exhibited putative ACC deaminase activity. Significant (p ≤ 0.05) differences in IRI activity were also observed between the studied plant niches. Surprisingly, all the cold-tolerant isolates showed ACC deaminase activity, independent of the plant niches, with 12 isolates showing the highest ACC deaminase activities of 13.21–39.56 mmol α KB mg protein−1 h−1. These isolates were categorized as ‘cold-tolerant hyper-ACC-degrading bacteria’, and identified as members of Pseudomonas, Serratia, and Staphylococcus genera. The results revealed the occurrence of cold-tolerant hyper-ACC-degrading bacteria in diverse plant niches of Antarctic vascular plants, that could be investigated as novel microbial inoculants to alleviate abiotic stresses in plants.

Author(s):  
Panagiotis G. Georgiou ◽  
Huba L. Marton ◽  
Alexander N. Baker ◽  
Thomas R. Congdon ◽  
Thomas F. Whale ◽  
...  

2021 ◽  
Vol 14 ◽  
pp. 117863612110242
Author(s):  
Sonal Suman ◽  
Tanuja

DDT is one of the most persistent pesticides among all the different types of organo-chlorine pesticides used. Among all the degradation methods, bacterial degradation of DDT is most effective. The present study was conducted to isolate different bacteria present in waste samples which have the ability to degrade DDT present in the soil in the minimum possible period of time and to observe the effect of different physical and chemical properties of the soil samples. Many pesticide degrading bacteria were isolated and identified through cultural, biochemical tests and further identified by 16S RNA sequencing method. The most potent strain DDT 1 growth in mineral salt medium supplemented with DDT as the only source of carbon (5-100 PPM) and was monitored at an optical density of 600 nm. The growth parameters at different physio-chemical conditions were further optimized. The result showed that Enterobacter cloacae had maximum growth in 15 days. FTIR analysis of the residual DDT after 15 days incubation showed that Enterobacter cloacae was able to degrade pesticide into its further metabolites of DDD, DDE, DDNU and other components can be used for biodegradation of DDT present in contaminated soil and water ecosystems.


2012 ◽  
Vol 19 (5) ◽  
pp. 1852-1858 ◽  
Author(s):  
Risky Ayu Kristanti ◽  
Masahiro Kanbe ◽  
Tony Hadibarata ◽  
Tadashi Toyama ◽  
Yasuhiro Tanaka ◽  
...  

2001 ◽  
Vol 13 (3) ◽  
pp. 271-279 ◽  
Author(s):  
Brent J. Sinclair ◽  
Heidi Sjursen

Cold tolerance of the springtail Gomphiocephalus hodgsoni Carpenter (Collembola: Hypogastruridae) was studied at Cape Bird, Ross Island, Antarctica (77°13′S, 166°26′E). Microclimate temperatures indicate a highly seasonal thermal environment, with winter minima <–39°C. Snow cover significantly buffers both minimum temperatures and cooling rates. Gomphiocephalus hodgsoni survives low temperatures by avoiding freezing. Mean low group supercooling points (SCPs) ranged from –35.4°C in October to –28.3°C in January. The lowest SCP measured was –38.0°C. The high SCP group was very small, making up only 18% of the population in January. In October, G. hodgsoni had a very high glycerol content (>80 μg mg−1 dry weight), although this declined rapidly to low levels (c. 7–10 μg mg−1 dry weight) in January. Quantities of glucose and trehalose were low during October, but steadily increased throughout the summer. Haemolymph osmolality was exceptionally high (up to 1755 mOsm kg−1) at the end of November, but this rapidly declined to c. 500 mOsm kg−1 by late December. The presence of thermal hystersis proteins was indicated by both osmometry on haemolymph samples and recrystallization inhibition studies of springtail homogenates. There was a strong relationship between glycerol content and SCP, but the relationship between haemolymph osmolality, SCP and carbohydrates is uncertain.


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