Cold stress promoting a psychrotolerant bacterium Pseudomonas fragi P121 producing trehaloase

Abstract

A newly isolated Pseudomonas fragi P121 strain in a soil sample taken from the Arctic Circle is able to produce trehalose. The P121 strain was able to grow at temperatures ranging from 4 to 25 °C, had an optimum pH of 6.5, and an optimum salt concentration of 2 %. The P121 strain had a survival rate of 29.1 % after being repeatedly frozen and thawed five times, and a survival rate of 78.9 % when placed in physiological saline for 15 days at 20 °C after cold shock, which is far higher than the type strain Pseudomonas fragi ATCC 4973. The P121 strain could produce 2.89 g/L trehalose, which was 18.6 % of dry cell weight within 52 h in a 25 L fermention tank using the malt extract prepared from barley as medium at 15 °C, while only 11.8 % of dry cell weight at 20 °C. These results suggested that cold stress promoted the strain producing trehalose. It is the first reported cold-tolerant bacterium that produces trehalose, which may protect cells against the cold environment.

Infection of Ophiocordyceps sinensis Fungus Causes Dramatic Changes in the Microbiota of Its Thitarodes Host

“…Pseudomonas spp. are regarded as psychrotolerant and broad-host-range entomopathogenic bacteria exhibiting insecticidal activity toward certain agricultural pests (Chen et al, 2014;Mei et al, 2016). It appears that these bacteria and fungi might be involved in the blastospore-mycelium transition during larval mummification process.…”

The Predominance of Psychrotrophic Pseudomonads on Aerobically Stored Chilled Red Meat

“…Certain bacterial and fungal species produce this compound under freezing conditions (Ohtake & Wang, 2011). Trehalose provides a protective effect and minimizes cell lysis (Mei et al, 2016). P121 also has the ability to provide protection to its cells by detoxifying harmful substances and using aromatic compounds as carbon and nitrogen sources, which is beneficial in surviving very low temperatures (Yanzhen, Yang, Xiangting, & Wei, 2016).…”

“…The bacterial strain P121, identified as P. fragi , is an isolate from Arctic Ocean coast soil where the average temperature is below 10 °C. It is a marine bacterium that can grow between 4 and 25 °C in culture medium with added sea salt (Mei, Huang, Liu, He, & Fang, ). Studies have found that the survival rate of the P121 strain was far higher than the survival rate of the P. fragi type strain ATCC 4973 after the same cold shock exposure.…”

Managing plant-environment-symbiont interactions to promote plant performance under low temperature stress

“…In addition to improving photosynthetic capacity and, thus, yield and biomass production, these symbiosis influence carbohydrate metabolism (e.g., trehalose biosynthesis in Pseudomonasfragi P121 (Table 2), Leucosporidium fellii (Table 1), and Mrakia frigida (Table 3), trehalose and glycerol biosynthesis in Saccharomyces cerevisiae, and upregulation of malate dehydrogenase in Rhizobium), which play a crucial role in cold acclimation (Sardesai and Babu 2001;Panadero et al 2006;Maggi et al 2013;Mei et al 2016). The production of unsaturated membrane lipids to maintain membrane fluidity, RNA chaperons to suppress the formation of undesired secondary RNA structures, the synthesis of antifreeze and cold shock proteins, as well as cold-active antioxidant enzymatic and non-enzymatic activities may also have a prominent role in microbiome cold acclimation (Maggi et al 2013;Ghobakhlou et al 2013).…”