The Potential Use of Ectoine Produced by a Moderately Halophilic Bacteria Chromohalobacter salexigens KT989776 for Enhancing Germination and Primary Seedling of Flax “Linum usitatissimum L.” under Salinity Conditions

Abstract

The similarity between plant and microbial cells encourage the use of microbial metabolites of halophilic bacteria for the alleviation of salt stress in plants. In the current research work, a compatible solute ectoine extracted from a moderately halophilic bacteria Chromohalobacter salexigens KT989776 was used to enhance flax germination and primary seedling under different levels of salinity. Two successive experiments including germination in Petri plates under six levels of salinity (0, 3, 5, 7, 9 and 11 dS.m-1) and a pot experiment under three irrigating water salinity levels (2, 3 and 4) with two types of ectoine application (spray and soil addition) were conducted. Germination parameters were recorded for the first experiment while a fresh and dry weight of plants and peroxidase activity in addition to sodium-potassium ratio were estimated in the pot experiment. Also, ectoine accumulation in plants was detected using HPLC. Results of LC-MS proved the production of ectoine by C. salexigens KT989776 and ectoine enhanced significantly all germination parameters of flax seeds, decreased sodium accumulation in the plant, increased potassium content, and lowered peroxidase and phenoloxidase activity. Also, HPLC analysis proved that ectoine was detected in all treated samples while not detected in non-treated control.

Transcriptome Analysis to Understand Salt Stress Regulation Mechanism of Chromohalobacter salexigens ANJ207

“…C. salexigens ANJ207 exhibits PGP traits, that is, siderophore production and Zn, P, and K solubilization, at higher salt concentrations and has shown promising results in wheat and rice (unpublished results). Although the beneficial plant growth-promoting effects of C. salexigens under salt stress have been observed by other workers ( Anbumalar and Ashokumar, 2016 ; Elsakhawy et al, 2019 ), the underlying molecular mechanisms and the genes responsible for salt tolerance, along with their gene expression levels, need to be identified to optimize the field applications of C. salexigens in agricultural and allied sectors. At present, limited information is available for understanding the dynamics of complex salt interactions and the genes responsible for salt tolerance in C. salexigens .…”

Employing Genomic Tools to Explore the Molecular Mechanisms behind the Enhancement of Plant Growth and Stress Resilience Facilitated by a Burkholderia Rhizobacterial Strain

“…The BJ3 genome was found to contain genes involved in the synthesis of metabolites capable of regulating osmotic stress; such metabolites included proline, glycine betaine, trehalose, and ectoine. Bacteria that produce these metabolites have been shown to alleviate osmotic stress in plants [ 47 , 48 , 49 , 50 ].…”

“…The BJ3 genome contains a notable number of genes involved in the synthesis of various osmolytes, which may regulate the osmotic balance in plants under osmotic stress conditions [ 47 , 48 , 49 , 50 ]. Consistently, the BJ3-treated Arabidopsis exhibited increased tolerance to both drought and salt stress.…”

Commentary: Piscirickettsia salmonis Produces a N-Acetyl-L-Homoserine Lactone as a Bacterial Quorum Sensing System-Related Molecule

“…Given the current lack of GC-MS data for the compound of interest, the inclusion of liquid chromatography-tandem mass spectrometry analyses for P. salmonis extracts could have been useful for comparative purposes. On the other hand, even though the ion at m/z 143 (resulting from a McLafferty rearrangement) is commonly used as a marker fragment for the screening of AHLs when the mass detector is operated in the SIM mode (Cataldi et al, 2004), this ion may also be potentially used as marker for the identification of other bacterial metabolites (Kaal et al, 2009;Elsakhawy et al, 2019).…”