Characterization of Siccibacter sp. Strain C2 a Novel Rhizobacterium that Enhances Tolerance of Barley to Salt Stress.

Plant growth promoting rhizobacteria (PGPR) arouse an increasing interest as an eco-friendly solution for improving crop tolerance to environmental stresses. In this study, we report the characterization of a novel halotolerant PGPR strain (named C2) identified in a screen of rhizospheric bacterial isolates from southeast of Tunisia. Phylogenetic analysis showed that strain C2 is most likely affiliated to the genus Siccibacter with Siccibacter turicensis as the closest species (98.19%). This strain was able to perform phosphate solubilization and production of indole acetic acid (IAA), siderophores, hydrogen cyanide (HCN), as well as different hydrolytic enzymes (proteases, amylases, cellulases, and lipases). The potential of strain C2 in enhancing salt stress tolerance of Hordeum vulgare was also investigated. Our greenhouse inoculation assays showed that strain C2 promotes barley growth in the presence of 400 mM NaCl by increasing biomass, root length, and chlorophyll contents. It has a positive effect on the photosynthetic efficiency, concomitantly with lower intercellular CO2 contents, compared to non-inoculated plants. Moreover, barley inoculation with strain C2 under salt stress, resulted in higher accumulation of proline and soluble sugars and alleviate the oxidative stress by decreasing hydrogen peroxide and malondialdehyde contents. Remarkably, this positive effect corroborates with a significant activation in the expression of a subset of barley stress responsive genes, including HVA1, HvDREB1, HvWRKY38 and HvP5CS. In summary, Siccibacter sp. strain C2 is able to enhance barley salt stress tolerance and should be leveraged in developing sustainable practices for cereal crop production.

Potential anti-inflammatory and antioxidant effects of Citrus aurantium essential oil against carbon tetrachloride-mediated hepatotoxicity: A biochemical, molecular and histopathological changes in adult rats.

The present study aimed (1) to investigate the chemical composition as well as the anti-inflammatory properties and in vitro antioxidant activity of Citrus aurantium peel essential oil (pEOCa) and (2) to evaluate its potential effect in vivo. The main results showed that the major components of pEOCa are Limonene and Linalool. Additionally, DPPH scavenging ability and ß-carotene bleaching inhibition tests confirmed the antioxidant capacity of pEOCa. Our oil reduced the production of NO by LPS-stimulated RAW264,7 macrophages in a concentration-dependent. This inhibition occurred at a transcriptional level. pEOCa in CCl4 treated rats alleviated hepatotoxicity as monitored by the improvement of hepatic oxidative stress biomarkers levels plasma biochemical parameters, and DNA molecule aspect. Furthermore, the mRNA gene expression of Cu-Zn SOD, CAT, and GPx increased under CCl4 + pEOCa exposure to reach the same value to the control. Similarly, antioxidant activities of these three enzymes changed in accordance with the mRNA levels. These results were confirmed by the histological results. It seems obvious that the treatment with pEOCa prevented liver damage induced by CCl4 , thus preventing the harmful effects of free radicals.