Wickerhamomyces anomalus WO2 inoculation protects Suaeda fruticosa from salt stress by the stimulation of the production of carotenoids and sugars and the augmentation of sodium translocation

The objectives of this study were to test the strain Wickerhamomyces anomalus WO2 as a plant growth-promoting yeast (PGPY), to evaluate the effect of its inoculation on the growth and physiological performance of Suaeda fruticosa subjected to salt stress, and to understand by which mechanism the yeast can protect the plant from high salinity. The results showed that the strain is halophilic, and grows at salt concentrations of up to 15%. Salinity caused decreases in chlorophyll a, b, and T in both inoculated and non-inoculated S. fruticosa. A significant increase in carotenoids was observed in W. anomalus WO2 inoculated plants. Inoculation enhanced the production of proteins, polyphenols and flavonoids at 1% of salinity, and sugars at all concentrations of NaCl. Although Na+ and K+ were higher in the leaves of non-inoculated plants compared to inoculated ones, the correlation of sodium translocation factor (TF) with salinity was very strong positive only in the inoculated plants. The production of carotenoids had a very strong positive relationship with salinity in inoculated plants, and a very strong negative correlation in non-inoculated plants. Soluble sugars were very strongly positively correlated with salinity in both inoculated and non-inoculated plants. However, a strong positive correlation of sugars with carotenoids was observed only in inoculated plants. This strain proved to be a promising candidate as a PGPY under salt stress. This work amends the PGPY bank with new strains having interesting abilities to resist high concentrations of NaCl and which can be used in the future as a biofertilizer.