Different Responses of Capsicum annuum L. Root and Shoot to Salt Stress with Pseudomonas putida Rs-198 Inoculation.

The aim of this work was to compare the different responses of the root and the shoot to salt stress with or without growth-promoting bacteria Pseudomonas putida Rs-198 application. The results revealed that lower salt stress did not show bad effects on plant growth although osmotic tolerance indictors were observed. The results showed that proline content increased by 7.75% and 20.20% in shoot and 323.73% and 449.38% in root under 150 mM and 300 mM salt treatment, respectively. Increasing salt stress also led to a reduction of peroxides enzyme (POD) activity by 16.50% and 15.49% in the shoot and 46.03% and 39.36% in the root under above salt treatments. More importantly, the changes observed in pepper roots were more pronounced than those in pepper shoots except for total soluble sugar and protein. In addition, inoculation of Pseudomonas putida Rs-198 could relieve the changes of these indicators. Further, these changes were more pronounced in non-inoculated control plants than in inoculated plants. Especially, Pseudomonas putida Rs-198-inoculated plants exhibited the greatest increase in polyphenol oxidase activity by 78.06% in shoot and POD activity by 25.22% in root compared with the non-inoculated plants at 150 mM NaCl stress. To the best of our knowledge, these results are the first reported that will more effectively explain the phenomena relationship between plant, salt stress, and plant growth-promoting bacteria. Physiological changes induced by Pseudomonas putida Rs-198 interaction in Capsicum annuum L. under salt stress. [ABSTRACT FROM AUTHOR]