Malondialdehyde and proline content in bean cultivars following the inoculation with endophytic bacteria

In model experiments, the effect of inoculation of common bean (Zolotistaya, Ufimskaya, Elsa cultivars) with endophytic Bacillus subtilis 10-4 and 26D was studied. The growth parameters as well as the content of proline and MDA of 7 and 21-day-old plants were evaluated. The high content of proline and MDA corresponded to the more resistant cultivars (Ufimskaya and Elza). Inoculation resulted in decrease of the MDA level. The ratio of MDA content in plants of synchronously developing cultivars Ufimskaya and Zolotistaya, inoculated with different strains of bacteria in relation to the uninoculated control, was similar both on the 7th and 21st days. The correlation coefficients of growth indicators with MDA were: for seedling mass - 0.72, for shoot length - 0.54, for root length - 0.85, and for number of lateral roots - 0.57. The proline content and dynamics were different in dependence of strain-cultivar combination. And correlation coefficients of proline content with growth parameters were: for seedling mass - 0.40, for shoot length - 0.76, for root length - 0.50, and for number of lateral roots - 0.48. A decrease in the level of MDA in inoculated 7-day-old seedlings compared to the control can serve as a marker for the selection of effective cultivar-strain combinations. The proline content due to its unstable dynamics and not high correlation with growth parameters makes it difficult to use this indicator for the selection of effective pairs of symbionts.

Automated summary

In this study, the effects of inoculating different cultivars of common bean with endophytic Bacillus subtilis were investigated. The results showed that inoculation led to a decrease in MDA level and the content of proline varied depending on the strain-cultivar combination. Additionally, the MDA level in 7-day-old seedlings can serve as a marker for selecting effective cultivar-strain combinations, while using proline as an indicator faces some difficulties.