Scrutinising the stress subduing effect of <i>Serratia marcescens</i> in <i>Meloidogyne incognita‐</i> stressed tomato seedlings

ABSTRACT The current study was planned to assess the potential of the bacterium, Serratia marcescens , in inducing morphological and biochemical changes in 10‐day‐old Solanum lycopersicum seedlings infected with Meloidogyne incognita . Seeds of tomato were allowed to germinate on autoclaved Petriplates lined with Whatman filter paper soaked in distilled water (Control), bacterial culture supernatant and bacterial culture cells in a BOD incubator. After germination, nematodes were inoculated @5 second‐stage juveniles (J2s)/seedlings and the experiment was terminated after 10 days of nematode inoculation. The results revealed that nematode inoculation decreased growth and modulated biochemical responses of S. lycopersicum seedlings. It also increased the content of oxidative stress markers. However, bacterial treatment reduced the harmful effects of nematode stress by lowering the levels of stress markers and enhancing the activity of antioxidants and content of proline and secondary metabolites. Additionally, bacterial treatment significantly reduced the number of galls and improved the growth of S. lycopersicum seedlings. This is the first study in which various parameters of nematode‐infected and S. marcescens ‐treated tomato seedlings were correlated to assess their relationship. Further, the findings suggest that S. marcescens is a promising plant growth promoter and can be used as a potent environmentally‐friendly strategy for nematode management.