Effect of beneficial indigenous microorganisms on tomato growth performance, productivity, and protection against Verticillium dahliae

The present work aimed to investigate the effect of potentially beneficial soil microorganisms in enhancing the tolerance of tomato plants against Verticillium wilt. The autochthonous mycorrhizal fungi "Rhizolive consortium" and plant growth-promoting rhizobacteria (PGPR) boost the growth and development of plants by providing well-adopted strategies and mechanisms to ensure good-quality production and protection to resist different pathogens including Verticillium dahliae . The application of these bio-agents alone and/or in combination with the pathogen was studied to evaluate their impact on tomato crops. In this study, eight treatments were applied: (i) Control, (ii) Rhizolive consortium (M), (iii) ER10 strain (B), (iv) combination of M and B (MB), (v) V. dahliae (V), (vi) Rhizolive consortium + V. dahliae (MV), (vii) ER10 strain + V. dahliae (BV), and (viii) Rhizolive consortium + ER10 strain + V. dahliae (MBV). Co-inoculation of Rhizolive consortium and ER10 strain significantly improved mycorrhizal frequency and intensity, growth and mineral nutrition of tomato plants. Furthermore, stomatal conductance and chlorophyll fluorescence were improved compared to the control. Moreover, the combination of these biostimulants reduced the disease severity and incidence by 26 and 28%, respectively, and the leaf damage index by 69% compared to plants inoculated with V. dahliae . In addition, the Rhizolive consortium alone or combined with ER10 strain resulted in improved antioxidant activities and stress markers. The synergistic interaction between Rhizolive consortium and ER10 strain promoted tomato yield and fruit quality compared to the control. The results highlight the importance of considering these beneficial soil microorganisms to promote plant resistance to Verticillium wilt disease.