Screening procedures for selecting rhizobacteria with biocontrol effects upon Fusarium verticillioides growth and fumonisin B1 production

LILIA CAVAGLIERI , A. PASSONE, MIRIAM ETCHEVERRY

RESEARCH IN MICROBIOLOGY

Elsevier

Lugar: Paris (Francia); Año: 2004 vol. 155 p. 747 - 754

0923-2508

Screening is a critical step in the discovery of microbial agents that can exert biological control on Fusarium verticillioides at root level. The objectives of this research were to determine the utility of niche overlap index to realise the first screening of maize rhizobacterial isolates at different water activities. Studies were conducted to evaluate different methods as second screening with different modes of action. The antifungal activity of bacterial isolates through antibiosis assay was checked and the influence of different isolates on Fusarium verticilliodes growth and fumonisin B1 was studied. Eleven competitive rhizobacterial isolates (Arthrobacter globiformis RC1, Azotobacter armeniacus RC2, Azotobacter armeniacus RC3, Arthrobacter globiformis RC4, Arthrobacter globiformis RC5, Azotobacter armeniacus RC6, Pseudomonas solanacearum RC7, B. subtilis RC8, B. subtilis RC9, Pseudomonas solanacearum RC10, B. subtilis RC11) were selected for the following studies. All bacteria were able to utilise the widest range of carbon sources and showed the highest NOIs at the water activities tested. All bacterial antagonists reduced the fumonisin B1 production at aW levels tested. The isolates belonging to Pseudomonas and Bacillus genera significantly inhibited the fumonisin B1 production which ranged between 70% and 100%. Also, Azotobacter armeniacus RC2 exerts an important fumonisin B1 reduction. The results of the present work suggest that Azotobacter armeniacus RC2, Azotobacter armeniacus RC3, B. subtilis RC8, B. subtilis RC9, B. subtilis RC11, Pseudomonas solanacearum RC7, Pseudomonas solanacearum RC10 could have practical value in the control of F. verticillioides root colonisation. This paper is part of an on-going study to determine their application at field level.