Antifungal Potential of <i>Azotobacter salinestris</i> Strain <i>Azt</i> 31 against Phytopathogenic <i>Fusarium</i> spp. Associated with Cereals

Antifungal efficacy of <i>Azotobacter salinestris</i> against trichothecene-producing <i>Fusarium</i> spp. was investigated in maize, sorghum, and wheat. The three cereals were subjected to four treatments as control (T1), <i>Fusarium</i> alone (T2), combination of <i>Fusarium</i> and <i>A. salinestris</i> treatment (T3), and only <i>A. salinestris</i> (T4). All the treatments were evaluated for total mass of seedlings, root and shoot length, seed germination, and vigor index (VI), and extent of rhizoplane colonization by <i>A. salinestris</i> was investigated. Further, greenhouse studies were conducted to learn the efficacy of <i>A. salinestris</i> in vivo conditions. Antifungal efficacy was tested by the dual-culture method which resulted in significant reduction in <i>Fusarium</i> growth. Infection by <i>Fusarium</i> was reduced up to 50% in treated cereals such as maize, sorghum, and wheat, and there was also significant increase in seedling mass in the three hosts. Maize showed the highest VI (1859.715), followed by sorghum (1470.84), and wheat (2804.123) with <i>A. salinestris</i> treatment. In addition, seed germination was enhanced to 76% in maize, 69% in sorghum, and 68% in wheat, respectively. Efficacy of rhizoplane colonization showed successful isolation of <i>A. salinestris</i> with high CFU rate, and furthermore, significant colonization inhibition by <i>Fusarium</i> spp. was observed. In the greenhouse conditions, on the 45th day of the experimental set-up, the highest shoot length/root length recorded in maize was 155.70/70.0 cm, in sorghum 165.90/48.0 cm, and in wheat 77.85/56.0 cm, and the maximum root mass recorded was 17.53 g in maize, 4.52 g in sorghum, and 1.90 g in wheat. Our present study showed that seed treatment by <i>A. salinestris,</i> may be used as an alternate biocontrol method against <i>Fusarium</i> infection in maize, sorghum, and wheat.