Bacillus cereus (OR975563) of maize rhizosphere can promote plant growth and potentially suppress mycotoxin (Fumonisin B1) during storage

Abstract Seed deterioration and development of toxins are the prime concern of maize seeds for maintaining quality and health during storage in Bangladesh. Endophytic and rhizospheric bacteria of maize were assessed for their growth suppressive potential against mycotoxigenic fungi (Fusarium oxysporum) and reduction of mycotoxin (Fumonisin B1) during storage. In this study, a total of 48 bacterial isolates were obtained and evaluated for their antifungal activity against Fusarium oxysporum. Four rhizospheric (8SISO4, 8SISO5, 14SISO14, and 16SISO16) which were identified as Bacillus velezensis (OR975558), Bacillus amyloliquefaciens (OR975561), Bacillus subtilis (OR975559) and Bacillus cereus (OR975563) and four endophytic (6RISO28, 9RISO31, 11RISO33, and 9RISO32) bacterial isolates which were identified as Bacillus tropicus (PP335187), Bacillus amyloliquefaciens (OR975562), Bacillus zanthoxyli (OR975560) and Bacillus amyloliquefaciens showed in vitro growth suppressive effect against F. oxysporum. Maize seeds were treated 1, 6 and 12 hours by immersing into bacterial suspension. Among the treatments, seeds treated with the isolate 6RISO28 showed the highest mycelial growth suppression (84.0%) against F. oxysporum. After 8 month of storage, the highest seed germination (68.7%), shoot length (5.1 cm), root length (8.1cm), disease incidence (23.3%) with a vigor index of 988.6 were recorded in the T23 (Maize seed dipping for 6 hr in 16SISO16) with the lowest Fumonisin concentration (4.5 ppm) and the highest mycelial growth suppression of Fusarium. Therefore, it can be opined that utilization of antagonistic bacteria can be a promising approach for the reduction of mycotoxin along with the improvement of seed and seedling health of maize during post-harvest storage.