Bacillus species’ contributions to the management of mycotoxigenic Fusarium species in cereals

Abstract

Cereals are an international commodity grown in almost all cultivable regions of the world.The three most important cereals that are destined for human and animal consumption are maize (Zea mays), wheat (Triticum spp.) and rice (Oryza sativa). These crops can be affected by biotic and abiotic factors in all phenological stages, affecting quality and final yield. The Fusarium graminearum species complex is the main causal agent of ear blights, root rots and crown rots, affecting yield, grain quality and safety, mainly due to the accumulation of certain mycotoxins from the trichothecenes group. Other Fusarium species such as F. proliferatum and F. verticillioides have the ability to produce fumonisins, which can cause severe mycotoxicosis in animals. Prevention of these phytopathogens is partially achieved via the use of a variety of management practices including the application of chemical fungicides, resistant varieties, crop rotation with non-host cultivars or tillage. The use of microorganisms for the control of phytopathogens is an emerging strategy that can be used as part of an integrated pest management. Bacillus species are important biocontrol agents, since they can adapt to extreme environmental conditions (temperature, salinity, water stress) and have the ability to produce secondary metabolites with a wide range of antifungal and antibacterial activity. In this review, the main characteristics of Bacillus species aiming to control phytopathogens through direct or indirect mechanisms are analyzed.