Maize protection against Bipolaris maydis using Lentinula edodes, Aloe vera and acibenzolar-S-methyl

Maize (Zea mays) is the most commonly produced grain worldwide. One of the factors that can lead to a decrease in productivity is the Southern Leaf Blight caused by Bipolaris maydis. This is common in the main producing regions and can promote losses of up to 70% under suitable conditions. A few genotypes are resistant to this fungus, and there is no record of fungicides for the disease in Brazil. In order to search for alternative control measures with lower environmental impacts, the objective of this study was to investigate the use of polysaccharide fractions extracted from shiitake or aloe, as well as acibenzolar-S-methyl (ASM), as potential inductors of resistance in maize against B. maydis. Tests were conducted with maize plants (hybrids P1630H and BM3063) to evaluate the effects of the products on reducing disease severity, inhibiting pathogen germination and activating guaiacol peroxidase and phenylalanine ammonia-lyase (PAL) activities. Aloe and ASM were not efficient to control the disease. Fraction PS1 from shiitake reduced the disease severity in both hybrids by approximately 60%. Meanwhile, fraction PS2 was efficient only in hybrid BM3063, where it promoted an increase in PAL activity. However, these fractions did not affect the spore germination of B. maydis. Therefore, the polysaccharide fractions from shiitake have the potential to control Southern Leaf Blight (B. maydis) in maize probably through the activation of plant defense mechanisms.