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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. [ABSTRACT FROM AUTHOR]

Superposed events of rock exposure, fracturing, and the hydrological dynamics, are key elements that influence epigenic karstification in carbonate reservoirs. However, they are not fully identified in seismic or well data. One way forward is a multiscale characterization of the porous system to understand karst development, from the pore scale to large caves, confined to high-permeability layers that can reach the basin scale. The present study investigates superposed meteoric dissolution events in carbonate rocks by combining the analyses of depositional setting, diagenesis, stratigraphic architecture, tectonics, and hydrological zones. We performed analyses of 130 plugs collected in 11 outcrops using petrographic, petrophysical, mineralogical, and geochemical analyses. The study area is the Cretaceous Jandaíra Formation in the Potiguar Basin, Brazil, where we identified a regional subaerial unconformity-SU (sequence boundary-1). This surface is characterized by a change in facies and depositional system between dolomitic peritidal deposits (depositional sequence 1) and tight-cemented calcite subtidal deposits (depositional sequence 2). A concentration of caves occurs below the SU. We conclude that subaerial unconformities (vadose surfaces) can develop better reservoir qualities with superposed freshwater leaching and karstification. They control the lateral reservoir zonation, whereas faults and fractures provide vertical pore distribution within the vadose/phreatic hydrological zones. Water table fluctuations can develop multilevel caves and conduits along the epiphreatic zones, increasing the reservoir thickness, which reaches 50–100 m in the Potiguar Basin. We recognized two previous subaerial unconformities at the basin scale using well and seismic data. These findings may have important implications for assessing reservoir location and quality in large areas. [Display omitted] • We investigate high-permeability karst layers in carbonate units. • Caves systems concentrate below subaerial unconformities at the basin scale. • Early diagenesis affected peritidal deposits, with dolomitization and karstification. • Meteoric fluids cement the overlying subtidal deposits during burial diagenesis. • Fractures, unconformities, and hydrology control thickness-extension of reservoir. [ABSTRACT FROM AUTHOR]