The Application of Phytohormones as Biostimulants in Corn Smut Infected Hungarian Sweet and Fodder Corn Hybrids.

Lóránt Szőke,László Radócz,Brigitta Tóth,Mátyás Danter,Béla Kovács,Mária Hájos,Makoena Moloi,Györgyi Biró,Dalma Rácz,Gabriella Kovács

doi:10.3390/plants10091822

Lóránt Szőke, László Radócz + Show 8 more

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https://doi.org/10.3390/plants10091822

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Abstract

The main goal of this research was to investigate the effects of corn smut (Ustilago maydis DC. Corda) infection on the morphological (plant height, and stem diameter), and biochemical parameters of Zea mays L. plants. The biochemical parameters included changes in the relative chlorophyll, malondialdehyde (MDA), and photosynthesis pigments’ contents, as well as the activities of antioxidant enzymes—ascorbate peroxidase (APX), guaiacol peroxidase (POD), and superoxide dismutase (SOD). The second aim of this study was to evaluate the impact of phytohormones (auxin, cytokinin, gibberellin, and ethylene) on corn smut-infected plants. The parameters were measured 7 and 11 days after corn smut infection (DACSI). Two hybrids were grown in a greenhouse, one fodder (Armagnac) and one a sweet corn (Desszert 73). The relative and the absolute amount of photosynthetic pigments were significantly lower in the infected plants in both hybrids 11 DACSI. Activities of the antioxidant enzymes and MDA content were higher in both infected hybrids. Auxin, cytokinin, and gibberellin application diminished the negative effects of the corn smut infection (CSI) in the sweet corn hybrid. Phytohormones i.e., auxin, gibberellin, and cytokinin can be a new method in protection against corn smut.

Highlights

Infected Desszert 73 (11 days after corn smut infection (DACSI)) treated with cytokinin, gibberellin, and auxin, had significantly higher chlorophyll-a content compared to infected control
Longer exposure to corn smut infection triggers the breakdown of the chlorophyll pigments
Corn smut infection significantly reduced the amount of photosynthetic pigments in both hybrids 11 DACSI (Figures 1–3)

Summary

Introduction

Connections between global warming and agriculture are well-studied [2]. A combination of abiotic and biotic stress factors, such as high temperature, water deficiency or over-supply, and biotic factors (e.g., pests, and pathogens), affect agricultural production negatively [3,4,5,6,7,8,9,10]. The outcomes of the effects of pathogens on the morphological and biochemical characteristics of host plants vary based on the pathogen [11,12,13,14,15]. One of the first reactions of host plants to biotic stress involves the overproduction of the reactive oxygen species (ROS)

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