Defense mechanisms involved in the resistance of maize cultivars to Bipolaris maydis

• Published in: European journal of plant pathology 2022-06, Vol.163 (2), p.269-277
• Main Authors: Schauffler, Giana Paula, dos Anjos Verzutti Fonseca, João, Di Piero, Robson Marcelo
• Format: Article
• Language: English
• Subjects: Agriculture; Ammonia; Antiinfectives and antibacterials; Appressoria; Biomedical and Life Sciences; Bipolaris maydis; Conidia; Corn; Crop damage; Crop development; Cultivars; Defense mechanisms; Ecology; Enzymatic activity; Enzyme activity; Evaluation; Flavonoids; Genotypes; Germination; Inoculation; Leaves; Life Sciences; Lipoxygenase; Liquid oxygen; Pathogens; Peroxidase; Phenolic compounds; Phenols; Phenylalanine; Phenylalanine ammonia-lyase; Plant Pathology; Plant Sciences; Zea mays
• ISSN: 0929-1873; 1573-8469
• DOI: 10.1007/s10658-022-02475-0

Maize ( Zea mays ) has economic and cultural importance worldwide. It is a highly domesticated plant commonly attacked by several pathogens, among them Bipolaris maydis , having potential to cause damages to the crop development and yields. This study aimed to investigate the plant’s defense mechanisms that could be associated with their resistance to the pathogen. In a greenhouse, four maize genotypes (P1630H, AG3700, SCS156 Colorado and 30K75Y) with different levels of resistance to the fungus were examined. In the phenological stage V4, the plants were inoculated with B. maydis (1 × 10 3 conidia.mL −1 ), and the severity of the disease was evaluated after ten days. Leaf samples were collected right before inoculation (0 h), and at 36, 72, 108 and 144 h after inoculation for determination of the peroxidase (POX), phenylalanine ammonia-lyase (PAL) and lipoxygenase (LOX) enzyme activity, as well as the content of phenolic compounds and flavonoids. The germination rate and formation of appressoria of B. maydis on the leaf surface of the four genotypes were also evaluated. Cultivar AG3700 exhibited a low disease severity, the highest activity of the POX and PAL and, on its leaf surface, a lesser degree of conidia germination and formation of double appressoria were observed. The activity of the POX and PAL enzymes and of antimicrobial compounds on maize resistance to B. maydis is discussed.