title: Soybean Resistance to Cercospora sojina Infection Is Reduced by Silicon.
abstract: Frogeye leaf spot, caused by Cercospora sojina, is one of the most important leaf diseases of soybean worldwide. Silicon (Si) is known to increase the resistance of several plant species to pathogens. The cultivars Bossier and Conquista, which are susceptible and resistant, respectively, to frogeye leaf spot, supplied and nonsupplied with Si were examined for the activities of defense enzymes and the concentrations of total soluble phenolics (TSP) and lignin-thioglycolic acid (LTGA) derivatives at 8, 14, and 16 days after inoculation (dai) with C. sojina. The importance of cell wall degrading enzymes (CWDE) to the infection process of C. sojina and the effect of Si on their activities were also determined. Soybean plants were grown in hydroponic culture containing either 0 or 2 mM Si (-Si and +Si, respectively) and noninoculated or C. sojina inoculated. Severity of frogeye leaf spot was higher in cultivar Bossier plants than cultivar Conquista and also in the +Si plants compared with their -Si counterparts. Except for the concentrations of TSP and LTGA derivatives, activities of defense enzymes and the CWDE did not change for +Si noninoculated plants regardless of the cultivar. The activities of lipoxygenases, phenylalanine ammonia-lyases, chitinases, and polyphenoloxidases as well as the activities of CWDE decreased for the +Si inoculated plants. The results from this study demonstrated that defense enzyme activities decreased in soybean plants supplied with Si, which compromised resistance to C. sojina infection.
authors.forename: Kelly Juliane Telles
authors.initials: KJ
authors.lastname: Nascimento
authors.forename: Daniel
authors.initials: D
authors.lastname: Debona
authors.forename: Sueny Kelly Santos
authors.initials: SK
authors.lastname: França
authors.forename: Mariana Gabriele Marcolino
authors.initials: MG
authors.lastname: Gonçalves
authors.forename: Fábio Murilo
authors.initials: FM
authors.lastname: DaMatta
authors.forename: Fabrício Ávila
authors.initials: FÁ
authors.lastname: Rodrigues
mesh_terms: D001203:Ascomycota / Q000472:pathogenicity*; D004156:Catechol Oxidase / Q000378:metabolism; D002688:Chitinases / Q000378:metabolism; D060467:Disease Resistance / Q000187:drug effects*; D008031:Lignin / Q000378:metabolism; D058945:Lipoxygenases / Q000378:metabolism; D010636:Phenols / Q000378:metabolism; D010650:Phenylalanine Ammonia-Lyase / Q000378:metabolism; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology; D018515:Plant Leaves / Q000187:drug effects / Q000276:immunology / Q000382:microbiology; D010940:Plant Proteins / Q000378:metabolism; D012825:Silicon / Q000009:adverse effects*; D013025:Glycine max / Q000187:drug effects* / Q000276:immunology / Q000382:microbiology
chemical_list: D010636:Phenols; D010940:Plant Proteins; D008031:Lignin; D004156:Catechol Oxidase; D058945:Lipoxygenases; D002688:Chitinases; D010650:Phenylalanine Ammonia-Lyase; D012825:Silicon
keywords: Glycine max; foliar disease