Induction of defense mechanisms involved in disease resistance of onion blight disease caused by Botrytis allii

Abstract

Botrytis umbel blight caused by Botrytis allii is a major disease that attacks onion crop. In vitro, Trichoderma viride, Penicillium chrysogenum, and Saccharomyces cerevisiae and extract of bitter apple fruits (Citrullus colocynthis) showed antagonistic effect and inhibited the mycelial growth of B. allii. Gas chromatography-mass spectrometry (GC-MS) analysis of bitter apple fruits showed the existence of 37 compounds and their derivatives. Among them, 10 compounds constituted 58.66% of the total analyses. Greenhouse experiment approved that the extract of bitter apple fruits was the most effective in reducing disease incidence and severity, followed by P. chrysogenum, when they were applied 2 days pre-inoculation with the pathogen. All treatments significantly increased the total phenolic contents than the untreated control, but the highest increase was obtained when S. cerevisiae and P. chrysogenum were applied. A positive correlation was found between the activity of bioagents and improvement of peroxidase and phenylalanine ammonia-lyase enzymes in onion plants to resist infection with the pathogen. P. chrysogenum caused the highest increase in polyphenoloxidase activity in infected onion plants, while S. cerevisiae showed the lowest level of this enzyme. The study approved that application of the bioagents not only protected the onions against Botrytis disease but also enhanced the content of antioxidant compounds in onions. This encourages the application of such preparations to manage the production of onion crop, especially in the organic farming that bans the application of any chemicals.

Molecular characterization of native pink pigmented facultative methylotrophs of chilli and their induced systemic resistance mechanism in management of anthracnose

“…Our study revealed association of increased phenolic content with disease suppression (or increased resistance) to C. capsici. This is in agreement with the previous reports on PGPR Trichoderma viridae, Penicillium chrysogenum and Saccharomyces cerevisiae against blight disease caused by Botrytis allii in onion (Hussein et al, 2018). Many phenolic compounds are known for their antimicrobial activities and function as precursors to structural polymers such as lignin or serve as signal molecules to activate plant defense genes (Dakora, 1996).…”

Molecular disparities among Botrytis species involved in onion umbel blight disease and its management using Bacillus subtilis PHYS7

“…Twenty-three isolates of Botrytis spp. were isolated from naturally diseased onion plants showing symptoms of Botrytis Onion Umbel Blight (BOUB), collected from different onion seed producing farms, Assiut, Egypt (Hussein et al, 2018). Onion leaves, showing disease symptoms, were cut in small pieces, sterilized for 2 min in 2% sodium hypochlorite solution then, plated onto Potato Dextrose Agar (PDA) medium and incubated at 27°C.…”

“…Among the fungal diseases, Botrytis byssoidea and B. allii the causal pathogens of umbel blight of onion are destructive pathogens that involved in a great reduction in the productivity. The umbel blight disease is an important disease that attacks the plant during the production of the seeds and could devastate the unprotected crops up to 70% (Hussein et al, 2018). Spores of B. byssoidea, B. allii, B. porri, and B. squamosa cause infection for seedlings of green and bulb onions (Hussein et al, 2018).…”

“…The umbel blight disease is an important disease that attacks the plant during the production of the seeds and could devastate the unprotected crops up to 70% (Hussein et al, 2018). Spores of B. byssoidea, B. allii, B. porri, and B. squamosa cause infection for seedlings of green and bulb onions (Hussein et al, 2018). du Toit et al (2004) reported the 4 diseases associated with onion seed crops causing blighting seed stalks and umbel and flower blight.…”

Indução de fitoalexinas por preparações de leveduras, Trichoderma e óleo essencial de Cymbopogon citratus Stapf.

“…E estudos voltados para a cultura da cebola também mostraram uma moderada redução na severidade da doença ferrugem da Botrytis, causada por Botrytis allii, ao se utilizar a S. cerevisiae como um dos tratamentos. E o mesmo ocasionou um aumento significativo no teor total de fenol, indicando um correlação com a redução do desenvolvimento de patógenos, já que tais compostos são substancias tóxicas aos patógenos, outra possibilidade é a resistência ter sido gerada pela alteração do pH do citoplasma da célula vegetal, que é alterado com o aumento do conteúdo fenólico (Khaledi, Taheri, Ta-righi2015;Hussein et al, 2018).…”