Jornal de Patologia Vegetal e Microbiologia

Abstrato

Evaluation of the Accumulation of Pathogenesis Related (PR) Proteins and Phenolic Compounds in Response to Biotic and Abiotic Elicitors as Mechanism for Immune Response to Fusarium Wilt Disease in Faba Bea

Montaser F Abdel-Monaim

Induction of plant defense against pathogen attack is regulated by a complex network of different signals. In the present study interaction between bio-agents (Bacillus megaterium, Pseudomonas fluorescens) and abiotic inducers (Bion and Chitosan) was used as new strategy to enhance Faba bean defense responses against wilt disease caused by Fusarium oxysporum. Thus, changes in various physiological defenses including pathogenesis related (PR) proteins, phenolic compounds, flavonoids compounds and lignin contents were investigated in Faba bean plants. Results appeared that all treatments significantly reduced wilt incidence under greenhouse and field conditions and increased fresh and dry weights of survival plants compared with untreated seeds. The combination between biotic and abiotic inducers more effective than used individually of them. The treatment B. megaterium+Bion recorded the highest reduction of wilt incidence and fresh, dry weights of survival plants. On the other hand, all treatments significantly increased growth and yield parameters compared with control during both growing seasons (2013-2014 and 2014-2015). Combined P. fluorescens+Bion and P. fluorescens+Chitosan recorded the highest all growth and yield parameters in both growing seasons. Under in vitro conditions, all tested biotic and abiotic inducers individually or in combination reduced leaner growth of the pathogen F. oxysporum., P. fluorescens+Bion followed by P. fluorescens+Chitosan recorded the highest inhibition percentage in this respect. On the other hand, all treatments increased activity of Chitinase and β-1,3-glucanase, phenolic, flavonoids compounds and lignin contents in Faba bean plants inoculated with F. oxysporum compared with untreated inoculated plant (control) during the experimental period. The combination between biotic and abiotic gave highly activities of chitinase, β-1, 3-glucanase enzymes and contents of phenols, flavonoids compounds and lignin than applied individually of them. Higher increase of PR proteins, phenolic and flavonoids compounds and lignin contests was obtained in plants treated with combined B. megaterium+Bion. On the light of the present study, it could be suggested that the use of Bion and Chitosan as natural safe materials alone or in combination with bio agents (P. fluorescens and B. megaterium) is considered one of low cost and effective applicable methods for controlling F. oxysporum causing wilt disease in Faba bean.