Abstract

Plant resists pathogen infection through physical and chemical defenses that may be application of some biotics and abiotics inducers. It has been found that pre treatment with bioagents Trichoderma harzianum,(Kan.), T. harzianum (Del.), T. harzianum (Pant), Trichoderma viride (Kan.), T. viride (Del.), T. viride (Pant),Aspergillus niger AN-27 (Kan.) Chaetosphaeridium globosum (Del.) and Pseudomonas fluorescens (Del.) provided induced resistance in plant against F. o. f.sp. lycopersici resulting declined disease incidence from 100 to 7.69%. The maximum inhibition was noted by T. harzianum (Kan.) isolates. The induction of resistance was associated with certain biochemical changes in tomato leaves. Treatment with bio-agents as inducers prior to challenge inoculation sensitized the seedling to produce increased level of soluble proteins. The maximum increase in soluble protein content was found in (T₁) T. harzianum (Kan.) treated plant showing 35.04 mg/g of fresh leaves against 20.49 mg/g of fresh leaves in case of control-II. A high content of phenols which are the indication of first stage of defense mechanism was also recorded in treated plant with maximum in T. harzianum (Kan.) treatment representing 2.62 g/mg of fresh leaves against 1.38 in control-I at 20 days of inoculation. The disease severity showed negative correlation with soluble protein (r=-0.6364) and total phenol (r=-0.7653). Protein profiling by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) revealed that the soil treated with T. harzianum (Kan.) to synthesize some new protein representing maximum number of 22 bands. The presence or absence of the bands in protein profiling might be responsible for resistance response against Fusarium oxysporum f.sp. lycopersici in tomato.

Key words: Biochemical change, biotic inducers, disease incidence, Fusarium wilt, protein profiling.