Indução de resistência a Fusarium oxysporum f. sp. Tracheiphilum em caupi: Eficiência de indutores abióticos e atividade enzimática elicitada

Abstract

The effect of abiotic inducers in two cowpea cultivars inoculated with Fusarium oxysporum f.sp. tracheiphilum (E. F. Smith) Snyder & Hansen was evaluated in relation to severity, disease control and enzyme activity. Aqueous solution of ASM (5.0 mg/mL), BABA (1.5 mM) or chitosan (2.0 mg/mL) was sprayed on the first pair of leaves of five-day-old cowpea plants, cultivars BR-17 Gurguéia and IPA-206. After seven days of elicitor application, inoculation was carried out with 20 mL of a 1 × 106 conidia/mL suspension of the ISO-PE isolate. Plants were harvested at five and 10 days after inoculation, and the activity of phenylalanine ammonia lyase (PAL), β-1.3-glucanase and peroxidase was analyzed. Significant difference between treatment with inducers and control was verified, mainly for ASM which provided a disease control of 68.9% and 71.59% for BR-17 Gurguéia and IPA-206 cultivars, respectively. ASM showed the best results related to β-1.3-glucanase, peroxidase and PAL and activities, especially for the cultivar IPA-206 five or 10 days. BABA and chitosan differed from the control for PAL and β-1.3-glucanase activity on cultivar IPA-206, five days after inoculation.