Phaseolin Induction on Common-Bean Cultivars and Biological Control of Colletotrichum lindemuthianum 89 Race by Baccharis trimera (Less.) Dc.

Abstract The objective of this work was to evaluate the fungitoxic effect of the aqueous extracts of Baccharis trimera on the mycelial growth of Colletotrichum lindemuthianum 89 race, as well as its effect on the accumulation of phaseolin in hypocotyls of different cultivars and common bean varieties. It was obtained 20% aqueous extract from plants collected in municipalities of the Western Region of Paraná. Blocks containing C. lindemuthianum mycelium were transferred to Petri dishes containing medium with the different extracts and incubated at 25 °C. The colonies diameter was measured until the 12th day. Effects of aqueous extracts on phaseolin production was evaluated in hypocotyls of Carioca, Cnpf 8104, Soberana, Tibatã, Uirapurú cultivars, as well as Rosinha and Vermelho varieties. Each one cultivar and variety hypocotyl was transferred separately to test tubes containing 500 μL of 20% aqueous extracts. Sterile water, Bion®, and UV was used as controls. The phaseolin production was measured in spectrophotometer [280 nm]. Results of the evaluation of the antifungal activity of aqueous extracts of Baccharis sp. specimens collected indicate that approximately 50% of the samples presented capacity to reduce between 74 and 92% of C. lindemuthianum growth. Cultivar Tibatã and Vermelho variety showed greater sensitivity over the applied treatments. Results of fungal filtrates and vegetal aqueous extracts presented a low capacity to induce the production of phaseolin in hypocotyls.