Control of Verticillium wilt in pepper with two bacterial-based productsand one fungal agent: a laboratory comparison
Abstract: Two commercial products, AstonaTM and BotrybelTM, consisting of spores of thebacteria Bacillus pumilus and Bacillus velezensis, respectively, were compared with a nonpathogenicisolate of Fusarium (Fo47) in the biocontrol of Verticillium dahliae in pepper(Capsicum annuum). The assays were conducted in a growth room with controlled temperature(25°C) and light (16h light – 8h dark). The biocontrol agents were applied once by dipping theroots of pepper plants in a suspension of the bacteria/fungus. 48h after this treatment, plants wereinoculated with a suspension of 106 conidia/ml. Symptoms as stunting, determined by stemlength, were recorded weekly for 4 weeks. A significant reduction of the symptoms was observedfor all the groups treated with any of the three biocontrol agents, but Fo47 was by far the mosteffective. The colonization of the plant by V. dahliae was monitored by sowing consecutivefragments of the stem in PDA supplemented with antibiotics. Samples of root and stem werecollected 48h after treatment with the biocontrol agents to be further analysed. Gene expressionof two defence-related genes and b-1,3-glucanase and chitinase enzyme activities were assayedsearching for an evidence of the induction of plant defence by the protectant bacteria/fungus.