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Inefficiency of acibenzolar-S-methyl in induction of resistance against bacterial wilt in common bean

The effect in the induction of resistance by acibenzolar-S-methyl was evaluated in three common bean (Phaseolus vulgaris) cultivars, with different levels of resistance to bacterial wilt under greenhouse conditions. The first assay evaluated the acibenzolar-S-methyl action in the induction of resistance against bacterial wilt; the second evaluated the action in the peroxidase and polyphenoloxidase activities as well as in total soluble protein level, in leaf and stem, without pathogen inoculation. In both assays, the inducer was sprayed at a dosage of 100 µg i.a./ml, five days after transplanting to pots. Acibenzolar-S-methyl was inefficient in controlling the disease in susceptible cultivar (IAC Carioca), nor did it improve the resistance level in resistant cultivars (IAC Carioca Akytã and IAC Carioca Pyatã). Peroxidase showed higher activity in inducer sprayed plants either in leaves or stems. In the sprayed plants, polyphenoloxidase showed higher activity only in stems. The total soluble protein level was higher in the stems of sprayed plants than in those that wern't sprayed, but levels did not differ in the leaves. The enzymes and proteins evaluated showed higher activity and levels in the leaves than in the stems.


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