Identification of phytopathogenic bacteria associated with a Post-Harvest Disease of garlic cloves in relation to cell-wall-degrading enzymes

ABSTRACT

Five bacterial isolates were isolated from soft rot of garlic cloves collected from different markets in Menia Governorate. The isolated bacteria caused soft rot of wounded cloves when inoculated into tissues. The bacterial isolates were compared for their degree of pathogenicity as well as for differences in the specific symptoms induced in the different hosts. Furthermore, new hosts for the isolated pathogens were recorded under experimental conditions. The isolated pathogenic bacteria were identified as Bacillus subtilis [three isolates], Bacillus pumilus [one isolate] and Bacillus coagulans [one isolate]. Furthermore, they proved active in degrading parenchymatous tissue of many tested plant organs. The extracts of experimentally diseased garlic cloves were active in pectinase [at pH 5 and 8] and carboxymethyl cellulase at pH 6. On the other hand, no enzyme activities for the tested enzymes were detected in healthy tissues. Some biological changes occurred during pathogenesis were investigated