Fruit Bronzing, a New Disease Affecting Jackfruit Caused by Pantoea stewartii (Smith) Mergaert et al.


Author(s): Ruben M. Gapasin1, Garcia, R. P.2, Christine T. Advincula3, De la Cruz, C.S.2 and Lucia M. Borines1,4

Abstract

Jackfruit bronzing, an unreported disease affecting jackfruit is characterized by yellowish-orange to reddish discoloration of the affected pulps and rags of the fruit. The etiology of this disease, its isolation, pathogenicity, characterization and identification is the scope of this study. The pathogen was isolated from infected jackfruit, pathogenicity was conducted to detached and attached fruits. The pathogen was identified based on its cultural and morphological characteristics, staining reactions, physiological and biochemical characteristics, other plant inoculations and DNA analysis using the polymerase chain reaction (PCR). The bacterium produces yellow pigment in culture, Gram negative, slightly pleomorphic non-motile, facultatively anaerobic short-rods, measuring 12 um in length, catalase positive, hydrolyzes gelatin and starch but not tween 80, produces acid from glucose, galactose, fructose and sucrose but not from lactose and maltose. It did not produce hypersensitivity to tobacco, caused pits on potato discs but not soft rot. It infected pineapple fruits causing localized lesions and infected corn producing the same symptom as bacterial wilt or Stewart’s disease. PCR analysis confirmed the cause as Pantoea stewartii (or Pantoea stewartii subsp. Stewartii (Smith) Mergaert et al)., formerly Erwinia stewartii (Smith) Dye.

Keywords : Bronzing, Jackfruit, Pantoea, Etiology, PCR

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