Abstract

ESCALONA, Yoleidy  and  CONTRERAS, Nancy. First report of bacterial blight of passion fruit (Passiflora edulis Sims f. flavicarpa) in Venezuela. Bioagro [online]. 2011, vol.23, n.1, pp.69-75. ISSN 1316-3361.

The cultivated passion fruit (Passiflora edulis Sims f. flavicarpa) is affected by several kinds of diseases. At the locality of Aroa, Yaracuy State, the plant has shown damages such as leaf spots, and this work was carried out to determine the identity of the causal agent of this disease. Symptomatic leaves were collected and transferred to the laboratory, disinfected with 2 % NaOCl and the isolation of a pale yellow bacteria was obtained on nutrient agar (NA) and yeast extract-dextrose-calcium carbonate ( YDC), which was inoculated into healthy plants of passion fruit. Once reproduced the symptoms, 15 days after inoculation, we proceeded to re-isolation obtaining colonies identical to the original ones, and the identification of the bacteria was obtained by its cultural, morphological, physiological, and biochemical characteristics. The isolated bacterium was Gram negative, with a rod shape, aerobic; with positive reaction for catalase, starch hydrolysis, production of H2S from cysteine, growth at 35 °C, esculin hydrolysis, gelatin liquefaction and protein digestion; with negative reaction for red phenol dextrose agar, oxidase, urease production, and nitrate reduction. It showed acid production from carbohydrates arabinose, glucose, mannose, cellobiose, fructose, galactose and trehalose. The isolate grew in the cultures Tween and SX. All these characteristics identified the causal agent as Xanthomonas axonopodis pv. passiflorae (Pereira) Gonçalves & Rosato, being this the first report of this bacterium causing bacterial blight in passion fruit in Venezuela.

Keywords : Bacterial disease; etiology; maracuyá; Xanthomonas.