First report of Pantoea stewartii subsp. stewartii causing fruit bronzing of jackfruit (Artocarpus heterophyllus), a new emerging disease in Peninsular Malaysia.
Recently, a disease known as jackfruit bronzing, suspected to be caused by the bacterium Pantoea stewartii, has been constantly found in the jackfruit crop. Typical symptoms of infected jackfruits are characterized by yellowish-orange to reddish discoloration of the affected pulps and rags in the fruit. During April 2016, diseased samples with bronzing symptom of jackfruits were collected in Muadzam Shah plantation of Pahang state. These fruits were excised, rinsed with sterilized distilled water containing 1% sodium hypochlorite, placed on nutrient agar medium using streak plate method, and incubated overnight at 28°C. Four representative bacterial colonies were obtained and selected for further characterization. Based on morphological, biochemical, molecular (analysis) and pathogenicity tests, the causal agent was identified as P. stewartii subsp. stewartii. This is thought to be the first report of bronzing disease caused by P. stewartii subsp. stewartii in jackfruit in Malaysia.