First report of enterobacter cloacae in shallot (Allium cepa L. Aggregatum group) in Indonesia

Abstract

Shallot (Allium cepa L. Aggregatum group) is one of the important vegetable crops in Indonesia. Shallots are very susceptible to diseases caused by pathogenic bacteria. Bacterial pathogens that infect onions generally can invade and infect species of other the genus Allium members. This study aims to identify the bacterial pathogens associated with shallot bulbs disease with phenotype and genotype approach (molecular). Sampling shallot bulbs disease conducted at two locations shallot production centers in Indonesia, namely the Regency of Bantul and Nganjuk in August-September 2012. Isolation initial bacterial pathogens of shallot bulbs disease using culture methods or pure culture. For phenotyping approach is done through observation of the colony and cell morphology, biochemistry, and physiology test bacteria. Whereas the genotyping approach, the identification is made based on the analysis of 16S rRNA sequences of technique Polymerase Chain Reactions (PCR). The results show that the identification of phenotypically UBNG21 isolates has characteristics in similarity with the characteristics of Enterobacter cloacae, causing bulb decay. Amplification of the 16S rRNA gene using PCR UBNG21 isolates produce 1500 bp fragment size. The results obtained by sequencing isolates UBNG21, which has a value of 97% homology with E. cloacae. The results of this study are the first report of the presence of E. cloacae associated with disease shallot bulbs in Indonesia.