First report of Chryseobacterium indologenes as causal agent for crown rot of papaya (Carica papaya L.) in peninsular Malaysia

Abstract

Bacterial strains were isolated from papaya plants showing the crown rot symptoms in peninsular Malaysia. Greasy and water-soaked lesions were observed on petiole axis, young stems and buds of the plants. Bacteria were then identified using the Biolog system showed that  the  bacterium  was  Chryseobacterium  indolegenes  with  a  similarity  (SIM)  index  of between  0.5  and 0.74  at  24  h  of  incubation  followed  by  standard morphological  and biochemical tests. The isolates were then confirmed by Polymerase Chain Reaction (PCR) and sequencing of the 16S rRNA gene and was successfully identified as C. indologenes with a 100% sequence similarity with reference strain (C. indolegenes strain LMG 8337; GenBank Acc. No: NR_042507.1). C indolegenes was consistently isolated from diseased papaya plants and the pathogenicity was confirmed by Koch’s postulate.

Keywords: papaya crown rot; Chryseobacterium indologenes