16S rDNA Sequence Analysis of Bacterial Isolates from Die-back Affected Sissoo Trees (Dalbergia sissoo Roxb.) in Bangladesh

A new form of disease called 'die-back' has been established in Dalbergia sissoo trees. This disease has reached epidemic proportions in Bangladesh as well as in other countries of South Asia and is characterized by browning of the leaves, signs of wilting, and trunk lesions with gum flow. The trees die within a few months. In order to investigate the causes of this die-back disease, samples were taken for a first trial in the Rajshahi division at two sites around Sherpur. For the isolation of bacteria, surface-sterilized plant material (leaves, twigs and trunk bark) from diseased trees was transferred to LB medium and incubated. After isolation of single colonies, various bacteria species could be identified by polymerase chain reaction analysis with two primers specific for highly conserved sequence regions in the bacterial 16S rDNA and by sequencing. First indications for the presence of bacteria with phytopathogenic potential were found.