Abstract—In 2017, cankers were observed on mature Populus nigra L. trees in Iran. The disease was characterized by copious amounts of brown exudation from cankers on the trunk, crotch and pruning scars in spring, summer and early autumn. Upon removal of the bark, reddish/brown lesions were visible in the woody tissue of the host. These symptoms were similar to those described on the same host in Spain. Isolations were performed from infected tissue. Pale cream bacterial colonies were consistently isolated from the infected tissue. The isolates were phenotypically identical to members of Pectobacteriaceae specifically Brenneria spp. The nucleotide sequences of the 16S rRNA and house-keeping genes, gyrB, infB, rpoB, and gapA indicated that the isolates from the trees in Iran were similar to Brenneria salicis, but formed a distinct cluster on their own suggesting that this was a new species of Brenneria. Pathogenicity tests were performed by inoculation of stems, trunks and shoots of age height where, poplar. At the site of inoculation, all isolates produced necrotic lesions and exudates 30 days after inoculation. Re-isolations and confirmation of their identity were performed fulfilling Koch’s postulates.
