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Shallow bark canker incited by Brenneria nigrifluens is considered one of the most dangerous diseases which can cause a significant reduction in walnut and timber production. During spring and summer of 2019, walnut gardens were surveyed for symptoms like leaf spot, fruit, and stem canker from four different regions of Golestan province located in Iran. A set of 11 Gram-negative bacteria were isolated from sample tissues with symptoms. In pathogenicity tests on unripe walnut fruits, all isolates caused typical black necrotic lesions covering almost the entire pericarp. Results of selected phenotypic tests and whole-cell protein patterns indicated that all isolates were the same as described for the type strain of B. nigrifluens. Phylogenetic analysis based on sequencing of the gyrB, rec A, and 16s rRNA genes of the representative isolate formed a unique clade, well-characterized, and separated from related species. The results of this study can have a bearing on the choice of disease management strategies.

Endophyte bacteria refers to the bacteria that live within plants. Fresh leaves of 23 sugar beet (Beta vulgaris L.) plants were collected from the west of Iran. After superficial disinfection, endophytic bacteria were isolated from the host tissue. Isolates were grouped based on their whole-cell protein electrophoresis patterns. One representative from each electrotype was selected and its morphological feature characterized according to the standard bacteriological criteria. The 16S rRNA encoding gene from these representatives was amplified using fD1 and rD1 universal primers, subjected to sequencing and aligned in the NCBI. The major occurring fingerprint types (electrotypes) were identified as Acinetobacter calcoaceticus, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia (25, 23, and 22 strains respectively). The other minor occurring electrotypes were identified as Streptomyces spp, Acetobacter spp, and Agrobacterium spp. This is the first report of A. calcoaceticus, P. aeruginosa, and S. maltophilia as an endophyte in the leaves of sugar beet.