Satureja khuzestanica is an endemic plant that is widely distributed in the southern parts of Iran. Since 2019, disease symptoms like leaf scorch, apparently healthy stems adjacent to dead or dying stems followed by collapsing and ultimately death of the plant have been observed in the southern regions of Iran. Altogether, forty samples with necrotic symptoms were collected from different regions. Forty isolates with rod-shaped colonies and fluorescent pigments produced under ultraviolet light on King’s B agar medium were isolated from symptomatic plants Only seven bacterial strains were randomly selected for further studies. These strains were Gram-negative, produced levan, showed strictly aerobic metabolism of glucose, none produced oxidase, arginine dehydrolase, and pectinase. They produced acid from glucose, arabinose, xylose, mannitol, mannose, sorbitol, and rhamnose All bacterial isolates caused a hypersensitive reaction on the tobacco (cv. Samsun) leaves. In all tests, Pseudomonas syringae pv. syringae (BPIC 242) was used as a positive control. Isolates were deposited in the Culture Collection of the Bu-Ali Sina University of Iran with the following numbers: MPS15, MPS18, MPS23, MPS27, MPS29, MPS34, and MPS 35. The 16 S rDNAfD1/rP2 (Weisburg et al. 1991) and gyrB-Fps/gyrB-Rps (Sarkar and Guttman 2004), respectively and sequenced. The sequences of 16 S rDNA (GenBank accession No. OK142734) and gyrB (OK169509) were 99.36–100% similar to those of P. syringae pv. syringae isolates including type strains from several hosts in multiple countries in the NCBI database (MK156158, JX826634 for 16 S, and KX160068, KU314662 for gyrB, respectively). PCR-based diagnosis (CTAB extraction) using RST31/33 primers for X. fastidiosa strains were negative for all symptomatic tested samples (Minsavage et al. 1994). Pathogenicity tests were conducted on nine S. khuzestanica plants by spray-inoculation with suspension of the seven representative isolates (1 ×107 CFU/ml). Two contro
