Identification of bacterial agents causing sugarcane pedunclesoft rot in Khuzestan Provine, Iran

Background and Aim : The flowering of sugarcane varieties is a ۱۰ to ۱۲ years process undercontrolled conditions in the greenhouse. For crossbreeding between selected parents of sugarcane,seed production, and selection of new cultivars and genotypes, flowering stems play an essentialrole in this strategic plant. In the flower production greenhouse, due to the high humidity forflowering, symptoms of a disease were observed in sugarcane plant, including irregular soft andwater-soaked lesions in the peduncle and top canes. In severe cases, the top cane become soft,peduncle breaks leading to the death of the flowers. Therefore, the current study aims to identifythe causal agent of the newly emerged disease on sugarcane in Iran.Methods : During ۲۰۲۰, suspected sugarcane samples were collected in the research green-houseof the Iranian Sugarcane Research and Training Institute (ISCRTI) in Khuzestan province(۳۰°۵۷'۰۴.۳"N and ۴۸°۳۲'۵۵.۹"E). Samples were placed in plastic bags and transferred to thelaboratory for bacterial isolation on YPGA and YDC media. To identify bacterial isolates,morphological, biochemical, and physiological characteristics were investigated. To perform thepathogenicity test, bacterial suspension (۱۰۶ CFU/ml) was injected into the peduncle undergreenhouse conditions. For molecular identification, ۱۶S rRNA and gyrB gene were sequenced inrepresentative strains.Results : The obtained bacterial strains were grouped in three clusters, and representatives wereselected from each group. In the pathogenicity test, symptoms of the disease included small, watersoakedlesions observed on the peduncle seven to ten days post-inoculation. Phylogenetic analysisof the target gene sequences showed that the causal agent belongs to different genera and species.Based on biochemical, molecular, and pathogenicity results, the representative strains wereidentified as, Serratia sp., Bacillus sp., Pantoea dispersa, and Pantoea agglomerans.Conclusion : Our results showed that these bacteria are serious threats to the sugarcane seedproduction greenhouses and it seems important to take suitable actions to control and prevent thespread of pathogens.

کلیدواژه ها:

emerged disease ، gyrB gene ، seed production ، sugarcane