Relief and Pathogenicity of Xanthomonas citri subsp. malvacearum from infected cotton leaves after 9 years and investigation of biochemical characteristics of isolates

Cotton bacterial blight is a important and quarantine diseases of cotton in Iran that appeared in cotton fields of Golestan province in 2005. Samples of infected leaves collected and served in room temperature. In 2014, sections from infected leaves washed with tap water, then were placed in a few drop sterile distilled water in room temperature for five hours. The suspension streaked on NA medium. After 48-72 hours isolated bacteria colonies yellow, circle and 1 mm diameter. The bacteria were negative in gram, oxidase and fermentative growth tests. All of isolates were positive oxidative growth and starch hydrolysis. The isolates used from glucose, inulin, urate, malonate, lactate and tripton but did not used from trehalose, L-rhamnose, D-raffinose, fucose, maltose, L.tartrate, D-galacturonate, acetate, nicotinate, glycine, casein, dulcitol, L-threonine, and adonitol. Isolates were variable in utilization of arabinose, D-fructose, D-xylose, melezitose, melibiose, guanine, L-cysteine, L-tryptophan, L-histidine, betaine, β-alanine, L-valine, D-sorbitol, citrate and L-maleate. In Pathogenicity test, bacterial suspension injected with sterile syringe into epidermis leaf of Golestan cotton cultivar. The water-soaked spots observed after 3 days that extended and revealed vein blight. The importance oftherole ofinfectedplant debrisin theincidence andspread of the diseaseisofparticular importance.