نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه گیاهپزشکی، دانشگاه آزاد اسلامی، واحد علوم و تحقیقات تهران، ایران
2 مؤسسه تحقیقات ثبت و گواهی بذر و نهال، سازمان تحقیقات، آموزش و ترویج کشاورزی، تهران، ایران.
3 گروه گیاهپزشکی، دانشگاه آزاد اسلامی، واحد علوم و تحقیقات تهران، ایران.
چکیده
کلیدواژه‌ها
عنوان مقاله [English]
نویسندگان [English]
Erwinia persicina (Ep) is a plant pathogenic bacterium with a wide range of host's, spread through infected seeds. Seeds carry a variety of surface microbes with complex interactions with each other and the host plant. The bacterium Ep was isolated during surveys from wheat fields infected with Xanthomonas translucens (Xt), the cause of bacterial leaf streak disease. From the ten samples of Mihan cultivar collected from different regions of Iran, just one Ep isolate was isolated from Markazi province and two isolates from Lorestan province. The isolated bacteria were identified based on some key biochemical traits and 16Sr RNA sequence analysis. The pathogenic or antagonistic activities of these three isolates were different. All isolates (Ais155, Ais238 and Ais255) produced an effective inhibitory zone against Xt under in vitro conditions. At the early stage after sowing the Ep treated seeds in artificially contaminated soil with Xt, the typical disease symptoms appeared weak with delay but it seems that the production of biofilm and enzyme activities of E. persicina (Ais155 isolate) and particularly high cellulase activity (in Ais238 isolate) cause more severe incidence of bacterial leaf streak disease (18.3 to 39.6%) in comparison with untreated seeds in infected soil. Indirect effect of seed treatment on disease severity were assayed through inoculum spraying plantlets that obtained from treated seeds. The Ais255 isolate indirectly increased plant relative resistance to Xt. It was concluded that Ep can reduce the severity of the disease via activating the plant's defense system. Further research is needed to prove the different dimensions of this effect.
کلیدواژه‌ها [English]
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