تأثير نظام استشعار النصاب العددي عند البكتيريا .Xanthomonas citri subsp malvacearum على إنبات بذور القطن وعلى تطور مرض التبقع الزاوي

Abstract EN

This research was conducted during the year 2019-2020 at Faculty of Agriculture-Damascus University, and aims to study the evaluation of the efficiency of DSF pure signal (≥ Sigma 90%) and DSFs (Diffusible Signal Factor) family- containing extract of culture of the bacteria Xanthomonas citri subsp.

malvacearum (Xcm S101), which mediated Quorum Sensing (QS) in Xcm $101 at improving the germination ability of cottonseeds Aleppo (33), and inducing the systemic resistance of plants to bacteria Xem S101 by soaking the seeds in DSF pure signal at concentration of 100 μM or different concentrations of DSFS-containing extract of culture of DSFs-containing extract of culture of the Xcm S101 at (0.25, 0.5, 1.25) mg/mL for 6 hours at 28 C°.

The results showed the efficiency of each of DSFs-containing extract of culture of the Xcm S101 at two concentrations 0.25, 0.5 mg/mL and DSF pure signal at concentration 100 µM at improving the germination ability of the cotton seeds, which the germination rate was 91.67-86.67 and 83.33%, respectively, comparing with the control, whose germination rate was 73.33%, after 72hr of seeds incubation, also the results showed that increasing the concentration of DSFs-containing extract of the culture of the Xcm S101 had a negative effect on the germination of the seeds, which the germination percentage decreased to 50% at concentration of 1.25 mg/mL comparing with the control after 72hr of seeds incubation.

The results showed that the plants which their seeds were treated by DSF pure signal at concentration of 100 μM or with DSFs-containing extract of culture of the Xcm S101 a concentration of 0.5 mg/mL had induced systemic resistance, which the severity of infection with Xcm S101 was decreased and the development of bacteria was reduced comparing with the control.