Antiphytoviral Studies from Certain Actinomycetal Isolates

SUMMARYThe present investigation was carried out as an effort to find natural antiviral agent from certain streptomyces ,which is the most abundant and are coverable actinomycete group in soil against ZYMV causing systemic viral infection on Cucumis sativus leavThis study included :1- Isolation and screening of fifty actinomycete isolates from certain cultivated soils at different regions in Sharkia Governorates,to enumerate active strains which have antiphytoviral activity.2- The results revealed that all of the tested isolates showed an inhibitory effect (as %of inhibition) on viral activity. The difference of the inhibitory effect depends on the type of the isolate.3- 10 out of 50 isolates exhibited considerable antiviral potentialities and was selected as the most potent actinomycetal isolates in their antiviral activities against ZYMV. It was chosen for further investigations .4- The effect of pre-rubbing with streptomyces cultural filterates on the infectivity of by ZYMV at different periods,1,6 ,12, 24, 36, 48 and 72 hours was studied. The results revealed that a remarkable inhibition at the first and 6 hours reach 85,90% res5- The selected actinomycete cultural filterates were applied on the leaves of Cucumis sativus plant post inoculation with ZYMV at different intervals from 1 up to 72 hrs, there was a variation in the inhibition pattern.6- It was clear that the pre-application of the tested actinomycete culture filterates of streptomycetes was far better than post application in inhbiting ZYMV infection.7- The most two potent isolates which recorded high antiviral action were identified and classified as belonging to S. albovinaceus Za1 and S. sparsogenes Za39 according to Bergey’s Mannual (1989) .8- Further studies aiming to optimize the environmental conditions and nutritional requirment of S. albovinaceus Za1 and S. sparsogenes Za39 for optimum antiviral production were recorded after incubation for 7days at pH 7. Starch, potassium nitrate, dipo9- Morphological changes of C. sativus leaves infected with ZYMV reaveled that application of S. albovinaceus Za1 and S. sparsogenes Za39 cultural filterates mixed with equal volume of ZYMV led to an improvement in morphological characters of cucumber pla10- The changes in some metabolic processes were studied in Cucumis sativus leaves infected with ZYMV. It showed a reduction the activities of protease, lipase and amylase enzymes,if compared with healthy ones. However, the reduction in these enzyme activ11- Ultra structural changes of cucumber leaves infected with ZYMV showed the presence of large vesicles inside the chloroplast if compared with the healthy one, while cells treated with a mixture of virus and antiviral substance produced by S. sparsogene