Authors:A. El-Sayed, G. El-Didamony, and K. Mansour
Two types of actinophages, φS and φL, were isolated from soil samples by using Streptomyces scabies MR13, a potato scab pathogen, as an indicator strain. The phages were partially characterized according to their physicochemical properties, plaques and particles morphology and their host-range. The host-range of these phages was narrow for φS and wide for φL. The adsorption rate constants of the φS and φL were 3.44 × 10−9 and 3.18 × 10−9 ml/min, and their burst sizes were 1.61 and 3.75 virions, respectively. One-step growth indicated that φS and φL have a latent period of 30 min followed by a rise period of 30 min. The temperate character of these phages was tested in other isolates of Streptomyces. Four of the phages (φSS3, φSS12, φSS13 and φSS17) were identified as temperate phages, since they were able to lysogenize SS3, SS12, SS13 and SS17. φSS3, φSS12 and φSS13 were homoimmune, and they were heteroimmune with respect to φSS17. The restriction barriers of lysogenic isolates (SS12, SS13 and SS17) interfered with the blockage of plaques formation by phages (φSS12, φSS13 or φSS17) propagated on them, about 75% of lysogenic isolates had restriction systems. The exposure of the lysogenic isolates (SS12, SS13 and SS17) to UV-irradiation prevented the possible restriction barriers of these isolates, and these barriers could be overcome.
Elesawy, A. A. and Szabó, I. M. (1981): A simplified method for isolating and detecting the frequency of occurrence of free-living Streptomycesscabies in infested soils. Acta Phytopathol. Acad. Sci. Hung. 16 , 67-72.
Bukhalid, R. A., Loria, R.: Cloning and expression of a gene from Streptomycesscabies encoding a putative pathogenicity factor. J Bacteriol 179 , 7776 (1997).
Cloning and expression of a gene from Streptomycesscabies encoding a
Authors:S. Babu, R. Nandakumar, S. Sriram, R. Jaisankar, V. Shanmugam, T. Raguchander, R. Samiyappan, and P. Balasubramania
Goyer, C., Vachon, J. and Beaulieu, C. (1998): Pathogenicity of Streptomycesscabies mutants altered in thaxtomin A production. Phytopathology 88, 442-445.
Pathogenicity of Streptomycesscabies mutants altered in thaxtomin A