Streptomyces spp. culture filtrates deconstruct Odontoglossum ringspot virus (ORSV) and Cymbidium mosaic virus (CymMV) virus coat

Odontoglossum ringspot virus (ORSV) and Cymbidium mosaic virus (CymMV) are very resistant viruses and survive without cells in soil or bench environment for up to 10 years. Two strategies may prevent the infection of these virus to the plants. Firstly, to rid the cultivation environment and agriculture tools of the virus particles, and secondly, to apply the anti-viral agent on the plant to prevent the infection of the viruses. These requires development of new type of anti-viral agents. Previously Streptomyces spp was isolated, and culture filtrate was demonstrated to be anti-viral. Two strains, SML-1 and CA5-NO6 were isolated. In this paper we presented tests to compare the effects of these two strains and other anti-viral agents, on ORSV and CymMV. The culture filtrate of Streptomyces spp. CA5-NO6 strain, as well as SML-1 strain, was tested for their ability to destroy coat protein of ORSV. Morphology of ORSV or CymMV was examined by atomic force microscopy (AFM) after treatment of the following: (1) The culture filtrate of CA5-NO6 strain (2) Trypsin, a known proteinase, (3) virusbom, an proprietary product sold in Taiwan claimed to work as an enzyme. Our results demonstrated that CA5-NO6 strain destroyed the coat protein slightly better than SML-1 strain. CA5-NO6 act on the ORSV virus in a different way to that of trypsin or virusbom, while different buffers result in different morphology of the same virus under AFM. Our data suggested the Streptomyces spp. culture filtrates deconstruct ORSV and CymMV virus coat by a mechanism not similar to those of trypsin or virubom, and both strains works, with CA5-NO6 slightly better than SML-1 strain. This provide evidence to support the further development for commercialization of the culture filtrates. (paper)