title: Human leukocyte interferon and the antiviral factor (AVF) from virus-infected plants stimulate plant tissues to produce nucleotides with antiviral activity.
abstract: Leaves of Nicotiana glutinosa and tobacco, as well as tobacco callus cultures, were treated with the plant antiviral factor AVF or with a purified subspecies of human leukocyte interferon. After incubation, a fraction containing short oligonucleotides was extracted directly from the plant tissue. In addition, a synthetase preparation was fractionated from treated tissues, which polymerized ATP in the presence of polyinosinic, polycytidylic acid (poly(I:C)). The various plant nucleotides were applied to tobacco mosaic virus (TMV)-infected leaf disks, the TMV content of which were determined by an enzyme-linked immunosorbent assay. The nucleotide fraction extracted directly from TMV-infected leaves exhibited a considerable antiviral activity, whereas similar fractions from AVF- or interferon-treated leaves did not, even though an antiviral state was induced in the tissue by these agents. However, when the synthetase fraction from TMV-infected, AVF-treated, or interferon-treated tissues was incubated with ATP and poly(I:C), the resultant, heat-stable, acid-soluble, polymerized ATP markedly inhibited TMV multiplication. It is concluded that the presence of double-stranded RNA is obligatory for the formation of the antiviral nucleotides. The analogy to interferon-induced resistance in animal tissues is discussed.
authors.affiliation: Virus Laboratory, The Hebrew University, Faculty of Agriculture, Rehovot 76100, Israel.
authors.forename: M
authors.initials: M
authors.lastname: Reichman
authors.forename: Y
authors.initials: Y
authors.lastname: Devash
authors.forename: R J
authors.initials: RJ
authors.lastname: Suhadolnik
authors.forename: I
authors.initials: I
authors.lastname: Sela