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Greenhouse-grown cucumber plants showed mosaic-type symptoms and irregular yellow spots on their leaves. The disease did not affect plant growth and the fruits remained symptom free. A virus having isometric particles, 30 nm in size, was isolated from the infected tissues and from recycled drainage water collected from tuff (volcanic rock) raised beds on which plants were grown. The virus was identified as a variant of cucumber leaf spot virus (CLSV) that has a host range similar but not identical to that of a previously described CLSV isolate. The overall nucleotide sequence identity between the RNAs of the Israeli isolate and the type isolate virus (accession numbers: DQ227315 and AY571334, respectively) amounts to 96%. [ABSTRACT FROM AUTHOR]

Yellows diseases in ornamental crops have become more common in Israel, and phytoplasmas have been detected in several crops. Recently, symptoms typical of a phytoplasma infection were observed on a large number of Limonium hybrids grown in commercial fields in Israel. Examination of samples from diseased plants by electron microscopy revealed the presence of pleiomorphic membrane-bound bodies in the phloem cells. Diseased plants were additionally analyzed by PCR using universal and nested primers and revealed upon sequencing products of 1143, 788 and 722 bp (Li-IL, Li-b2-IL, Li-v3-IL, respectively). Analysis of the PCR products, associated with infected Limonium, clustered within two major groups of phytoplasmas (16SrV and 16SrIX), elm yellows and almond witches broom. This is the first published record of these phytoplasmas in Israel. [ABSTRACT FROM AUTHOR]

Summary. A virus was isolated from Verbena plants that bore virus-like symptoms. The virus, for which the name Verbena latent virus (VeLV) is proposed, was consistently isolated from these plants, both with and without disease symptoms. Electron microscopy studies of ultrathin sections of infected Verbena tissues revealed the presence of elongated flexuous virus particles, ca. 650 nm in length. Its experimental host range was limited to Verbena spp. and Nicotiana clevelandii. No inclusion bodies or specific cytopathological effects, were observed. Electrophoresis of dissociated purified virus preparation in sodium dodecyl sulfate-polyacrylamide gel revealed a major protein component with a molecular mass of 38.9 kDa. Polyclonal antibodies which could specifically bind to virus particles were produced. A portion of the viral RNA was cloned and sequenced; it comprised 2503 nucleotides and contained part of three open reading frames (ORFs) which from the 5′ to the 3′-ends, potentially encode for 489 amino acids (ORF1), a 25.8-kDa protein (ORF2) and a 12-kDa protein (ORF3). Comparison of the predicted amino acid sequence with those of other plant viruses revealed 40–60% identity with several carlaviruses. In the light of particle morphology, absence of specific cytopathological effects in ultrathin sections, and genomic and serological properties, it is suggested that this virus belongs to the genus Carlavirus. [ABSTRACT FROM AUTHOR]

The biological, serological, and molecular characteristics of a newly isolated L4 resistance-breaking isolate of Pepper mild mottle virus (PMMoV) were studied. The new pathotype of PMMoV is closely related to the Israeli pathotypes P1,2 and P1,2,3 of the virus; however, the mosaic symptoms caused by this new pathotype on pepper plants with an L4 genotype were more severe than the mild mosaic symptoms caused by other common pathotypes of the virus in susceptible plants. The predicted amino acid sequence of the putative coat protein (CP) of the newly described pathotype has two amino acid mismatches when compared with the CP of pathotype P1,2, leucine to glutamine at position 47, and alanine to glycine at position 87. The CP of the new pathotype has one amino acid mismatch when compared with P1,2,3, having alanine instead of glycine at position 87. Based on its biological characteristics, the new pathotype was designated P1,2,3,4 of PMMoV-Is. A method is described for the differentiation among the three PMMoV pathotypes using restriction cleavage analysis of reverse-transcription polymerase chain reaction products made from virus-infected plants. An additional unique MnlI site in the CP gene of the newly isolated P1,2,3,4 allows its distinction from the other two isolates, while BglI cleaved only products of the P1,2 pathotype. [ABSTRACT FROM AUTHOR]