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The interactions of lime witches' broom phytoplasma (LWBP, 16SrII-B) with alfalfa witches' broom phytoplasma (AWBP, 16SrII-C), tomato witches' broom phytoplasma (TWBP, 16SrII-D), sesame phyllody phytoplasma (SPhP, 16SrIX-C) and rapeseed phyllody phytoplasma (RPhP, 16SrI-B) were studied in periwinkle plants graft-inoculated either with each phytoplasma alone or with LWBP and a second phytoplasma. The latter was inoculated below or above the site of LWBP inoculation, and was applied either simultaneously or non-simultaneously. In all treatments and all replications, the plants doubly inoculated with LWBP + SPhP or LWBP + AWBP showed milder symptoms and lived longer than those singly inoculated with LWBP, SPhP, or AWBP. In plants with mixed infection by LWBP + RPhP or LWBP + TWBP, characteristic symptoms were present regardless of the grafting order or inoculation site. Analysis of quantitative PCR data showed that the mean concentrations of LWBP in all doubly inoculated plants were less than in plants inoculated with LWBP alone. In the SPhP inoculated plants, a substantial decrease in LWBP concentration was measured, followed in order of decreasing concentration in the AWBP, TWBP, and RPhP inoculated plants. In the mixed infections, greater reduction in LWBP concentration was found in non-simultaneous inoculations and when the second phytoplasma was grafted below the site of LWBP inoculation. Based on symptoms and quantitative PCR results, the interactions of LWBP with SPhP and AWBP resulted in greater cross-protection than interactions of LWBP with RPhP and TWBP. [ABSTRACT FROM AUTHOR]

Background: Maize Iranian mosaic virus (MIMV, genus Nucleorhabdovirus, family Rhabdoviridae) causes an economically important disease in maize and other gramineous crops in Iran. MIMV negative-sense RNA genome sequence of 12,426 nucleotides has recently been completed. Maize Genetics and Genomics database shows that 39,498 coding genes and 4,976 non-coding genes of maize have been determined, but still some transcripts could not be annotated. The molecular host cell responses of maize to MIMV infection including differential gene expression have so far not been elucidated. Methodology/Principal findings: Complementary DNA libraries were prepared from total RNA of MIMV-infected and mock-inoculated maize leaves and sequenced using Illumina HiSeq 2500. Cleaned raw transcript reads from MIMV-infected maize were mapped to reads from uninfected maize and to a maize reference genome. Differentially expressed transcripts were characterized by gene ontology and biochemical pathway analyses. Transcriptome data for selected genes were validated by real-time quantitative PCR. Conclusion/Significance: Approximately 42 million clean reads for each treatment were obtained. In MIMV-infected maize compared to uninfected plants, 1689 transcripts were up-regulated and 213 transcripts were down-regulated. In response to MIMV infection, several pathways were activated in maize including immune receptor signaling, metabolic pathways, RNA silencing, hormone-mediated pathways, protein degradation, protein kinase and ATP binding activity, and fatty acid metabolism. Also, several transcripts including those encoding hydrophobic protein RCI2B, adenosylmethionine decarboxylase NAC transcription factor and nucleic acid binding, leucine-rich repeat, heat shock protein, 26S proteasome, oxidoreductases and endonuclease activity protein were up-regulated. These data will contribute to the identification of genes and pathways involved in plant-virus interactions that may serve as future targets for improved disease control. [ABSTRACT FROM AUTHOR]

Maize Iranian mosaic virus (MIMV; Mononegavirales, Rhabdoviridae, Nucleorhabdovirus) infects maize and several other poaceous plants. MIMV encodes six proteins, i.e., nucleocapsid protein (N), polymerase cofactor phosphoprotein (P), putative movement protein (P3), matrix protein (M), glycoprotein (G), and large RNA-dependent RNA polymerase (L). In the present study, MIMV gene expression and genetic polymorphism of an MIMV population in maize were determined. N, P, P3, and M protein genes were more highly expressed than the 5′ terminal G and L genes. Twelve single nucleotide polymorphisms were identified across the genome within a MIMV population in maize from RNA-Seq read data pooled from three infected plants indicating genomic variations of potential importance to evolution of the virus. MIMV N, P, and M proteins that are known to be involved in rhabdovirus replication and transcription were characterized as to their intracellular localization and interactions. N protein accumulated exclusively in the nucleus and interacted with itself and with P protein. P protein accumulated in both the nucleus and cell periphery and interacted with itself, N and M proteins in the nucleus. M protein was localized in the cell periphery and on endomembranes, and interacted with P protein in the nucleus. MIMV proteins show a distinctive combination of intracellular localizations and interactions. [ABSTRACT FROM AUTHOR]

The complete nucleotide sequence of an Iranian isolate of Barley yellow striate mosaic virus (BYSMV) L gene comprising 6171 nucleotides was determined using the random polymerase chain reaction followed by filling of gaps by the use of specific primers. The deduced L protein sequence of BYSMV showed similarities with the L proteins of other plant rhabdoviruses and contained polymerase module motifs characteristic of RNA-dependent RNA polymerases of negative-strand RNA viruses. Pairwise and multiple alignments and phylogenetic analysis of BYSMV L protein revealed that it was more closely related to cytorhabdoviruses. These results revealed that, on the basis of polymerase gene, the Iranian isolate of BYSMV and Northern cereal mosaic virus (NCMV) appeared to be the most closely related plant rhabdoviruses sequenced to date. Interestingly, the amino acid sequence identity of BYSMV/NCMV (61.3%), shared more than twice the amino acid sequence identity compared with the next two most similar cytorabdoviruses, Lettuce necrotic yellows virus (28.8%) and Lettuce yellow mottle virus (28.2%). In this paper, we discuss the similarities and differences of BYSMV with other rhabdoviruses which support the classification of BYSMV as a distinct Cytorhabdovirus. This is the first report of BYSMV genome sequences. [ABSTRACT FROM AUTHOR]