Comparative Pollen Morphology of Selected Species of <i>Blumea</i> DC. and <i>Cyathocline</i> Cass. and Its Taxonomic Significance

The pollen morphology of 20 species from Blumea and Cyathocline Cass. was investigated using a light microscope (LM) and scanning electron microscopy (SEM) to explore their taxonomic significance. This study showed that pollen grains of these species were usually tricolporate, rarely tetracolporate (B. sinuata). Nine pollen types were distinguishable through the exine sculpture characters and the number of apertures. It was easily distinguished Cyathocline from species of Blumea s. str. by its much smaller size (15.04 μm × 15.07 μm) and sparse and longer spines (24 spines, spine length 4.23 μm) with acute apex, which suggest that C. purpurea might not belong to the genus Blumea s. str. The palynological characteristics indicated that Section Macrophllae and Section Paniculatae of Blumea were not monophyletic groups. The pollen morphology differentiation of B. lacera clade is consistent with the interspecific relationship revealed by the molecular phylogenetic tree. However, the pollen morphology of the Blumea densiflora clade is inconsistent with the interspecific relationship based on molecular phylogenetic analysis. This palynology research can only partly support the previously published molecular phylogeny of Blumea s. str

Influenza H7N9 and H9N2 viruses:coexistence in poultry linked to human H7N9 infection and genome characteristics

Avian influenza virus A of the novel H7N9 reassortant subtype was recently found to cause severe human respiratory infections in China. Live poultry markets were suspected locations of the human H7N9 infection sources, based on the cases' exposure histories and sequence similarities between viral isolates. To explore the role of live poultry markets in the origin of the novel H7N9 virus, we systematically examined poultry and environmental specimens from local markets and farms in Hangzhou, using real-time reverse transcription-PCR (RT-PCR) as well as high-throughput next-generation sequencing (NGS). RT-PCR identified specimens positive for the H7 and N9 genomic segments in all of the 12 poultry markets epidemiologically linked to 10 human H7N9 cases. Chickens, ducks, and environmental specimens from the markets contained heavily mixed subtypes, including H7, N9, H9, and N2 and sometimes H5 and N1. The idea of the coexistence of H7N9 and H9N2 subtypes in chickens was further supported by metagenomic sequencing. In contrast, human H7N9 infection cases (n = 31) were all negative for H9N2 virus according to real-time RT-PCR. The six internal segments were indistinguishable for the H7N9 and H9N2 viruses. The H9, N2, and internal-segment sequences were very close to the sequence of the H9N2 virus circulating in chickens in China recently. Our results provide direct evidence that H9N2 strains coexisted with the novel human-pathogenic H7N9 influenza virus in epidemiologically linked live poultry markets. Avian influenza A virus of the H9N2 subtype likely made a recent contribution to the evolution of the H7N9 virus and continues to do so. IMPORTANCE Our results suggest that avian influenza A virus of the H9N2 subtype likely made a recent contribution to the evolution of the H7N9 virus, a novel reassortant avian influenza virus A subtype, and continues to do so. The finding helps shed light on how the H7N9 virus emerged, spread, and transmitted to humans. It is of considerable interest for assessing the risk of the possible emergence of novel reassortant viruses with enhanced transmissibility to humans