title: Pollen transmission of asparagus virus 2 (AV-2) may facilitate mixed infection by two AV-2 isolates in asparagus plants.
abstract: Asparagus virus 2 (AV-2) is a member of the genus Ilarvirus and thought to induce the asparagus decline syndrome. AV-2 is known to be transmitted by seed, and the possibility of pollen transmission was proposed 25 years ago but not verified. In AV-2 sequence analyses, we have unexpectedly found mixed infection by two distinct AV-2 isolates in two asparagus plants. Because mixed infections by two related viruses are normally prevented by cross protection, we suspected that pollen transmission of AV-2 is involved in mixed infection. Immunohistochemical analyses and in situ hybridization using AV-2-infected tobacco plants revealed that AV-2 was localized in the meristem and associated with pollen grains. To experimentally produce a mixed infection via pollen transmission, two Nicotiana benthamiana plants that were infected with each of two AV-2 isolates were crossed. Derived cleaved-amplified polymorphic sequence analysis identified each AV-2 isolate in the progeny seedlings, suggesting that pollen transmission could indeed result in a mixed infection, at least in N. benthamiana.
authors.forename: Ryusuke
authors.initials: R
authors.lastname: Kawamura
authors.forename: Hanako
authors.initials: H
authors.lastname: Shimura
authors.forename: Tomofumi
authors.initials: T
authors.lastname: Mochizuki
authors.forename: Satoshi T
authors.initials: ST
authors.lastname: Ohki
authors.forename: Chikara
authors.initials: C
authors.lastname: Masuta
mesh_terms: D027761:Asparagus Plant / Q000821:virology*; D056738:Cross Protection; D035264:Flowers / Q000166:cytology / Q000821:virology; D054884:Host-Pathogen Interactions; D019179:Ilarvirus / Q000302:isolation & purification / Q000502:physiology*; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D018519:Meristem / Q000166:cytology / Q000821:virology; D010935:Plant Diseases / Q000821:virology*; D018520:Plant Shoots / Q000166:cytology / Q000821:virology; D011058:Pollen / Q000166:cytology / Q000821:virology*; D054817:Pollination; D036226:Seedlings / Q000166:cytology / Q000821:virology; D012639:Seeds / Q000166:cytology / Q000821:virology; D014026:Nicotiana / Q000166:cytology / Q000821:virology