title: Cell Death and Cell Cycle Arrest of Silene latifolia Stamens and Pistils After Microbotryum lychnidis-dioicae Infection.
abstract: Mechanisms of suppression of pistil primordia in male flowers and of stamen primordia in female flowers differ in diclinous plants. In this study, we investigated how cell death and cell cycle arrest are related to flower organ formation in Silene latifolia. Using in situ hybridization and a TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling) assay, we detected both cell cycle arrest and cell death in suppressed stamens of female flowers and suppressed pistils of male flowers in S. latifolia. In female flowers infected with Microbotryum lychnidis-dioicae, developmental suppression of stamens is released, and cell cycle arrest and cell death do not occur. Smut spores are formed in S. latifolia anthers infected with M. lychnidis-dioicae, followed by cell death in the endothelium, middle layer, tapetal cells and pollen mother cells. Cell death is difficult to detect using a fluorescein isothiocyanate-labeled TUNEL assay due to strong autofluorescence in the anther. We therefore combined a TUNEL assay in an infrared region with transmission electron microscopy to detect cell death in anthers. We show that following infection by M. lychnidis-dioicae, a TUNEL signal was not detected in the endothelium, middle layer or pollen mother cells, and cell death with outflow of cell contents, including the nucleoplast, was observed in tapetal cells.
authors.affiliation: Department of Integrated Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kawamoto
authors.affiliation: Bioscience and Biotechnology Center, Nagoya University, Chikusa, Nagoya, Japan.
authors.forename: Kaori
authors.initials: K
authors.lastname: Yamanaka
authors.affiliation: Department of Health and Environmental Sciences, Kyoto University Graduate School of Medicine, Yoshida Konoe, Sakyo, Kyoto, Japan.
authors.forename: Ayako
authors.initials: A
authors.lastname: Koizumi
authors.affiliation: Department of Geriatric Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Aiko
authors.initials: A
authors.lastname: Hirata
authors.affiliation: Department of Agriculture, Forestry and Fisheries, Yaeyama Agriculture, Forestry and Fisheries Promotion Center, Maezato, Ishigaki, Okinawa, Japan.
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Kawano
mesh_terms: D001487:Basidiomycota / Q000502:physiology*; D059447:Cell Cycle Checkpoints / Q000502:physiology; D016923:Cell Death / Q000502:physiology; D035264:Flowers / Q000378:metabolism* / Q000382:microbiology; D011058:Pollen / Q000378:metabolism / Q000382:microbiology; D029751:Silene / Q000378:metabolism* / Q000382:microbiology*
keywords: Microbotryum lychnidis-dioicae; Silene latifolia; Tapetum; Anther development