title: PIN2-like proteins may contribute to the regulation of morphogenetic processes during spermatogenesis in Chara vulgaris.
abstract: PIN2-like auxin transporters are expressed, preferentially in a polarized manner, in antheridial cells of freshwater green alga Chara vulgaris , considered to be the closest relative of the present-day land plants. Chara vulgaris represents a group of advanced multicellular green algae that are considered as the closest relatives of the present-day land plants. A highly specialized structure of its male sex organs (antheridia) includes filaments consisting of generative cells, which after a series of synchronous divisions transform into mature sperm, and non-generative cells comprising outer shield cells, cylindrical manubria, and central complex of capitular cells from which antheridial filaments arise. Immunofluorescence observations indicate that PIN2-like proteins (PIN2-LPs), recognized by antibodies against PIN-FORMED2 (PIN2) auxin transporter in Arabidopsis thaliana, are expressed in both types of antheridial cells and, in most of them, preferentially accumulate in a polarized manner. The appearance of PIN2-LPs in germ-line cells is strictly confined to the proliferative period of spermatogenesis and their quantities increase steadily till antheridial filaments reach the 16-celled stage. An enhanced level of PIN2-LPs observed in the central cell walls separating two asynchronously developing parts of antheridial filaments (characterized by the plugged plasmodesmata) is correlated with an enhanced deposition of callose. Intense PIN2-LPs immunofluorescence maintained in the capitular cells and its altering polarity in manubria suggest a pivotal role of these cells in the regulation of auxin transport directionality during the whole time of antheridial ontogenesis. Immunohistochemical staining of IAA revealed a clear-cut correspondence between localization sites of auxins and PIN2-LPs. It seems probable then that a supplementary developmental mechanism has evolved in Chara, by which all antheridial elements may be integrated at the supra-cellular level via plasma membrane-targeted PIN2-LPs and auxin-mediated processes.
authors.affiliation: Department of Cytophysiology, Faculty of Biology and Environmental Protection, University of Łódź, Pomorska 141/143, 90-236, Lodz, Poland.
authors.forename: Aneta
authors.initials: A
authors.lastname: Żabka
authors.affiliation: Department of Cytophysiology, Faculty of Biology and Environmental Protection, University of Łódź, Pomorska 141/143, 90-236, Lodz, Poland.
authors.forename: Justyna Teresa
authors.initials: JT
authors.lastname: Polit
authors.affiliation: Department of Cytophysiology, Faculty of Biology and Environmental Protection, University of Łódź, Pomorska 141/143, 90-236, Lodz, Poland.
authors.forename: Konrad
authors.initials: K
authors.lastname: Krajewski
authors.affiliation: Department of Cytophysiology, Faculty of Biology and Environmental Protection, University of Łódź, Pomorska 141/143, 90-236, Lodz, Poland.
authors.forename: Patrycja
authors.initials: P
authors.lastname: Paciorek
authors.affiliation: Department of Cytophysiology, Faculty of Biology and Environmental Protection, University of Łódź, Pomorska 141/143, 90-236, Lodz, Poland.
authors.forename: Jolanta
authors.initials: J
authors.lastname: Juszczak
authors.affiliation: Department of Cytophysiology, Faculty of Biology and Environmental Protection, University of Łódź, Pomorska 141/143, 90-236, Lodz, Poland.
authors.forename: Mateusz
authors.initials: M
authors.lastname: Nowak
authors.affiliation: Department of Cytophysiology, Faculty of Biology and Environmental Protection, University of Łódź, Pomorska 141/143, 90-236, Lodz, Poland. jamasz@biol.uni.lodz.pl.
authors.forename: Janusz
authors.initials: J
authors.lastname: Maszewski
mesh_terms: D020418:Algal Proteins / Q000378:metabolism*; D002473:Cell Wall / Q000378:metabolism; D044784:Chara / Q000166:cytology / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D005718:Gametogenesis; D007210:Indoleacetic Acids / Q000378:metabolism; D008954:Models, Biological; D009024:Morphogenesis
chemical_list: D020418:Algal Proteins; D007210:Indoleacetic Acids
keywords: Callose; Chara vulgaris; IAA; PIN2-like proteins; Polar auxin transport; Spermatogenesis