caa a22 4500 606208720 CHVBK 20210128101024.0 cr unu---uuuuu 210128e20150101xx s 000 0 eng 10.1007/s00425-014-2178-z doi (NATIONALLICENCE)springer-10.1007/s00425-014-2178-z Calreticulin expression in relation to exchangeable Ca2+ level that changes dynamically during anthesis, progamic phase, and double fertilization in Petunia [Elektronische Daten] [Robert Lenartowski, Anna Suwińska, Marta Lenartowska] Calcium (Ca2+) plays essential roles in plant sexual reproduction, but the sites and the mechanism of Ca2+ mobile storage during pollen-pistil interactions have not been fully defined. Because the Ca2+-buffering protein calreticulin (CRT) is able to bind and sequester Ca2+, it can serve as a mobile intracellular store of easily releasable Ca2+ and control its local concentration within the cytoplasm. Our previous studies showed an enhanced expression of Petunia hybrida CRT gene (PhCRT) during pistil transmitting tract maturation, pollen germination and tube outgrowth on the stigma, gamete fusion, and early embryogenesis. Here, we demonstrate that elevated expression of CRT results in the accumulation of this protein in response to anthesis, pollination, sperm cells deposition within the receptive synergid and fertilization, when the level of exchangeable Ca2+ changes dynamically. CRT localizes mainly to the endoplasmic reticulum and Golgi compartments in the pistil transmitting tract cells, germinated pollen/tubes, and sporophytic/gametophytic cells of the ovule and corresponds with loosely bound Ca2+. Additionally, the immunogold research shows, for the first time, highly selective CRT distribution in specific nuclear sub-domains. On the basis of our results, we discuss the possible functions of CRT with respect to the critical role of Ca2+ homeostasis during key events of the multi-step process of generative reproduction in angiosperms. The Author(s), 2014 Calcium homeostasis nationallicence Chaperone activity nationallicence Embryo sac nationallicence Nucleus nationallicence Pollen germination and tube growth nationallicence Receptive synergid nationallicence Stigma nationallicence Ca2+ ppts : Calcium-antimonate precipitates nationallicence CRT : Calreticulin gene nationallicence CRT : Calreticulin protein nationallicence CRT PAb : Polyclonal antibody against CRT nationallicence Ecm : Extracellular matrix nationallicence GFP : Green fluorescent protein nationallicence HDEL : ER-retention sequence of plant CRT nationallicence NLS : Nuclear localization signal nationallicence NR : Nuclear reticulum nationallicence PP1 : First stage of the progamic phase nationallicence PP2 : Second stage of the progamic phase nationallicence PP3 : Third stage of the progamic stage nationallicence PhCRT : Petunia hybrida calreticulin gene nationallicence Sitt : Stigma transmitting tract nationallicence Sytt : Style transmitting tract nationallicence UPI : Unpollinated immature pistil nationallicence UPM : Unpollinated mature pistil nationallicence Lenartowski Robert Laboratory of Isotope and Instrumental Analysis, Faculty of Biology and Environment Protection, Nicolaus Copernicus University, Toruń, Poland aut Suwińska Anna Laboratory of Developmental Biology, Faculty of Biology and Environment Protection, Nicolaus Copernicus University, Toruń, Poland aut Lenartowska Marta Laboratory of Developmental Biology, Faculty of Biology and Environment Protection, Nicolaus Copernicus University, Toruń, Poland aut Planta Springer Berlin Heidelberg 241/1(2015-01-01), 209-227 0032-0935 241:1<209 2015 241 425 https://doi.org/10.1007/s00425-014-2178-z text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00425-014-2178-z text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Lenartowski Robert Laboratory of Isotope and Instrumental Analysis, Faculty of Biology and Environment Protection, Nicolaus Copernicus University, Toruń, Poland aut NATIONALLICENCE 700 1- Suwińska Anna Laboratory of Developmental Biology, Faculty of Biology and Environment Protection, Nicolaus Copernicus University, Toruń, Poland aut NATIONALLICENCE 700 1- Lenartowska Marta Laboratory of Developmental Biology, Faculty of Biology and Environment Protection, Nicolaus Copernicus University, Toruń, Poland aut NATIONALLICENCE 773 0- Planta Springer Berlin Heidelberg 241/1(2015-01-01), 209-227 0032-0935 241:1<209 2015 241 425