title: Dual role of tree florigen activation complex component FD in photoperiodic growth control and adaptive response pathways.
abstract: A complex consisting of evolutionarily conserved FD, flowering locus T (FT) proteins is a regulator of floral transition. Intriguingly, FT orthologs are also implicated in developmental transitions distinct from flowering, such as photoperiodic control of bulbing in onions, potato tuberization, and growth cessation in trees. However, whether an FT-FD complex participates in these transitions and, if so, its mode of action, are unknown. We identified two closely related FD homologs, FD-like 1 (FDL1) and FD-like 2 (FDL2), in the model tree hybrid aspen. Using gain of function and RNAi-suppressed FDL1 and FDL2 transgenic plants, we show that FDL1 and FDL2 have distinct functions and a complex consisting of FT and FDL1 mediates in photoperiodic control of seasonal growth. The downstream target of the FT-FD complex in photoperiodic control of growth is Like AP1 (LAP1), a tree ortholog of the floral meristem identity gene APETALA1. Intriguingly, FDL1 also participates in the transcriptional control of adaptive response and bud maturation pathways, independent of its interaction with FT, presumably via interaction with abscisic acid insensitive 3 (ABI3) transcription factor, a component of abscisic acid (ABA) signaling. Our data reveal that in contrast to its primary role in flowering, FD has dual roles in the photoperiodic control of seasonal growth and stress tolerance in trees. Thus, the functions of FT and FD have diversified during evolution, and FD homologs have acquired roles that are independent of their interaction with FT.
authors.affiliation: Umea Plant Science Center, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, S-901 87 Umea, Sweden;
authors.forename: Szymon
authors.initials: S
authors.lastname: Tylewicz
authors.affiliation: Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan; and.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tsuji
authors.affiliation: Umea Plant Science Center, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, S-901 87 Umea, Sweden;
authors.forename: Pál
authors.initials: P
authors.lastname: Miskolczi
authors.affiliation: Umea Plant Science Center, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, S-901 87 Umea, Sweden;
authors.forename: Anna
authors.initials: A
authors.lastname: Petterle
authors.affiliation: Umea Plant Science Center, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, S-901 87 Umea, Sweden;
authors.forename: Abdul
authors.initials: A
authors.lastname: Azeez
authors.affiliation: Umea Plant Science Center, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, S-901 87 Umea, Sweden;
authors.forename: Kristoffer
authors.initials: K
authors.lastname: Jonsson
authors.affiliation: Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan; and.
authors.forename: Ko
authors.initials: K
authors.lastname: Shimamoto
authors.affiliation: Umea Plant Science Center, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, S-901 87 Umea, Sweden; College of Science, King Saud University, Riyadh 11362, Saudi Arabia rishi.bhalerao@slu.se.
authors.forename: Rishikesh P
authors.initials: RP
authors.lastname: Bhalerao
mesh_terms: D000222:Adaptation, Physiological; D060405:Florigen / Q000378:metabolism*; D017440:Photoperiod; D014197:Trees / Q000254:growth & development / Q000502:physiology*
chemical_list: D060405:Florigen
keywords: adaptive response; bud set; growth cessation; hybrid aspen; seasonal growth