title: The shoot meristem identity gene TFL1 is involved in flower development and trafficking to the protein storage vacuole.
abstract: Plants are unique in their ability to store proteins in specialized protein storage vacuoles (PSVs) within seeds and vegetative tissues. Although plants use PSV proteins during germination, before photosynthesis is fully functional, the roles of PSVs in adult vegetative tissues are not understood. Trafficking pathways to PSVs and lytic vacuoles appear to be distinct. Lytic vacuoles are analogous evolutionarily to yeast and mammalian lysosomes. However, it is unclear whether trafficking to PSVs has any analogy to pathways in yeast or mammals, nor is PSV ultrastructure known in Arabidopsis vegetative tissue. Therefore, alternative approaches are required to identify components of this pathway. Here, we show that an Arabidopsis thaliana mutant that disrupts PSV trafficking identified TERMINAL FLOWER 1 (TFL1), a shoot meristem identity gene. The tfl1-19/mtv5 (for "modified traffic to the vacuole") mutant is specifically defective in trafficking of proteins to the PSV. TFL1 localizes to endomembrane compartments and colocalizes with the putative delta-subunit of the AP-3 adapter complex. Our results suggest a developmental role for the PSV in vegetative tissues.
authors.affiliation: Center for Plant Cell Biology, University of California, Riverside, CA 92521, USA.
authors.forename: Eun Ju
authors.initials: EJ
authors.lastname: Sohn
authors.forename: Marcela
authors.initials: M
authors.lastname: Rojas-Pierce
authors.forename: Songqin
authors.initials: S
authors.lastname: Pan
authors.forename: Clay
authors.initials: C
authors.lastname: Carter
authors.forename: Antonio
authors.initials: A
authors.lastname: Serrano-Mislata
authors.forename: Francisco
authors.initials: F
authors.lastname: Madueño
authors.forename: Enrique
authors.initials: E
authors.lastname: Rojo
authors.forename: Marci
authors.initials: M
authors.lastname: Surpin
authors.forename: Natasha V
authors.initials: NV
authors.lastname: Raikhel
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism* / Q000648:ultrastructure; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D035264:Flowers / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D018519:Meristem / Q000235:genetics / Q000378:metabolism*; D046529:Microscopy, Electron, Transmission; D016253:Microscopy, Immunoelectron; D021381:Protein Transport; D014617:Vacuoles / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D029681:Arabidopsis Proteins; C102864:TFL1 protein, Arabidopsis