title: The promoter of ZmMRP-1, a maize transfer cell-specific transcriptional activator, is induced at solute exchange surfaces and responds to transport demands.
abstract: Transfer cells have specializations that facilitate the transport of solutes across plant exchange surfaces. ZmMRP-1 is a maize (Zea mays) endosperm transfer cell-specific transcriptional activator that plays a central role in the regulatory pathways controlling transfer cell differentiation and function. The present work investigates the signals controlling the expression of ZmMRP-1 through the production of transgenic lines of maize, Arabidopsis, tobacco and barley containing ZmMRP-1promoter:GUS reporter constructs. The GUS signal predominantly appeared in regions of active transport between source and sink tissues, including nematode-induced feeding structures and at sites of vascular connection between developing organs and the main plant vasculature. In those cases, promoter induction was associated with the initial developmental stages of transport structures. Significantly, transfer cells also differentiated in these regions suggesting that, independent of species, location or morphological features, transfer cells might differentiate in a similar way under the influence of conserved induction signals. In planta and yeast experiments showed that the promoter activity is modulated by carbohydrates, glucose being the most effective inducer.
authors.affiliation: Departamento de Biología Celular y Genética, Universidad de Alcalá, Campus Universitario, Carretera Madrid-Barcelona Km 33.600, 28871, Alcalá de Henares, Madrid, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Barrero
authors.forename: Joaquín
authors.initials: J
authors.lastname: Royo
authors.forename: Carmen
authors.initials: C
authors.lastname: Grijota-Martinez
authors.forename: Christian
authors.initials: C
authors.lastname: Faye
authors.forename: Wyatt
authors.initials: W
authors.lastname: Paul
authors.forename: Soledad
authors.initials: S
authors.lastname: Sanz
authors.forename: H-H
authors.initials: HH
authors.lastname: Steinbiss
authors.forename: Gregorio
authors.initials: G
authors.lastname: Hueros
mesh_terms: D000818:Animals; D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000469:parasitology; D001692:Biological Transport; D018506:Gene Expression Regulation, Plant; D018525:Germination; D001467:Hordeum / Q000235:genetics; D009348:Nematoda; D009928:Organ Specificity; D010940:Plant Proteins / Q000235:genetics*; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics*; D036226:Seedlings / Q000166:cytology / Q000235:genetics; D012639:Seeds / Q000166:cytology / Q000235:genetics; D013499:Surface Properties; D014026:Nicotiana / Q000235:genetics; D015534:Trans-Activators / Q000235:genetics*; D003313:Zea mays / Q000166:cytology / Q000235:genetics* / Q000469:parasitology
chemical_list: D010940:Plant Proteins; D015534:Trans-Activators