The maize transcription factor myb-related protein-1 is a key regulator of the differentiation of transfer cells.
Transfer cells are highly modified plant cells specialized in the transport of solutes. They differentiate at many plant exchange surfaces, including phloem loading and unloading zones such as those present in the sink organs and seeds. In maize (Zea mays) seeds, transfer cells are located at the base of the endosperm. It is currently unknown how apical-basal polarity is established or why the peripheral cells at the base of the endosperm differentiate into transfer instead of aleurone cells. Here, we show that in epidermal cells committed to develop into aleurone cells, the ectopic expression of the transfer cell-specific transcriptional activator Myb-Related Protein-1 (MRP-1) is sufficient to temporarily transform them into transfer cells. These transformed cells acquire distinct transfer cell features, such as cell wall ingrowths and an elongated shape. In addition, they express a number of MRP-1 target genes presumably involved in defense. We also show that the expression of MRP-1 is needed to maintain the transfer cell phenotype. Later in development, an observed reduction in the ectopic expression of MRP-1 was followed by the reversion of the transformed cells, which then acquire aleurone cell features.
Gómez
Elisa
E
Departamento de Biología Celular y Genética, Universidad de Alcalá, 28871 Alcalá de Henares, Madrid, Spain.
Royo
Joaquín
J
Muñiz
Luis M
LM
Sellam
Olivier
O
Paul
Wyatt
W
Gerentes
Denise
D
Barrero
Cristina
C
López
Maribel
M
Perez
Pascual
P
Hueros
Gregorio
G
D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology*; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D017403:In Situ Hybridization; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics / Q000502:physiology*; D030821:Plants, Genetically Modified / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D003313:Zea mays / Q000166:cytology* / Q000235:genetics / Q000378:metabolism*
D010940:Plant Proteins