The maize root stem cell niche: a partnership between two sister cell populations.
Using transcript profile analysis, we explored the nature of the stem cell niche in roots of maize (Zea mays). Toward assessing a role for specific genes in the establishment and maintenance of the niche, we perturbed the niche and simultaneously monitored the spatial expression patterns of genes hypothesized as essential. Our results allow us to quantify and localize gene activities to specific portions of the niche: to the quiescent center (QC) or the proximal meristem (PM), or to both. The data point to molecular, biochemical and physiological processes associated with the specification and maintenance of the niche, and include reduced expression of metabolism-, redox- and certain cell cycle-associated transcripts in the QC, enrichment of auxin-associated transcripts within the entire niche, controls for the state of differentiation of QC cells, a role for cytokinins specifically in the PM portion of the niche, processes (repair machinery) for maintaining DNA integrity and a role for gene silencing in niche stabilization. To provide additional support for the hypothesized roles of the above-mentioned and other transcripts in niche specification, we overexpressed, in Arabidopsis, homologs of representative genes (eight) identified as highly enriched or reduced in the maize root QC. We conclude that the coordinated changes in expression of auxin-, redox-, cell cycle- and metabolism-associated genes suggest the linkage of gene networks at the level of transcription, thereby providing additional insights into events likely associated with root stem cell niche establishment and maintenance.
Jiang
Keni
K
Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA.
Zhu
Tong
T
Diao
Zhaoyan
Z
Huang
Haiyan
H
Feldman
Lewis J
LJ
D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D016000:Cluster Analysis; D004734:Energy Metabolism / Q000235:genetics; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics; D007210:Indoleacetic Acids / Q000378:metabolism; D018519:Meristem / Q000166:cytology; D018613:Microscopy, Confocal; D010084:Oxidation-Reduction; D018517:Plant Roots / Q000166:cytology* / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D055153:Stem Cell Niche / Q000166:cytology* / Q000378:metabolism; D014158:Transcription, Genetic; D003313:Zea mays / Q000166:cytology* / Q000235:genetics
D029681:Arabidopsis Proteins; D018797:Cell Cycle Proteins; D007210:Indoleacetic Acids; D012333:RNA, Messenger