title: Control of patterns of symmetric cell division in the epidermal and cortical tissues of the Arabidopsis root.
abstract: Controlled cell division is central to the growth and development of all multicellular organisms. Within the proliferating zone of the Arabidopsis root, regular symmetric divisions give rise to patterns of parallel files of cells, the genetic basis of which remains unclear. We found that genotypes impaired in the TONNEAU1a (TON1a) gene display misoriented symmetric divisions in the epidermis and have no division defects in the underlying cortical tissue. The TON1a gene encodes a microtubule-associated protein. We show that in the ton1a mutant, epidermal and cortical cells do not form narrow, ring-like preprophase bands (PPBs), which are plant-specific, cytoskeletal structures that predict the position of the division plane before mitosis. The results indicate that in the cortex but not in the epidermis, division plane positioning and patterning can proceed correctly in the absence of both a functional TON1a and PPB formation. Differences between tissues in how they respond to the signals that guide symmetric division orientation during patterning might provide the basis for organised organ growth in the absence of cell movements.
authors.affiliation: Department of Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, UK.
authors.forename: Yanwen
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, UK.
authors.forename: Michail
authors.initials: M
authors.lastname: Iakovidis
authors.affiliation: Department of Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, UK s.costa2537@gmail.com.
authors.forename: Silvia
authors.initials: S
authors.lastname: Costa
mesh_terms: D000483:Alleles; D017360:Arabidopsis / Q000166:cytology*; D029681:Arabidopsis Proteins / Q000235:genetics; D002455:Cell Division; D018519:Meristem / Q000166:cytology; D008870:Microtubules / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D019441:Plant Epidermis / Q000166:cytology*; D018517:Plant Roots / Q000166:cytology*
chemical_list: D029681:Arabidopsis Proteins
keywords: Cortex; Epidermis; Meristem; Preprophase band; TON1a; Tissue patterning