title: HAWAIIAN SKIRT regulates the quiescent center-independent meristem activity in Arabidopsis roots.
abstract: Root apical meristem (RAM) drives post-embryonic root growth by constantly supplying cells through mitosis. It is composed of stem cells and their derivatives, the transit-amplifying (TA) cells. Stem cell organization and its maintenance in the RAM are well characterized, however, their relationships with TA cells remain unclear. SHORTROOT (SHR) is critical for root development. It patterns cell types and promotes the post-embryonic root growth. Defective root growth in the shr has been ascribed to the lack of quiescent center (QC), which maintains the surrounding stem cells. However, our recent investigation indicated that SHR maintains TA cells independently of QC by modulating PHABULOSA (PHB) through miRNA165/6. PHB controls TA cell activity by modulating cytokinin levels and type B Arabidopsis Response Regulator activity, in a dosage-dependent manner. To further understand TA cell regulation, we conducted a shr suppressor screen. With an extensive mutagenesis screen followed by genome sequencing of a pooled F2 population, we discovered two suppressor alleles with mutations in HAWAIIAN SKIRT (HWS). HWS, encoding an F-box protein with kelch domain, is expressed, partly depending on SHR, in the root cap and in the pericycle of the differentiation zone. Interestingly, root growth in the shr hws was more active than the wild-type roots for the first 7 days after germination, without recovering QC. Contrary to shr phb, shr hws did not show a recovery of cytokinin signaling. These indicate that HWS affects QC-independent TA cell activities through a pathway distinctive from PHB.
authors.affiliation: School of Biological Sciences, College of Natural Science, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Korea.
authors.forename: Eun-Sol
authors.initials: ES
authors.lastname: Kim
authors.affiliation: School of Biological Sciences, College of Natural Science, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Korea.
authors.forename: Goh
authors.initials: G
authors.lastname: Choe
authors.affiliation: Boyce Thompson Institute for Plant Research, Tower Rd., Ithaca, NY, 14853, USA.
authors.forename: Jose
authors.initials: J
authors.lastname: Sebastian
authors.affiliation: School of Biological Sciences, College of Natural Science, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Korea.
authors.forename: Kook Hui
authors.initials: KH
authors.lastname: Ryu
authors.affiliation: Boyce Thompson Institute for Plant Research, Tower Rd., Ithaca, NY, 14853, USA.
authors.forename: Linyong
authors.initials: L
authors.lastname: Mao
authors.affiliation: Boyce Thompson Institute for Plant Research, Tower Rd., Ithaca, NY, 14853, USA.
authors.forename: Zhangjun
authors.initials: Z
authors.lastname: Fei
authors.affiliation: School of Biological Sciences, College of Natural Science, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Korea.|Plant Genomics and Breeding Institute, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Korea.
authors.forename: Ji-Young
authors.identifier: http://orcid.org/0000-0002-7631-5127
authors.initials: JY
authors.lastname: Lee
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D003583:Cytokinins / Q000378:metabolism; D044783:F-Box Proteins / Q000235:genetics / Q000378:metabolism*; D018525:Germination; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D018519:Meristem / Q000166:cytology / Q000235:genetics / Q000254:growth & development; D009154:Mutation; D010937:Plant Growth Regulators / Q000378:metabolism; D018517:Plant Roots / Q000166:cytology / Q000235:genetics / Q000254:growth & development
chemical_list: D029681:Arabidopsis Proteins; D003583:Cytokinins; D044783:F-Box Proteins; C000613822:HWS protein, Arabidopsis; D018398:Homeodomain Proteins; C114647:PHB protein, Arabidopsis; D010937:Plant Growth Regulators