title: Cytokinin-dependent secondary growth determines root biomass in radish (Raphanus sativus L.).
abstract: The root serves as an essential organ in plant growth by taking up nutrients and water from the soil and supporting the rest of the plant body. Some plant species utilize roots as storage organs. Sweet potatoes (Ipomoea batatas), cassava (Manihot esculenta), and radish (Raphanus sativus), for example, are important root crops. However, how their root growth is regulated remains unknown. In this study, we characterized the relationship between cambium and radial root growth in radish. Through a comparative analysis with Arabidopsis root expression data, we identified putative cambium-enriched transcription factors in radish and analysed their expression in representative inbred lines featuring distinctive radial growth. We found that cell proliferation activities in the cambium positively correlated with radial growth and final yields of radish roots. Expression analysis of candidate transcription factor genes revealed that some genes are differentially expressed between inbred lines and that the difference is due to the distinct cytokinin response. Taken together, we have demonstrated for the first time, to the best of our knowledge, that cytokinin-dependent radial growth plays a key role in the yields of root crops.
authors.affiliation: School of Biological Sciences, College of Natural Science, Seoul National University, Seoul 151-747, Korea.
authors.forename: Geupil
authors.initials: G
authors.lastname: Jang
authors.affiliation: School of Biological Sciences, College of Natural Science, Seoul National University, Seoul 151-747, Korea.
authors.forename: Jung-Hun
authors.initials: JH
authors.lastname: Lee
authors.affiliation: School of Biological Sciences, College of Natural Science, Seoul National University, Seoul 151-747, Korea.
authors.forename: Khushboo
authors.initials: K
authors.lastname: Rastogi
authors.affiliation: Department of Horticultural Crop Research, National Institute of Horticultural and Herbal Science, Wanju 565-852, Korea.
authors.forename: Suhyoung
authors.initials: S
authors.lastname: Park
authors.affiliation: Department of Biology, Daejeon University, Daejeon 300-716, Korea.
authors.forename: Sang-Hun
authors.initials: SH
authors.lastname: Oh
authors.affiliation: School of Biological Sciences, College of Natural Science, Seoul National University, Seoul 151-747, Korea jl924@snu.ac.kr.
authors.forename: Ji-Young
authors.identifier: http://orcid.org/0000-0002-7631-5127
authors.initials: JY
authors.lastname: Lee
mesh_terms: D018533:Biomass; D058506:Cambium / Q000166:cytology / Q000235:genetics / Q000254:growth & development; D002455:Cell Division; D003583:Cytokinins / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D018517:Plant Roots / Q000166:cytology / Q000235:genetics / Q000254:growth & development; D031224:Raphanus / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D003583:Cytokinins; D010940:Plant Proteins; D014157:Transcription Factors
keywords: Cambium; Raphanus sativus; cytokinin; root biomass; secondary growth.