title: A synthetic auxin (NAA) suppresses secondary wall cellulose synthesis and enhances elongation in cultured cotton fiber.
abstract: Use of a synthetic auxin (naphthalene-1-acetic acid, NAA) to start (Gossypium hirsutum) ovule/fiber cultures hindered fiber secondary wall cellulose synthesis compared with natural auxin (indole-3-acetic acid, IAA). In contrast, NAA promoted fiber elongation and ovule weight gain, which resulted in larger ovule/fiber units. To reach these conclusions, fiber and ovule growth parameters were measured and cell wall characteristics were examined microscopically. The differences in fiber from NAA and IAA culture were underpinned by changes in the expression patterns of marker genes for three fiber developmental stages (elongation, the transition stage, and secondary wall deposition), and these gene expression patterns were also analyzed quantitatively in plant-grown fiber. The results demonstrate that secondary wall cellulose synthesis: (1) is under strong transcriptional control that is influenced by auxin; and (2) must be specifically characterized in the cotton ovule/fiber culture system given the many protocol variables employed in different laboratories.
authors.affiliation: Department of Crop Science, North Carolina State University, Campus Box 7620, Raleigh, NC 27695, USA.
authors.forename: Bir
authors.initials: B
authors.lastname: Singh
authors.forename: Hannah D
authors.initials: HD
authors.lastname: Cheek
authors.forename: Candace H
authors.initials: CH
authors.lastname: Haigler
mesh_terms: D002473:Cell Wall / Q000378:metabolism*; D002482:Cellulose / Q000096:biosynthesis*; D032561:Cotton Fiber; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D003368:Gossypium / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D007210:Indoleacetic Acids / Q000378:metabolism*; D009280:Naphthaleneacetic Acids / Q000378:metabolism; D010937:Plant Growth Regulators / Q000378:metabolism; D012639:Seeds / Q000254:growth & development / Q000378:metabolism
chemical_list: D007210:Indoleacetic Acids; D009280:Naphthaleneacetic Acids; D010937:Plant Growth Regulators; C034182:1-naphthaleneacetic acid; D002482:Cellulose