title: Gibberellin-Regulation and Genetic Variations in Leaf Elongation for Tall Fescue in Association with Differential Gene Expression Controlling Cell Expansion.
abstract: Leaf elongation rate (LER) is an important factor controlling plant growth and productivity. The objective of this study was to determine whether genetic variation in LER for a fast-growing ('K-31'), and a dwarf cultivar ('Bonsai') of tall fescue (Festuca arundinacea) and gibberellic acid (GA) regulation of LER were associated with differential expression of cell-expansion genes. Plants were treated with GA3, trinexapac-ethyl (TE) (GA inhibitor), or water (untreated control) in a hydroponic system. LER of 'K-31' was 63% greater than that of 'Bonsai', which corresponded with 32% higher endogenous GA4 content in leaf and greater cell elongation and production rates under the untreated control condition. Exogenous application of GA3 significantly enhanced LER while TE treatment inhibited leaf elongation due to GA3-stimulation or TE-inhibition of cell elongation and production rate in leaves for both cultivars. Real-time quantitative polymerase chain reaction analysis revealed that three α-expansins, one β-expansin, and three xyloglucan endotransglycosylase (XET) genes were associated with GA-stimulation of leaf elongation, of which, the differential expression of EXPA4 and EXPA7 was related to the genotypic variation in LER of two cultivars. Those differentially-expressed expansin and XET genes could play major roles in genetic variation and GA-regulated leaf elongation in tall fescue.
authors.affiliation: National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China.|Department of Plant Biology and Pathology, Rutgers University, New Brunswick, NJ, 08901, United States of America.
authors.forename: Qian
authors.initials: Q
authors.lastname: Xu
authors.affiliation: Department of Crop Science, Michigan State University, East Lansing, MI, 48824, United States of America.
authors.forename: Sanalkumar
authors.initials: S
authors.lastname: Krishnan
authors.affiliation: Department of Crop Science, Michigan State University, East Lansing, MI, 48824, United States of America.
authors.forename: Emily
authors.initials: E
authors.lastname: Merewitz
authors.affiliation: National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China.
authors.forename: Jichen
authors.initials: J
authors.lastname: Xu
authors.affiliation: Department of Plant Biology and Pathology, Rutgers University, New Brunswick, NJ, 08901, United States of America.
authors.forename: Bingru
authors.initials: B
authors.lastname: Huang
mesh_terms: D031751:Festuca / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005838:Genotype; D005875:Gibberellins / Q000037:antagonists & inhibitors / Q000494:pharmacology; D016695:Glycosyltransferases / Q000235:genetics*; D006899:Mixed Function Oxygenases / Q000235:genetics; D018515:Plant Leaves / Q000187:drug effects / Q000254:growth & development*; D010940:Plant Proteins / Q000235:genetics*
chemical_list: D005875:Gibberellins; D010940:Plant Proteins; C095825:expansin protein, plant; C007842:gibberellic acid; D006899:Mixed Function Oxygenases; C121463:gibberellin 2-dioxygenase; D016695:Glycosyltransferases; C073693:xyloglucan endotransglycosylase