title: SUPPRESSOR OF PHYTOCHROME B4-#3 Represses Genes Associated with Auxin Signaling to Modulate Hypocotyl Growth.
abstract: Developing seedlings are well equipped to alter their growth in response to external factors in order to maximize their chances of survival. SUPPRESSOR OF PHYTOCHROME B4-#3 (SOB3) and other members of the AT-HOOK MOTIF CONTAINING NUCLEAR LOCALIZED (AHL) family of transcription factors modulate the development of Arabidopsis (Arabidopsis thaliana) by repressing hypocotyl elongation in young seedlings growing in light. However, the molecular mechanism behind how AHLs influence seedling development is largely unknown. We have identified genes associated with auxin-mediated hypocotyl elongation as downstream targets of SOB3. We found that YUCCA8 (YUC8) as well as members of the SMALL AUXIN UP-REGULATED RNA19 (SAUR19) subfamily were down-regulated in the short-hypocotyl, gain-of-function SOB3-D mutant and up-regulated in the dominant-negative, tall-hypocotyl sob3-6 mutant. SOB3-D and sob3-6 hypocotyls also exhibited altered sensitivity to the polar auxin transport inhibitor N-1-napthylphthalamic acid, suggesting a critical connection between auxin and the modulation of seedling elongation by SOB3 Finally, we found that overexpression of GREEN FLUORESCENT PROTEIN-SAUR19 in the SOB3-D line partially rescued defects in hypocotyl elongation, and SOB3 bound directly to the promoters of YUC8 and SAUR19 subfamily members. Taken together, these data indicate that SOB3 modulates hypocotyl elongation in young seedlings by directly repressing the transcription of genes associated with auxin signaling.
authors.affiliation: Molecular Plant Sciences Graduate Program (D.S.F., C.N.J., K.N.L., J.Z., M.M.N.) and Department of Crop and Soil Sciences (D.S.F., C.N.J., J.Z., M.M.N.), Washington State University, Pullman, Washington 99164; andRIKEN Center for Sustainable Resource Science, Tsurumi, Yokohama, Kanagawa 230-0045, Japan (A.I., K.S.).
authors.forename: David S
authors.identifier: 0000-0002-6879-0323
authors.initials: DS
authors.lastname: Favero
authors.affiliation: Molecular Plant Sciences Graduate Program (D.S.F., C.N.J., K.N.L., J.Z., M.M.N.) and Department of Crop and Soil Sciences (D.S.F., C.N.J., J.Z., M.M.N.), Washington State University, Pullman, Washington 99164; andRIKEN Center for Sustainable Resource Science, Tsurumi, Yokohama, Kanagawa 230-0045, Japan (A.I., K.S.).
authors.forename: Caitlin N
authors.identifier: 0000-0002-7259-4237
authors.initials: CN
authors.lastname: Jacques
authors.affiliation: Molecular Plant Sciences Graduate Program (D.S.F., C.N.J., K.N.L., J.Z., M.M.N.) and Department of Crop and Soil Sciences (D.S.F., C.N.J., J.Z., M.M.N.), Washington State University, Pullman, Washington 99164; andRIKEN Center for Sustainable Resource Science, Tsurumi, Yokohama, Kanagawa 230-0045, Japan (A.I., K.S.).
authors.forename: Akira
authors.initials: A
authors.lastname: Iwase
authors.affiliation: Molecular Plant Sciences Graduate Program (D.S.F., C.N.J., K.N.L., J.Z., M.M.N.) and Department of Crop and Soil Sciences (D.S.F., C.N.J., J.Z., M.M.N.), Washington State University, Pullman, Washington 99164; andRIKEN Center for Sustainable Resource Science, Tsurumi, Yokohama, Kanagawa 230-0045, Japan (A.I., K.S.).
authors.forename: Kimberly Ngan
authors.identifier: 0000-0002-1053-6445
authors.initials: KN
authors.lastname: Le
authors.affiliation: Molecular Plant Sciences Graduate Program (D.S.F., C.N.J., K.N.L., J.Z., M.M.N.) and Department of Crop and Soil Sciences (D.S.F., C.N.J., J.Z., M.M.N.), Washington State University, Pullman, Washington 99164; andRIKEN Center for Sustainable Resource Science, Tsurumi, Yokohama, Kanagawa 230-0045, Japan (A.I., K.S.).
authors.forename: Jianfei
authors.identifier: 0000-0002-7684-9575
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Molecular Plant Sciences Graduate Program (D.S.F., C.N.J., K.N.L., J.Z., M.M.N.) and Department of Crop and Soil Sciences (D.S.F., C.N.J., J.Z., M.M.N.), Washington State University, Pullman, Washington 99164; andRIKEN Center for Sustainable Resource Science, Tsurumi, Yokohama, Kanagawa 230-0045, Japan (A.I., K.S.).
authors.forename: Keiko
authors.identifier: 0000-0002-9209-8230
authors.initials: K
authors.lastname: Sugimoto
authors.affiliation: Molecular Plant Sciences Graduate Program (D.S.F., C.N.J., K.N.L., J.Z., M.M.N.) and Department of Crop and Soil Sciences (D.S.F., C.N.J., J.Z., M.M.N.), Washington State University, Pullman, Washington 99164; andRIKEN Center for Sustainable Resource Science, Tsurumi, Yokohama, Kanagawa 230-0045, Japan (A.I., K.S.) mmneff@wsu.edu.
authors.forename: Michael M
authors.identifier: 0000-0003-2170-5555
authors.initials: MM
authors.lastname: Neff
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D049452:Green Fluorescent Proteins / Q000378:metabolism; D018546:Hypocotyl / Q000235:genetics / Q000254:growth & development*; D007210:Indoleacetic Acids / Q000378:metabolism*; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics; D013696:Temperature
chemical_list: D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; D007210:Indoleacetic Acids; D012097:Repressor Proteins; C528618:SOB3 protein, Arabidopsis; D049452:Green Fluorescent Proteins