title: The MADS-Domain Factors AGAMOUS-LIKE15 and AGAMOUS-LIKE18, along with SHORT VEGETATIVE PHASE and AGAMOUS-LIKE24, Are Necessary to Block Floral Gene Expression during the Vegetative Phase.
abstract: Multiple factors, including the MADS-domain proteins AGAMOUS-LIKE15 (AGL15) and AGL18, contribute to the regulation of the transition from vegetative to reproductive growth. AGL15 and AGL18 were previously shown to act redundantly as floral repressors and upstream of FLOWERING LOCUS T (FT) in Arabidopsis (Arabidopsis thaliana). A series of genetic and molecular experiments, primarily focused on AGL15, was performed to more clearly define their role. agl15 agl18 mutations fail to suppress ft mutations but show additive interactions with short vegetative phase (svp) mutations in ft and suppressor of constans1 (soc1) backgrounds. Chromatin immunoprecipitation analyses with AGL15-specific antibodies indicate that AGL15 binds directly to the FT locus at sites that partially overlap those bound by SVP and FLOWERING LOCUS C. In addition, expression of AGL15 in the phloem effectively restores wild-type flowering times in agl15 agl18 mutants. When agl15 agl18 mutations are combined with agl24 svp mutations, the plants show upward curling of rosette and cauline leaves, in addition to early flowering. The change in leaf morphology is associated with elevated levels of FT and ectopic expression of SEPALLATA3 (SEP3), leading to ectopic expression of floral genes. Leaf curling is suppressed by sep3 and ft mutations and enhanced by soc1 mutations. Thus, AGL15 and AGL18, along with SVP and AGL24, are necessary to block initiation of floral programs in vegetative organs.
authors.affiliation: Department of Botany, University of Wisconsin, Madison, Wisconsin 53706 (D.E.F., C.-T.W., B.J.A., R.S., P.K.H.); andDepartment of Plant and Soil Sciences, University of Kentucky, Lexington, Kentucky 40546 (Y.Z., S.E.P.) dfernand@wisc.edu.
authors.forename: Donna E
authors.initials: DE
authors.lastname: Fernandez
authors.affiliation: Department of Botany, University of Wisconsin, Madison, Wisconsin 53706 (D.E.F., C.-T.W., B.J.A., R.S., P.K.H.); andDepartment of Plant and Soil Sciences, University of Kentucky, Lexington, Kentucky 40546 (Y.Z., S.E.P.).
authors.forename: Chieh-Ting
authors.initials: CT
authors.lastname: Wang
authors.affiliation: Department of Botany, University of Wisconsin, Madison, Wisconsin 53706 (D.E.F., C.-T.W., B.J.A., R.S., P.K.H.); andDepartment of Plant and Soil Sciences, University of Kentucky, Lexington, Kentucky 40546 (Y.Z., S.E.P.).
authors.forename: Yumei
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: Department of Botany, University of Wisconsin, Madison, Wisconsin 53706 (D.E.F., C.-T.W., B.J.A., R.S., P.K.H.); andDepartment of Plant and Soil Sciences, University of Kentucky, Lexington, Kentucky 40546 (Y.Z., S.E.P.).
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Adamczyk
authors.affiliation: Department of Botany, University of Wisconsin, Madison, Wisconsin 53706 (D.E.F., C.-T.W., B.J.A., R.S., P.K.H.); andDepartment of Plant and Soil Sciences, University of Kentucky, Lexington, Kentucky 40546 (Y.Z., S.E.P.).
authors.forename: Rajneesh
authors.initials: R
authors.lastname: Singhal
authors.affiliation: Department of Botany, University of Wisconsin, Madison, Wisconsin 53706 (D.E.F., C.-T.W., B.J.A., R.S., P.K.H.); andDepartment of Plant and Soil Sciences, University of Kentucky, Lexington, Kentucky 40546 (Y.Z., S.E.P.).
authors.forename: Pamela K
authors.initials: PK
authors.lastname: Hall
authors.affiliation: Department of Botany, University of Wisconsin, Madison, Wisconsin 53706 (D.E.F., C.-T.W., B.J.A., R.S., P.K.H.); andDepartment of Plant and Soil Sciences, University of Kentucky, Lexington, Kentucky 40546 (Y.Z., S.E.P.).
authors.forename: Sharyn E
authors.initials: SE
authors.lastname: Perry