nana plant2 Encodes a Maize Ortholog of the Arabidopsis Brassinosteroid Biosynthesis Gene DWARF1, Identifying Developmental Interactions between Brassinosteroids and Gibberellins.
A small number of phytohormones dictate the pattern of plant form affecting fitness via reproductive architecture and the plant's ability to forage for light, water, and nutrients. Individual phytohormone contributions to plant architecture have been studied extensively, often following a single component of plant architecture, such as plant height or branching. Both brassinosteroid (BR) and gibberellin (GA) affect plant height, branching, and sexual organ development in maize (Zea mays). We identified the molecular basis of the nana plant2 (na2) phenotype as a loss-of-function mutation in one of the two maize paralogs of the Arabidopsis (Arabidopsis thaliana) BR biosynthetic gene DWARF1 (DWF1). These mutants accumulate the DWF1 substrate 24-methylenecholesterol and exhibit decreased levels of downstream BR metabolites. We utilized this mutant and known GA biosynthetic mutants to investigate the genetic interactions between BR and GA. Double mutants exhibited additivity for some phenotypes and epistasis for others with no unifying pattern, indicating that BR and GA interact to affect development but in a context-dependent manner. Similar results were observed in double mutant analyses using additional BR and GA biosynthetic mutant loci. Thus, the BR and GA interactions were neither locus nor allele specific. Exogenous application of GA3 to na2 and d5, a GA biosynthetic mutant, also resulted in a diverse pattern of growth responses, including BR-dependent GA responses. These findings demonstrate that BR and GA do not interact via a single inclusive pathway in maize but rather suggest that differential signal transduction and downstream responses are affected dependent upon the developmental context.
Department of Horticulture and Landscape Architecture (N.B.B., T.H., J.B., B.S.), Department of Biochemistry (N.B.B., B.P.D.), and Department of Botany and Plant Pathology (G.J.), Purdue University, West Lafayette, Indiana 47907; and RIKEN Center for Sustainable Resource Science, Wako-shi, Saitama 351-0198, Japan (S.F.).
Norman B
0000-0002-6572-5999
NB
Best
Department of Horticulture and Landscape Architecture (N.B.B., T.H., J.B., B.S.), Department of Biochemistry (N.B.B., B.P.D.), and Department of Botany and Plant Pathology (G.J.), Purdue University, West Lafayette, Indiana 47907; and RIKEN Center for Sustainable Resource Science, Wako-shi, Saitama 351-0198, Japan (S.F.).
Thomas
0000-0002-2707-2771
T
Hartwig
Department of Horticulture and Landscape Architecture (N.B.B., T.H., J.B., B.S.), Department of Biochemistry (N.B.B., B.P.D.), and Department of Botany and Plant Pathology (G.J.), Purdue University, West Lafayette, Indiana 47907; and RIKEN Center for Sustainable Resource Science, Wako-shi, Saitama 351-0198, Japan (S.F.).
Josh
J
Budka
Department of Horticulture and Landscape Architecture (N.B.B., T.H., J.B., B.S.), Department of Biochemistry (N.B.B., B.P.D.), and Department of Botany and Plant Pathology (G.J.), Purdue University, West Lafayette, Indiana 47907; and RIKEN Center for Sustainable Resource Science, Wako-shi, Saitama 351-0198, Japan (S.F.).
Shozo
S
Fujioka
Department of Horticulture and Landscape Architecture (N.B.B., T.H., J.B., B.S.), Department of Biochemistry (N.B.B., B.P.D.), and Department of Botany and Plant Pathology (G.J.), Purdue University, West Lafayette, Indiana 47907; and RIKEN Center for Sustainable Resource Science, Wako-shi, Saitama 351-0198, Japan (S.F.).
Gurmukh
G
Johal
Department of Horticulture and Landscape Architecture (N.B.B., T.H., J.B., B.S.), Department of Biochemistry (N.B.B., B.P.D.), and Department of Botany and Plant Pathology (G.J.), Purdue University, West Lafayette, Indiana 47907; and RIKEN Center for Sustainable Resource Science, Wako-shi, Saitama 351-0198, Japan (S.F.) bschulz1@umd.edu bdilkes@purdue.edu.
Burkhard
0000-0001-5291-2763
B
Schulz
Department of Horticulture and Landscape Architecture (N.B.B., T.H., J.B., B.S.), Department of Biochemistry (N.B.B., B.P.D.), and Department of Botany and Plant Pathology (G.J.), Purdue University, West Lafayette, Indiana 47907; and RIKEN Center for Sustainable Resource Science, Wako-shi, Saitama 351-0198, Japan (S.F.) bschulz1@umd.edu bdilkes@purdue.edu.
Brian P
0000-0003-2799-954X
BP
Dilkes
D000483:Alleles; D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics*; D053898:Biosynthetic Pathways / Q000235:genetics; D060406:Brassinosteroids / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D056426:Genetic Loci; D005875:Gibberellins / Q000378:metabolism*; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D010088:Oxidoreductases / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D003313:Zea mays / Q000235:genetics* / Q000254:growth & development*
D029681:Arabidopsis Proteins; D060406:Brassinosteroids; C091574:DIM1 protein, Arabidopsis; D005875:Gibberellins; D010940:Plant Proteins; D012333:RNA, Messenger; D010088:Oxidoreductases; C022673:delta 24-sterol reductase