Mutations in the pale aleurone color1 regulatory gene of the Zea mays anthocyanin pathway have distinct phenotypes relative to the functionally similar TRANSPARENT TESTA GLABRA1 gene in Arabidopsis thaliana.
The pale aleurone color1 (pac1) locus, required for anthocyanin pigment in the aleurone and scutellum of the Zea mays (maize) seed, was cloned using Mutator transposon tagging. pac1 encodes a WD40 repeat protein closely related to anthocyanin regulatory proteins ANTHOCYANIN11 (AN11) (Petunia hybrida [petunia]) and TRANSPARENT TESTA GLABRA1 (TTG1) (Arabidopsis thaliana). Introduction of a 35S-Pac1 transgene into A. thaliana complemented multiple ttg1 mutant phenotypes, including ones nonexistent in Z. mays. Hybridization of Z. mays genomic BAC clones with the pac1 sequence identified an additional related gene, mp1. PAC1 and MP1 deduced protein sequences were used as queries to build a phylogenetic tree of homologous WD40 repeat proteins, revealing an ancestral gene duplication leading to two clades in plants, the PAC1 clade and the MP1 clade. Subsequent duplications within each clade have led to additional WD40 repeat proteins in particular species, with all mutants defective in anthocyanin expression contained in the PAC1 clade. Substantial differences in pac1, an11, and ttg1 mutant phenotypes suggest the evolutionary divergence of regulatory mechanisms for several traits that cannot be ascribed solely to divergence of the dicot and monocot protein sequences.
Carey
Charles C
CC
Department of Plant Sciences, University of Arizona, Tucson, Arizona 85721, USA. chandler@ag.arizona.edu
Strahle
Josie T
JT
Selinger
David A
DA
Chandler
Vicki L
VL
D000483:Alleles; D000595:Amino Acid Sequence; D000872:Anthocyanins / Q000378:metabolism*; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D022081:Cell Surface Extensions / Q000235:genetics / Q000502:physiology; D004251:DNA Transposable Elements / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020449:Repetitive Sequences, Amino Acid / Q000235:genetics / Q000502:physiology; D012639:Seeds / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D003313:Zea mays / Q000235:genetics* / Q000378:metabolism
D000872:Anthocyanins; D029681:Arabidopsis Proteins; D004251:DNA Transposable Elements; D010940:Plant Proteins; D012333:RNA, Messenger; C121067:TTG1 protein, Arabidopsis