Mosaic analysis of the liguleless3 mutant phenotype in maize by coordinate suppression of mutator-insertion alleles.
Liguleless3-O (Lg3-O) transforms the leaf blade, auricle and ligule into sheath around the midrib region. We conducted a genetic mosaic analysis of the Lg3 phenotype to determine the site of Lg3 gene action. Combining the Mutator (Mu) suppressible Lg3-Or211 and a1-mum2 alleles in a Mu-active background generated a stock wherein somatic loss of Mu activity resulted in anthocyanin-marked clonal sectors expressing Lg3 in the leaf. Lg3-Or211 plants appear wild type in a Mu-active line, but Mu-inactive plants express a severe Lg3 phenotype. We observed four sector classes: wild type, sheath-like with ligule displacement, sheath-like with ectopic ligule, and auricle-like. The mutation does not cause transformation to a specific cell or regional identity. Lg3-Or211 activity in the mesophyll alters wild-type epidermal cell fates; activity in epidermis seems functionless. Lg3 mutant activity has a nonautonomous, cell-layer-specific function in the transverse dimension. In the lateral dimension, sectors of Lg3 mutant phenotype can exhibit either cell-autonomous or nonautonomous effects. Our work demonstrates that mosaic analysis by coordinate suppression of Mu-induced alleles is useful for analyzing the cell autonomy of genetically defined functions.
Fowler
J E
JE
Department of Plant Biology, University of California, Berkeley 94720, USA.
Muehlbauer
G J
GJ
Freeling
M
M
D000483:Alleles; D003433:Crosses, Genetic; D004251:DNA Transposable Elements; D017343:Genes, Plant; D006720:Homozygote; D009030:Mosaicism; D016254:Mutagenesis, Insertional; D009154:Mutation; D010641:Phenotype; D018515:Plant Leaves; D013489:Suppression, Genetic; D003313:Zea mays / Q000235:genetics*
D004251:DNA Transposable Elements