yucca6, a dominant mutation in Arabidopsis, affects auxin accumulation and auxin-related phenotypes.
Auxin plays critical roles in many aspects of plant growth and development. Although a number of auxin biosynthetic pathways have been identified, their overlapping nature has prevented a clear elucidation of auxin biosynthesis. Recently, Arabidopsis (Arabidopsis thaliana) mutants with supernormal auxin phenotypes have been reported. These mutants exhibit hyperactivation of genes belonging to the YUCCA family, encoding putative flavin monooxygenase enzymes that result in increased endogenous auxin levels. Here, we report the discovery of fertile dominant Arabidopsis hypertall1-1D and hypertall1-2D (yucca6-1D, -2D) mutants that exhibit typical auxin overproduction phenotypic alterations, such as epinastic cotyledons, increased apical dominance, and curled leaves. However, unlike other auxin overproduction mutants, yucca6 plants do not display short or hairy root phenotypes and lack morphological changes under dark conditions. In addition, yucca6-1D and yucca6-2D have extremely tall (>1 m) inflorescences with extreme apical dominance and twisted cauline leaves. Microarray analyses revealed that expression of several indole-3-acetic acid-inducible genes, including Aux/IAA, SMALL AUXIN-UP RNA, and GH3, is severalfold higher in yucca6 mutants than in the wild type. Tryptophan (Trp) analog feeding experiments and catalytic activity assays with recombinant YUCCA6 indicate that YUCCA6 is involved in a Trp-dependent auxin biosynthesis pathway. YUCCA6:GREEN FLUORESCENT PROTEIN fusion protein indicates YUCCA6 protein exhibits a nonplastidial subcellular localization in an unidentified intracellular compartment. Taken together, our results identify YUCCA6 as a functional member of the YUCCA family with unique roles in growth and development.
Kim
Jeong Im
JI
Center for Plant Environmental Stress Physiology , Purdue University, West Lafayette, Indiana 47906-2010, USA.
Sharkhuu
Altanbadralt
A
Jin
Jing Bo
JB
Li
Pinghua
P
Jeong
Jae Cheol
JC
Baek
Dongwon
D
Lee
Sang Yeol
SY
Blakeslee
Joshua J
JJ
Murphy
Angus S
AS
Bohnert
Hans J
HJ
Hasegawa
Paul M
PM
Yun
Dae-Jin
DJ
Bressan
Ray A
RA
D000483:Alleles; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D035264:Flowers / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D005799:Genes, Dominant / Q000235:genetics; D007210:Indoleacetic Acids / Q000378:metabolism*; D005810:Multigene Family; D016254:Mutagenesis, Insertional; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D018515:Plant Leaves / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism
D029681:Arabidopsis Proteins; D004269:DNA, Bacterial; D018744:DNA, Plant; D007210:Indoleacetic Acids; C036483:T-DNA; C030737:indoleacetic acid