Pleiotropic physiological consequences of feedback-insensitive phenylalanine biosynthesis in Arabidopsis thaliana.
A large proportion of plant carbon flow passes through the shikimate pathway to phenylalanine, which serves as a precursor for numerous secondary metabolites. To identify new regulatory mechanisms affecting phenylalanine metabolism, we isolated Arabidopsis thaliana mutants that are resistant to the phytotoxic amino acid m-tyrosine, a structural analog of phenylalanine. Map-based cloning identified adt2-1D, a dominant point mutation causing a predicted serine to alanine change in the regulatory domain of ADT2 (arogenate dehydratase 2). Relaxed feedback inhibition and increased expression of the mutant enzyme caused up to 160-fold higher accumulation of free phenylalanine in rosette leaves, as well as altered accumulation of several other primary and secondary metabolites. In particular, abundance of 2-phenylethylglucosinolate, which is normally almost undetectable in leaves of the A. thaliana Columbia-0 accession, is increased more than 30-fold. Other observed phenotypes of the adt2-1D mutant include abnormal leaf development, resistance to 5-methyltryptophan, reduced growth of the generalist lepidopteran herbivore Trichoplusia ni (cabbage looper) and increased salt tolerance.
Huang
Tengfang
T
Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, USA.
Tohge
Takayuki
T
Lytovchenko
Anna
A
Fernie
Alisdair R
AR
Jander
Georg
G
D000818:Animals; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism* / Q000469:parasitology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D055162:Biocatalysis / Q000187:drug effects; D053898:Biosynthetic Pathways; D004351:Drug Resistance / Q000235:genetics; D025461:Feedback, Physiological / Q000502:physiology; D005961:Glucosinolates / Q000378:metabolism; D006790:Host-Parasite Interactions; D006836:Hydro-Lyases / Q000235:genetics / Q000378:metabolism*; D007113:Immunity, Innate / Q000235:genetics; D015394:Molecular Structure; D009036:Moths / Q000502:physiology; D009154:Mutation; D010649:Phenylalanine / Q000096:biosynthesis* / Q000737:chemistry / Q000494:pharmacology; D010935:Plant Diseases / Q000235:genetics / Q000469:parasitology; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism / Q000469:parasitology; D030821:Plants, Genetically Modified; D055049:Salt Tolerance / Q000235:genetics; D014364:Tryptophan / Q000031:analogs & derivatives / Q000494:pharmacology; D014443:Tyrosine / Q000494:pharmacology
D029681:Arabidopsis Proteins; D005961:Glucosinolates; C004182:5-methyltryptophan; D014443:Tyrosine; D010649:Phenylalanine; D014364:Tryptophan; C015566:3-tyrosine; D006836:Hydro-Lyases; C022437:pretyrosine dehydratase