A paramutation phenomenon is involved in the genetics of maize low phytic acid1-241 (lpa1-241) trait.
So far, in maize, three classes of mutants involved in phytic acid biosynthesis have been isolated: lpa1, lpa2 and lpa3. In 2007, a gene tagging experiment performed by Shi et al. found that mutations in ZmMRP4 (multidrug resistance-associated proteins 4) gene cause lpa1 phenotype. In previous studies, we isolated and described a single recessive lpa mutation (originally named lpa241), which was allelic to the lpa1-1 mutant, and was consequently renamed lpa1-241. It showed a decrease in the expression of the myo-inositol (Ins)-3-phosphate synthase gene (mips1S). In this study, we present genetic and molecular analyses of the lpa1-241 mutation that indicate an epigenetic origin of this trait, that is, a paramutagenic interaction that results in meiotically heritable changes in ZmMRP4 gene expression, causing a strong pleiotropic effect on the whole plant. The use of a 5-Azacytidine treatment provided data suggesting an association between gene methylation and the lpa1-241 phenotype. To our knowledge, this is the first report of a paramutagenic activity not involving flavonoid biosynthesis in maize, but regarding a key enzyme of an important metabolic pathway in plants.
Pilu
R
R
Dipartimento di Produzione Vegetale, Università degli Studi di Milano, Via celoria 2, Milan, Italy. salvatore.pilu@unimi.it
Panzeri
D
D
Cassani
E
E
Cerino Badone
F
F
Landoni
M
M
Nielsen
E
E
D001374:Azacitidine / Q000494:pharmacology; D019175:DNA Methylation; D018506:Gene Expression Regulation, Plant; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D010641:Phenotype; D010833:Phytic Acid / Q000096:biosynthesis*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D019655:Quantitative Trait, Heritable; D003313:Zea mays / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism
D001374:Azacitidine; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D010833:Phytic Acid; D010940:Plant Proteins