Modulation of intracellular proline levels affects flowering time and inflorescence architecture in Arabidopsis.
We reported previously that the plant oncogene rolD anticipates and stimulates flowering in Nicotiana tabacum, and encodes ornithine cyclodeaminase, an enzyme catalysing the conversion of ornithine to proline. To investigate on the possible role of proline in flowering, we altered the expression of AtP5CS1, encoding the rate-limiting enzyme of proline biosynthesis in plants. Accordingly we characterized a mutant line containing a T-DNA insertion into AtP5CS1 and introduced in Arabidopsis thaliana AtP5CS1 under the control of the CaMV35S promoter. As expected homozygous p5cs1 mutants behaved as late flowering. In addition p5cs1 mutants exhibited a shorter size and contained lower levels of proline, compared to wild type. 35S-P5CS1 plants, manifested, early in development, overexpression of P5CS1 and accumulation of proline, leading to early flowering, both under long- and short-day conditions. Later in development, down-regulation of P5CS1 occurred in 35S-P5CS1 leaves, leading to proline reduction, and, in turn, impaired bolting and stunted growth. Salt-stress restored expression of P5CS1 and proline accumulation in P5CS1-transformed plants, as well as rescuing growth. Our data suggest that proline plays a key role in flower transition, bolting and coflorescence formation.
Mattioli
Roberto
R
Istituto Pasteur Fondazione Cenci Bolognetti, Dipartimento di Genetica e Biologia Molecolare, Università di Roma La Sapienza, P.le Aldo Moro 5, Rome 00185, Italy.
Marchese
Daniele
D
D'Angeli
Simone
S
Altamura
Maria Maddalena
MM
Costantino
Paolo
P
Trovato
Maurizio
M
D050842:1-Pyrroline-5-Carboxylate Dehydrogenase / Q000235:genetics / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D035264:Flowers / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D042541:Intracellular Space / Q000378:metabolism; D009154:Mutation; D009953:Ornithine-Oxo-Acid Transaminase / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011392:Proline / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012965:Sodium Chloride / Q000494:pharmacology; D013997:Time Factors
D029681:Arabidopsis Proteins; D012333:RNA, Messenger; D012965:Sodium Chloride; D011392:Proline; D050842:1-Pyrroline-5-Carboxylate Dehydrogenase; D009953:Ornithine-Oxo-Acid Transaminase