title: The proline biosynthetic genes P5CS1 and P5CS2 play overlapping roles in Arabidopsis flower transition but not in embryo development.
abstract: Overexpression of the proline biosynthetic gene P5CS1 results in early flowering in Arabidopsis. However, the p5cs1 loss-of-function mutant exhibits a modest delay in flowering, suggesting that P5CS2, a duplicated P5CS1 gene present in the Arabidopsis, may also play a role in flower transition. In situ mRNA hybridizations and quantitative reverse transcription-polymerase chain reaction (RT-PCR) revealed that P5CS1 and P5CS2 are expressed at similar levels and with the same pattern of expression in vegetative and floral shoot apical meristems as well as in axillary meristems. Arabidopsis lines homozygous for the p5cs1 mutant and simultaneously heterozygous for the p5cs2 mutation showed a stronger late-flowering phenotype than p5cs1 single mutants, confirming that also P5CS2 plays a role in flower transition and supporting the notion of overlapping functions of the two P5CS genes in this developmental process. P5CS1 and P5CS2 have identical messenger RNA (mRNA) distributions also in embryos, but only p5cs2 mutant embryos exhibit alterations of the cellular division planes and consequently stop developing. This suggests a specific role of P5CS2 in embryogenesis and an involvement of proline in cell division. Accordingly, exogenous proline accelerated organ growth and meristem formation, and stimulated expression of the cell cycle-related protein CYCB1;1.
authors.affiliation: Istituto Pasteur Fondazione Cenci Bolognetti, Dipartimento di Genetica e Biologia Molecolare, Università di Roma La Sapienza, P.le Aldo Moro 5, 00185, Roma, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Mattioli
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Falasca
authors.forename: Sabrina
authors.initials: S
authors.lastname: Sabatini
authors.forename: Maria Maddalena
authors.initials: MM
authors.lastname: Altamura
authors.forename: Paolo
authors.initials: P
authors.lastname: Costantino
authors.forename: Maurizio
authors.initials: M
authors.lastname: Trovato
mesh_terms: D017360:Arabidopsis / Q000196:embryology / Q000235:genetics* / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D053898:Biosynthetic Pathways / Q000235:genetics*; D035264:Flowers / Q000235:genetics / Q000502:physiology*; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics; D005816:Genetic Complementation Test; D050698:Glutamate-5-Semialdehyde Dehydrogenase / Q000235:genetics* / Q000378:metabolism; D006720:Homozygote; D017403:In Situ Hybridization; D018519:Meristem / Q000235:genetics; D009097:Multienzyme Complexes / Q000235:genetics* / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D009928:Organ Specificity / Q000235:genetics; D010641:Phenotype; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics* / Q000378:metabolism; D018517:Plant Roots / Q000254:growth & development; D011392:Proline / Q000096:biosynthesis*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D012639:Seeds / Q000235:genetics / Q000254:growth & development*
chemical_list: D029681:Arabidopsis Proteins; D009097:Multienzyme Complexes; D012333:RNA, Messenger; C583835:delta(1)-pyrroline-5-carboxylate synthetase, Arabidopsis; D011392:Proline; D050698:Glutamate-5-Semialdehyde Dehydrogenase; D017853:Phosphotransferases (Alcohol Group Acceptor)