Functional conservation of PISTILLATA activity in a pea homolog lacking the PI motif.
Current understanding of floral development is mainly based on what we know from Arabidopsis (Arabidopsis thaliana) and Antirrhinum majus. However, we can learn more by comparing developmental mechanisms that may explain morphological differences between species. A good example comes from the analysis of genes controlling flower development in pea (Pisum sativum), a plant with more complex leaves and inflorescences than Arabidopsis and Antirrhinum, and a different floral ontogeny. The analysis of UNIFOLIATA (UNI) and STAMINA PISTILLOIDA (STP), the pea orthologs of LEAFY and UNUSUAL FLORAL ORGANS, has revealed a common link in the regulation of flower and leaf development not apparent in Arabidopsis. While the Arabidopsis genes mainly behave as key regulators of flower development, where they control the expression of B-function genes, UNI and STP also contribute to the development of the pea compound leaf. Here, we describe the characterization of P. sativum PISTILLATA (PsPI), a pea MADS-box gene homologous to B-function genes like PI and GLOBOSA (GLO), from Arabidopsis and Antirrhinum, respectively. PsPI encodes for an atypical PI-type polypeptide that lacks the highly conserved C-terminal PI motif. Nevertheless, constitutive expression of PsPI in tobacco (Nicotiana tabacum) and Arabidopsis shows that it can specifically replace the function of PI, being able to complement the strong pi-1 mutant. Accordingly, PsPI expression in pea flowers, which is dependent on STP, is identical to PI and GLO. Interestingly, PsPI is also transiently expressed in young leaves, suggesting a role of PsPI in pea leaf development, a possibility that fits with the established role of UNI and STP in the control of this process.
Berbel
Ana
A
Departamento de Biología del Desarrollo, Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Científicas, Campus de la Universidad Politécnica de Valencia, Spain.
Navarro
Cristina
C
Ferrándiz
Cristina
C
Cañas
Luis Antonio
LA
Beltrán
José-Pío
JP
Madueño
Francisco
F
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D029681:Arabidopsis Proteins / Q000737:chemistry*; D017124:Conserved Sequence; D035264:Flowers / Q000235:genetics / Q000254:growth & development / Q000648:ultrastructure; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D026161:MADS Domain Proteins / Q000737:chemistry*; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D018532:Pisum sativum / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D010802:Phylogeny; D018515:Plant Leaves / Q000235:genetics; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics / Q000502:physiology*; D030821:Plants, Genetically Modified; D017386:Sequence Homology, Amino Acid; D014026:Nicotiana / Q000235:genetics
D029681:Arabidopsis Proteins; D026161:MADS Domain Proteins; C090225:PISTILLATA protein, Arabidopsis; D010940:Plant Proteins