The CELL NUMBER REGULATOR FW2.2 protein regulates cell-to-cell communication in tomato by modulating callose deposition at plasmodesmata.

FW2.2 (standing for FRUIT WEIGHT 2.2), the founding member of the CELL NUMBER REGULATOR (CNR) gene family, was the first cloned gene underlying a quantitative trait locus (QTL) governing fruit size and weight in tomato (Solanum lycopersicum).

In search of the still unknown function of FW2.2/CELL NUMBER REGULATOR, a major regulator of fruit size in tomato.

The FW2.2 gene is associated with the major quantitative trait locus (QTL) governing fruit size in tomato, and acts by negatively controlling cell division during fruit development. FW2.

The Tomato Guanylate-Binding Protein SlGBP1 Enables Fruit Tissue Differentiation by Maintaining Endopolyploid Cells in a Non-Proliferative State.

Cell fate maintenance is an integral part of plant cell differentiation and the production of functional cells, tissues, and organs. Fleshy fruit development is characterized by the accumulation of water and solutes in the enlarging cells of parenchymatous tissues. In tomato (), this process is associated with endoreduplication in mesocarp cells.

At-MINI ZINC FINGER2 and Sl-INHIBITOR OF MERISTEM ACTIVITY, a Conserved Missing Link in the Regulation of Floral Meristem Termination in Arabidopsis and Tomato.

In angiosperms, the gynoecium is the last structure to develop within the flower due to the determinate fate of floral meristem (FM) stem cells. The maintenance of stem cell activity before its arrest at the stage called FM termination affects the number of carpels that develop. The necessary inhibition at this stage of (), which is responsible for stem cell maintenance, involves a two-step mechanism.

Transcriptome profiling of sorted endoreduplicated nuclei from tomato fruits: how the global shift in expression ascribed to DNA ploidy influences RNA-Seq data normalization and interpretation.

As part of normal development most eukaryotic organisms, ranging from insects and mammals to plants, display variations in nuclear ploidy levels resulting from somatic endopolyploidy. Endoreduplication is the major source of endopolyploidy in higher plants. Endoreduplication is a remarkable characteristic of the fleshy pericarp tissue of developing tomato fruits, where it establishes a highly integrated cellular system that acts as a morphogenetic factor supporting cell growth.

Dealing with paralogy in RADseq data: in silico detection and single nucleotide polymorphism validation in L.

The RADseq technology allows researchers to efficiently develop thousands of polymorphic loci across multiple individuals with little or no prior information on the genome. However, many questions remain about the biases inherent to this technology. Notably, sequence misalignments arising from paralogy may affect the development of single nucleotide polymorphism (SNP) markers and the estimation of genetic diversity.

Identification of Two New Mechanisms That Regulate Fruit Growth by Cell Expansion in Tomato.

Key mechanisms controlling fruit weight and shape at the levels of meristem, ovary or very young fruit have already been identified using natural tomato diversity. We reasoned that new developmental modules prominent at later stages of fruit growth could be discovered by using new genetic and phenotypic diversity generated by saturated mutagenesis. Twelve fruit weight and tissue morphology mutants likely affected in late fruit growth were selected among thousands of fruit size and shape EMS mutants available in our tomato EMS mutant collection.

Fruit growth-related genes in tomato.

Tomato (Solanum lycopersicum Mill.) represents a model species for all fleshy fruits due to its biological cycle and the availability of numerous genetic and molecular resources. Its importance in human nutrition has made it one of the most valuable worldwide commodities.

Endoreduplication and fruit growth in tomato: evidence in favour of the karyoplasmic ratio theory.

The growth of a plant organ depends upon the developmental processes of cell division and cell expansion. The activity of cell divisions sets the number of cells that will make up the organ; the cell expansion activity then determines its final size. Among the various mechanisms that may influence the determination of cell size, endopolyploidy by means of endoreduplication appears to be of great importance in plants.

The specific overexpression of a cyclin-dependent kinase inhibitor in tomato fruit mesocarp cells uncouples endoreduplication and cell growth.

The size of tomato fruit results from the combination of cell number and cell size, which are respectively determined by the cell division and cell expansion processes. As fruit growth is mainly sustained by cell expansion, the development of fleshy pericarp tissue is characterized by numerous rounds of endoreduplication inducing a spectacular increase in DNA ploidy and mean cell size. Although a clear relationship exists between endoreduplication and cell growth in plants, the exact role of endoreduplication has not been clearly elucidated.

Elucidating the functional role of endoreduplication in tomato fruit development.

Background: Endoreduplication is the major source of endopolyploidy in higher plants. The process of endoreduplication results from the ability of cells to modify their classical cell cycle into a partial cell cycle where DNA synthesis occurs independently from mitosis. Despite the ubiquitous occurrence of the phenomenon in eukaryotic cells, the physiological meaning of endoreduplication remains vague, although several roles during plant development have been proposed, mostly related to cell differentiation and cell size determination.

The Anaphase Promoting Complex activator CCS52A, a key factor for fruit growth and endoreduplication in Tomato.

Tomato fruit growth is characterized by the occurrence of numerous rounds of DNA endoreduplication in connection to cell expansion and final fruit size determination. Endoreduplication occurs as an impairment of mitosis, which can originate from the selective degradation of M-phase-specific cyclins via the ubiquitin-mediated proteolytic pathway, requiring the E3 ubiquitin ligase Anaphase Promoting Complex/Cyclosome (APC/C). In plants CCS52A is the ortholog of CDH1/FZR proteins from yeast, drosophila and human, belonging to the WD40-repeat protein family.

Functional characterization of the tomato cyclin-dependent kinase inhibitor SlKRP1 domains involved in protein-protein interactions.

• Cyclin-dependent kinase (CDK) inhibitors (kip-related proteins, KRPs) play a major role in the regulation of plant cell cycle in antagonizing its progression, and are thus regulators of development. The primary sequence of KRPs is characterized by the existence of conserved motifs, for which we have limited information on their functional significance. • We performed a functional analysis of various domains present in KRPs from tomato.

Functional analysis of the anaphase promoting complex activator CCS52A highlights the crucial role of endo-reduplication for fruit growth in tomato.

Tomato fruit growth is characterized by the occurrence of numerous rounds of DNA endo-reduplication in connection with cell expansion and final fruit size determination. Endo-reduplication is an impairment of mitosis that originates from the selective degradation of M phase-specific cyclins via the ubiquitin-mediated proteolytic pathway, requiring the E3 ubiquitin ligase anaphase promoting complex/cyclosome (APC/C). Two types of APC/C activators, namely CCS52 and CDC20 proteins, exist in plants.

Expression of a constitutively activated plasma membrane H+-ATPase alters plant development and increases salt tolerance.

The plasma membrane proton pump ATPase (H(+)-ATPase) plays a major role in the activation of ion and nutrient transport and has been suggested to be involved in several physiological processes, such as cell expansion and salt tolerance. Its activity is regulated by a C-terminal autoinhibitory domain that can be displaced by phosphorylation and the binding of regulatory 14-3-3 proteins, resulting in an activated enzyme. To better understand the physiological consequence of this activation, we have analyzed transgenic tobacco (Nicotiana tabacum) plants expressing either wild-type plasma membrane H(+)-ATPase4 (wtPMA4) or a PMA4 mutant lacking the autoinhibitory domain (DeltaPMA4), generating a constitutively activated enzyme.

The cell cycle-associated protein kinase WEE1 regulates cell size in relation to endoreduplication in developing tomato fruit.

Tomato fruit size results from the combination of cell number and cell size which are respectively determined by cell division and cell expansion processes. As fruit growth is mainly sustained by cell expansion, the development of pericarp and locular tissues is characterized by the concomitant arrest of mitotic activity, inhibition of cyclin-dependent kinase (CDK) activity, and numerous rounds of endoreduplication inducing a spectacular increase in DNA ploidy and mean cell size. To decipher the molecular basis of the endoreduplication-associated cell growth in fruit, we investigated the putative involvement of the WEE1 kinase (Solly;WEE1).

Molecular characterization of a WEE1 gene homologue in tomato (Lycopersicon esculentum Mill.).

Early fruit development in tomato (Lycopersicon esculentum Mill.) proceeds in two distinct phases of growth that comprise cell division and cell expansion, respectively. In pericarp and the jelly like locular tissue of tomato fruit, the transition between cell division to cell expansion is characterized by the arrest of mitotic activity, numerous rounds of nuclear DNA endoreduplication and the inhibition of Cyclin-Dependent Kinase A (CDKA) activity.

The plasma membrane proton pump ATPase: the significance of gene subfamilies.

The plasma membrane proton pump ATPase (H(+)-ATPase) plays a central role in transport across the plasma membrane. As a primary transporter, it mediates ATP-dependent H(+) extrusion to the extracellular space, thus creating pH and potential differences across the plasma membrane that activate a large set of secondary transporters. In several species, the H(+)-ATPase is encoded by a family of approximately 10 genes, classified into 5 gene subfamilies and we might ask what can this tell us about the concept, and the evolution, of gene families in plants.