Loss-of-functional mutation in ANGUSTIFOLIA3 causes leucine hypersensitivity and hypoxia response during Arabidopsis thaliana seedling growth.

Introduction: The ANGUSTIFOLIA3 (AN3) gene encodes a transcriptional co-activator for cell proliferation in Arabidopsis thaliana leaves. We previously showed that Physcomitrium patens AN3 orthologs promote gametophore shoot formation through arginine metabolism.

Objectives: We analyzed the role of AN3 in Arabidopsis thaliana to understand how seedling growth is regulated by metabolic and physiological modulations.

Impaired inosine monophosphate dehydrogenase leads to plant-specific ribosomal stress responses in Arabidopsis thaliana.

Nucleotides are the building blocks of living organisms and their biosynthesis must be tightly regulated. Inosine monophosphate dehydrogenase (IMPDH) is a rate-limiting enzyme in GTP synthesis that is essential for biological activities, such as RNA synthesis. In animals, the suppression of IMPDH function causes ribosomal stress (also known as nucleolar stress), a disorder in ribosome biogenesis that results in cell proliferation defects and apoptosis.

Characterization of the Arabidopsis Mutant oligocellula6-D Reveals the Importance of Leaf Initiation in Determining the Final Leaf Size.

The leaf is a determinate organ with a final size under genetic control. Numerous factors that regulate the final leaf size have been identified in Arabidopsis thaliana; although most of these factors play their roles during the growth of leaf primordia, much less is known about leaf initiation and its effects on the final leaf size. In this study, we characterized oligocellula6-D (oli6-D), a semidominant mutant of A.

Correction: Suppression of class I compensated cell enlargement by xs2 mutation is mediated by salicylic acid signaling.

[This corrects the article DOI: 10.1371/journal.pgen.

Tissue-targeted inorganic pyrophosphate hydrolysis in a mutant reveals that excess inorganic pyrophosphate triggers developmental defects in a cell-autonomous manner.

Excess PPi triggers developmental defects in a cell-autonomous manner. The level of inorganic pyrophosphate (PPi) must be tightly regulated in all kingdoms for the proper execution of cellular functions. In plants, the vacuolar proton pyrophosphatase (H-PPase) has a pivotal role in PPi homeostasis.

Stem integrity in requires a load-bearing epidermis.

Because plant cells are glued to each other via their cell walls, failure to coordinate growth among adjacent cells can create cracks in tissues. Here, we find that the unbalanced growth of inner and outer tissues in the () mutant of stretched epidermal cells, ultimately generating cracks in stems. Stem growth slowed before cracks appeared along stems, whereas inner pith cells became drastically distorted and accelerated their growth, yielding to stress, after the appearance of cracks.

Metabolic Control of Gametophore Shoot Formation through Arginine in the Moss Physcomitrium patens.

Shoot formation is accompanied by active cell proliferation and expansion, requiring that metabolic state adapts to developmental control. Despite the importance of such metabolic reprogramming, it remains unclear how development and metabolism are integrated. Here, we show that disruption of ANGUSTIFOLIA3 orthologs (PpAN3s) compromises gametophore shoot formation in the moss Physcomitrium patens due to defective cell proliferation and expansion.

Suppression of class I compensated cell enlargement by xs2 mutation is mediated by salicylic acid signaling.

The regulation of leaf size has been studied for decades. Enhancement of post-mitotic cell expansion triggered by impaired cell proliferation in Arabidopsis is an important process for leaf size regulation, and is known as compensation. This suggests a key interaction between cell proliferation and cell expansion during leaf development.

an3-Mediated Compensation Is Dependent on a Cell-Autonomous Mechanism in Leaf Epidermal Tissue.

Leaves are formed by coordinated growth of tissue layers driven by cell proliferation and expansion. Compensation, in which a defect in cell proliferation induces compensated cell enlargement (CCE), plays an important role in cell-size determination during leaf development. We previously reported that CCE triggered by the an3 mutation is observed in epidermal and subepidermal layers in Arabidopsis thaliana (Arabidopsis) leaves.

The bRPS6-Family Protein RFC3 Prevents Interference by the Splicing Factor CFM3b during Plastid rRNA Biogenesis in .

Plastid ribosome biogenesis is important for plant growth and development. REGULATOR OF FATTY ACID COMPOSITION3 (RFC3) is a member of the bacterial ribosomal protein S6 family and is important for lateral root development. dramatically reduces the plastid rRNA level and produces lateral roots that lack stem cells.

/ Promotes Cell Proliferation With and During Leaf Development in .

Organ size regulation is dependent on the precise spatial and temporal regulation of cell proliferation and cell expansion. A number of transcription factors have been identified that play a key role in the determination of aerial lateral organ size, but their functional relationship to various chromatin modifiers has not been well understood. To understand how leaf size is regulated, we previously isolated the () mutant of that develops smaller first leaves than the wild type (WT) mainly due to a reduction in the cell number.

Two Nucleolar Proteins, GDP1 and OLI2, Function As Ribosome Biogenesis Factors and Are Preferentially Involved in Promotion of Leaf Cell Proliferation without Strongly Affecting Leaf Adaxial-Abaxial Patterning in .

Leaf abaxial-adaxial patterning is dependent on the mutual repression of leaf polarity genes expressed either adaxially or abaxially. In , this process is strongly affected by mutations in ribosomal protein genes and in ribosome biogenesis genes in a sensitized genetic background, such as (). Most ribosome-related mutants by themselves do not show leaf abaxialization, and one of their typical phenotypes is the formation of pointed rather than rounded leaves.

Plastid translation is essential for lateral root stem cell patterning in .

The plastid evolved from a symbiotic cyanobacterial ancestor and is an essential organelle for plant life, but its developmental roles in roots have been largely overlooked. Here, we show that plastid translation is connected to the stem cell patterning in lateral root primordia. The gene encodes a plastid-localized protein that is a conserved bacterial ribosomal protein S6 of β/γ proteobacterial origin.

Evidence for a Role of ANAC082 as a Ribosomal Stress Response Mediator Leading to Growth Defects and Developmental Alterations in Arabidopsis.

Ribosome-related mutants in share several notable characteristics regarding growth and development, which implies the existence of a common pathway that responds to disorders in ribosome biogenesis. As a first step to explore this pathway genetically, we screened a mutagenized population of (), a temperature-sensitive mutant that is impaired in pre-rRNA processing, and isolated (), a suppressor mutant in which the defects of cell proliferation observed in at the restrictive temperature was markedly rescued. was identified as a missense mutation of the NAC transcription factor gene The mutation greatly alleviated the developmental abnormalities of and four other tested ribosome-related mutants, including However, the impaired pre-rRNA processing in and was not relieved by Expression of was localized to regions where phenotypic effects of ribosome-related mutations are readily evident and was elevated in and compared with the wild type.

Spatially Different Tissue-Scale Diffusivity Shapes ANGUSTIFOLIA3 Gradient in Growing Leaves.

The spatial gradient of signaling molecules is pivotal for establishing developmental patterns of multicellular organisms. It has long been proposed that these gradients could arise from the pure diffusion process of signaling molecules between cells, but whether this simplest mechanism establishes the formation of the tissue-scale gradient remains unclear. Plasmodesmata are unique channel structures in plants that connect neighboring cells for molecular transport.

Double-stranded RNA-binding protein DRB3 negatively regulates anthocyanin biosynthesis by modulating PAP1 expression in Arabidopsis thaliana.

The model plant Arabidopsis thaliana has five double-stranded RNA-binding proteins (DRB1-DRB5), two of which, DRB1 and DRB4, are well characterized. In contrast, the functions of DRB2, DRB3 and DRB5 have yet to be elucidated. In this study, we tried to uncover their functions using drb mutants and DRB-over-expressed lines.

Nitrogen dioxide regulates organ growth by controlling cell proliferation and enlargement in Arabidopsis.

• To gain more insight into the physiological function of nitrogen dioxide (NO₂), we investigated the effects of exogenous NO₂ on growth in Arabidopsis thaliana. • Plants were grown in air without NO₂ for 1 wk after sowing and then grown for 1-4 wk in air with (designated treated plants) or without (control plants) NO₂. Plants were irrigated semiweekly with a nutrient solution containing 19.

Class III compensation, represented by KRP2 overexpression, depends on V-ATPase activity in proliferative cells.

Compensation refers to an increase in cell size when the cell number is significantly decreased due to the mutation or gain of function of a gene that negatively affects the cell cycle. Given the importance of coordinated growth during organogenesis in both animal and plant systems, compensation is important to understand the mechanism of size regulation. In leaves, cell division precedes cell differentiation (which involves cell expansion); therefore, a decrease in cell number triggers enhanced cell expansion (compensated cell expansion; hereafter, CCE).

Promotion of chloroplast proliferation upon enhanced post-mitotic cell expansion in leaves.

Background: Leaves are determinate organs; hence, precise control of cell proliferation and post-mitotic cell expansion is essential for their growth. A defect in cell proliferation often triggers enhanced post-mitotic cell expansion in leaves. This phenomenon is referred to as 'compensation'.

Enhanced cell expansion in a KRP2 overexpressor is mediated by increased V-ATPase activity.

Decreased cell numbers during leaf development often trigger increased cell size, a phenomenon called compensation. In compensation-exhibiting mutants, the unusually high cell expansion activity occurs through two different mechanisms during the post-mitotic stage of leaf development, except in the KIP-RELATED PROTEIN 2-overexpressing line (KRP2 o/e), whose cell sizes are 2-fold greater during proliferative growth. However, the molecular basis of compensated cell expansion (CCE) has not been characterized.

ANGUSTIFOLIA3 signaling coordinates proliferation between clonally distinct cells in leaves.

Coordinated proliferation between clonally distinct cells via inter-cell-layer signaling largely determines the size and shape of plant organs. Nonetheless, the signaling mechanism underlying this coordination in leaves remains elusive because of a lack of understanding of the signaling molecule (or molecules) involved. ANGUSTIFOLIA3 (AN3, also called GRF-INTERACTING FACTOR1) encodes a putative transcriptional coactivator with homology to human synovial sarcoma translocation protein.

How do 'housekeeping' genes control organogenesis?--Unexpected new findings on the role of housekeeping genes in cell and organ differentiation.

In recent years, an increasing number of mutations in what would appear to be 'housekeeping genes' have been identified as having unexpectedly specific defects in multicellular organogenesis. This is also the case for organogenesis in seed plants. Although it is not surprising that loss-of-function mutations in 'housekeeping' genes result in lethality or growth retardation, it is surprising when (1) the mutant phenotype results from the loss of function of a 'housekeeping' gene and (2) the mutant phenotype is specific.

Berberine enhances defects in the establishment of leaf polarity in asymmetric leaves1 and asymmetric leaves2 of Arabidopsis thaliana.

Leaves develop as flat lateral organs from the indeterminate shoot apical meristem. The establishment of polarity along three-dimensional axes, proximal-distal, medial-lateral, and adaxial-abaxial axes, is crucial for the growth of normal leaves. The mutations of ASYMMETRIC LEAVES1 (AS1) and AS2 of Arabidopsis thaliana cause defects in repression of the indeterminate state and the establishment of axis formation in leaves.