scholarly journals Cantil: a previously unreported organ in wild-type Arabidopsis regulated by FT, ERECTA and heterotrimeric G proteins

Development ◽  
2021 ◽  
Vol 148 (11) ◽  
Author(s):  
Timothy E. Gookin ◽  
Sarah M. Assmann
Keyword(s):  
G Proteins ◽  
Heterotrimeric G Proteins ◽  
Wild Type ◽  
Flowering Locus T ◽  
Long Day ◽  
Receptor Like Kinase ◽  
Per Se ◽  
Delayed Flowering ◽  
Delayed Phase ◽  
Short Days

ABSTRACT We describe a previously unreported macroscopic Arabidopsis organ, the cantil, named for its ‘cantilever’ function of holding the pedicel at a distance from the stem. Cantil development is strongest at the first nodes after the vegetative to reproductive inflorescence transition; cantil magnitude and frequency decrease acropetally. Cantils develop in wild-type Arabidopsis accessions (e.g. Col-0, Ws and Di-G) as a consequence of delayed flowering in short days; cantil formation is observed in long days when flowering is delayed by null mutation of the floral regulator FLOWERING LOCUS T. The receptor-like kinase ERECTA is a global positive regulator of cantil formation; therefore, cantils never form in the Arabidopsis strain Ler. ERECTA functions genetically upstream of heterotrimeric G proteins. Cantil expressivity is repressed by the specific heterotrimeric complex subunits GPA1, AGB1 and AGG3, which also play independent roles: GPA1 suppresses distal spurs at cantil termini, while AGB1 and AGG3 suppress ectopic epidermal rippling. These G protein mutant traits are recapitulated in long-day flowering gpa1-3 ft-10 plants, demonstrating that cantils, spurs and ectopic rippling occur as a function of delayed phase transition, rather than as a function of photoperiod per se.

The early-flowering mutant efs is involved in the autonomous promotion pathway of Arabidopsis thaliana

Development ◽  
1999 ◽  
Vol 126 (21) ◽  
pp. 4763-4770 ◽  
Author(s):  
W.J. Soppe ◽  
L. Bentsink ◽  
M. Koornneef
Keyword(s):  
Arabidopsis Thaliana ◽  
Flowering Time ◽  
Double Mutant ◽  
Plant Size ◽  
Early Flowering ◽  
Wild Type ◽  
Late Flowering ◽  
Long Day ◽  
Short Days ◽  
Transition To Flowering

The transition to flowering is a crucial moment in a plant's life cycle of which the mechanism has only been partly revealed. In a screen for early flowering, after mutagenesis of the late-flowering fwa mutant of Arabidopsis thaliana, the early flowering in short days (efs) mutant was identified. Under long-day light conditions, the recessive monogenic efs mutant flowers at the same time as wild type but, under short-day conditions, the mutant flowers much earlier. In addition to its early-flowering phenotype, efs has several pleiotropic effects such as a reduction in plant size, fertility and apical dominance. Double mutant analysis with several late-flowering mutants from the autonomous promotion (fca and fve) and the photoperiod promotion (co, fwa and gi) pathways of flowering showed that efs reduces the flowering time of all these mutants. However, efs is completely epistatic to fca and fve but additive to co, fwa and gi, indicating that EFS is an inhibitor of flowering specifically involved in the autonomous promotion pathway. A vernalisation treatment does not further reduce the flowering time of the efs mutant, suggesting that vernalisation promotes flowering through EFS. By comparing the length of the juvenile and adult phases of vegetative growth for wild-type, efs and the double mutant plants, it is apparent that efs mainly reduces the length of the adult phase.

scholarly journals The G alpha i homologue gna-1 controls multiple differentiation pathways in Neurospora crassa.

1996 ◽  
Vol 7 (8) ◽  
pp. 1283-1297 ◽  
Author(s):  
F D Ivey ◽  
P N Hodge ◽  
G E Turner ◽  
K A Borkovich
Keyword(s):  
Neurospora Crassa ◽  
G Proteins ◽  
Solid Medium ◽  
Sexual Cycle ◽  
Heterotrimeric G Proteins ◽  
Wild Type ◽  
Multiple Phenotypes ◽  
Multiple Differentiation ◽  
Differentiation Pathways ◽  
Type Strains

Heterotrimeric G proteins are components of principal signaling pathways in eukaryotes. In higher organisms, alpha subunits of G proteins have been divided into four families, Gi, Gs, Gq, and G12. We previously identified a G alpha i homologue gna-1 in the filamentous fungus Neurospora crassa. Now we report that deletion of gna-1 leads to multiple phenotypes during the vegetative and sexual cycles in N. crassa. On solid medium, delta gna-1 strains have a slower rate of hyphal apical extension than wild type, a rate that is more pronounced under hyperosmotic conditions or in the presence of a cellophane overlay. delta gna-1 mutants accumulate less mass than wild-type strains, and their mass accumulation is not affected in the same way by exposure to light. delta gna-1 strains are defective in macroconidiation, possessing aerial hyphae that are shorter, contain abnormal swellings, and differentiate adherent macroconidia. During the sexual cycle, delta gna-1 strains are fertile as males. However, the mutants are female-sterile, producing small, aberrant female reproductive structures. After fertilization, delta gna-1 female structures do not enlarge and develop normally, and no sexual spores are produced. Thus, mutation of gna-1 results in sex-specific loss of fertility.

scholarly journals Knockout of Arabidopsis Serotonin N-Acetyltransferase-2 Reduces Melatonin Levels and Delays Flowering

Biomolecules ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 712 ◽  
Author(s):  
Hyoung Yool Lee ◽  
Kyungjin Lee ◽  
Kyoungwhan Back
Keyword(s):  
Arabidopsis Thaliana ◽  
Enzyme Activity ◽  
Amino Acid ◽  
Plant Growth ◽  
Wild Type ◽  
Knockout Mutant ◽  
Flowering Locus T ◽  
Amino Acid Homology ◽  
Delayed Flowering

Melatonin plays roles in both plant growth and defense. Serotonin N-acetyltransferase (SNAT) catalyzes formation of N-acetylserotonin (NAS) from serotonin. Plants contain two SNAT isogenes, which exhibit low-level amino acid homology. We studied the Arabidopsis thaliana SNAT2 (AtSNAT2) gene; we prepared recombinant SNAT2 protein and characterized a snat2 knockout mutant. The SNAT2 protein exhibited 27% amino acid homology with SNAT1; the Km was 232 μM and the Vmax was 2160 pmol/min/mg protein. Melatonin inhibited SNAT enzyme activity in vitro. SNAT2 mRNA was abundantly expressed in flowers; the melatonin content of flowers of the snat2 mutant was significantly less than that of wild-type flowers. The mutant exhibited delayed flowering and reductions in leaf area and biomass compared to the wild type. Delayed flowering was attributable to reductions in the expression levels of the gibberellin biosynthetic genes ent-kaurene synthase (KS) and FLOWERING LOCUS T (FT).

scholarly journals G-Alpha Subunit Abundance and Activity Differentially Regulate β-Catenin Signaling

2018 ◽  
Vol 39 (5) ◽  
Author(s):  
Arshiya Banu ◽  
Karen J. Liu ◽  
Alistair J. Lax ◽  
Agamemnon E. Grigoriadis
Keyword(s):  
G Proteins ◽  
Pasteurella Multocida ◽  
Alpha Subunit ◽  
Dependent Manner ◽  
Heterotrimeric G Proteins ◽  
Wild Type ◽  
Content Type ◽  
Alpha Subunits ◽  
Licl Treatment ◽  
Signal Transduction Proteins

ABSTRACT Heterotrimeric G proteins are signal transduction proteins involved in regulating numerous signaling events. In particular, previous studies have demonstrated a role for G-proteins in regulating β-catenin signaling. However, the link between G-proteins and β-catenin signaling is controversial and appears to depend on G-protein specificity. We describe a detailed analysis of a link between specific G-alpha subunits and β-catenin using G-alpha subunit genetic knockout and knockdown approaches. The Pasteurella multocida toxin was utilized as a unique tool to activate G-proteins, with LiCl treatment serving as a β-catenin signaling agonist. The results show that Pasteurella multocida toxin (PMT) significantly enhanced LiCl-induced active β-catenin levels in HEK293T cells and mouse embryo fibroblasts. Evaluation of the effect of specific G-alpha proteins on the regulation of β-catenin showed that Gq/11 and G12/13 knockout cells had significantly higher levels of active and total β-catenin than wild-type cells. The stimulation of active β-catenin by PMT and LiCl was lost upon both constitutive and transient knockdown of G12 and G13 but not Gq. Based on our results, we conclude that endogenous G-alpha proteins are negative regulators of active β-catenin; however, PMT-activated G-alpha subunits positively regulate LiCl-induced β-catenin expression in a G12/13-dependent manner. Hence, G-alpha subunit regulation of β-catenin is context dependent.

scholarly journals GmFULc Is Induced by Short Days in Soybean and May Accelerate Flowering in Transgenic Arabidopsis thaliana

2021 ◽  
Vol 22 (19) ◽  
pp. 10333
Author(s):  
Jingzhe Sun ◽  
Mengyuan Wang ◽  
Chuanlin Zhao ◽  
Tianmeng Liu ◽  
Zhengya Liu ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Flowering Time ◽  
Transcriptional Activity ◽  
Developmental Process ◽  
Transgenic Arabidopsis ◽  
Mads Box ◽  
Wild Type ◽  
Transcription Factor Family ◽  
Flowering Locus T ◽  
Short Days

Flowering is an important developmental process from vegetative to reproductive growth in plant; thus, it is necessary to analyze the genes involved in the regulation of flowering time. The MADS-box transcription factor family exists widely in plants and plays an important role in the regulation of flowering time. However, the molecular mechanism of GmFULc involved in the regulation of plant flowering is not very clear. In this study, GmFULc protein had a typical MADS domain and it was a member of MADS-box transcription factor family. The expression analysis revealed that GmFULc was induced by short days (SD) and regulated by the circadian clock. Compared to wild type (WT), overexpression of GmFULc in transgenic Arabidopsis caused significantly earlier flowering time, while ful mutants flowered later, and overexpression of GmFULc rescued the late-flowering phenotype of ful mutants. ChIP-seq of GmFULc binding sites identified potential direct targets, including TOPLESS (TPL), and it inhibited the transcriptional activity of TPL. In addition, the transcription levels of FLOWERING LOCUS T (FT), SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1 (SOC1) and LEAFY (LFY) in the downstream of TPL were increased in GmFULc- overexpressionArabidopsis, suggesting that the early flowering phenotype was associated with up-regulation of these genes. Our results suggested that GmFULc inhibited the transcriptional activity of TPL and induced expression of FT, SOC1 and LFY to promote flowering.

scholarly journals Canonical Heterotrimeric G Proteins Regulating Mating and Virulence ofCryptococcus neoformans

2007 ◽  
Vol 18 (11) ◽  
pp. 4201-4209 ◽  
Author(s):  
Lie Li ◽  
Gui Shen ◽  
Zheng-Guang Zhang ◽  
Yan-Li Wang ◽  
Jill K. Thompson ◽  
...  
Keyword(s):  
Cryptococcus Neoformans ◽  
G Proteins ◽  
Heterotrimeric G Proteins ◽  
Human Pathogen ◽  
Signaling Mechanism ◽  
Pheromone Signaling ◽  
Rgs Protein ◽  
Per Se ◽  
Opportunistic Human Pathogen

Perturbation of pheromone signaling modulates not only mating but also virulence in Cryptococcus neoformans, an opportunistic human pathogen known to encode three Gα, one Gβ, and two Gγ subunit proteins. We have found that Gαs Gpa2 and Gpa3 exhibit shared and distinct roles in regulating pheromone responses and mating. Gpa2 interacted with the pheromone receptor homolog Ste3α, Gβ subunit Gpb1, and RGS protein Crg1. Crg1 also exhibited in vitro GAP activity toward Gpa2. These findings suggest that Gpa2 regulates mating through a conserved signaling mechanism. Moreover, we found that Gγs Gpg1 and Gpg2 both regulate pheromone responses and mating. gpg1 mutants were attenuated in mating, and gpg2 mutants were sterile. Finally, although gpa2, gpa3, gpg1, gpg2, and gpg1 gpg2 mutants were fully virulent, gpa2 gpa3 mutants were attenuated for virulence in a murine model. Our study reveals a conserved but distinct signaling mechanism by two Gα, one Gβ, and two Gγ proteins for pheromone responses, mating, and virulence in Cryptococcus neoformans, and it also reiterates that the link between mating and virulence is not due to mating per se but rather to certain mating-pathway components that encode additional functions promoting virulence.

scholarly journals Olfactory desensitization requires membrane targeting of receptor kinase mediated by beta gamma-subunits of heterotrimeric G proteins.

1994 ◽  
Vol 269 (1) ◽  
pp. 37-40
Author(s):  
I. Boekhoff ◽  
J. Inglese ◽  
S. Schleicher ◽  
W.J. Koch ◽  
R.J. Lefkowitz ◽  
...  
Keyword(s):  
G Proteins ◽  
Membrane Targeting ◽  
Heterotrimeric G Proteins ◽  
Receptor Kinase ◽  
Gamma Subunits
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