scholarly journals Cytokinin promotes jasmonic acid accumulation in the control of maize leaf growth

2019 ◽  
Author(s):  
Aimee N. Uyehara ◽  
Angel R. Del Valle-Echevarria ◽  
Charles T. Hunter ◽  
Hilde Nelissen ◽  
Kirin Demuynck ◽  
...  
Keyword(s):  
Growth Rate ◽  
Cell Division ◽  
Jasmonic Acid ◽  
Leaf Growth ◽  
Leaf Size ◽  
Wild Type ◽  
Cytokinin Signaling ◽  
Transcript Accumulation ◽  
Maize Leaf ◽  
Pathway Gene

AbstractGrowth of plant organs results from the combined activity of cell division and cell expansion. The coordination of these two processes depends on the interplay between multiple hormones that determine final organ size. Using the semidominant Hairy Sheath Frayed1 (Hsf1) maize mutant, that hypersignals the perception of cytokinin (CK), we show that CK can reduce leaf size and growth rate by decreasing cell division. Linked to CK hypersignaling, the Hsf1 mutant has increased jasmonic acid (JA) content, a hormone that can inhibit cell division. Treatment of wild type seedlings with exogenous JA reduces maize leaf size and growth rate, while JA deficient maize mutants have increased leaf size and growth rate. Expression analysis revealed increased transcript accumulation of several JA pathway genes in the Hsf1 leaf growth zone. A transient treatment of growing wild type maize shoots with exogenous CK also induced JA pathway gene expression, although this effect was blocked by co-treatment with cycloheximide. Together our results suggest that CK can promote JA accumulation possibly through increased expression of specific JA pathway genes.One sentence summaryCytokinin-signaling upregulates the jasmonate biosynthesis pathway, resulting in jasmonate accumulation and influences on maize leaf growth.

scholarly journals Nitrate Induction of Primary Root Growth Requires Cytokinin Signaling in Arabidopsis thaliana

2019 ◽  
Vol 61 (2) ◽  
pp. 342-352 ◽  
Author(s):  
Pamela A Naulin ◽  
Grace I Armijo ◽  
Andrea S Vega ◽  
Karem P Tamayo ◽  
Diana E Gras ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Division ◽  
Root Growth ◽  
Primary Root ◽  
Growth Arrest ◽  
Root Tip ◽  
Wild Type ◽  
Cytokinin Signaling ◽  
Control Growth ◽  
Primary Root Growth

Abstract Nitrate can act as a potent signal to control growth and development in plants. In this study, we show that nitrate is able to stimulate primary root growth via increased meristem activity and cytokinin signaling. Cytokinin perception and biosynthesis mutants displayed shorter roots as compared with wild-type plants when grown with nitrate as the only nitrogen source. Histological analysis of the root tip revealed decreased cell division and elongation in the cytokinin receptor double mutant ahk2/ahk4 as compared with wild-type plants under a sufficient nitrate regime. Interestingly, a nitrate-dependent root growth arrest was observed between days 5 and 6 after sowing. Wild-type plants were able to recover from this growth arrest, while cytokinin signaling or biosynthesis mutants were not. Transcriptome analysis revealed significant changes in gene expression after, but not before, this transition in contrasting genotypes and nitrate regimes. We identified genes involved in both cell division and elongation as potentially important for primary root growth in response to nitrate. Our results provide evidence linking nitrate and cytokinin signaling for the control of primary root growth in Arabidopsis thaliana.

scholarly journals A Local Maximum in Gibberellin Levels Regulates Maize Leaf Growth by Spatial Control of Cell Division

2012 ◽  
Vol 22 (13) ◽  
pp. 1183-1187 ◽  
Author(s):  
Hilde Nelissen ◽  
Bart Rymen ◽  
Yusuke Jikumaru ◽  
Kirin Demuynck ◽  
Mieke Van Lijsebettens ◽  
...  
Keyword(s):  
Cell Division ◽  
Leaf Growth ◽  
Local Maximum ◽  
Spatial Control ◽  
Maize Leaf

scholarly journals The reduction in maize leaf growth under mild drought affects the transition between cell division and cell expansion and cannot be restored by elevated gibberellic acid levels

2017 ◽  
Vol 16 (2) ◽  
pp. 615-627 ◽  
Author(s):  
Hilde Nelissen ◽  
Xiao-Huan Sun ◽  
Bart Rymen ◽  
Yusuke Jikumaru ◽  
Mikko Kojima ◽  
...  
Keyword(s):  
Cell Division ◽  
Gibberellic Acid ◽  
Cell Expansion ◽  
Leaf Growth ◽  
Maize Leaf ◽  
Mild Drought

Reversion of the MR variant of Candida albicans

1969 ◽  
Vol 15 (9) ◽  
pp. 1051-1054
Author(s):  
Rosalee Ireland ◽  
A. Sarachek
Keyword(s):  
Growth Rate ◽  
Candida Albicans ◽  
Cell Division ◽  
Incubation Temperature ◽  
High Rate ◽  
Type Condition ◽  
Wild Type ◽  
Spontaneous Repair

Previous studies have indicated that the minute-rough (MR) colonial variant of Candida albicans arises through mutation of an extrachromosomal hereditary determinant. The MR variant's high rate of reversion to the wild-type condition suggests either that (a) the determinant undergoes frequent spontaneous repair or that (b) variant cells bear both normal and mutant determinants which segregate at cell division. Analyses presented here of the effects of growth rate, nutrition, incubation temperature, and metabolic antagonists upon reversion favor the view that reversion is due to repair of mutant determinants.

scholarly journals A Local Maximum in Gibberellin Levels Regulates Maize Leaf Growth by Spatial Control of Cell Division

2012 ◽  
Vol 22 (13) ◽  
pp. 1266 ◽  
Author(s):  
Hilde Nelissen ◽  
Bart Rymen ◽  
Yusuke Jikumaru ◽  
Kirin Demuynck ◽  
Mieke Van Lijsebettens ◽  
...  
Keyword(s):  
Cell Division ◽  
Leaf Growth ◽  
Local Maximum ◽  
Spatial Control ◽  
Maize Leaf

scholarly journals Deficiency of RgpG Causes Major Defects in Cell Division and Biofilm Formation, and Deficiency of LytR-CpsA-Psr Family Proteins Leads to Accumulation of Cell Wall Antigens in Culture Medium by Streptococcus mutans

2017 ◽  
Vol 83 (17) ◽  
Author(s):  
Arpan De ◽  
Sumei Liao ◽  
Jacob P. Bitoun ◽  
Randy Roth ◽  
Wandy L. Beatty ◽  
...  
Keyword(s):  
Growth Rate ◽  
Cell Wall ◽  
Cell Division ◽  
Streptococcus Mutans ◽  
Biofilm Formation ◽  
Cell Envelope ◽  
Biosynthesis Pathway ◽  
Wild Type ◽  
Triple Mutant ◽  
Content Type

ABSTRACTStreptococcus mutansis known to possess rhamnose-glucose polysaccharide (RGP), a major cell wall antigen.S. mutansstrains deficient inrgpG, encoding the first enzyme of the RGP biosynthesis pathway, were constructed by allelic exchange. ThergpGdeficiency had no effect on growth rate but caused major defects in cell division and altered cell morphology. Unlike the coccoid wild type, thergpGmutant existed primarily in chains of swollen, “squarish” dividing cells. Deficiency ofrgpGalso causes significant reduction in biofilm formation (P< 0.01). Double and triple mutants with deficiency inbrpAand/orpsr, genes coding for the LytR-CpsA-Psr family proteins BrpA and Psr, which were previously shown to play important roles in cell envelope biogenesis, were constructed using thergpGmutant. There were no major differences in growth rates between the wild-type strain and thergpG brpAandrgpG psrdouble mutants, but the growth rate of thergpG brpA psrtriple mutant was reduced drastically (P< 0.001). Under transmission electron microscopy, both double mutants resembled thergpGmutant, while the triple mutant existed as giant cells with multiple asymmetric septa. When analyzed by immunoblotting, thergpGmutant displayed major reductions in cell wall antigens compared to the wild type, while little or no signal was detected with the double and triple mutants and thebrpAandpsrsingle mutants. These results suggest that RgpG inS. mutansplays a critical role in cell division and biofilm formation and that BrpA and Psr may be responsible for attachment of cell wall antigens to the cell envelope.IMPORTANCEStreptococcus mutans, a major etiological agent of human dental caries, produces rhamnose-glucose polysaccharide (RGP) as the major cell wall antigen. This study provides direct evidence that deficiency of RgpG, the first enzyme of the RGP biosynthesis pathway, caused major defects in cell division and morphology and reduced biofilm formation byS. mutans, indicative of a significant role of RGP in cell division and biofilm formation inS. mutans. These results are novel not only inS. mutans, but also other streptococci that produce RGP. This study also shows that the LytR-CpsA-Psr family proteins BrpA and Psr inS. mutansare involved in attachment of RGP and probably other cell wall glycopolymers to the peptidoglycan. In addition, the results also suggest that BrpA and Psr may play a direct role in cell division and biofilm formation inS. mutans. This study reveals new potential targets to develop anticaries therapeutics.

Variegation in Selaginella martensii f. albovariegata. I. Expression and inheritance

1982 ◽  
Vol 60 (11) ◽  
pp. 2375-2383 ◽  
Author(s):  
James A. Tanno ◽  
Terry R. Webster
Keyword(s):  
Cell Division ◽  
Chloroplast Dna ◽  
Maternal Inheritance ◽  
Leaf Growth ◽  
Green Growth ◽  
Wild Type ◽  
Reciprocal Crosses ◽  
Leaf Variegation ◽  
White Tissue ◽  
Stable Leaf

Selaginella martensii f. albovariegata is a variegated sport which produces distinctly white tissue in an irregular fashion. Typical specimens possess not only variegated branches but some branches exhibiting uniformly green growth and others showing completely white growth. Variegated and green branches often change in character as they grow, while white branches are stable. Leaf variegation patterns are highly variable and strongly influenced by the cell division patterns of early leaf growth. Reciprocal crosses between wild-type S. martensii and f. albovariegata show maternal inheritance of variegation, suggesting cytoplasmic control. Further crosses, involving progeny of selected reciprocal crosses, also indicate a lack of direct nuclear influence on variegation. The details of character expression and inheritance can be accounted for on the basis of a random sorting of normal and defective cytoplasmic factors at cell division. Recent characterizations of chloroplast DNA for several species of green plants suggest that the DNA molecules within the plastid may represent the sorting factor.

scholarly journals Effects of cofD gene knock-out on the methanogenesis of Methanobrevibacter ruminantium

AMB Express ◽  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jian Ma ◽  
Xueying Wang ◽  
Ting Zhou ◽  
Rui Hu ◽  
Huawei Zou ◽  
...  
Keyword(s):  
Growth Rate ◽  
Specific Growth ◽  
Production Capacity ◽  
Maximum Amount ◽  
Logarithmic Phase ◽  
Wild Type ◽  
Knock Out ◽  
Maximum Biomass ◽  
Reproductive Ability ◽  
Methanobrevibacter Ruminantium

AbstractThis study aimed to investigate the effects of cofD gene knock-out on the synthesis of coenzyme F420 and production of methane in Methanobrevibacter ruminantium (M. ruminantium). The experiment successfully constructed a cofD gene knock-out M. ruminantium via homologous recombination technology. The results showed that the logarithmic phase of mutant M. ruminantium (12 h) was lower than the wild-type (24 h). The maximum biomass and specific growth rate of mutant M. ruminantium were significantly lower (P < 0.05) than those of wild-type, and the maximum biomass of mutant M. ruminantium was approximately half of the wild-type; meanwhile, the proliferation was reduced. The synthesis amount of coenzyme F420 of M. ruminantium was significantly decreased (P < 0.05) after the cofD gene knock-out. Moreover, the maximum amount of H2 consumed and CH4 produced by mutant were 14 and 2% of wild-type M. ruminantium respectively. In conclusion, cofD gene knock-out induced the decreased growth rate and reproductive ability of M. ruminantium. Subsequently, the synthesis of coenzyme F420 was decreased. Ultimately, the production capacity of CH4 in M. ruminantium was reduced. Our research provides evidence that cofD gene plays an indispensable role in the regulation of coenzyme F420 synthesis and CH4 production in M. ruminantium.

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