scholarly journals Molecular Basis for Natural Vegetative Propagation via Regeneration in North American Lake Cress, Rorippa aquatica (Brassicaceae)

2019 ◽  
Vol 61 (2) ◽  
pp. 353-369 ◽  
Author(s):  
Rumi Amano ◽  
Hokuto Nakayama ◽  
Risa Momoi ◽  
Emi Omata ◽  
Shizuka Gunji ◽  
...  
Keyword(s):  
Shoot Regeneration ◽  
Vegetative Propagation ◽  
Molecular Basis ◽  
Auxin Transport ◽  
Vascular Tissue ◽  
De Novo ◽  
Leaf Explants ◽  
Experimental Models ◽  
Polar Auxin Transport ◽  
Proximal Side

Abstract Some plant species have a striking capacity for regeneration in nature, including regeneration of the entire individual from explants. However, due to the lack of suitable experimental models, the regulatory mechanisms of spontaneous whole plant regeneration are mostly unknown. In this study, we established a novel model system to study these mechanisms using an amphibious plant within Brassicaceae, Rorippa aquatica, which naturally undergoes vegetative propagation via regeneration from leaf fragments. Morphological and anatomical observation showed that both de novo root and shoot organogenesis occurred from the proximal side of the cut edge transversely with leaf vascular tissue. Time-series RNA-seq analysis revealed that auxin and cytokinin responses were activated after leaf amputation and that regeneration-related genes were upregulated mainly on the proximal side of the leaf explants. Accordingly, we found that both auxin and cytokinin accumulated on the proximal side. Application of a polar auxin transport inhibitor retarded root and shoot regeneration, suggesting that the enhancement of auxin responses caused by polar auxin transport enhanced de novo organogenesis at the proximal wound site. Exogenous phytohormone and inhibitor applications further demonstrated that, in R. aquatica, both auxin and gibberellin are required for root regeneration, whereas cytokinin is important for shoot regeneration. Our results provide a molecular basis for vegetative propagation via de novo organogenesis.

scholarly journals Regulation of Polar Auxin Transport by AtPIN1 in Arabidopsis Vascular Tissue

Science ◽  
1998 ◽  
Vol 282 (5397) ◽  
pp. 2226-2230 ◽  
Author(s):  
L. Ga lweiler ◽  
C. Guan ◽  
A. Mu ller ◽  
E. Wisman ◽  
K. Mendgen ◽  
...  
Keyword(s):  
Auxin Transport ◽  
Vascular Tissue ◽  
Polar Auxin Transport

Development of an efficient protocol for high frequency in vitro regeneration of a horticultural plant Primulina tamiana (B.L. Burtt) Mich. Möller & A. Webber

2014 ◽  
Vol 94 (7) ◽  
pp. 1281-1287 ◽  
Author(s):  
Priya Padmanabhan ◽  
Susan J. Murch ◽  
J. Alan Sullivan ◽  
Praveen K. Saxena
Keyword(s):  
Shoot Regeneration ◽  
High Frequency ◽  
De Novo ◽  
Shoot Organogenesis ◽  
In Vitro Regeneration ◽  
Leaf Explants ◽  
Root Induction ◽  
Horticultural Plant ◽  
Leaf Segments

Padmanabhan, P., Murch, S. J., Sullivan, J. A. and Saxena, P. K. 2014. Development of an efficient protocol for high frequency in vitro regeneration of a horticultural plant Primulina tamiana (B.L. Burtt) Mich. Möller & A. Webber. Can. J. Plant Sci. 94: 1281–1287. A rapid and efficient in vitro regeneration system was established for Primulina tamiana, an attractive ornamental plant of horticultural importance. The successful regeneration protocol employed induction of shoot organogenesis on leaf explants. Among the various plant growth regulators evaluated, thidiazuron (TDZ) proved to be the most effective in inducing rapid de novo shoot formation. The highest shoot regeneration frequency within the shortest time from leaf explants was obtained on medium enriched with 2.5 µM TDZ. Furthermore, leaf segments were found to be a more suitable explant for in vitro shoot regeneration compared with petiole explants. The abaxial side of the leaf segments, which was in contact with the culture medium, generated more shoots than the adaxial side. Scanning electron microscopic studies carried out at various stages of de novo shoot differentiation demonstrated that shoot organogenesis involved the formation of actively dividing regions from the epidermal and subepidermal layers of the explants. In vitro rooting of the regenerated shoots was attempted using two different auxins, IAA (3-indoleacetic acid) and 3-indolebutyric acid (IBA) (0, 0.1, 0.5, 1.0, 2.0, and 5.0 µM). The optimum concentration for root induction was found to be 5 µM IBA. Approximately, 98% of the regenerated plants survived transfer and acclimation to greenhouse conditions.

scholarly journals The effects of β-lactam antibiotics and hygromycin B on de novo shoot organogenesis in apple cv. Golden Delicious

2018 ◽  
Vol 70 (1) ◽  
pp. 179-190 ◽  
Author(s):  
Mariana Stanisic ◽  
Slavica Ninkovic ◽  
Jelena Savic ◽  
Tatjana Cosic ◽  
Nevena Mitic
Keyword(s):  
Shoot Regeneration ◽  
De Novo ◽  
Shoot Organogenesis ◽  
In Vitro Regeneration ◽  
Leaf Explants ◽  
Selection Procedure ◽  
Transformation Process ◽  
Hygromycin B ◽  
Golden Delicious

Since the genetic transformation of the apple is strongly genotype-dependent and generally inefficient, the evaluation of factors affecting shoot regeneration are crucial for the establishment of a successful transformation process. In this report, we evaluated the effects of the ?-lactam antibiotics meropenem and timentin on in vitro regeneration via de novo shoot organogenesis from leaf explants of apple cv. Golden Delicious, as well as on the growth of the Agrobacterium tumefaciens strain EHA 105, and compared them with the commonly used ?-lactam cefotaxime. Also, we report for the first time the effect of hygromycin B as a selective agent in the domesticated apple, as regards shoot regeneration and shoot multiplication efficiency. We observed that cefotaxime and timentin at concentrations higher than 100 mg L-1 were sufficient to prevent Agrobacterium growth during a two-week period, while meropenem exhibited an inhibitory effect on bacterial growth at all tested concentrations (25-150 mg L-1). Cefotaxime at a concentration of 300 mg L-1 increased the number of regenerated shoots per explant (9.39) in comparison with the control (7.67). In contrast to cefotaxime, meropenem and timentin caused a decrease in shoot regeneration efficiency, but larger and more developed shoots were obtained on meropenem (25-125 mg L-1) after the same period of cultivation. Hygromycin B at a concentration of 5 mg L-1 or higher completely inhibited shoot regeneration and induced explant tissue necrosis. Therefore, the selection procedure with a final concentration of 4 mg L-1 throughout organogenesis and 10 mg L-1 for further shoot growth and multiplication is recommended for an efficient transformation process in apple cv. Golden Delicious.

scholarly journals The PINOID protein kinase regulates organ development in Arabidopsis by enhancing polar auxin transport

Development ◽  
2001 ◽  
Vol 128 (20) ◽  
pp. 4057-4067 ◽  
Author(s):  
René Benjamins ◽  
Ab Quint ◽  
Dolf Weijers ◽  
Paul Hooykaas ◽  
Remko Offringa
Keyword(s):  
Protein Kinase ◽  
Auxin Transport ◽  
Vascular Tissue ◽  
Primary Root ◽  
Ectopic Expression ◽  
Polar Auxin Transport ◽  
Fine Tuning ◽  
35S Promoter ◽  
Serine Threonine Kinase ◽  
Transport Inhibitors

Arabidopsis pinoid mutants show a strong phenotypic resemblance to the pin-formed mutant that is disrupted in polar auxin transport. The PINOID gene was recently cloned and found to encode a protein-serine/threonine kinase. Here we show that the PINOID gene is inducible by auxin and that the protein kinase is present in the primordia of cotyledons, leaves and floral organs and in vascular tissue in developing organs or proximal to meristems. Overexpression of PINOID under the control of the constitutive CaMV 35S promoter (35S::PID) resulted in phenotypes also observed in mutants with altered sensitivity to or transport of auxin. A remarkable characteristic of high expressing 35S::PID seedlings was a frequent collapse of the primary root meristem. This event triggered lateral root formation, a process that was initially inhibited in these seedlings. Both meristem organisation and growth of the primary root were rescued when seedlings were grown in the presence of polar auxin transport inhibitors, such as naphthylphtalamic acid (NPA). Moreover, ectopic expression of PINOID cDNA under control of the epidermis-specific LTP1 promoter provided further evidence for the NPA-sensitive action of PINOID. The results presented here indicate that PINOID functions as a positive regulator of polar auxin transport. We propose that PINOID is involved in the fine-tuning of polar auxin transport during organ formation in response to local auxin concentrations.

scholarly journals The Prion-Like Spreading of Alpha-Synuclein in Parkinson’s Disease: Update on Models and Hypotheses

2021 ◽  
Vol 22 (15) ◽  
pp. 8338
Author(s):  
Asad Jan ◽  
Nádia Pereira Gonçalves ◽  
Christian Bjerggaard Vaegter ◽  
Poul Henning Jensen ◽  
Nelson Ferreira
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Molecular Mechanisms ◽  
De Novo ◽  
Alpha Synuclein ◽  
Experimental Models ◽  
Cellular Factors ◽  
Recent Developments ◽  
Novel Targets ◽  
Presynaptic Protein

The pathological aggregation of the presynaptic protein α-synuclein (α-syn) and propagation through synaptically coupled neuroanatomical tracts is increasingly thought to underlie the pathophysiological progression of Parkinson’s disease (PD) and related synucleinopathies. Although the precise molecular mechanisms responsible for the spreading of pathological α-syn accumulation in the CNS are not fully understood, growing evidence suggests that de novo α-syn misfolding and/or neuronal internalization of aggregated α-syn facilitates conformational templating of endogenous α-syn monomers in a mechanism reminiscent of prions. A refined understanding of the biochemical and cellular factors mediating the pathological neuron-to-neuron propagation of misfolded α-syn will potentially elucidate the etiology of PD and unravel novel targets for therapeutic intervention. Here, we discuss recent developments on the hypothesis regarding trans-synaptic propagation of α-syn pathology in the context of neuronal vulnerability and highlight the potential utility of novel experimental models of synucleinopathies.

scholarly journals Membrane Sterol Composition in Arabidopsis thaliana Affects Root Elongation via Auxin Biosynthesis

2021 ◽  
Vol 22 (1) ◽  
pp. 437
Author(s):  
Meng Wang ◽  
Panpan Li ◽  
Yao Ma ◽  
Xiang Nie ◽  
Markus Grebe ◽  
...  
Keyword(s):  
Root Elongation ◽  
Auxin Transport ◽  
Sterol Composition ◽  
Polar Auxin Transport ◽  
Sterol Biosynthesis ◽  
Auxin Biosynthesis ◽  
Root Tip ◽  
Auxin Signaling ◽  
Auxin Response ◽  
Short Root

Plant membrane sterol composition has been reported to affect growth and gravitropism via polar auxin transport and auxin signaling. However, as to whether sterols influence auxin biosynthesis has received little attention. Here, by using the sterol biosynthesis mutant cyclopropylsterol isomerase1-1 (cpi1-1) and sterol application, we reveal that cycloeucalenol, a CPI1 substrate, and sitosterol, an end-product of sterol biosynthesis, antagonistically affect auxin biosynthesis. The short root phenotype of cpi1-1 was associated with a markedly enhanced auxin response in the root tip. Both were neither suppressed by mutations in polar auxin transport (PAT) proteins nor by treatment with a PAT inhibitor and responded to an auxin signaling inhibitor. However, expression of several auxin biosynthesis genes TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS1 (TAA1) was upregulated in cpi1-1. Functionally, TAA1 mutation reduced the auxin response in cpi1-1 and partially rescued its short root phenotype. In support of this genetic evidence, application of cycloeucalenol upregulated expression of the auxin responsive reporter DR5:GUS (β-glucuronidase) and of several auxin biosynthesis genes, while sitosterol repressed their expression. Hence, our combined genetic, pharmacological, and sterol application studies reveal a hitherto unexplored sterol-dependent modulation of auxin biosynthesis during Arabidopsis root elongation.

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