Auxin regulates lateral meristem activation in developing gametophytes of Ceratopteris richardii

2006 ◽  
Vol 84 (10) ◽  
pp. 1520-1530 ◽  
Author(s):  
Michele Gregorich ◽  
Roxanne Fisher
Keyword(s):  
Auxin Transport ◽  
Time Lag ◽  
Naphthaleneacetic Acid ◽  
Ceratopteris Richardii ◽  
Exogenous Auxin ◽  
Auxin Regulation ◽  
Lateral Meristem ◽  
Naphthylphthalamic Acid ◽  
Reduced Activity ◽  
Chlorophenoxyisobutyric Acid

This study investigates the auxin regulation of lateral meristem activation in the gametophytes of the fern Ceratopteris richardii Brongn. Exogenous auxin in the form of α-naphthaleneacetic acid or 2,4,5-trichlorophenoxy-acetic acid repressed the activation of the lateral meristem, and generated a male-like body plan. The auxin antagonist p-chlorophenoxyisobutyric acid reduced activity of both the apical and lateral meristems, and produced a circular-shaped gametophyte. Disrupting auxin transport with 2,3,5-triiodobenzoic acid led to a time lag in lateral meristem activation, while disrupting auxin transport with n-1-naphthylphthalamic acid produced several different body plans generated by the formation of a second lateral meristem. These findings suggest auxin mediates the activation of the lateral meristem and regulates lateral meristem function. In addition, auxin transport may be necessary for communication between the lateral meristem and other regions of the developing gametophyte. Auxin also controls the position of rhizoids produced by the gametophyte, and exogenous auxin interferes with the sexual differentiation of the gametophyte. These results are summarized in a model of how auxin regulates lateral meristem activation and meristem activity during gametophyte development in C. richardii.

scholarly journals Differential effects of N-1-naphthylphthalamic acid (NPA) and 2,3,5-triiodobenzoic acid (TIBA) on auxin control of swelling of the shoots of Bryophyllum calycinum Salisb.

2017 ◽  
Vol 70 (3) ◽  
Author(s):  
Marian Saniewski ◽  
Justyna Góraj-Koniarska ◽  
Eleonora Gabryszewska ◽  
Kensuke Miyamoto ◽  
Junichi Ueda
Keyword(s):  
Acetic Acid ◽  
Differential Effect ◽  
Auxin Transport ◽  
Differential Mode ◽  
Treatment Area ◽  
Simultaneous Application ◽  
Triiodobenzoic Acid ◽  
Intact Plants ◽  
Naphthylphthalamic Acid ◽  
Indole 3 Acetic Acid

The effects of <em>N</em>-1-naphthylphthalamic acid (NPA) and 2,3,5-triiodobenzoic acid (TIBA) on the swelling of the stem in intact and decapitated plants of <em>Bryophyllum calycinum</em> in relation to the interaction with auxin, indole-3-acetic acid (IAA), are described. NPA induced conspicuous local internode swelling only in the area of its application in intact plants and in the decapitated internode in the case of simultaneous application of IAA on the top of the internode. By contrast, TIBA applied to an internode of intact plants induced swelling along the entire internode above the treatment area, and similar results were obtained in the decapitated internode when TIBA was applied in the middle of the internode and IAA was applied onto the top of the internode. The differential effect of NPA and TIBA on stem swelling in <em>B. calycinum</em> is discussed in relation to their differential mode of action on auxin transport.

Reduced Naphthylphthalamic Acid Binding in the tir3 Mutant of Arabidopsis Is Associated with a Reduction in Polar Auxin Transport and Diverse Morphological Defects

1997 ◽  
Vol 9 (5) ◽  
pp. 745 ◽  
Author(s):  
Max Ruegger ◽  
Elizabeth Dewey ◽  
Lawrence Hobbie ◽  
Dana Brown ◽  
Paul Bernasconi ◽  
...  
Keyword(s):  
Auxin Transport ◽  
Polar Auxin Transport ◽  
Morphological Defects ◽  
Naphthylphthalamic Acid

Auxin regulation of gibberellin biosynthesis in the roots of pea (Pisum sativum)

2009 ◽  
Vol 36 (4) ◽  
pp. 362 ◽  
Author(s):  
Diana E. Weston ◽  
James B. Reid ◽  
John J. Ross
Keyword(s):  
Pisum Sativum ◽  
Inhibitory Effect ◽  
Gibberellin Biosynthesis ◽  
Growth Inhibitory ◽  
Auxin Regulation ◽  
Auxin Transport Inhibitor ◽  
Naphthylphthalamic Acid ◽  
Pea Roots ◽  
High Auxin ◽  
Ga Biosynthesis

Auxin promotes GA biosynthesis in the aboveground parts of plants. However, it has not been demonstrated previously that this interaction occurs in roots. To understand the interactions between auxin and GAs in these organs, we treated wild-type pea (Pisum sativum L.) roots with the inhibitors of auxin action, p-chlorophenoxyisobutyric acid (PCIB) and yokonolide B (YkB), and with the auxin transport inhibitor N-1-naphthylphthalamic acid (NPA). These compounds generally downregulated GA synthesis genes and upregulated GA deactivation genes, and reduced the level of the bioactive GA1. These effects indicate that in pea roots, auxin at normal endogenous levels stimulates GA biosynthesis. We show also that supra-optimal levels of exogenous auxin reduce the endogenous level of bioactive GA in roots, although the effect appears too small to account for the strong growth-inhibitory effect of high auxin levels.

scholarly journals A quantitative study of cotyledon positioning in conifer development

Botany ◽  
2016 ◽  
Vol 94 (11) ◽  
pp. 1063-1074 ◽  
Author(s):  
David M. Holloway ◽  
Byron Brook ◽  
JooHyun Kang ◽  
Cameron Wong ◽  
Michael Wu
Keyword(s):  
Pseudotsuga Menziesii ◽  
Quantitative Study ◽  
Growth Regulator ◽  
Auxin Transport ◽  
Picea Sitchensis ◽  
Common Mechanism ◽  
Developmental Patterns ◽  
Second Stage ◽  
Spacing Distance ◽  
Naphthylphthalamic Acid

The number of cotyledons in angiosperm monocots and dicots is tightly constrained. But in the gymnosperm Pinaceae (pine family), which includes many of the conifers, cotyledon number (nc) can vary widely, commonly from 2 to 12. Conifer cotyledons form in whorled rings on a domed embryo geometry. We measured the diameter of embryos and counted the cotyledons to determine the radial positioning of the whorl and the circumferential spacing between cotyledons. Results were similar between Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), Sitka spruce (Picea sitchensis (L.) H.Karst.), and larch (Larix × leptoeuropaea, synonymous with L. × marschlinsii Coaz), indicating a common mechanism for cotyledon positioning in conifers. Disrupting transport of the growth regulator auxin (with 1-N-naphthylphthalamic acid (NPA)) led to cup-shaped embryos, indicating that whorl (ring) formation is separable from cotyledon patterning within the ring. NPA inhibits cotyledon outgrowth, but not the spacing (distance) between cotyledons. The NPA effect is direct; it does not operate indirectly on embryo size. These results support a hierarchical model for cotyledon positioning in conifers, in which a first stage (not requiring auxin transport) sets the whorl position, constraining the second stage (which requires auxin transport) to form cotyledons within this whorl. Similarly, recent studies in Arabidopsis have shown that different components of complex developmental patterns can have different transport properties; this aspect of patterning may be shared across plants.

scholarly journals Strigolactones Promote Leaf Elongation in Tall Fescue through Upregulation of Cell Cycle Genes and Downregulation of Auxin Transport Genes in Tall Fescue under Different Temperature Regimes

2019 ◽  
Vol 20 (8) ◽  
pp. 1836
Author(s):  
Hu ◽  
Zhang ◽  
Huang
Keyword(s):  
Cell Cycle ◽  
Tall Fescue ◽  
Festuca Arundinacea ◽  
Auxin Transport ◽  
Leaf Growth ◽  
Naphthaleneacetic Acid ◽  
Synthetic Analog ◽  
Plant Tolerance ◽  
Leaf Elongation ◽  
Temperature Regimes

Strigolactones (SLs) have recently been shown to play roles in modulating plant architecture and improving plant tolerance to multiple stresses, but the underlying mechanisms for SLs regulating leaf elongation and the influence by air temperature are still unknown. This study aimed to investigate the effects of SLs on leaf elongation in tall fescue (Festuca arundinacea, cv. ‘Kentucky-31′) under different temperature regimes, and to determine the interactions of SLs and auxin in the regulation of leaf growth. Tall fescue plants were treated with GR24 (synthetic analog of SLs), naphthaleneacetic acid (NAA, synthetic analog), or N-1-naphthylphthalamic acid (NPA, auxin transport inhibitor) (individually and combined) under normal temperature (22/18 °C) and high-temperature conditions (35/30 °C) in controlled-environment growth chambers. Exogenous application of GR24 stimulated leaf elongation and mitigated the heat inhibition of leaf growth in tall fescue. GR24-induced leaf elongation was associated with an increase in cell numbers, upregulated expression of cell-cycle-related genes, and downregulated expression of auxin transport-related genes in elongating leaves. The results suggest that SLs enhance leaf elongation by stimulating cell division and interference with auxin transport in tall fescue.

scholarly journals Activation of Big Grain1 significantly improves grain size by regulating auxin transport in rice

2015 ◽  
Vol 112 (35) ◽  
pp. 11102-11107 ◽  
Author(s):  
Linchuan Liu ◽  
Hongning Tong ◽  
Yunhua Xiao ◽  
Ronghui Che ◽  
Fan Xu ◽  
...  
Keyword(s):  
Grain Size ◽  
Auxin Transport ◽  
Vascular Tissue ◽  
Plant Biomass ◽  
Key Factors ◽  
Auxin Distribution ◽  
New Strategy ◽  
Dna Insertion ◽  
Auxin Transport Inhibitor ◽  
Naphthylphthalamic Acid

Grain size is one of the key factors determining grain yield. However, it remains largely unknown how grain size is regulated by developmental signals. Here, we report the identification and characterization of a dominant mutant big grain1 (Bg1-D) that shows an extra-large grain phenotype from our rice T-DNA insertion population. Overexpression of BG1 leads to significantly increased grain size, and the severe lines exhibit obviously perturbed gravitropism. In addition, the mutant has increased sensitivities to both auxin and N-1-naphthylphthalamic acid, an auxin transport inhibitor, whereas knockdown of BG1 results in decreased sensitivities and smaller grains. Moreover, BG1 is specifically induced by auxin treatment, preferentially expresses in the vascular tissue of culms and young panicles, and encodes a novel membrane-localized protein, strongly suggesting its role in regulating auxin transport. Consistent with this finding, the mutant has increased auxin basipetal transport and altered auxin distribution, whereas the knockdown plants have decreased auxin transport. Manipulation of BG1 in both rice and Arabidopsis can enhance plant biomass, seed weight, and yield. Taking these data together, we identify a novel positive regulator of auxin response and transport in a crop plant and demonstrate its role in regulating grain size, thus illuminating a new strategy to improve plant productivity.

The white-tip nematode, Aphelenchoides besseyi, exhibits an auxin-orientated behaviour affecting its migration and propagation

Nematology ◽  
2014 ◽  
Vol 16 (7) ◽  
pp. 837-845 ◽  
Author(s):  
Hui Feng ◽  
Ying Shao ◽  
Li-hui Wei ◽  
Cun-yi Gao ◽  
Yi-jun Zhou
Keyword(s):  
Auxin Transport ◽  
Naphthaleneacetic Acid ◽  
Male Sterile ◽  
Auxin Level ◽  
Rice Plants ◽  
Transport Inhibitor ◽  
Large Numbers ◽  
Auxin Concentration ◽  
Aphelenchoides Besseyi ◽  
Auxin Transport Inhibitor

Aphelenchoides besseyi is an obligate parasite that often causes white-tip symptoms in rice plants. The nematode exhibits ectoparasitic behaviour with its infection rate matching the development of rice plants. Few studies have analysed how A. besseyi migration is influenced by chemical and host factors. Here, we focused on the effects of auxins on nematode migration and propagation. Exposure of A. besseyi to an auxin gradient created by a Pluronic F-127 gel resulted in nematode aggregation at the highest auxin concentration tested, 100 μm. Inoculation on the susceptible cv. Ningjing1 produced more nematodes than on the resistant rice cv. Tetep, which correlated with their endogenous auxin levels. Young panicles treated with 1-naphthaleneacetic acid produced more grains and nematodes, whereas plants treated with the auxin transport inhibitor, 2,3,5-triiodobenzoic acid, led to fewer nematodes in the seeds. In addition, A. besseyi rarely migrated and multiplied in the plants of the male sterile rice cv. Zhenshan97A, which had insufficient auxin level in pollen and thus could not generate any grains in most panicles. However, large numbers of nematodes were observed in seeds of cv. Zhenshan97A that had received pollens from the maintainer cv. Zhenshan97B. The results indicate that auxin might play a key role in the migration and propagation of A. besseyi.

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