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

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.

Author(s):  
Durgesh Kumar Tripathi ◽  
Padmaja Rai ◽  
Gea Guerriero ◽  
Shivesh Sharma ◽  
Francisco J Corpas ◽  
...  

Abstract Arsenic (As) negatively affects plant development. Using rice as a model, this study evaluates how the application of silicon (10 µM Si) can favour the formation of adventitious roots under arsenate stress (50 µM As V) as a mechanism to mitigate its negative effects. Indeed, the simultaneous application of As V and Si up-regulated the expression of genes involved in nitric oxide (NO) metabolism (OsNOA1), cell cycle progression (G2-M, OsCDKA1), auxin (IAA, indole-3-acetic acid) biosynthesis (OsYUCCA1 and OsTAA1) and transport (OsPIN1, OsPIN5 and OsPIN10) and Si uptake (OsLsi1 and OsLsi2), which accompanied adventitious root formation. Furthermore, Si triggered the expression and activity of MDHAR and DHAR involved in ascorbate recycling. The treatment with L-NAME, an inhibitor of NO generation, significantly suppressed adventitious root formation, even in the presence of Si; however, supplying NO in the growth media rescued its effects. The data obtained suggest that both NO and IAA are essential for Si-mediated adventitious root formation under As V stress. Interestingly, TIBA (a polar auxin transport inhibitor) suppressed adventitious root formation, even in the presence of Si and SNP (an NO donor), suggesting that Si is involved in a mechanism whereby a cellular signal is triggered and requires NO formation first and, then, IAA.


1993 ◽  
Vol 48 (1-2) ◽  
pp. 35-40 ◽  
Author(s):  
Andreas Jacobi ◽  
Rolf Zettl ◽  
Klaus Palme ◽  
Dietrich Werner

Binding of tritiated indole-3-acetic acid ([3H]IAA) to symbiosome membranes of soybean nodules occurred in a protein-dependent manner and was competitively inhibited by unlabeled indole-3-acetic acid (IAA), 1-naphthaleneacetic acid (1-NAA) and dithiothreitol (DTT), but not by tryptophan and benzoic acid. The symbiosome membranes bound IAA with a KD of 1 × 10-6 m. Photoaffinity labeling identified an auxin-binding protein (ABP) in the symbiosome membrane with an apparent molecular mass of 23 kDa. This 23 kDa protein was labeled either with 5-azido-[7-3H]indole-3-acetic acid ([3H]N3IAA) or with 5′-azido-[3,6-3H2]-1-naphthylphthalamic acid ([3H2]N3NPA). Labeling of the 23 kDa protein with [3H]N3IAA was competitively inhibited by unlabeled IAA and 1-NAA. NPA and quercetin, inhibitors of polar auxin transport, as well as rutin, a glycosylated derivative of quercetin, competed with IAA for binding. Conversely, [3H2]N3NPA labeling was inhibited by unlabeled IAA and NPA. The 23 kDa symbiosome membrane protein was partially solubilized with Triton X-100 and nearly completely using Triton X-114. The observation that auxin transport inhibitors compete with IAA for binding suggests that the symbiosome membrane ABP could be part of an auxin efflux carrier system required to control the auxin concentration in infected soybean nodule cells.


2004 ◽  
Vol 120 (3) ◽  
pp. 501-508 ◽  
Author(s):  
Anne Jambois ◽  
Franck Anicet Ditengou ◽  
Tomonori Kawano ◽  
Alain Delbarre ◽  
Frederic Lapeyrie

1983 ◽  
Vol 61 (4) ◽  
pp. 1064-1071 ◽  
Author(s):  
Karol E. Paterson

Two auxin transport inhibitors, triodobenzoic acid and 3,3a-dihydro-2-(p-methoxyphenyl)-8H-pyrazol(5,1-a)isoindol-8-one, inhibited the number of plantlets regenerated from leaves of Crassula argentea. This inhibition can be partially overcome with indole 3-acetic acid. The antiauxin, parachlorophenoxyisobutyric acid, reduced the amount of auxin-induced regeneration for 14 days in culture. High concentrations of isopentenyl adenine inhibited the auxin-induced regeneration response, but not the reduction in polarity of plantlet regeneration caused by exogenous auxin.


2017 ◽  
Author(s):  
Maya Khasin ◽  
Rebecca R. Cahoon ◽  
Kenneth W. Nickerson ◽  
Wayne R. Riekhof

AbstractIndole-3-acetic acid is a ubiquitous small molecule found in all domains of life. It is the predominant and most active auxin in seed plants, where it coordinates a variety of complex growth and development processes. The potential origin of auxin signaling in algae remains a matter of some controversy. In order to clarify the evolutionary context of algal auxin signaling, we undertook a genomic survey to assess whether auxin acts as a signaling molecule in the emerging model chlorophyte Chlorella sorokiniana UTEX 1230. C. sorokiniana produces the auxin indole-3-acetic acid (IAA), which was present in both the cell pellet and in the supernatant at a concentration of ~ 1 nM, and its genome encodes orthologs of genes related to auxin synthesis, transport, and signaling in higher plants. Candidate orthologs for the canonical AUX/IAA signaling pathway were not found; however, auxin-binding protein 1 (ABP1), an alternate auxin receptor, is present and highly conserved at essential auxin binding and zinc coordinating residues. Additionally, candidate orthologs for PIN proteins, responsible for intercellular, vectorial auxin transport in higher plants, were not found, but PILs (PIN-Like) proteins, a recently discovered family that mediates intracellular auxin transport, were identified. The distribution of auxin related gene in this unicellular chlorophyte demonstrates that a core suite of auxin signaling components was present early in the evolution of plants. Understanding the simplified auxin signaling pathways in chlorophytes will aid in understanding phytohormone signaling and crosstalk in seed plants, and in understanding the diversification and integration of developmental signals during the evolution of multicellular plants.


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