scholarly journals Enhanced polar auxin transport in tomato polycotyledon mutant seems to be related to glutathione levels

2019 ◽  
Author(s):  
Sapana Nongmaithem ◽  
Rachana Ponukumatla ◽  
Yellamaraju Sreelakshmi ◽  
Pierre Frasse ◽  
Mondher Bouzayen ◽  
...  
Keyword(s):  
Microarray Analysis ◽  
Auxin Transport ◽  
Buthionine Sulfoximine ◽  
Polar Auxin Transport ◽  
Glutathione Metabolism ◽  
Root Tips ◽  
Short Root ◽  
Hydroxyphenylacetic Acid ◽  
Naphthylphthalamic Acid

AbstractGlutathione-dependent root growth in Arabidopsis is linked to polar auxin transport (PAT). Arabidopsis mutants with reduced glutathione (GSH) levels also show reduced PAT. To gain an insight into the relationship between PAT and GSH level, we analysed tomato polycotyledon mutant, pct1-2, which has enhanced PAT. Microarray analysis of gene expression in pct1-2 mutant revealed underexpression of several genes related to glutamate and glutathione metabolism. In consonance with microarray analysis, enzymatic as well as in-vivo assay revealed higher glutathione level in the early phase of pct1-2 seedling growth than WT. The inhibition of auxin transport by 2,3,5-triiodobenzoic acid (TIBA) reduced both GSH level and PIN1 expression in pct1-2 root tips. The reduction of in vivo GSH accumulation in pct1-2 root tips by buthionine sulfoximine (BSO) stimulated elongation of the short root of pct1-2 mutant akin to TIBA. The rescue of short root phenotype of pct1-2 mutant was restricted to TIBA and BSO. The other auxin transport inhibitors 1-N-naphthylphthalamic acid (NPA), 2-[4-(diethylamino)-2-hydroxybenzoyl] benzoic acid (BUM), 3-chloro-4-hydroxyphenylacetic acid (CHPAA), brefeldin and gravacin inhibited root elongation in both WT and pct1-2 mutant. Our results indicate a relationship between PAT and GSH level in tomato akin to Arabidopsis. Our work also highlights that TIBA rescues short root phenotype of the pct1-2 mutant by acting on a PAT component distinct from the site of action of other PAT inhibitors.

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.

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

scholarly journals Ethylene Does Not Promote Adventitious Root Initiation on Apple Microcuttings

1996 ◽  
Vol 121 (5) ◽  
pp. 880-885 ◽  
Author(s):  
James F. Harbage ◽  
Dennis P. Stimart
Keyword(s):  
Carboxylic Acid ◽  
Auxin Transport ◽  
Adventitious Rooting ◽  
Polar Auxin Transport ◽  
Root Initiation ◽  
Ethylene Evolution ◽  
Basal Section ◽  
Naphthylphthalamic Acid ◽  
Transport Inhibitors

We investigated the role of ethylene on adventitious rooting of `Gala' (easy-to-root) and `Triple Red Delicious' (difficult-to-root) apple (Malus domestica Borkh.) microcuttings. Root count increased significantly as IBA level increased, with highest root counts on `Gala'. Ethylene evolution increased significantly with IBA level without significant differences between cultivars. Basal section removal of microcuttings in the area of root origin reduced root count without changing ethylene evolution. Ethylene treatment of proliferated shoots before microcutting excision failed to enhance rooting. IBA-induced ethylene evolution was eliminated nearly by AVG, but root count remained IBA dependent. ACC reversed IBA plus AVG rooting inhibition, but ACC alone failed to influence root count. Polar auxin transport inhibitors NPA and TIBA stimulated ethylene evolution without increasing root count. Adventitious rooting of apple microcuttings was not associated with ethylene. Chemical names used: 1-H-indole-3-butyric acid (IBA); aminoethoxyvinylglycine (AVG); 1-aminocyclopropane-1-carboxylic acid (ACC); 2,3,5-triiodobenzoic acid (TIBA); N-1-naphthylphthalamic acid (NPA).

scholarly journals Mode of Action of 1-Naphthylphthalamic Acid in Conspicuous Local Stem Swelling of Succulent Plant, Bryophyllum calycinum: Relevance to the Aspects of Its Histological Observation and Comprehensive Analyses of Plant Hormones

2021 ◽  
Vol 22 (6) ◽  
pp. 3118
Author(s):  
Agnieszka Marasek-Ciolakowska ◽  
Michał Dziurka ◽  
Urszula Kowalska ◽  
Justyna Góraj-Koniarska ◽  
Marian Saniewski ◽  
...  
Keyword(s):  
Jasmonic Acid ◽  
Plant Hormones ◽  
Mode Of Action ◽  
Auxin Transport ◽  
Polar Auxin Transport ◽  
Histological Observation ◽  
Succulent Plant ◽  
Cell Layers ◽  
Naphthylphthalamic Acid ◽  
Succulent Plants

The mode of action of 1-naphthylphthalamic acid (NPA) to induce conspicuous local stem swelling in the area of its application to the growing internode in intact Bryophyllum calycinum was studied based on the aspects of histological observation and comprehensive analyses of plant hormones. Histological analyses revealed that NPA induced an increase in cell size and numerous cell divisions in the cortex and pith, respectively, compared to untreated stem. In the area of NPA application, vascular tissues had significantly wider cambial zones consisting of 5–6 cell layers, whereas phloem and xylem seemed not to be affected. This indicates that stem swelling in the area of NPA application is caused by stimulation of cell division and cell enlargement mainly in the cambial zone, cortex, and pith. Comprehensive analyses of plant hormones revealed that NPA substantially increased endogenous levels of indole-3-acetic acid (IAA) in the swelling area. NPA also increased endogenous levels of cytokinins, jasmonic acid, and its precursor, 12-oxo-phytodienoic acid, but did not increase abscisic acid and gibberellin levels. It was shown, using radiolabeled 14C-IAA, that NPA applied to the middle of internode segments had little effect on polar auxin transport, while 2,3,5-triiodobenzoic acid substantially inhibited it. These results strongly suggest that NPA induces changes in endogenous levels of plant hormones, such as IAA, cytokinins, and jasmonic acid, and their hormonal crosstalk results in a conspicuous local stem swelling. The possible different mode of action of NPA from other polar auxin transport inhibitors in succulent plants is extensively discussed.

Auxin and ETTIN in Arabidopsis gynoecium morphogenesis

Development ◽  
2000 ◽  
Vol 127 (18) ◽  
pp. 3877-3888 ◽  
Author(s):  
J.L. Nemhauser ◽  
L.J. Feldman ◽  
P.C. Zambryski
Keyword(s):  
Auxin Transport ◽  
Floral Organ ◽  
Polar Auxin Transport ◽  
Auxin Response ◽  
Auxin Transport Inhibitor ◽  
Increased Sensitivity ◽  
Auxin Flux ◽  
Naphthylphthalamic Acid

The phytohormone auxin has wide-ranging effects on growth and development. Genetic and physiological approaches implicate auxin flux in determination of floral organ number and patterning. This study uses a novel technique of transiently applying a polar auxin transport inhibitor, N-1-naphthylphthalamic acid (NPA), to developing Arabidopsis flowers to further characterize the role of auxin in organogenesis. NPA has marked effects on floral organ number as well as on regional specification in wild-type gynoecia, as defined by morphological and histological landmarks for regional boundaries, as well as tissue-specific reporter lines. NPA's effects on gynoecium patterning mimic the phenotype of mutations in ETTIN, a member of the auxin response factor family of transcription factors. In addition, application of different concentrations of NPA reveal an increased sensitivity of weak ettin alleles to disruptions in polar auxin transport. In contrast, the defects found in spatula gynoecia are partially rescued by treatment with NPA. A model is proposed suggesting an apical-basal gradient of auxin during gynoecium development. This model provides a mechanism linking ETTIN's putative transcriptional regulation of auxin-responsive genes to the establishment or elaboration of tissue patterning during gynoecial development.

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