The SAR1 gene of Arabidopsis acts downstream of the AXR1 gene in auxin response

Development ◽  
1997 ◽  
Vol 124 (8) ◽  
pp. 1583-1591
Author(s):  
A. Cernac ◽  
C. Lincoln ◽  
D. Lammer ◽  
M. Estelle
Keyword(s):  
Leaf Morphology ◽  
Primary Root ◽  
Resistant Mutant ◽  
Wild Type ◽  
Auxin Response ◽  
Seedling Morphology ◽  
Major Function ◽  
Root Hair Development ◽  
Auxin Resistance ◽  
Hair Development

A screen for suppressors of the auxin resistant mutant axr1 in Arabidopsis thaliana has identified at least three second site suppressor loci called Suppressor of Auxin Resistance (SAR). In this study we focus on the SAR1 gene. Previous studies have documented the effects of the axr1 mutations on auxin-inhibition of root growth, auxin-induced gene expression, seedling morphology and aerial morphology. In this study, we show that the axr1 mutations also affect root hair development and epidermal cell length. The sar1-1 mutation suppresses at least partially, every aspect of the axr1 phenotype. Genetic experiments indicate that this suppression is gene specific. When crossed with the auxin-resistant mutant aux1-7, the suppressor has little affect on auxin response. However, the morphology of sar1-1 aux1-7 inflorescences is different from either of the single mutants indicating that both genes play a role in auxin mediated development of the inflorescence. The sar1-1 mutation also affects morphology in an AXR1 background. sar1-1 plants are shorter than wild-type, have altered leaf morphology, flower earlier than wild-type plants and appear to have reduced cell division in the primary root. In most respects sar1-1 axr1 and sar1 AXR1 plants are indistinguishable, indicating that sar1 both suppresses and is epistatic to axr1. Based on these results, we propose that SAR1 acts after AXR1 and that a major function of AXR1 is to relieve SAR1 mediated repression of auxin response.

scholarly journals Contribution of Root Hair Development to Sulfate Uptake in Arabidopsis

Plants ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 106 ◽  
Author(s):  
Kimura ◽  
Ushiwatari ◽  
Suyama ◽  
Tominaga-Wada ◽  
Wada ◽  
...  
Keyword(s):  
Root Biomass ◽  
Primary Root ◽  
Root Hairs ◽  
Sulfur Deficiency ◽  
Sulfate Uptake ◽  
High Affinity ◽  
Root Hair Development ◽  
Uptake Rates ◽  
Hair Development ◽  
Lower Expression

Root hairs often contribute to nutrient uptake from environments, but the contribution varies among nutrients. In Arabidopsis, two high-affinity sulfate transporters, SULTR1;1 and SULTR1;2, are responsible for sulfate uptake by roots. Their increased expression under sulfur deficiency (−S) stimulates sulfate uptake. Inspired by the higher and lower expression, respectively, of SULTR1;1 in mutants with more (werwolf [wer]) and fewer (caprice [cpc]) root hairs, we examined the contribution of root hairs to sulfate uptake. Sulfate uptake rates were similar among plant lines under both sulfur sufficiency (+S) and −S. Under −S, the expression of SULTR1;1 and SULTR1;2 was negatively correlated with the number of root hairs. These results suggest that both −S-induced SULTR expression and sulfate uptake rates were independent of the number of root hairs. In addition, we observed (1) a negative correlation between primary root lengths and number of root hairs and (2) a greater number of root hairs under −S than under +S. These observations suggested that under both +S and −S, sulfate uptake was influenced by the root biomass rather than the number of root hairs.

scholarly journals Heterologous Expression of GbTCP4, a Class II TCP Transcription Factor, Regulates Trichome Formation and Root Hair Development in Arabidopsis

Genes ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 726 ◽  
Author(s):  
Yi Wang ◽  
Yuehua Yu ◽  
Quanjia Chen ◽  
Guanghong Bai ◽  
Wenwei Gao ◽  
...  
Keyword(s):  
Root Hair ◽  
Cotton Fiber ◽  
Transgenic Arabidopsis ◽  
Primary Root ◽  
Class Ii ◽  
Gene Transcript ◽  
Transcript Levels ◽  
Root Hair Development ◽  
Trichome Formation ◽  
Hair Development

Two class I family teosinte branched1/cycloidea/proliferating cell factor1 (TCP) proteins from allotetraploid cotton are involved in cotton fiber cell differentiation and elongation and root hair development. However, the biological function of most class II TCP proteins is unclear. This study sought to reveal the characteristics and functions of the sea-island cotton class II TCP gene GbTCP4 by biochemical, genetic, and molecular biology methods. GbTCP4 protein localizes to nuclei, binding two types of TCP-binding cis-acting elements, including the one in its promoter. Expression pattern analysis revealed that GbTCP4 is widely expressed in tissues, with the highest level in flowers. GbTCP4 is expressed at different fiber development stages and has high transcription in fibers beginning at 5 days post anthesis (DPA). GbTCP4 overexpression increases primary root hair length and density and leaf and stem trichomes in transgenic Arabidopsis relative to wild-type plants (WT). GbTCP4 binds directly to the CAPRICE (CPC) promoter, increasing CPC transcript levels in roots and reducing them in leaves. Compared with WT plants, lignin content in the stems of transgenic Arabidopsis overexpressing GbTCP4 increased, and AtCAD5 gene transcript levels increased. These results suggest that GbTCP4 regulates trichome formation and root hair development in Arabidopsis and may be a candidate gene for regulating cotton fiber elongation.

scholarly journals CHROMOSOMAL BASIS OF THE MEROZYGOSITY IN A PARTIALLY DIPLOID MUTANT OF PNEUMOCOCCUS

Genetics ◽  
1975 ◽  
Vol 80 (4) ◽  
pp. 667-678
Author(s):  
Mary Lee S Ledbetter ◽  
Rollin D Hotchkiss
Keyword(s):  
High Efficiency ◽  
Point Mutations ◽  
Resistant Mutant ◽  
Chromosomal Marker ◽  
Structural Abnormality ◽  
C Cells ◽  
Wild Type ◽  
Chromosomal Locus ◽  
Low Efficiency ◽  
Derivatives Of

ABSTRACT A sulfonamide-resistant mutant of pneumococcus, sulr-c, displays a genetic instability, regularly segregating to wild type. DNA extracts of derivatives of the strain possess transforming activities for both the mutant and wild-type alleles, establishing that the strain is a partial diploid. The linkage of sulr-c to strr-61, a stable chromosomal marker, was established, thus defining a chromosomal locus for sulr-c. DNA isolated from sulr-c cells transforms two mutant recipient strains at the same low efficiency as it does a wild-type recipient, although the mutant property of these strains makes them capable of integrating classical "low-efficiency" donor markers equally as efficiently as "high efficiency" markers. Hence sulr-c must have a different basis for its low efficiency than do classical low efficiency point mutations. We suggest that the DNA in the region of the sulr-c mutation has a structural abnormality which leads both to its frequent segregation during growth and its difficulty in efficiently mediating genetic transformation.

scholarly journals 3,4-dehydro-L-proline Induces Programmed Cell Death in the Roots of Brachypodium distachyon

2021 ◽  
Vol 22 (14) ◽  
pp. 7548
Author(s):  
Artur Pinski ◽  
Alexander Betekhtin ◽  
Jolanta Kwasniewska ◽  
Lukasz Chajec ◽  
Elzbieta Wolny ◽  
...  
Keyword(s):  
Cell Death ◽  
Brachypodium Distachyon ◽  
Root Hairs ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Cell Wall Proteins ◽  
Root Epidermis ◽  
Root Hair Development ◽  
Transmission Electron ◽  
Hair Development

As cell wall proteins, the hydroxyproline-rich glycoproteins (HRGPs) take part in plant growth and various developmental processes. To fulfil their functions, HRGPs, extensins (EXTs) in particular, undergo the hydroxylation of proline by the prolyl-4-hydroxylases. The activity of these enzymes can be inhibited with 3,4-dehydro-L-proline (3,4-DHP), which enables its application to reveal the functions of the HRGPs. Thus, to study the involvement of HRGPs in the development of root hairs and roots, we treated seedlings of Brachypodium distachyon with 250 µM, 500 µM, and 750 µM of 3,4-DHP. The histological observations showed that the root epidermis cells and the cortex cells beneath them ruptured. The immunostaining experiments using the JIM20 antibody, which recognizes the EXT epitopes, demonstrated the higher abundance of this epitope in the control compared to the treated samples. The transmission electron microscopy analyses revealed morphological and ultrastructural features that are typical for the vacuolar-type of cell death. Using the TUNEL test (terminal deoxynucleotidyl transferase dUTP nick end labelling), we showed an increase in the number of nuclei with damaged DNA in the roots that had been treated with 3,4-DHP compared to the control. Finally, an analysis of two metacaspases’ gene activity revealed an increase in their expression in the treated roots. Altogether, our results show that inhibiting the prolyl-4-hydroxylases with 3,4-DHP results in a vacuolar-type of cell death in roots, thereby highlighting the important role of HRGPs in root hair development and root growth.

scholarly journals The Histone Chaperone NRP1 Interacts with WEREWOLF to Activate GLABRA2 in Arabidopsis Root Hair Development

2017 ◽  
Vol 29 (2) ◽  
pp. 260-276 ◽  
Author(s):  
Yan Zhu ◽  
Liang Rong ◽  
Qiang Luo ◽  
Baihui Wang ◽  
Nana Zhou ◽  
...  
Keyword(s):  
Root Hair ◽  
Histone Chaperone ◽  
Arabidopsis Root ◽  
Root Hair Development ◽  
Hair Development
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