scholarly journals Plant growth and phosphorus accumulation of wild type and two root hair mutants of Arabidopsis thaliana (Brassicaceae)

2000 ◽  
Vol 87 (7) ◽  
pp. 958-963 ◽  
Author(s):  
Terence R. Bates ◽  
Jonathan P. Lynch
Keyword(s):  
Arabidopsis Thaliana ◽  
Plant Growth ◽  
Root Hair ◽  
Wild Type ◽  
Phosphorus Accumulation

scholarly journals PGPR-Induced Growth Stimulation and Nutrient Acquisition in Maize: Do Root Hairs Matter?

2018 ◽  
Vol 49 (3) ◽  
pp. 164-172 ◽  
Author(s):  
N. F. Weber ◽  
I. Herrmann ◽  
F. Hochholdinger ◽  
U. Ludewig ◽  
G. Neumann
Keyword(s):  
Plant Growth ◽  
Root Growth ◽  
Root Hair ◽  
Root Hairs ◽  
Plant Growth Promoting Rhizobacteria ◽  
Nutrient Acquisition ◽  
Root Production ◽  
Wild Type ◽  
Wild Type Line ◽  
Pgpr Strain

Abstract Here we describe the effects of the well-characterized, commercial plant growth-promoting rhizobacteria (PGPR) strain Pseudomonas sp. DSMZ 13134 (Proradix®) on plant growth, root morphology, and nutrient acquisition of a maize mutant (rth2) with impaired root hair production as compared with the corresponding wild type line, to study the importance of root hairs for the interaction of the PGPR strain with the host plant. The study was conducted in rhizobox culture with a sand–soil mixture and moderate P supply. Root hair development of the mutant was clearly impaired, reflected by slower growth and limited elongation as compared with the wild type line. This defect was compensated by more intense root growth and fine root production of the mutant which was particularly expressed after inoculation with Proradix®. By contrast, PGPR inoculation had no effect on root hair length. The beneficial effects of Proradix® on root growth were reflected in higher shoot contents of the macronutrients P and K. Interestingly, negative effects on shoot accumulation of the micronutrients Zn and Cu were observed. These findings support proposed PGPR effects of this strain but also show limitations that may be explained by additional strain-specific properties. Possible implications of these findings are discussed.

scholarly journals The Effect of AtHKT1;1 or AtSOS1 Mutation on the Expressions of Na+ or K+ Transporter Genes and Ion Homeostasis in Arabidopsis thaliana under Salt Stress

2019 ◽  
Vol 20 (5) ◽  
pp. 1085 ◽  
Author(s):  
Qian Wang ◽  
Chao Guan ◽  
Pei Wang ◽  
Qing Ma ◽  
Ai-Ke Bao ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Salt Stress ◽  
Plant Growth ◽  
Expression Profiles ◽  
Ion Homeostasis ◽  
Wild Type ◽  
Na Transport ◽  
K Uptake ◽  
Selective Transport ◽  
K Transport

HKT1 and SOS1 are two key Na+ transporters that modulate salt tolerance in plants. Although much is known about the respective functions of HKT1 and SOS1 under salt conditions, few studies have examined the effects of HKT1 and SOS1 mutations on the expression of other important Na+ and K+ transporter genes. This study investigated the physiological parameters and expression profiles of AtHKT1;1, AtSOS1, AtHAK5, AtAKT1, AtSKOR, AtNHX1, and AtAVP1 in wild-type (WT) and athkt1;1 and atsos1 mutants of Arabidopsis thaliana under 25 mM NaCl. We found that AtSOS1 mutation induced a significant decrease in transcripts of AtHKT1;1 (by 56–62% at 6–24 h), AtSKOR (by 36–78% at 6–24 h), and AtAKT1 (by 31–53% at 6–24 h) in the roots compared with WT. This led to an increase in Na+ accumulation in the roots, a decrease in K+ uptake and transportation, and finally resulted in suppression of plant growth. AtHKT1;1 loss induced a 39–76% (6–24 h) decrease and a 27–32% (6–24 h) increase in transcripts of AtSKOR and AtHAK5, respectively, in the roots compared with WT. At the same time, 25 mM NaCl decreased the net selective transport capacity for K+ over Na+ by 92% in the athkt1;1 roots compared with the WT roots. Consequently, Na+ was loaded into the xylem and delivered to the shoots, whereas K+ transport was restricted. The results indicate that AtHKT1;1 and AtSOS1 not only mediate Na+ transport but also control ion uptake and the spatial distribution of Na+ and K+ by cooperatively regulating the expression levels of relevant Na+ and K+ transporter genes, ultimately regulating plant growth under salt stress.

scholarly journals Knockout of Arabidopsis Serotonin N-Acetyltransferase-2 Reduces Melatonin Levels and Delays Flowering

Biomolecules ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 712 ◽  
Author(s):  
Hyoung Yool Lee ◽  
Kyungjin Lee ◽  
Kyoungwhan Back
Keyword(s):  
Arabidopsis Thaliana ◽  
Enzyme Activity ◽  
Amino Acid ◽  
Plant Growth ◽  
Wild Type ◽  
Knockout Mutant ◽  
Flowering Locus T ◽  
Amino Acid Homology ◽  
Delayed Flowering

Melatonin plays roles in both plant growth and defense. Serotonin N-acetyltransferase (SNAT) catalyzes formation of N-acetylserotonin (NAS) from serotonin. Plants contain two SNAT isogenes, which exhibit low-level amino acid homology. We studied the Arabidopsis thaliana SNAT2 (AtSNAT2) gene; we prepared recombinant SNAT2 protein and characterized a snat2 knockout mutant. The SNAT2 protein exhibited 27% amino acid homology with SNAT1; the Km was 232 μM and the Vmax was 2160 pmol/min/mg protein. Melatonin inhibited SNAT enzyme activity in vitro. SNAT2 mRNA was abundantly expressed in flowers; the melatonin content of flowers of the snat2 mutant was significantly less than that of wild-type flowers. The mutant exhibited delayed flowering and reductions in leaf area and biomass compared to the wild type. Delayed flowering was attributable to reductions in the expression levels of the gibberellin biosynthetic genes ent-kaurene synthase (KS) and FLOWERING LOCUS T (FT).

scholarly journals Cyanobacteria-Derived Proline Increases Stress Tolerance in Arabidopsis thaliana Root Hairs by Suppressing Programmed Cell Death

2020 ◽  
Vol 11 ◽  
Author(s):  
Alysha Chua ◽  
Orla L. Sherwood ◽  
Laurence Fitzhenry ◽  
Carl K.-Y. Ng ◽  
Paul F. McCabe ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Death ◽  
Programmed Cell Death ◽  
Stress Tolerance ◽  
Root Hair ◽  
Root Hairs ◽  
Biologically Active ◽  
Nostoc Muscorum ◽  
Sensitivity Threshold ◽  
Wild Type

Nitrogen-fixing heterocystous cyanobacteria are used as biofertilizer inoculants for stimulating plant growth but can also alleviate plant stress by exometabolite secretion. However, only a small number of studies have focused on elucidating the identity of said bioactives because of the wide array of exuded compounds. Here, we used the root hair assay (RHA) as a rapid programmed cell death (PCD) screening tool for characterizing the bioactivity of cyanobacteria Nostoc muscorum conditioned medium (CM) on Arabidopsis thaliana root hair stress tolerance. We found that heat-stressed A. thaliana pre-treated with N. muscorum CM fractions exhibited significantly lower root hair PCD levels compared to untreated seedlings. Treatment with CM increased stress tolerance by suppressing PCD in root hairs but not necrosis, indicating the bioactive compound was specifically modulating the PCD pathway and not a general stress response. Based on documented N. muscorum exometabolites, we identified the stress-responsive proline as a compound of interest and strong evidence from the ninhydrin assay and HPLC indicate that proline is present in N. muscorum CM. To establish whether proline was capable of suppressing PCD, we conducted proline supplementation experiments. Our results showed that exogenous proline had a similar effect on root hairs as N. muscorum CM treatment, with comparable PCD suppression levels and insignificant necrosis changes. To verify proline as one of the biologically active compounds in N. muscorum CM, we used three mutant A. thaliana lines with proline transporter mutations (lht1, aap1 and atprot1-1::atprot2-3::atprot3-2). Compared with the wild-type seedlings, PCD-suppression in lht1and aap1 mutants was significantly reduced when supplied with low proline (1–5 μM) levels. Similarly, pre-treatment with N. muscorum CM resulted in elevated PCD levels in all three mutant lines compared to wild-type seedlings. Our results show that plant uptake of cyanobacteria-derived proline alters their root hair PCD sensitivity threshold. This offers evidence of a novel biofertilizer mechanism for reducing stress-induced PCD levels, independent of the existing mechanisms documented in the literature.

scholarly journals Arbuscular mycorrhizal colonization outcompetes root hairs in maize under low phosphorus availability

2020 ◽  
Vol 127 (1) ◽  
pp. 155-166
Author(s):  
Xiaomin Ma ◽  
Xuelian Li ◽  
Uwe Ludewig
Keyword(s):  
Gene Expression ◽  
Plant Growth ◽  
Root Hair ◽  
Root Hairs ◽  
Arbuscular Mycorrhizal ◽  
Transporter Gene ◽  
Hair Length ◽  
Wild Type ◽  
Mycorrhizal Dependency ◽  
P Deficiency

Abstract Background and Aims An increase in root hair length and density and the development of arbuscular mycorrhiza symbiosis are two alternative strategies of most plants to increase the root–soil surface area under phosphorus (P) deficiency. Across many plant species, root hair length and mycorrhization density are inversely correlated. Root architecture, rooting density and physiology also differ between species. This study aims to understand the relationship among root hairs, arbuscular mycorrhizal fungi (AMF) colonization, plant growth, P acquisition and mycorrhizal-specific Pi transporter gene expression in maize. Methods Using nearly isogenic maize lines, the B73 wild type and the rth3 root hairless mutant, we quantified the effect of root hairs and AMF infection in a calcareous soil under P deficiency through a combined analysis of morphological, physiological and molecular factors. Key Results Wild-type root hairs extended the rhizosphere for acid phosphatase activity by 0.5 mm compared with the rth3 hairless mutant, as measured by in situ zymography. Total root length of the wild type was longer than that of rth3 under P deficiency. Higher AMF colonization and mycorrhiza-induced phosphate transporter gene expression were identified in the mutant under P deficiency, but plant growth and P acquisition were similar between mutant and the wild type. The mycorrhizal dependency of maize was 33 % higher than the root hair dependency. Conclusions The results identified larger mycorrhizal dependency than root hair dependency under P deficiency in maize. Root hairs and AMF inoculation are two alternative ways to increase Pi acquisition under P deficiency, but these two strategies compete with each other.

scholarly journals The Plastid-Localized AtFtsHi3 Pseudo-Protease of Arabidopsis thaliana Has an Impact on Plant Growth and Drought Tolerance

2021 ◽  
Vol 12 ◽  
Author(s):  
Laxmi S. Mishra ◽  
Sanatkumar Mishra ◽  
Daniel F. Caddell ◽  
Devin Coleman-Derr ◽  
Christiane Funk
Keyword(s):  
Arabidopsis Thaliana ◽  
Drought Tolerance ◽  
Plant Growth ◽  
Crop Production ◽  
Molecular Mechanisms ◽  
Wild Type ◽  
Drought Tolerant ◽  
Darwinian Fitness ◽  
Intrinsic Water Use Efficiency ◽  
Stomata Size

While drought severely affects plant growth and crop production, the molecular mechanisms of the drought response of plants remain unclear. In this study, we demonstrated for the first time the effect of the pseudo-protease AtFtsHi3 of Arabidopsis thaliana on overall plant growth and in drought tolerance. An AtFTSHi3 knock-down mutant [ftshi3-1(kd)] displayed a pale-green phenotype with lower photosynthetic efficiency and Darwinian fitness compared to wild type (Wt). An observed delay in seed germination of ftshi3-1(kd) was attributed to overaccumulation of abscisic acid (ABA); ftshi3-1(kd) seedlings showed partial sensitivity to exogenous ABA. Being exposed to similar severity of soil drying, ftshi3-1(kd) was drought-tolerant up to 20 days after the last irrigation, while wild type plants wilted after 12 days. Leaves of ftshi3-1(kd) contained reduced stomata size, density, and a smaller stomatic aperture. During drought stress, ftshi3-1(kd) showed lowered stomatal conductance, increased intrinsic water-use efficiency (WUEi), and slower stress acclimation. Expression levels of ABA-responsive genes were higher in leaves of ftshi3-1(kd) than Wt; DREB1A, but not DREB2A, was significantly upregulated during drought. However, although ftshi3-1(kd) displayed a drought-tolerant phenotype in aboveground tissue, the root-associated bacterial community responded to drought.

Arabidopsis thaliana Root Hair Cell Cytoplasmic pH (pHc) Imaging

BIO-PROTOCOL ◽  
2015 ◽  
Vol 5 (7) ◽  
Author(s):  
Ling Bai ◽  
Yun Zhou ◽  
Pengtao Wang ◽  
Chun-Peng Song
Keyword(s):  
Arabidopsis Thaliana ◽  
Hair Cell ◽  
Root Hair ◽  
Cytoplasmic Ph ◽  
Root Hair Cell

scholarly journals Inhibition of cell expansion enhances cortical microtubule stability in the root apex of Arabidopsis thaliana

2021 ◽  
Vol 28 (1) ◽  
Author(s):  
Veronica Giourieva ◽  
Emmanuel Panteris
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Wall ◽  
Cell Expansion ◽  
Cortical Microtubule ◽  
Root Apex ◽  
Cellulose Synthase ◽  
Cellulose Biosynthesis ◽  
Cortical Microtubules ◽  
Wild Type ◽  
Microtubule Stability

Abstract Background Cortical microtubules regulate cell expansion by determining cellulose microfibril orientation in the root apex of Arabidopsis thaliana. While the regulation of cell wall properties by cortical microtubules is well studied, the data on the influence of cell wall to cortical microtubule organization and stability remain scarce. Studies on cellulose biosynthesis mutants revealed that cortical microtubules depend on Cellulose Synthase A (CESA) function and/or cell expansion. Furthermore, it has been reported that cortical microtubules in cellulose-deficient mutants are hypersensitive to oryzalin. In this work, the persistence of cortical microtubules against anti-microtubule treatment was thoroughly studied in the roots of several cesa mutants, namely thanatos, mre1, any1, prc1-1 and rsw1, and the Cellulose Synthase Interacting 1 protein (csi1) mutant pom2-4. In addition, various treatments with drugs affecting cell expansion were performed on wild-type roots. Whole mount tubulin immunolabeling was applied in the above roots and observations were performed by confocal microscopy. Results Cortical microtubules in all mutants showed statistically significant increased persistence against anti-microtubule drugs, compared to those of the wild-type. Furthermore, to examine if the enhanced stability of cortical microtubules was due to reduced cellulose biosynthesis or to suppression of cell expansion, treatments of wild-type roots with 2,6-dichlorobenzonitrile (DCB) and Congo red were performed. After these treatments, cortical microtubules appeared more resistant to oryzalin, than in the control. Conclusions According to these findings, it may be concluded that inhibition of cell expansion, irrespective of the cause, results in increased microtubule stability in A. thaliana root. In addition, cell expansion does not only rely on cortical microtubule orientation but also plays a regulatory role in microtubule dynamics, as well. Various hypotheses may explain the increased cortical microtubule stability under decreased cell expansion such as the role of cell wall sensors and the presence of less dynamic cortical microtubules.

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