Danger-Associated Peptides Interact with PIN-Dependent Local Auxin Distribution to Inhibit Root Growth in Arabidopsis

It has been previously reported that POST-applied isoxaben can effectively control established hairy bittercress. Experiments were conducted to determine the relative importance of root vs. foliar entry of POST-applied isoxaben. At a common isoxaben rate of 0.56 kg/ha, foliar-only and foliar plus soil applications provided 10.5 and 23.3% control, respectively, as determined by fresh weight reduction. In contrast, soil-only application provided 47.0% control. Hairy bittercress foliar absorption of14C–isoxaben did not exceed 15% of the amount applied after 72 h. Therefore, the comparatively less effectiveness of foliar-only applications may be attributed primarily to limited absorption. Minimal isoxaben concentration required to inhibit root growth of hydroponically grown hairy bittercress was 0.0025 mg/L. Higher concentrations were required to produce a response in the foliage. Sorption of isoxaben by pine bark rooting substrate, typical of what is used in container nursery production, exceeded 99% of amount applied after 36 h. Even with 99% sorption, the probable concentration within the aqueous phase remains sufficient to inhibit hairy bittercress root growth. Additional studies with14C–isoxaben established that approximately 35% of the root-absorbed isoxaben was translocated into the foliage. Translocation from the roots into the foliage was reduced to 16% when the experiment was repeated during environmental conditions less favorable for vegetative growth (i.e., longer day length and higher temperature). Results indicate that the control of hairy bittercress with POST-applied isoxaben is likely the result of root absorption and root-growth inhibition. Expression of phytotoxicity within the foliage is also a component, but is dependent upon the root-absorbed isoxaben being translocated into the foliage. Extent of this translocation is dependent upon plant maturity and prevalent environmental conditions.

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Overexpression of OsPIN2 Regulates Root Growth and Formation in Response to Phosphate Deficiency in Rice

International Journal of Molecular Sciences ◽

10.3390/ijms20205144 ◽

2019 ◽

Vol 20 (20) ◽

pp. 5144

Author(s):

Huwei Sun ◽

Xiaoli Guo ◽

Fugui Xu ◽

Daxia Wu ◽

Xuhong Zhang ◽

...

Keyword(s):

Root Growth ◽

Growth And Development ◽

Plant Root ◽

Lateral Roots ◽

Root Hairs ◽

Phosphate Deficiency ◽

P Deficiency ◽

Auxin Distribution ◽

Seminal Roots ◽

Underlying Mechanisms

The response of root architecture to phosphate (P) deficiency is critical in plant growth and development. Auxin is a key regulator of plant root growth in response to P deficiency, but the underlying mechanisms are unclear. In this study, phenotypic and genetic analyses were undertaken to explore the role of OsPIN2, an auxin efflux transporter, in regulating the growth and development of rice roots under normal nutrition condition (control) and low-phosphate condition (LP). Higher expression of OsPIN2 was observed in rice plants under LP compared to the control. Meanwhile, the auxin levels of roots were increased under LP relative to control condition in wild-type (WT) plants. Compared to WT plants, two overexpression (OE) lines had higher auxin levels in the roots under control and LP. LP led to increased seminal roots (SRs) length and the root hairs (RHs) density, but decreased lateral roots (LRs) density in WT plants. However, overexpression of OsPIN2 caused a loss of sensitivity in the root response to P deficiency. The OE lines had a shorter SR length, lower LR density, and greater RH density than WT plants under control. However, the LR and RH densities in the OE lines were similar to those in WT plants under LP. Compared to WT plants, overexpression of OsPIN2 had a shorter root length through decreased root cell elongation under control and LP. Surprisingly, overexpression of OsPIN2 might increase auxin distribution in epidermis of root, resulting in greater RH formation but less LR development in OE plants than in WT plants in the control condition but levels similar of these under LP. These results suggest that higher OsPIN2 expression regulates rice root growth and development maybe by changing auxin distribution in roots under LP condition.

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Bioactive l-DOPA induced quinoprotein formation to inhibit root growth of cucumber seedlings

Journal of Pesticide Science ◽

10.1584/jpestics.d13-005 ◽

2013 ◽

Vol 38 (2) ◽

pp. 68-73 ◽

Cited By ~ 8

Author(s):

Muhammad Naeem Mushtaq ◽

Yukari Sunohara ◽

Hiroshi Matsumoto

Keyword(s):

Root Growth ◽

Cucumber Seedlings ◽

Inhibit Root Growth

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Nickel Toxicity Targets Cell Wall-Related Processes and PIN2-Mediated Auxin Transport to Inhibit Root Elongation and Gravitropic Responses in Arabidopsis

Plant and Cell Physiology ◽

10.1093/pcp/pcz217 ◽

2019 ◽

Vol 61 (3) ◽

pp. 519-535 ◽

Cited By ~ 11

Author(s):

Alexandra Leškov� ◽

Milan Zvar�k ◽

Takao Araya ◽

Ricardo F H Giehl

Keyword(s):

Heavy Metal ◽

Root Growth ◽

Fossil Fuels ◽

Environmental Concern ◽

Plant Cell Walls ◽

Nickel Toxicity ◽

Auxin Distribution ◽

Leaf Chlorosis ◽

Transcriptional Changes ◽

Cell Niche

Abstract Contamination of soils with heavy metals, such as nickel (Ni), is a major environmental concern due to increasing pollution from industrial activities, burning of fossil fuels, incorrect disposal of sewage sludge, excessive manure application and the use of fertilizers and pesticides in agriculture. Excess Ni induces leaf chlorosis and inhibits plant growth, but the mechanisms underlying growth inhibition remain largely unknown. A detailed analysis of root development in Arabidopsis thaliana in the presence of Ni revealed that this heavy metal induces gravitropic defects and locally inhibits root growth by suppressing cell elongation without significantly disrupting the integrity of the stem cell niche. The analysis of auxin-responsive reporters revealed that excess Ni inhibits shootward auxin distribution. Furthermore, we found that PIN2 is very sensitive to Ni, as the presence of this heavy metal rapidly reduced PIN2 levels in roots. A transcriptome analysis also showed that Ni affects the expression of many genes associated with plant cell walls and that Ni-induced transcriptional changes are largely independent of iron (Fe). In addition, we raised evidence that excess Ni increases the accumulation of reactive oxygen species and disturbs the integrity and orientation of microtubules. Together, our results highlight which processes are primarily targeted by Ni to alter root growth and development.

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Conserved LBL1-ta-siRNA and miR165/166-RLD1/2 modules regulate root development in maize

Development ◽

10.1242/dev.190033 ◽

2020 ◽

Vol 148 (1) ◽

pp. dev190033

Author(s):

Vibhav Gautam ◽

Archita Singh ◽

Sandeep Yadav ◽

Sharmila Singh ◽

Pramod Kumar ◽

...

Keyword(s):

Root Growth ◽

Root Development ◽

Lateral Roots ◽

Root System Architecture ◽

Maize Root ◽

Altered Expression ◽

Auxin Distribution ◽

Seminal Roots ◽

Crown Roots

ABSTRACTRoot system architecture and anatomy of monocotyledonous maize is significantly different from dicotyledonous model Arabidopsis. The molecular role of non-coding RNA (ncRNA) is poorly understood in maize root development. Here, we address the role of LEAFBLADELESS1 (LBL1), a component of maize trans-acting short-interfering RNA (ta-siRNA), in maize root development. We report that root growth, anatomical patterning, and the number of lateral roots (LRs), monocot-specific crown roots (CRs) and seminal roots (SRs) are significantly affected in lbl1-rgd1 mutant, which is defective in production of ta-siRNA, including tasiR-ARF that targets AUXIN RESPONSE FACTOR3 (ARF3) in maize. Altered accumulation and distribution of auxin, due to differential expression of auxin biosynthesis and transporter genes, created an imbalance in auxin signalling. Altered expression of microRNA165/166 (miR165/166) and its targets, ROLLED1 and ROLLED2 (RLD1/2), contributed to the changes in lbl1-rgd1 root growth and vascular patterning, as was evident by the altered root phenotype of Rld1-O semi-dominant mutant. Thus, LBL1/ta-siRNA module regulates root development, possibly by affecting auxin distribution and signalling, in crosstalk with miR165/166-RLD1/2 module. We further show that ZmLBL1 and its Arabidopsis homologue AtSGS3 proteins are functionally conserved.

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A chemical genetic screen reveals that iminosugar inhibitors of plant glucosylceramide synthase inhibit root growth in Arabidopsis and cereals

Scientific Reports ◽

10.1038/s41598-018-34749-1 ◽

2018 ◽

Vol 8 (1) ◽

Cited By ~ 2

Author(s):

Michael D. Rugen ◽

Mathieu M. J. L. Vernet ◽

Laila Hantouti ◽

Amalia Soenens ◽

Vasilios M. E. Andriotis ◽

...

Keyword(s):

Root Growth ◽

Genetic Screen ◽

Glucosylceramide Synthase ◽

Chemical Genetic ◽

Inhibit Root Growth

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Ammonium affects cell viability to inhibit root growth in Arabidopsis

Journal of Zhejiang University SCIENCE B ◽

10.1631/jzus.b1000335 ◽

2011 ◽

Vol 12 (6) ◽

pp. 477-484 ◽

Cited By ~ 9

Author(s):

Cheng Qin ◽

Ke-ke Yi ◽

Ping Wu

Keyword(s):

Root Growth ◽

Cell Viability ◽

Inhibit Root Growth

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The Ca2+ sensor protein CMI1 fine tunes root development, auxin distribution and responses

10.1101/488536 ◽

2018 ◽

Author(s):

Ora Hazak ◽

Elad Mamon ◽

Meirav Lavy ◽

Hasana Sternberg ◽

Smrutisanjita Behera ◽

...

Keyword(s):

Root Growth ◽

Root Development ◽

Lateral Root ◽

Developmental Plasticity ◽

Molecular Mechanisms ◽

Ectopic Expression ◽

Growth Arrest ◽

Root Hairs ◽

Root Tip ◽

Auxin Distribution

Signaling cross-talks between auxin, a regulator of plant development and Ca2+, a universal second messenger have been proposed to modulate developmental plasticity in plants. However, the underlying molecular mechanisms are largely unknown. Here we report that in Arabidopsis roots, auxin elicits specific Ca2+ signaling pattern that spatially coincide with the expression pattern of auxin-regulated genes. We identified the EF-hand protein CMI1 (Ca2+ sensor Modulator of ICR1) as an interactor of the ROP effector ICR1 (Interactor of Constitutively active ROP). CMI1 is monomeric in solution, changes its secondary structure at Ca2+ concentrations ranging from 10-9 to 10-8 M and its interaction with ICR1 is Ca2+ dependent, involving a conserved hydrophobic pocket. cmi1 mutants display an increased auxin response including shorter primary roots, longer root hairs, longer hypocotyls and altered lateral root formation while ectopic expression of CMI1 induces root growth arrest and reduced auxin responses at the root tip. When expressed alone, CMI1 is localized at the plasma membrane, the cytoplasm and in nuclei. Interaction of CMI1 and ICR1 results in exclusion of CMI1 from nuclei and suppression of the root growth arrest. CMI1 expression is directly upregulated by auxin while expression of auxin induced genes is enhanced in cmi1 concomitantly with repression of auxin induced Ca2+ increases in the lateral root cap and vasculature, indicating that CMI1 represses early auxin responses. Collectively, our findings identify a crucial function of Ca2+ signaling and CMI1 in root growth and suggest an auxin-Ca2+ regulatory feedback loop that fine tunes root development.

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Perspectives on Discovery of Microbial Phytotoxins with Herbicidal Activity

Weed Technology ◽

10.1017/s0890037x00032395 ◽

1988 ◽

Vol 2 (4) ◽

pp. 525-532 ◽

Cited By ~ 16

Author(s):

Horace G. Cutler

Keyword(s):

Natural Products ◽

Root Growth ◽

Specific Activity ◽

High Specific Activity ◽

Herbicidal Activity ◽

Biologically Active ◽

Natural State ◽

Natural Herbicides ◽

Synthetic Derivative ◽

Inhibit Root Growth

Biologically active natural products of microbial origin are attractive candidates for possible use in agriculture. They may be obtained by fermentation, used in their natural state, or subjected to synthetic modification for specific uses. These natural products are characterized by high specific activity and high selectivity, and they are biodegradable. The structures are extremely diverse and represent many classes of compounds ranging from very complex to simple. Cyclocarbamide A and B, fromStreptoverticilliumsp., have marked preemergence herbicidal activity. Nigerazine A and B, fromAspergillus nigervan Tieghem, also inhibit root growth in certain plants. Citreoviridin, fromPenicillium charlesiiSmith, preferentially controls the growth of monocotyledonous plants, as does a synthetic derivative of cladosporin, fromAspergillus repensDeBary, which bleaches chloroplasts. The 12-membered fungal macrolides (macrocyclic lactones) also inhibit root growth in many test plants and offer templates for further synthetic work. Herbicidins, fromStreptomyces saganonensis, are particularly effective against barnyardgrass, goosegrass, tufted mannagrass, and green panicum.Alternaria eichorniaeNag Raj et Ponnappa produces a toxin that is active against waterhyacinth and represents one of the more exotic structures. The macrocyclic trichothecenes are a significant class of natural products that tend to concentrate against a gradient in seeds of certain plants, which resist these microbially derived metabolites thereby producing seed with “built-in” natural herbicides.

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