scholarly journals Karrikin-sensing protein KAI2 is a new player in regulating root growth patterns

2017 ◽  
Author(s):  
Stéphanie M. Swarbreck ◽  
Yannick Guerringue ◽  
Elsa Matthus ◽  
Fiona J. C. Jamieson ◽  
Julia M. Davies
Keyword(s):  
Arabidopsis Thaliana ◽  
Plasma Membrane ◽  
Root Growth ◽  
Genetic Data ◽  
Growth Direction ◽  
Growth Patterns ◽  
Membrane Glycoprotein ◽  
Radial Expansion ◽  
Branching Pattern ◽  
Root Plasma Membrane

SummaryRoots form highly complex systems varying in growth direction and branching pattern to forage for nutrients efficiently. Here mutations in the KAI2 (KARRIKIN INSENSITIVE) α/β-fold hydrolase and the MAX2 (MORE AXILLARY GROWTH 2) F-box leucine-rich protein, which together perceive karrikins (smoke-derived butenolides), caused alteration in root growth direction (root skewing and waving) of Arabidopsis thaliana. This exaggerated root skewing was independent of endogenous strigolactone perception by the D14 α/β-fold hydrolase and MAX2. Thus KAI2/MAX2’s regulation of root growth may be through perception of endogenous KAI2-ligands, which have yet to be identified. Degradation targets of the KAI2/MAX2 complex, SMAX1 (SUPPRESSOR OF MAX2-1) and SMXL6,7,8 (SUPPRESSOR OF MAX2-1-LIKE) are also involved in the regulation of root skewing. Genetic data reveal a new potential target for degradation, as mutation in the SKS3 (SKU5 similar) but not the SKU5/SKS17 root plasma membrane glycoprotein suppresses the exaggerated root skewing induced by the lack of MAX2. In Arabidopsis thaliana therefore, the KAI2 karrikin-sensing protein acts to limit root skewing, and we propose a mechanism involving root radial expansion as the mutant’s gravitropic and mechano-sensing responses remained largely unaffected.

Effects of elevated carbon dioxide and sucrose concentrations on Arabidopsis thaliana root architecture and anatomy

2007 ◽  
Vol 85 (3) ◽  
pp. 324-330 ◽  
Author(s):  
Elaine Lee-Ho ◽  
Linda J. Walton ◽  
David M. Reid ◽  
Edward C. Yeung ◽  
Leonid V. Kurepin
Keyword(s):  
Carbon Dioxide ◽  
Arabidopsis Thaliana ◽  
Root Growth ◽  
Lateral Root ◽  
Sucrose Concentration ◽  
Secondary Growth ◽  
Elevated Carbon Dioxide ◽  
Branching Pattern ◽  
Growth Morphology ◽  
The Media

The objective of this study was to evaluate the effects of elevated carbon dioxide and sucrose concentrations on Arabidopsis thaliana L. Heynh root growth, morphology, and architecture. Two levels of CO2, 360 (ambient) and 900 (elevated) μmol·mol–1, and various sucrose concentrations were used. A. thaliana plants grown on a phytagar medium in small chambers with elevated CO2 had longer roots, more lateral root growth and a more dichotomous branching pattern than plants grown in ambient CO2. Roots in elevated CO2 had wider root diameters, and showed considerably more secondary growth such as larger diameter vascular cylinders and better-developed periderm. Addition of sucrose to the media closely resembled the effects of elevated CO2. Further, the increase in sucrose concentration had a more pronounced effect on root morphology under ambient, than elevated CO2. Thus, both elevated CO2 and increased sucrose concentrations promote root growth by increasing their number, length, and diameter, and by changing the branching pattern from herringbone to dichotomous.

scholarly journals Glucose control of root growth direction in Arabidopsis thaliana

2014 ◽  
Vol 65 (12) ◽  
pp. 2981-2993 ◽  
Author(s):  
Manjul Singh ◽  
Aditi Gupta ◽  
Ashverya Laxmi
Keyword(s):  
Arabidopsis Thaliana ◽  
Root Growth ◽  
Glucose Control ◽  
Growth Direction

Root and Stem Growth Patterns of Young `Mauritius' Lychee Trees

HortScience ◽  
1996 ◽  
Vol 31 (5) ◽  
pp. 815-818 ◽  
Author(s):  
Thomas E. Marler ◽  
Leah E. Willis
Keyword(s):  
Root Growth ◽  
Stem Growth ◽  
Growth Patterns ◽  
Extension Growth ◽  
Glass Wall ◽  
Litchi Chinensis ◽  
Root Extension ◽  
Stem Extension ◽  
Root Observation

`Mauritius' lychee (Litchi chinensis Sonn.) trees were planted in root observation chambers in July 1990 to determine the pattern of root and stem extension growth during 12 months. Root and stem lengths were measured at intervals ranging from 7 to 18 days from Aug. 1990 until Aug. 1991. During each period of active canopy growth, up to six stem tips were tagged and measured. Root growth was determined by measuring tracings of the extension of each root in a visible plane of the glass wall of the observation chambers. Stem growth was cyclic, with distinct periods of rapid extension followed by periods with no extension. In contrast, root growth was fairly continuous with only three periods of no visible root extension. Mean absolute extension rates were higher for stems than for roots. There were no consistent relationships between the timing of root and stem extension growth.

scholarly journals Sound Waves Promote Arabidopsis thaliana Root Growth by Regulating Root Phytohormone Content

2021 ◽  
Vol 22 (11) ◽  
pp. 5739
Author(s):  
Joo Yeol Kim ◽  
Hyo-Jun Lee ◽  
Jin A Kim ◽  
Mi-Jeong Jeong
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Division ◽  
Root Growth ◽  
Apical Meristem ◽  
Cell Number ◽  
Root Apical Meristem ◽  
Control Group ◽  
Auxin Signaling ◽  
Ethylene Signaling ◽  
Sound Waves

Sound waves affect plants at the biochemical, physical, and genetic levels. However, the mechanisms by which plants respond to sound waves are largely unknown. Therefore, the aim of this study was to examine the effect of sound waves on Arabidopsis thaliana growth. The results of the study showed that Arabidopsis seeds exposed to sound waves (100 and 100 + 9k Hz) for 15 h per day for 3 day had significantly longer root growth than that in the control group. The root length and cell number in the root apical meristem were significantly affected by sound waves. Furthermore, genes involved in cell division were upregulated in seedlings exposed to sound waves. Root development was affected by the concentration and activity of some phytohormones, including cytokinin and auxin. Analysis of the expression levels of genes regulating cytokinin and auxin biosynthesis and signaling showed that cytokinin and ethylene signaling genes were downregulated, while auxin signaling and biosynthesis genes were upregulated in Arabidopsis exposed to sound waves. Additionally, the cytokinin and auxin concentrations of the roots of Arabidopsis plants increased and decreased, respectively, after exposure to sound waves. Our findings suggest that sound waves are potential agricultural tools for improving crop growth performance.

scholarly journals A family of pathogen-induced cysteine-rich transmembrane proteins is involved in plant disease resistance

Planta ◽  
2021 ◽  
Vol 253 (5) ◽  
Author(s):  
Marciel Pereira Mendes ◽  
Richard Hickman ◽  
Marcel C. Van Verk ◽  
Nicole M. Nieuwendijk ◽  
Anja Reinstädler ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Plasma Membrane ◽  
Disease Resistance ◽  
Plant Disease Resistance ◽  
Transmembrane Proteins ◽  
Series Data ◽  
Immune Gene ◽  
Biological Processes ◽  
Hypocotyl Growth ◽  
Enhanced Resistance

Abstract Main conclusion Overexpression of pathogen-induced cysteine-rich transmembrane proteins (PCMs) in Arabidopsis thaliana enhances resistance against biotrophic pathogens and stimulates hypocotyl growth, suggesting a potential role for PCMs in connecting both biological processes. Abstract Plants possess a sophisticated immune system to protect themselves against pathogen attack. The defense hormone salicylic acid (SA) is an important player in the plant immune gene regulatory network. Using RNA-seq time series data of Arabidopsis thaliana leaves treated with SA, we identified a largely uncharacterized SA-responsive gene family of eight members that are all activated in response to various pathogens or their immune elicitors and encode small proteins with cysteine-rich transmembrane domains. Based on their nucleotide similarity and chromosomal position, the designated Pathogen-induced Cysteine-rich transMembrane protein (PCM) genes were subdivided into three subgroups consisting of PCM1-3 (subgroup I), PCM4-6 (subgroup II), and PCM7-8 (subgroup III). Of the PCM genes, only PCM4 (also known as PCC1) has previously been implicated in plant immunity. Transient expression assays in Nicotiana benthamiana indicated that most PCM proteins localize to the plasma membrane. Ectopic overexpression of the PCMs in Arabidopsis thaliana resulted in all eight cases in enhanced resistance against the biotrophic oomycete pathogen Hyaloperonospora arabidopsidis Noco2. Additionally, overexpression of PCM subgroup I genes conferred enhanced resistance to the hemi-biotrophic bacterial pathogen Pseudomonas syringae pv. tomato DC3000. The PCM-overexpression lines were found to be also affected in the expression of genes related to light signaling and development, and accordingly, PCM-overexpressing seedlings displayed elongated hypocotyl growth. These results point to a function of PCMs in both disease resistance and photomorphogenesis, connecting both biological processes, possibly via effects on membrane structure or activity of interacting proteins at the plasma membrane.

scholarly journals Low ABA concentration promotes root growth and hydrotropism through relief of ABA INSENSITIVE 1-mediated inhibition of plasma membrane H+-ATPase 2

2021 ◽  
Vol 7 (12) ◽  
pp. eabd4113
Author(s):  
Rui Miao ◽  
Wei Yuan ◽  
Yue Wang ◽  
Irene Garcia-Maquilon ◽  
Xiaolin Dang ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Root Growth ◽  
Experimental System ◽  
Aba Signaling ◽  
Wild Type ◽  
Normal Medium ◽  
C Terminus ◽  
Quadruple Mutant ◽  
Aba Insensitive ◽  
Aba Receptors

The hab1-1abi1-2abi2-2pp2ca-1 quadruple mutant (Qabi2-2) seedlings lacking key negative regulators of ABA signaling, namely, clade A protein phosphatases type 2C (PP2Cs), show more apoplastic H+ efflux in roots and display an enhanced root growth under normal medium or water stress medium compared to the wild type. The presence of low ABA concentration (0.1 micromolar), inhibiting PP2C activity via monomeric ABA receptors, enhances root apoplastic H+ efflux and growth of the wild type, resembling the Qabi2-2 phenotype in normal medium. Qabi2-2 seedlings also demonstrate increased hydrotropism compared to the wild type in obliquely-oriented hydrotropic experimental system, and asymmetric H+ efflux in root elongation zone is crucial for root hydrotropism. Moreover, we reveal that Arabidopsis ABA-insensitive 1, a key PP2C in ABA signaling, interacts directly with the C terminus of Arabidopsis plasma membrane H+-dependent adenosine triphosphatase 2 (AHA2) and dephosphorylates its penultimate threonine residue (Thr947), whose dephosphorylation negatively regulates AHA2.

PLC1 and H2O2 Mediated the Allelopathic Effect of Oridonin on Root Growth in Arabidopsis thaliana

2021 ◽  
Author(s):  
Yue Zhang ◽  
Yanhuang An ◽  
Ning Yang ◽  
Wei Wang ◽  
Ruirui Liu ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Root Growth ◽  
Allelopathic Effect
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