scholarly journals A Role for Auxin in Ethylene-Dependent Inducible Aerenchyma Formation in Rice Roots

Plants ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 610 ◽  
Author(s):  
Takaki Yamauchi ◽  
Akihiro Tanaka ◽  
Nobuhiro Tsutsumi ◽  
Yoshiaki Inukai ◽  
Mikio Nakazono
Keyword(s):  
Oxygen Deficiency ◽  
Ethylene Biosynthesis ◽  
Auxin Signaling ◽  
Root Tips ◽  
Cortical Cells ◽  
Aerenchyma Formation ◽  
Rice Roots ◽  
Rice Mutant ◽  
Gas Space ◽  
The Relationship

Internal oxygen diffusion from shoot to root tips is enhanced by the formation of aerenchyma (gas space) in waterlogged soils. Lysigenous aerenchyma is created by programmed cell death and subsequent lysis of the root cortical cells. Rice (Oryza sativa) forms aerenchyma constitutively under aerobic conditions and increases its formation under oxygen-deficient conditions. Recently, we have demonstrated that constitutive aerenchyma formation is regulated by auxin signaling mediated by Auxin/indole-3-acetic acid protein (AUX/IAA; IAA). While ethylene is involved in inducible aerenchyma formation, the relationship of auxin and ethylene during aerenchyma formation remains unclear. Here, we examined the effects of oxygen deficiency and ethylene on aerenchyma formation in the roots of a rice mutant (iaa13) in which auxin signaling is suppressed by a mutation in the degradation domain of IAA13 protein. The results showed that AUX/IAA-mediated auxin signaling contributes to ethylene-dependent inducible aerenchyma formation in rice roots. An auxin transport inhibitor abolished aerenchyma formation under oxygen-deficient conditions and reduced the expression of genes encoding ethylene biosynthesis enzymes, further supporting the idea that auxin is involved in ethylene-dependent inducible aerenchyma formation. Based on these studies, we propose a mechanism that underlies the relationship between auxin and ethylene during inducible aerenchyma formation in rice roots.

scholarly journals Ethylene Biosynthesis Is Promoted by Very-Long-Chain Fatty Acids during Lysigenous Aerenchyma Formation in Rice Roots

2015 ◽  
Vol 169 (1) ◽  
pp. 180-193 ◽  
Author(s):  
Takaki Yamauchi ◽  
Katsuhiro Shiono ◽  
Minoru Nagano ◽  
Aya Fukazawa ◽  
Miho Ando ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Ethylene Biosynthesis ◽  
Long Chain Fatty Acids ◽  
Aerenchyma Formation ◽  
Rice Roots ◽  
Long Chain ◽  
Chain Fatty Acids

Evidence for Anoxic Zones in 2-3 mm Tips of Aerenchymatous Maize Roots Under Low O2 Supply

1995 ◽  
Vol 22 (5) ◽  
pp. 723 ◽  
Author(s):  
J Gibbs ◽  
GD Bruxelle ◽  
W Armstrong ◽  
H Greenway
Keyword(s):  
Fold Increase ◽  
Growth Reduction ◽  
Root Tips ◽  
Cortical Cells ◽  
Aerenchyma Formation ◽  
Metabolic Cooperation ◽  
Primary Roots ◽  
Maize Roots ◽  
O2 Supply ◽  
Anoxic Zones

Root elongation and the production of the end-products of anaerobic catabolism, ethanol, alanine and lactate, were measured in intact maize roots and excised tips exposed to a variety of oxygen regimes. Elongation was retarded by 56 and 44% respectively in intact aerenchymatous primary roots of maize incubated in 0.1% stagnant agar, or exposed to 0.06 mol m-3 external O2 in gas-sparged solution. This growth reduction was accompanied by a 3-5-fold increase in alanine as a percentage of total soluble amino acids in the 0-2 mm root tips. The increase in this value was not in response to ethylene or translocation of alanine from other parts of the root. Moreover, in excised tips exposed to 0.06 mol O2 m-3, net production of ethanol, alanine and lactate occurred. Even so, these root tips continued to elongate at 30% of the rate observed in aerated excised root tips. It appears that adaptation of maize to O2 deficiency may involve a combination of aerenchyma formation and tolerance to anoxia. We suggest that metabolic cooperation, in the form of symplastic transport of energy-rich compounds, might exist between cortical cells receiving adequate oxygen supply and cells in anoxic zones.

scholarly journals Auxin-Induced SaARF4 Downregulates SaACO4 to Inhibit Lateral Root Formation in Sedum alfredii Hance

2021 ◽  
Vol 22 (3) ◽  
pp. 1297
Author(s):  
Dong Xu ◽  
Zhuchou Lu ◽  
Guirong Qiao ◽  
Wenmin Qiu ◽  
Longhua Wu ◽  
...  
Keyword(s):  
Lateral Root ◽  
Ethylene Biosynthesis ◽  
Luciferase Assay ◽  
Sedum Alfredii ◽  
Ethylene Synthesis ◽  
Root Tips ◽  
Sedum Alfredii Hance ◽  
Auxin Distribution ◽  
Distribution Mode ◽  
High Level

Lateral root (LR) formation promotes plant resistance, whereas high-level ethylene induced by abiotic stress will inhibit LR emergence. Considering that local auxin accumulation is a precondition for LR generation, auxin-induced genes inhibiting ethylene synthesis may thus be important for LR development. Here, we found that auxin response factor 4 (SaARF4) in Sedum alfredii Hance could be induced by auxin. The overexpression of SaARF4 decreased the LR number and reduced the vessel diameters. Meanwhile, the auxin distribution mode was altered in the root tips and PIN expression was also decreased in the overexpressed lines compared with the wild-type (WT) plants. The overexpression of SaARF4 could reduce ethylene synthesis, and thus, the repression of ethylene production decreased the LR number of WT and reduced PIN expression in the roots. Furthermore, the quantitative real-time PCR, chromatin immunoprecipitation sequencing, yeast one-hybrid, and dual-luciferase assay results showed that SaARF4 could bind the promoter of 1-aminocyclopropane-1-carboxylate oxidase 4 (SaACO4), associated with ethylene biosynthesis, and could downregulate its expression. Therefore, we concluded that SaARF4 induced by auxin can inhibit ethylene biosynthesis by repressing SaACO4 expression, and this process may affect auxin transport to delay LR development.

scholarly journals The Structure of the Insect Egg-Shell in Relation to the Respiration of the Embryo

1950 ◽  
Vol 26 (4) ◽  
pp. 327-334
Author(s):  
P. H. TUFT
Keyword(s):  
Rhodnius Prolixus ◽  
Gaseous Exchange ◽  
Insect Egg ◽  
Physical Conditions ◽  
Egg Shell ◽  
Gas Space ◽  
The Relationship ◽  
Sufficient Oxygen

1. The site of gaseous exchange in the eggs of Rhodnius prolixus (Stahl) is shown to be the rim of the cap which covers the anterior end of the egg. Most of the oxygen consumed by the embryo enters the egg through the micropyles and pseudomicropyles which penetrate the shell in this region. 2. The physical conditions necessary for the passage of sufficient oxygen through these pores is discussed. A continuous gas space under the shell--the presence of which can be deduced on theoretical grounds--is shown to exist in the Rhodnius egg. 3. The relationship between waterproofing and the permeability of the shell to oxygen is discussed.

scholarly journals An NADPH Oxidase RBOH Functions in Rice Roots during Lysigenous Aerenchyma Formation under Oxygen-Deficient Conditions

2017 ◽  
Vol 29 (4) ◽  
pp. 775-790 ◽  
Author(s):  
Takaki Yamauchi ◽  
Miki Yoshioka ◽  
Aya Fukazawa ◽  
Hitoshi Mori ◽  
Naoko K. Nishizawa ◽  
...  
Keyword(s):  
Nadph Oxidase ◽  
Aerenchyma Formation ◽  
Rice Roots

scholarly journals A Positive Tropism of Rice Roots toward a Nutrient Source

2019 ◽  
Vol 61 (3) ◽  
pp. 546-553
Author(s):  
Kiyoshi Yamazaki ◽  
Yoshihiro Ohmori ◽  
Toru Fujiwara
Keyword(s):  
Cell Elongation ◽  
Lateral Roots ◽  
Fourth Power ◽  
Nutrient Concentrations ◽  
Root Tips ◽  
High Moisture ◽  
Nutrient Source ◽  
Directional Growth ◽  
Rice Roots ◽  
Differential Cell

Abstract Plants take up water and nutrients through roots, and uptake efficiency depends on root behavior. Roots recognize the moisture gradient in the soil and grow toward the direction of high moisture. This phenomenon is called hydrotropism, and it contributes to efficient water uptake. As nutrients in soil are also unevenly distributed, it is beneficial for plants to grow their roots in the direction of increasing nutrient concentrations, but such a phenomenon has not been demonstrated. Here, we describe the directional growth of roots in response to a nutrient gradient. Using our assay system, the gradient of a nitrogen nutrient, NH4+, was sufficient to stimulate positive tropic responses of rice lateral roots. This phenomenon is a tropism of plant roots to nutrients; hence, we propose the name ‘nutritropism’. As well as other tropisms, differential cell elongation was observed before the elongation zone during nutritropism, but the pattern promoting cell elongation preferentially on the non-stimulated side was opposite to those in root hydrotropism and gravitropism. Our evaluation of the NH4+ gradient suggested that the root tips responded to a sub-micromolar difference in NH4+ concentration on both sides of the root. Hydrotropism, gravitropism and phototropism were described in plants as the ‘power of movement’ by Charles and Francis Darwin in 1880, and these three tropisms have attracted the attention of plant scientists for more than 130 years. Our discovery of nutritropism represents the fourth ‘power of movement’ in plants and provides a novel root behavioral property used by plants to acquire nutrients efficiently.

scholarly journals The Secrets of Beautiful Hair: Why is it Flexible and Elastic?

Cosmetics ◽  
2019 ◽  
Vol 6 (3) ◽  
pp. 40 ◽  
Author(s):  
Mikako Ezure ◽  
Noriyuki Tanji ◽  
Yukari Nishita ◽  
Takashi Mizooku ◽  
Shinobu Nagase ◽  
...  
Keyword(s):  
Physical Properties ◽  
Layered Structure ◽  
Outer Layer ◽  
New Technology ◽  
Selective Reduction ◽  
Cell Distribution ◽  
Cortical Cells ◽  
The Difference ◽  
The Relationship ◽  
Hair Surface

Beautiful hair, so called “SHINAYAKA” hair in Japanese, has a good appearance not only when stationary but also when in motion, and it is a highly desirable hair condition for Japanese consumers. We investigated such SHINAYAKA hair, which was selected by sensory evaluation, for the relationship between physical properties, such as flexibility and elasticity, and hair structure. It has already been reported that human hair cortical cells have two types, similar to wool: the ortho-like cortex and the para-like cortex. Microscopic observation revealed that the ortho-like cortex is distributed in the outer layer of the hair (near the hair surface) and the para-like cortex exists in the inner layer (near the center of the fiber). This cell distribution, a concentric double-layered structure, was deemed to be a characteristic of SHINAYAKA hair. Furthermore, analysis of physical properties showed the difference between the elasticity of the outer layer and inner layer, and that this difference was bigger in SHINAYAKA hair compared to other hair. This phenomenon was observed not only in Japanese hair, but also in Caucasian hair. In addition, we have developed a new technology for creating “SHINAYAKA” hair by treatment with succinic acid. Inflexible and inelastic hair can be changed by this treatment, and its flexibility and elasticity improve by selective reduction of stiffness of the outer layer.

Identification of genes expressed in maize root cortical cells during lysigenous aerenchyma formation using laser microdissection and microarray analyses

2010 ◽  
Vol 190 (2) ◽  
pp. 351-368 ◽  
Author(s):  
Imene Rajhi ◽  
Takaki Yamauchi ◽  
Hirokazu Takahashi ◽  
Shunsaku Nishiuchi ◽  
Katsuhiro Shiono ◽  
...  
Keyword(s):  
Laser Microdissection ◽  
Maize Root ◽  
Cortical Cells ◽  
Aerenchyma Formation ◽  
Microarray Analyses

MAPKs as a cross point in H2O2 and auxin signaling under combined cadmium and zinc stress in rice roots

2014 ◽  
Vol 61 (5) ◽  
pp. 608-618 ◽  
Author(s):  
F. Y. Zhao ◽  
M. M. Han ◽  
S. Y. Zhang ◽  
J. Ren ◽  
F. Hu ◽  
...  
Keyword(s):  
Auxin Signaling ◽  
Cross Point ◽  
Zinc Stress ◽  
Rice Roots
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