PARTICIPATION OF ENT3 TRANSPORTER IN CYTOKININ DISTRIBUTION BETWEEN THE ROOT AND THE SHOOT AND IN REGULATION OF GROWTH RESPONSE OF ARABIDOPSIS PLANTS TO INCREASED LEVEL OF MINERAL NUTRITION

The nitrogenous base riboside transporter ENT3 is known for its ability to transport ribosylated cytokinins across the membrane. However, its role in the distribution of cytokinins between plant organs has not yet been studied. For this purpose, we compared the content and distribution of either endogenous cytokinins or the exogenous trans-zeatin riboside introduced into the nutrient solution in mutant ent3-1 plants and the parent genotype Columbia. In the mutant, the accumulation of endogenous cytokinins in the roots was suppressed, and the ability to deliver exogenous trans-zeatin riboside to shoots increased. The roots of ent3-1 were about 15% longer and had a lower cytokinin concentration. A thirtyfold increase in the concentration of macronutrients led to inhibition of root elongation in the original Columbia line, but not in ent3-1 plants. This growth response occured in accordance with the content of cytokinins in the roots: in Columbia plants, cytokinins accumulated in these organs. The increase in the level of hormones in the roots of ent3-1 was to a lesser extent and was not significant. It was concluded that the ENT3 transporter is involved in the distribution of endogenous cytokinins between the apoplast and symplast, facilitating their uptake by root cells, thereby limiting the export of cytokinins to shoots through the xylem, and can play an important adaptive role in changing the level of mineral nutrition.

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Limitation of Cytokinin Export to the Shoots by Nucleoside Transporter ENT3 and Its Linkage with Root Elongation in Arabidopsis

Cells ◽

10.3390/cells10020350 ◽

2021 ◽

Vol 10 (2) ◽

pp. 350

Author(s):

Alla Korobova ◽

Bulat Kuluev ◽

Torsten Möhlmann ◽

Dmitriy Veselov ◽

Guzel Kudoyarova

Keyword(s):

Root Elongation ◽

Zeatin Riboside ◽

Mineral Nutrient ◽

Endogenous Cytokinin ◽

Nucleoside Transporter ◽

Wild Type ◽

Root Cells ◽

Dna Insertion ◽

Endogenous Cytokinins

The trans-membrane carrier AtENT3 is known to transport externally supplied cytokinin ribosides and thus promote uptake by cells. However, its role in distributing either exogenous or endogenous cytokinins within the intact plant has not hitherto been reported. To test this, we used ent3-1 mutant Arabidopsis seedlings in which the gene is not expressed due to a T-DNA insertion, and examined the effect on the concentration and distribution of either endogenous cytokinins or exogenous trans-zeatin riboside applied to the roots. In the mutant, accumulation of endogenous cytokinins in the roots was reduced and capacity to deliver externally supplied trans-zeatin riboside to the shoots was increased suggesting involvement of equilibrative nucleoside (ENT) transporter in the control of cytokinin distribution in the plants. Roots of ent3-1 were longer in the mutant in association with their lower cytokinin concentration. We concluded that the ENT3 transporter participates in partitioning endogenous cytokinins between the apoplast and the symplast by facilitating their uptake by root cells thereby limiting cytokinin export to the shoots through the xylem. Dilution of the mineral nutrient solution lowered endogenous cytokinin concentration in the roots of both wild type (WT) and ent3-1 plants accompanied by promotion of root elongation. Nevertheless, cytokinin content was lower, while roots were longer in the ent3-1 mutant than in the WT under either normal or deficient mineral nutrition suggesting a significant role of ENT3 transporter in the control of cytokinin level in the roots and the rate of their elongation.

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Ultrastructural changes in sunflower root cells in relation to boron deficiency and added auxin

Canadian Journal of Botany ◽

10.1139/b80-110 ◽

1980 ◽

Vol 58 (8) ◽

pp. 856-866 ◽

Cited By ~ 53

Author(s):

Ann M. Hirsch ◽

John G. Torrey

Keyword(s):

Cell Expansion ◽

Root Elongation ◽

Membrane Integrity ◽

Ultrastructural Level ◽

Ultrastructural Changes ◽

Boron Deficiency ◽

Endogenous Auxin ◽

Root Cells ◽

Seedling Roots ◽

Inhibition Of Root Elongation

The responses of sunflower root cells to conditions of boron deficiency and to the addition of exogenous auxin were studied on the ultrastructural level. Although gross morphological effects such as inhibition of root elongation and a change in the direction of cell expansion from longitudinal to radial are similar in both auxin-treated and boron-deficient seedling roots, ultrastructural changes are different in the two treatments. An increase in cell wall thickness and a loss of membrane integrity are seen as early as 6 h in seedlings grown without boron. Auxin-treated root cells do not show this response. A role for boron may involve maintenance of membrane integrity rather than determining endogenous auxin levels.

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Effect of in planta phosphorus on aluminum-induced inhibition of root elongation in wheat

Plant and Soil ◽

10.1007/s11104-015-2566-6 ◽

2015 ◽

Vol 395 (1-2) ◽

pp. 307-315 ◽

Cited By ~ 3

Author(s):

Ji Feng Shao ◽

Jing Che ◽

Rong Fu Chen ◽

Jian Feng Ma ◽

Ren Fang Shen

Keyword(s):

Root Elongation ◽

In Planta ◽

Inhibition Of Root Elongation

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Mineral nutrition of slash pine in subtropical australia. I. stand growth response to fertilization

Fertilizer Research ◽

10.1007/bf00750750 ◽

1995 ◽

Vol 41 (2) ◽

pp. 93-100 ◽

Cited By ~ 23

Author(s):

Z. H. Xu ◽

J. A. Simpson ◽

D. O. Osborne

Keyword(s):

Mineral Nutrition ◽

Growth Response ◽

Slash Pine ◽

Stand Growth ◽

Subtropical Australia

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Role of salicylic acid in alleviating the inhibition of root elongation by suppressing ethylene emission in rice under Al toxicity conditions

Plant Growth Regulation ◽

10.1007/s10725-019-00554-7 ◽

2019 ◽

Vol 90 (3) ◽

pp. 475-487 ◽

Cited By ~ 2

Author(s):

Chun Quan Zhu ◽

Wen Jun Hu ◽

Xiao Chuang Cao ◽

Lian Feng Zhu ◽

Zhi Gang Bai ◽

...

Keyword(s):

Salicylic Acid ◽

Root Elongation ◽

Al Toxicity ◽

Ethylene Emission ◽

Inhibition Of Root Elongation

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Blue Light-Triggered Chemical Reactions Underlie Phosphate Deficiency-Induced Inhibition of Root Elongation of Arabidopsis Seedlings Grown in Petri Dishes

Molecular Plant ◽

10.1016/j.molp.2019.08.001 ◽

2019 ◽

Vol 12 (11) ◽

pp. 1515-1523 ◽

Cited By ~ 19

Author(s):

Zai Zheng ◽

Zhen Wang ◽

Xiaoyue Wang ◽

Dong Liu

Keyword(s):

Blue Light ◽

Chemical Reactions ◽

Root Elongation ◽

Phosphate Deficiency ◽

Petri Dishes ◽

Inhibition Of Root Elongation

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Hydrogen-rich water alleviates aluminum-induced inhibition of root elongation in alfalfa via decreasing nitric oxide production

Journal of Hazardous Materials ◽

10.1016/j.jhazmat.2013.12.029 ◽

2014 ◽

Vol 267 ◽

pp. 40-47 ◽

Cited By ~ 49

Author(s):

Meng Chen ◽

Weiti Cui ◽

Kaikai Zhu ◽

Yanjie Xie ◽

Chunhua Zhang ◽

...

Keyword(s):

Nitric Oxide ◽

Root Elongation ◽

Nitric Oxide Production ◽

Oxide Production ◽

Inhibition Of Root Elongation

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Inhibition of nitric oxide synthase (NOS) underlies aluminum-induced inhibition of root elongation in Hibiscus moscheutos

New Phytologist ◽

10.1111/j.1469-8137.2007.02005.x ◽

2007 ◽

Vol 174 (2) ◽

pp. 322-331 ◽

Cited By ~ 136

Author(s):

Qiu-Ying Tian ◽

Dong-Hua Sun ◽

Min-Gui Zhao ◽

Wen-Hao Zhang

Keyword(s):

Nitric Oxide ◽

Nitric Oxide Synthase ◽

Root Elongation ◽

Oxide Synthase ◽

Inhibition Of Root Elongation

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Solute is imported to elongating root cells of barley as a pressure driven-flow of solution

Functional Plant Biology ◽

10.1071/fp03231 ◽

2004 ◽

Vol 31 (4) ◽

pp. 391 ◽

Cited By ~ 24

Author(s):

Nick Gould ◽

Michael R. Thorpe ◽

Peter E. H. Minchin ◽

Jeremy Pritchard ◽

Philip J. White

Keyword(s):

Hydrostatic Pressure ◽

Pressure Difference ◽

Root Elongation ◽

Root Cell ◽

Root Cells ◽

High K ◽

K Concentration ◽

Pressure Driven Flow ◽

Low K ◽

Pressure Driven

This work relates solute import to elongating root cells in barley to the water relations of the symplastic pathway under conditions of varied plant K+ status. K+ is a major constituent of phloem sieve element (SE) sap, and as an osmoticum, it is believed to have a role in maintaining SE hydrostatic pressure and thus sap flow from source to sink tissue. The hypothesis that the solute import to elongating root cells is linked to pressure driven flow from the sieve tube is examined.Plants were grown in solutions containing either 0.05 mM (low K) or 2.05 mM (high K) K+ concentration. Solute import to the root elongation zone was estimated from biomass accumulation over time accounting for respiration and root elongation rate. SE sap K+ concentration was measured using X-ray microanalyses and osmotic pressure by picolitre osmometry. SE hydrostatic pressure was measured directly with a pressure probe glued onto an excised aphid stylet. Elongating root cell hydrostatic pressure was measured using a cell pressure probe.The low-K plants had lower SE K+ concentration and SE hydrostatic pressure compared to the high-K plants, but the elongating root cell hydrostatic pressure was similar in both treatments, thus the pressure difference between the SE and elongating root cells was less in the low-K plants compared to the high-K plants.The solute import rate to elongating root cells was lower in the low K plants and the reduction could be accounted for as a pressure driven solute flux, with a reduction both in the pressure difference between root sieve elements and elongating cells, and in the sap concentration.

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