Adaptation of roots to low water potentials by changes in cell wall extensibility and cell wall proteins

Wu, Yajun; Cosgrove, Daniel J.

doi:10.1093/jexbot/51.350.1543

Cited by 277 publications

(180 citation statements)

References 94 publications

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“…While wild-type plants responded to osmotic stress by increasing their root to shoot ratio, the ratio in amy3 bam1 remained unchanged compared with nonstress conditions ( Figure 2F). Adjustment of root growth under stress is an important survival strategy, allowing plants to expand the root (at the expense of shoot growth) to increase nutrient and water uptake capacity (Wu and Cosgrove, 2000;Rogers and Benfey, 2015;Roycewicz and Malamy, 2012). Our results are consistent with these observations and reveal a function of starch degradation in controlling root growth in response to osmotic stress ( Figure 9).…”

Section: A Critical Role For Starch Degradation In Osmotic Stress Tolsupporting

confidence: 89%

Regulation of Leaf Starch Degradation by Abscisic Acid Is Important for Osmotic Stress Tolerance in Plants

et al. 2016

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Starch serves functions that range over a timescale of minutes to years, according to the cell type from which it is derived. In guard cells, starch is rapidly mobilized by the synergistic action of b-AMYLASE1 (BAM1) and a-AMYLASE3 (AMY3) to promote stomatal opening. In the leaves, starch typically accumulates gradually during the day and is degraded at night by BAM3 to support heterotrophic metabolism. During osmotic stress, starch is degraded in the light by stress-activated BAM1 to release sugar and sugar-derived osmolytes. Here, we report that AMY3 is also involved in stress-induced starch degradation. Recently isolated Arabidopsis thaliana amy3 bam1 double mutants are hypersensitive to osmotic stress, showing impaired root growth. amy3 bam1 plants close their stomata under osmotic stress at similar rates as the wild type but fail to mobilize starch in the leaves. 14 C labeling showed that amy3 bam1 plants have reduced carbon export to the root, affecting osmolyte accumulation and root growth during stress. Using genetic approaches, we further demonstrate that abscisic acid controls the activity of BAM1 and AMY3 in leaves under osmotic stress through the AREB/ABF-SnRK2 kinase-signaling pathway. We propose that differential regulation and isoform subfunctionalization define starch-adaptive plasticity, ensuring an optimal carbon supply for continued growth under an ever-changing environment.

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Section: A Critical Role For Starch Degradation In Osmotic Stress Tolsupporting

confidence: 89%

Regulation of Leaf Starch Degradation by Abscisic Acid Is Important for Osmotic Stress Tolerance in Plants

et al. 2016

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“…However, the positive feedback reaction has not been reproducibly observed in pea stems (T.T. and T.H., unpublished results) and also was not observed in maize primary roots (10). In the present communication, we examine whether xyloglucan oligosaccharides control the elongation growth of plant cells.…”

mentioning

confidence: 78%

Suppression and acceleration of cell elongation by integration of xyloglucans in pea stem segments

Takeda

Furuta

Awano

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

181

141

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Xyloglucan is a key polymer in the walls of growing plant cells. Using split pea stem segments and stem segments from which the epidermis had been peeled off, we demonstrate that the integration of xyloglucan mediated by the action of wall-bound xyloglucan endotransglycosylase suppressed cell elongation, whereas that of its fragment oligosaccharide accelerated it. Whole xyloglucan was incorporated into the cell wall and induced the rearrangement of cortical microtubules from transverse to longitudinal; in contrast, the oligosaccharide solubilized xyloglucan from the cell wall and maintained the microtubules in a transverse orientation. This paper proposes that xyloglucan metabolism controls the elongation of plant cells.X yloglucan, which occurs widely in the primary walls of higher plants, possesses a 1,4-␤-glucan backbone with 1,6-␣-xylosyl residues along the backbone. Because the 1,4-␤-glucan backbone can bind specifically to cellulose microfibrils by hydrogen bonds (1), the xyloglucan probably contributes to the rigidity of the cell wall by cross-linking adjacent microfibrils (2). In fact, microfibrils seem to be coated with xyloglucan, which is located both on and between microfibrils throughout cell elongation (3). Masking xyloglucans in cell walls should prevent xyloglucan metabolism; in agreement with this prediction, an antibody specific to xyloglucan prevented an auxin-induced decrease in molecular size of xyloglucan and inhibited indole-3-acetic acid (IAA)-induced cell elongation in azuki hypocotyl segments (4). Xyloglucan endotransglycosylase (XET) has been proposed to participate in the dynamic changes of xyloglucan cross-linking (5, 6), but there is little direct evidence for this hypothesis. The question at issue concerns the structural function of xyloglucan, namely whether xyloglucan contributes to the extensibility of the wall by cross-linking adjacent microfibrils.Fucose-containing xyloglucan oligosaccharides have been shown to inhibit auxin-induced elongation of pea stems (7,8). Their inhibitory activity is approximately maximal at a concentration of 10 Ϫ8 to 10 Ϫ9 M. In the absence of auxin, a high concentration (Ͼ10 Ϫ8 M) of xyloglucan oligosaccharide did not inhibit but slightly promoted cell elongation in pea stem segments (9). Thus, the oligosaccharides may provide either negative or positive feedback control during cell elongation. However, the positive feedback reaction has not been reproducibly observed in pea stems (T.T. and T.H., unpublished results) and also was not observed in maize primary roots (10). In the present communication, we examine whether xyloglucan oligosaccharides control the elongation growth of plant cells.In cylindrical plant organs such as roots or stems, cells expand anisotropically, with the direction of most rapid growth parallel to the long axis of the organ, leading to elongation of the organ. It has been known for many years that the direction of elongation is perpendicular to the direction of net orientation of cellulose microfibrils (11). Therefore, paral...

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“…51 A number of experimental data globally indicates that the transition zone of the root may be considered as a sort of sensory center, enabling the root apex to continuously monitor environment parameters and to trigger appropriate responses. [51][52][53][54][55][56][57][58][59][60][61][62][63] Future studies will be needed to deepen the role of this unique root zone in translating the external stimuli in motoric responses.…”

Section: The Root Transition Zonementioning

confidence: 99%

NO signaling is a key component of the root growth response to nitrate inZea maysL.

Trevisan

Manoli

Quaggiotti

2014

Plant Signaling & Behavior

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To search for nutrients and water, roots need to efficiently explore large soil volumes. To this aim they generate complex root systems, allowing them to maximize their resource allocation efficiency. 1 Despite the vital importance of roots, the difficulty in accessing intact root systems for analysis, particularly under field conditions, have slowed down the breeding programs for plant's adaptation to environmental restrictions. 2,3 The capacity of plants to take up nutrients and water is mainly determined by changes in the architecture of the root system. 1 Three major processes affect the overall architecture of the root system: the rate of cell division, the rate of cell differentiation, and the extent of expansion and elongation of cells. [4][5][6] Disturbs in any of these 3 processes can affect the whole root-system architecture and the capacity of plants to survive and develop in adverse environments (Giehl et al. 7 and references therein).The root system results from the coordinated control of both genetic endogenous programs (regulating growth and organogenesis) and the action of abiotic and biotic environmental stimuli. 8,9 The dynamic control of the overall root system architecture (RSA) throughout time finally determines root plasticity and allows plants to efficiently adapt to environmental constraints. 10 The soil-environment from which plants extract nutrients and water is extremely heterogeneous, both spatially and temporally. 11 Among the nutrients present in soil, nitrate (NO 3 − ) may vary by an order of magnitude within centimeters or over the course of a day. 12 The effects of NO 3 − on the root system are complex and depend on several factors, such as the concentration available to the plant, the endogenous nitrogen status and the sensitivity of the species. 10,13,14 A considerable part of the studies aimed to unravel the mechanisms controlling RSA growth and development in response to nitrate have been focused on lateral roots (LR), 8,13,[15][16][17][18][19][20] while the nitrate-regulation of the primary root growth is still unclear. Beside NO 3 − , auxin has been demonstrated to strongly affect and control the LR development, [21][22][23][24] and an increasing number of studies suggests an overlap between auxin and NO 3 − signaling pathways in controlling LR development. [25][26][27][28][29][30][31][32][33] NO 3 -has a Doubtful Role in Regulating the Growth of Primary RootsDespite the high amount of reports published on nitrate effects on root elongation, the lack of univocal results makes it difficult to clearly decipher this response ( Table 1). In Arabidopsis thaliana, inhibition of primary root growth has been observed when nitrate is applied homogeneously at high concentrations (50 mM) for 7 d, but not in a range between 0.1 and 10 mM. 35 On the contrary, in this same species Linkohr et al. 36 showed an inhibition of primary root elongation with the increase of nitrate concentration already beyond 0.01 mM, but in this case seedlings were IAA, indole-3-acetic acid; SNP, sodium n...

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Adaptation of roots to low water potentials by changes in cell wall extensibility and cell wall proteins

Cited by 277 publications

References 94 publications

Regulation of Leaf Starch Degradation by Abscisic Acid Is Important for Osmotic Stress Tolerance in Plants

Regulation of Leaf Starch Degradation by Abscisic Acid Is Important for Osmotic Stress Tolerance in Plants

Suppression and acceleration of cell elongation by integration of xyloglucans in pea stem segments

NO signaling is a key component of the root growth response to nitrate inZea maysL.

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