A comprehensive strategy for identifying long-distance mobile peptides in xylem sap

Organic acids exuded from plant roots significantly modify uptake and long-distance translocation of metals. Little is known about the effect of amino acids on metal ion uptake by plant roots. The present study investigated the effects of exogenous amino acids (histidine and glycine) in a nutrient solution on root uptake and xylem sap transport of cadmium (Cd) in triticale (× Triticosecale cv. Elinor) and bread wheat (Triticum aestivum L. cv. Back Cross Rushan). Plant seedlings were grown in a Cd-free modified Hoagland nutrient solution to which 1 µm Cd was added with either 50 µm histidine or 50 µm glycine or without amino acids at 4 weeks after germination. A control treatment consisted of a nutrient solution free of Cd and amino acids. In bread wheat, addition of histidine to the Cd-containing nutrient solution resulted in a higher operationally defined symplastic Cd fraction but a lower apoplastic one in the roots. In triticale, addition of either amino acid decreased the symplastic Cd fraction but increased the apoplastic one. Addition of histidine to the nutrient solution increased Cd concentration in wheat xylem sap but had no significant effect on Cd concentration in triticale xylem sap. Compared with the Cd-only treatment, the glycine-containing treatment led to significantly reduced Cd concentrations in xylem sap of both plant species. Wheat plants supplied with histidine and Cd accumulated greater amounts of Cd in their shoots than those supplied with Cd alone. Glycine had no significant effects on the Cd content of wheat shoots but decreased it in triticale shoots. Results indicate that the effects of amino acids on plant root uptake and xylem sap translocation of Cd depend on the type of amino acid supplemented. This finding is of great importance for selecting and/or breeding cultivars with Cd-toxicity tolerance.

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In vivo pressure gradient heterogeneity increases flow contribution of small diameter vessels in grapevine

Nature Communications ◽

10.1038/s41467-019-13673-6 ◽

2019 ◽

Vol 10 (1) ◽

Cited By ~ 8

Author(s):

Martin Bouda ◽

Carel W. Windt ◽

Andrew J. McElrone ◽

Craig R. Brodersen

Keyword(s):

Sap Flow ◽

Xylem Sap ◽

Small Diameter ◽

Fourth Power ◽

First Year ◽

Long Distance ◽

Xylem Sap Flow ◽

Flow Mri ◽

Vessel Network

AbstractLeaves lose approximately 400 H2O molecules for every 1 CO2 gained during photosynthesis. Most long-distance water transport in plants, or xylem sap flow, serves to replace this water to prevent desiccation. Theory predicts that the largest vessels contribute disproportionately to overall sap flow because flow in pipe-like systems scales with the fourth power of radius. Here, we confront these theoretical flow predictions for a vessel network reconstructed from X-ray μCT imagery with in vivo flow MRI observations from the same sample of a first-year grapevine stem. Theoretical flow rate predictions based on vessel diameters are not supported. The heterogeneity of the vessel network gives rise to transverse pressure gradients that redirect flow from wide to narrow vessels, reducing the contribution of wide vessels to sap flow by 15% of the total. Our results call for an update of the current working model of the xylem to account for its heterogeneity.

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The Role of Amino Acids in the Long-Distance Transport of La and Y in the Xylem Sap of Tomato

Biological Trace Element Research ◽

10.1007/s12011-008-8277-6 ◽

2008 ◽

Vol 129 (1-3) ◽

pp. 239-250 ◽

Cited By ~ 9

Author(s):

Jun-liang Wu ◽

Zheng-gui Wei ◽

Hai-yan Zhao ◽

Hui-xin Li ◽

Feng Hu

Keyword(s):

Amino Acids ◽

Xylem Sap ◽

Long Distance ◽

Long Distance Transport ◽

Distance Transport

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Seed-Borne Cercospora beticola can Initiate Cercospora Leaf Spot from Sugar Beet (Beta vulgaris L.) Fruit Tissue

Phytopathology ◽

10.1094/phyto-03-21-0113-r ◽

2021 ◽

Author(s):

Rebecca Spanner ◽

Jonathan Neubauer ◽

Thies M. Heick ◽

Michael Grusak ◽

Olivia Hamilton ◽

...

Keyword(s):

Sugar Beet ◽

Beta Vulgaris ◽

Leaf Spot ◽

Xylem Sap ◽

Cercospora Beticola ◽

Cercospora Leaf Spot ◽

Internal Transcribed Spacer Region ◽

Long Distance ◽

True Seed ◽

Commercial Sugar

Cercospora leaf spot (CLS) is a globally important disease of sugar beet (Beta vulgaris L.) caused by the fungus Cercospora beticola. Long-distance movement of C. beticola has been indirectly evidenced in recent population genetic studies, suggesting potential dispersal via seed. Commercial sugar beet “seed” consists of the reproductive fruit (true seed surrounded by maternal pericarp tissue) coated in artificial pellet material. In this study, we confirmed the presence of viable C. beticola in sugar beet fruit for 10 of 37 tested seed lots. All isolates harbored the G143A mutation associated with quinone outside inhibitor resistance and 32 of 38 isolates had reduced demethylation inhibitor sensitivity (EC50 > 1 µg/ml). Planting of commercial sugar beet seed demonstrated the ability of seed-borne inoculum to initiate CLS in sugar beet. Cercospora beticola DNA was detected in DNA isolated from xylem sap, suggesting the vascular system is used to systemically colonize the host. We established nuclear ribosomal internal transcribed spacer region amplicon sequencing using the MinION platform to detect fungi in sugar beet fruit. Fungi from 19 different genera were identified from 11 different sugar beet seed lots, but Fusarium, Alternaria, and Cercospora were consistently the three most dominant taxa, comprising an average of 93% relative read abundance over 11 seed lots. We also present evidence that C. beticola resides in the pericarp of sugar beet fruit, rather than the true seed. The presence of seed-borne inoculum should be considered when implementing integrated disease management strategies for CLS of sugar beet in the future.

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ABA flow modelling in Ricinus communis exposed to salt stress and variable nutrition

Journal of Experimental Botany ◽

10.1093/jxb/erw291 ◽

2016 ◽

Vol 67 (18) ◽

pp. 5301-5311 ◽

Cited By ~ 6

Author(s):

Andreas D Peuke

Keyword(s):

Salt Stress ◽

Nutrient Limitation ◽

De Novo ◽

Ricinus Communis ◽

Leaf Growth ◽

Xylem Sap ◽

Phloem Transport ◽

Phosphorus Limitation ◽

Long Distance ◽

N Source

Abstract In a series of experiments with Ricinus communis, abscisic acid (ABA) concentrations in tissues and transport saps, its de novo biosynthesis, long-distance transport, and metabolism (degradation) were affected by nutritional conditions, nitrogen (N) source, and nutrient limitation, or salt stress. In the present study these data were statistically re-evaluated, and new correlations presented that underpin the importance of this universal phytohormone. The biggest differences in ABA concentration were observed in xylem sap. N source had the strongest effect; however, nutrient limitation (particularly phosphorus limitation) and salt also had significant effects. ABA was found in greater concentration in phloem sap compared with xylem sap; however, the effect of treatment on ABA concentration in phloem was lower. In the leaves, ABA concentration was most variable compared with the other tissues. This variation was only affected by the N source. In roots, ABA was significantly decreased by nutrient limitation. Of the compartments in which ABA was quantified, xylem sap ABA concentration was most significantly correlated with leaf stomatal conductance and leaf growth. Additionally, ABA concentration in xylem was significantly correlated to that in phloem, indicating a 6-fold concentration increase from xylem to phloem. The ABA flow model showed that biosynthesis of ABA in roots affected the xylem flow of ABA. Moreover, ABA concentration in xylem affected the degradation of the phytohormone in shoots and also its export from shoots via phloem. The role of phloem transport is discussed since it stimulates ABA metabolism in roots.

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Identification of a Tri-Iron(III), Tri-Citrate Complex in the Xylem Sap of Iron-Deficient Tomato Resupplied with Iron: New Insights into Plant Iron Long-Distance Transport

Plant and Cell Physiology ◽

10.1093/pcp/pcp170 ◽

2009 ◽

Vol 51 (1) ◽

pp. 91-102 ◽

Cited By ~ 154

Author(s):

Rubén Rellán-Álvarez ◽

Justo Giner-Martínez-Sierra ◽

Jesús Orduna ◽

Irene Orera ◽

José Ángel Rodríguez-Castrillón ◽

...

Keyword(s):

Xylem Sap ◽

Long Distance ◽

Citrate Complex ◽

Long Distance Transport ◽

Iron Deficient ◽

Distance Transport

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The Possible Role of Non-Structural Carbohydrates in the Regulation of Tree Hydraulics

International Journal of Molecular Sciences ◽

10.3390/ijms21010144 ◽

2019 ◽

Vol 21 (1) ◽

pp. 144 ◽

Cited By ~ 10

Author(s):

Martina Tomasella ◽

Elisa Petrussa ◽

Francesco Petruzzellis ◽

Andrea Nardini ◽

Valentino Casolo

Keyword(s):

Water Transport ◽

Tree Mortality ◽

Current Knowledge ◽

Soluble Sugars ◽

Xylem Sap ◽

Published Data ◽

Plant Responses ◽

Long Distance ◽

Plant Hydraulics ◽

Frost Stress

The xylem is a complex system that includes a network of dead conduits ensuring long-distance water transport in plants. Under ongoing climate changes, xylem embolism is a major and recurrent cause of drought-induced tree mortality. Non-structural carbohydrates (NSC) play key roles in plant responses to drought and frost stress, and several studies putatively suggest their involvement in the regulation of xylem water transport. However, a clear picture on the roles of NSCs in plant hydraulics has not been drawn to date. We summarize the current knowledge on the involvement of NSCs during embolism formation and subsequent hydraulic recovery. Under drought, sugars are generally accumulated in xylem parenchyma and in xylem sap. At drought-relief, xylem functionality is putatively restored in an osmotically driven process involving wood parenchyma, xylem sap and phloem compartments. By analyzing the published data on stem hydraulics and NSC contents under drought/frost stress and subsequent stress relief, we found that embolism build-up positively correlated to stem NSC depletion, and that the magnitude of post-stress hydraulic recovery positively correlated to consumption of soluble sugars. These findings suggest a close relationship between hydraulics and carbohydrate dynamics. We call for more experiments on hydraulic and NSC dynamics in controlled and field conditions.

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High Molecular Weight Organic Compounds in the Xylem Sap of Mangroves: Implications for Long-Distance Water Transport

Botanica Acta ◽

10.1111/j.1438-8677.1994.tb00789.x ◽

1994 ◽

Vol 107 (4) ◽

pp. 218-229 ◽

Cited By ~ 58

Author(s):

U. Zimmermann ◽

J. J. Zhu ◽

F. C. Meinzer ◽

G. Goldstein ◽

H. Schneider ◽

...

Keyword(s):

Molecular Weight ◽

High Molecular Weight ◽

Organic Compounds ◽

Water Transport ◽

Xylem Sap ◽

Long Distance

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Bioinformatic Exploration of the Targets of Xylem Sap miRNAs in Maize under Cadmium Stress

International Journal of Molecular Sciences ◽

10.3390/ijms20061474 ◽

2019 ◽

Vol 20 (6) ◽

pp. 1474 ◽

Cited By ~ 10

Author(s):

Baoxiang Wang ◽

Dan Cheng ◽

Ziyan Chen ◽

Manman Zhang ◽

Guoqiang Zhang ◽

...

Keyword(s):

High Throughput Sequencing ◽

Molecular Genetic ◽

Xylem Sap ◽

Target Prediction ◽

Cadmium Stress ◽

Maize Seedlings ◽

Abiotic Stress Response ◽

Long Distance ◽

Bioinformatic Tools ◽

Genetic Mechanisms

Cadmium (Cd) has the potential to be chronically toxic to humans through contaminated crop products. MicroRNAs (miRNAs) can move systemically in plants. To investigate the roles of long-distance moving xylem miRNAs in regulating maize response to Cd stress, three xylem sap small RNA (sRNA) libraries were constructed for high-throughput sequencing to identify potential mobile miRNAs in Cd-stressed maize seedlings and their putative targets in maize transcriptomes. In total, about 199 miRNAs (20–22 nucleotides) were identified in xylem sap from maize seedlings, including 97 newly discovered miRNAs and 102 known miRNAs. Among them, 10 miRNAs showed differential expression in xylem sap after 1 h of Cd treatment. Two miRNAs target prediction tools, psRNAtarget (reporting the inhibition pattern of cleavage) and DPMIND (discovering Plant MiRNA-Target Interaction with degradome evidence), were used in combination to identify, via bioinformatics, the targets of 199 significantly expressed miRNAs in maize xylem sap. The integrative results of these two bioinformatic tools suggested that 27 xylem sap miRNAs inhibit 34 genes through cleavage with degradome evidence. Moreover, nearly 300 other genes were also the potential miRNAs cleavable targets without available degradome data support, and the majority of them were enriched in abiotic stress response, cell signaling, transcription regulation, as well as metal handling. These approaches and results not only enhanced our understanding of the Cd-responsive long-distance transported miRNAs from the view of xylem sap, but also provided novel insights for predicting the molecular genetic mechanisms mediated by miRNAs.

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ABC transporter OsABCG18 controls the shootward transport of cytokinins and grain yield in rice

Journal of Experimental Botany ◽

10.1093/jxb/erz382 ◽

2019 ◽

Vol 70 (21) ◽

pp. 6277-6291 ◽

Cited By ~ 7

Author(s):

Jiangzhe Zhao ◽

Ningning Yu ◽

Min Ju ◽

Biao Fan ◽

Yanjun Zhang ◽

...

Keyword(s):

Grain Yield ◽

Oryza Sativa L ◽

Xylem Sap ◽

In Planta ◽

Long Distance ◽

Efflux Transport ◽

Long Distance Transport ◽

Atp Binding Cassette Transporter ◽

Novel Strategy ◽

Distance Transport

Abstract Cytokinins are one of the most important phytohormones and play essential roles in multiple life processes in planta. Root-derived cytokinins are transported to the shoots via long-distance transport. The mechanisms of long-distance transport of root-derived cytokinins remain to be demonstrated. In this study, we report that OsABCG18, a half-size ATP-binding cassette transporter from rice (Oryza sativa L.), is essential for the long-distance transport of root-derived cytokinins. OsABCG18 encodes a plasma membrane protein and is primarily expressed in the vascular tissues of the root, stem, and leaf midribs. Cytokinin profiling, as well as [14C]trans-zeatin tracer, and xylem sap assays, demonstrated that the shootward transport of root-derived cytokinins was significantly suppressed in the osabcg18 mutants. Transport assays in tobacco (Nicotiana benthamiana) indicated that OsABCG18 exhibited efflux transport activities for various substrates of cytokinins. While the mutation reduced root-derived cytokinins in the shoot and grain yield, overexpression of OsABCG18 significantly increased cytokinins in the shoot and improved grain yield. The findings for OsABCG18 as a transporter for long-distance transport of cytokinin provide new insights into the cytokinin transport mechanism and a novel strategy to increase cytokinins in the shoot and promote grain yield.

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