Dataset Information

Proteomics of isolated sieve tubes from N.tabacum

ABSTRACT: Symplasmicly connected cells called sieve elements form a network of tubes in the phloem of vascular plants. Sieve elements have essential functions as they provide routes for photoassimilate distribution, the exchange of developmental signals, and the coordination of defense responses. Nonetheless, they are the least understood main type of plant cells. They are extremely sensitive, possess a reduced endomembrane system without Golgi apparatus, and lack nuclei and translation machineries, so that transcriptomics and similar techniques cannot be applied. Moreover, the analysis of phloem exudates as a proxy for sieve element composition is marred by methodological problems. We developed a simple protocol for the isolation of sieve elements from leaves and stems of Nicotiana tabacum at sufficient amounts for large-scale proteome analysis. By quantifying the enrichment of individual proteins in purified sieve element relative to bulk phloem preparations, proteins of increased likelyhood to function specifically in sieve elements were identified. To evaluate the validity of this approach, YFP-constructs of genes encoding three of the candidate proteins were expressed in plants. Tagged proteins occurred exclusively in sieve elements. Two of them, a putative cytochrome b561/ferric reductase and a reticulon-like protein, appeared restricted to ER segments that were inaccessible to the luminal ER marker, HDEL-GFP, suggesting a previously unknown differentiation of the endomembrane system in sieve elements. Evidently, our list of promising candidate proteins provides a valuable exploratory tool for sieve element biology.

INSTRUMENT(S): Orbitrap Fusion

ORGANISM(S): Nicotiana Tabacum (common Tobacco)

TISSUE(S): Plant Cell, Leaf, Stem

SUBMITTER: Joerg Hofmann

LAB HEAD: Michael Knoblauch

PROVIDER: PXD030457 | Pride | 2022-02-17

REPOSITORIES: Pride

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Publications

Proteomics of isolated sieve tubes from <i>Nicotiana tabacum</i>: sieve element-specific proteins reveal differentiation of the endomembrane system.

Liu Yan Y Vasina Viktoriya V VV Kraner Max E ME Peters Winfried S WS Sonnewald Uwe U Knoblauch Michael M

Proceedings of the National Academy of Sciences of the United States of America 20220101 1

Symplasmicly connected cells called sieve elements form a network of tubes in the phloem of vascular plants. Sieve elements have essential functions as they provide routes for photoassimilate distribution, the exchange of developmental signals, and the coordination of defense responses. Nonetheless, they are the least understood main type of plant cells. They are extremely sensitive, possess a reduced endomembrane system without Golgi apparatus, and lack nuclei and translation machineries, so th ...[more]

PMID: 34983847

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Project description:Phloem is the primary conduit through which photosynthates, hormones, and other biologically important molecules are distributed from aerial plant organs downward and throughout the plant. Increasing evidence suggests that phloem contents are diverse and play a critical role in biotic and abiotic stress adaptation. Drought causes the greatest decreases in agricultural crop productivity among all biotic and abiotic stresses, and the link between water deficiency and phloem protein contents is relatively unexplored. Here we employed the EDTA-facilitated phloem exudate collection method from Solanum lycopersicum leaves during a period of drought stress and recovery. Our analysis resulted in the confident identification and quantification of 2,558 proteins. Comparing our data with previous findings confirms that our exudate collection strategy enriched for known phloem proteins. Independent of drought, enrichment analysis of the total phloem exudate protein profiles from all samples suggest that the exchange of proteins into the phloem is more complex than previously thought, including additional protein chaperone systems, branched-chain amino acid synthesis proteins, trehalose metabolism, and RNA silencing proteins. During the experiment we observed 169 proteins whose abundance changed significantly within the phloem sap, the majority of which were impacted specifically in response to drought. Among these were proteins involved in lipid metabolism, chaperone-mediated protein folding, carboxylic acid metabolism, abscisic acid signaling, cytokinin biosynthesis, and amino acid metabolism are significantly upregulated during drought. Conversely, proteins involved in lipid signaling, sphingolipid metabolism, cell wall organization, carbohydrate metabolism, and a mitogen-activated protein kinase are downregulated in response to drought. Many of these observations are consistent with previous literature findings at the whole plant level but have not been localized to the vasculature in tomato, suggesting phloem plays a critical role in adaptation to drought stress in tomato .

Dataset Information

Proteomics of isolated sieve tubes from N.tabacum

Publications

Proteomics of isolated sieve tubes from <i>Nicotiana tabacum</i>: sieve element-specific proteins reveal differentiation of the endomembrane system.

Similar Datasets

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