Comprehensive protein profiling of tomato phloem exudates during drought stress and recovery
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ABSTRACT: 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 .
INSTRUMENT(S): Q Exactive HF
ORGANISM(S): Solanum Lycopersicum
TISSUE(S): Plant Cell, Phloem
SUBMITTER: Aaron Ogden
LAB HEAD: Josh Adkins
PROVIDER: PXD018993 | Pride | 2020-06-26
REPOSITORIES: Pride
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