Phloem Exudate Protein Profiles during Drought and Recovery Reveal Abiotic Stress Responses in Tomato Vasculature

• Published in: International journal of molecular sciences 2020-06, Vol.21 (12), p.4461
• Main Authors: Ogden, Aaron J, Bhatt, Jishnu J, Brewer, Heather M, Kintigh, Jack, Kariuki, Samwel M, Rudrabhatla, Sairam, Adkins, Joshua N, Curtis, Wayne R
• Format: Article
• Language: English
• Subjects: Abiotic stress; Abscisic acid; Adaptation, Physiological; BASIC BIOLOGICAL SCIENCES; Biological activity; Biosynthesis; Carbohydrate metabolism; Carbohydrates; Carboxylic acids; Cell walls; Chain branching; Cytokinins; Datasets; Depth profiling; Drought; Droughts; Experiments; Exudates; Exudates and Transudates - metabolism; Exudation; Lipid metabolism; Lipids; MAP kinase; Metabolism; Metabolites; Ontology; Phloem; Phloem - metabolism; phloem exudate; Photosynthesis; Plant Proteins - metabolism; Protein folding; Protein kinase; Protein turnover; Proteins; proteomics; RNA-mediated interference; Signal Transduction; Solanum lycopersicum - growth & development; Solanum lycopersicum - metabolism; Stress, Physiological; Transcription; Trehalose
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms21124461

Drought is the leading cause of agricultural yield loss among all abiotic stresses, and the link between water deficit and phloem protein contents is relatively unexplored. Here we collected phloem exudates from leaves during periods of drought stress and recovery. Our analysis identified 2558 proteins, the most abundant of which were previously localized to the phloem. Independent of drought, enrichment analysis of the total phloem exudate protein profiles from all samples suggests that the protein content of phloem sap is complex, and includes proteins that function in chaperone systems, branched-chain amino acid synthesis, trehalose metabolism, and RNA silencing. We observed 169 proteins whose abundance changed significantly within the phloem sap, either during drought or recovery. Proteins that became significantly more abundant during drought include members of lipid metabolism, chaperone-mediated protein folding, carboxylic acid metabolism, abscisic acid signaling, cytokinin biosynthesis, and amino acid metabolism. Conversely, proteins involved in lipid signaling, sphingolipid metabolism, cell wall organization, carbohydrate metabolism, and a mitogen-activated protein kinase are decreased during drought. Our experiment has achieved an in-depth profiling of phloem sap protein contents during drought stress and recovery that supports previous findings and provides new evidence that multiple biological processes are involved in drought adaptation.