Location: Children's Nutrition Research CenterTitle: Effects of Fe and Mn deficiencies on the protein profiles of tomato (Solanum lycopersicum) xylem sap as revealed by shotgun analyses
|CEBALLOS-LAITA, LAURA - Instituto De Investigacion Sanitaria Aragon|
|GUTIERREZ-CARBONELL, ELAIN - Instituto De Investigacion Sanitaria Aragon|
|TAKAHASHI, DAISUKE - Iwate University|
|ABADIA, ANUNCIACION - Instituto De Investigacion Sanitaria Aragon|
|UEMURA, MATSUO - Iwate University|
|ABADIA, JAVIER - Instituto De Investigacion Sanitaria Aragon|
|LOPEZ-MILLAN, ANA FLOR - Children'S Nutrition Research Center (CNRC)|
Submitted to: Journal of Proteomics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/24/2017
Publication Date: 1/6/2018
Citation: Ceballos-Laita, L., Gutierrez-Carbonell, E., Takahashi, D., Abadia, A., Uemura, M., Abadia, J., Lopez-Millan, A.F. 2018. Effects of Fe and Mn deficiencies on the protein profiles of tomato (Solanum lycopersicum) xylem sap as revealed by shotgun analyses. Journal of Proteomics. 170:117-129. https://doi.org/10.1016/j.jprot.2017.08.018.
Interpretive Summary: The xylem pathway in plants is responsible for water and mineral movement from roots to shoots. The liquid moving through this pathway is referred to as xylem sap. Xylem sap also contains proteins, but little is known about the composition or role of these proteins, nor how the diversity of these proteins might change when the plant is challenged with a nutritional stress. In this study, xylem sap proteins were measured and characterized in tomato plants grown with full nutrients or with nutrient solutions lacking iron or manganese. We found different mixtures of xylem sap proteins in response to the nutrient deficiencies, relative to the full nutrient conditions. In general, when deprived of iron or manganese, plants produced more proteins that were involved in protecting plant cells from unstable molecules. These deficiencies also resulted in more proteins that could alter the structure of plant cell walls. These results will help us understand some of the ways in which crop plants cope with inadequate levels of essential minerals and will suggest ways to help the plant maintain optimal performance and productivity when challenged with nutritional deficiencies.
Technical Abstract: The aim of this work was to study the effects of Fe and Mn deficiencies on the xylem sap proteome of tomato using a shotgun proteomic approach, with the final goal of elucidating plant response mechanisms to these stresses. This approach yielded 643 proteins reliably identified and quantified with 70% of them predicted as secretory. Iron and Mn deficiencies caused statistically significant and biologically relevant abundance changes in 119 and 118 xylem sap proteins, respectively. In both deficiencies, metabolic pathways most affected were protein metabolism, stress/oxidoreductases and cell wall modifications. First, results suggest that Fe deficiency elicited more stress responses than Mn deficiency, based on the changes in oxidative and proteolytic enzymes. Second, both nutrient deficiencies affect the secondary cell wall metabolism, with changes in Fe deficiency occurring via peroxidase activity, and in Mn deficiency involving peroxidase, Cu-oxidase and fasciclin-like arabinogalactan proteins. Third, the primary cell wall metabolism was affected by both nutrient deficiencies, with changes following opposite directions as judged from the abundances of several glycoside-hydrolases with endo-glycolytic activities and pectin esterases. Fourth, signaling pathways via xylem involving CLE and/or lipids as well as changes in phosphorylation and N-glycosylation also play a role in the responses to these stresses. Biological significance In spite of being essential for the delivery of nutrients to the shoots, our knowledge of xylem responses to nutrient deficiencies is very limited. The present work applies a shotgun proteomic approach to unravel the effects of Fe and Mn deficiencies on the xylem sap proteome. Overall, Fe deficiency seems to elicit more stress in the xylem sap proteome than Mn deficiency, based on the changes measured in proteolytic and oxido-reductase proteins, whereas both nutrients exert modifications in the composition of the primary and secondary cell wall. Cell wall modifications could affect the mechanical and permeability properties of the xylem sap vessels, and therefore ultimately affect solute transport and distribution to the leaves. Results also suggest that signaling cascades involving lipid and peptides might play a role in nutrient stress signaling and pinpoint interesting candidates for future studies. Finally, both nutrient deficiencies seem to affect phosphorylation and glycosylation processes, again following an opposite pattern.