Project description:The pathological interaction between oak trees and Phytophthora cinnamomi has implications in the cork oak decline observed over the last decades in the Iberian Peninsula. During host colonization, the phytopathogen secretes effector molecules like elicitins to increase disease effectiveness. The objective of this study was to unravel the proteome changes associated to with the cork oak immune response triggered by P. cinnamomi inoculation in a long-term assay, through SWATH-MS quantitative proteomics performed in the oak leaves. Using the Arabidopis thaliana proteome database as a reference, 424 proteins have been confidently quantified in cork oak leaves, of which 80 proteins showed a p-value below 0.05 or a fold-change greater than 2 or less than 0.5 in their levels between control and inoculated samples being considered as altered. The inoculation of cork oak roots with P. cinnamomi increased the levels of proteins associated with protein-DNA complex assembly, lipid oxidation, response to endoplasmic reticulum stress, and pyridine-containing compound metabolic process in the leaves. In opposition, several proteins associated with cellular metabolic compound salvage and monosaccharide catabolic process had significantly decreased abundances. The most significant abundance variations were observed for the Ribulose 1,5-Bisphosphate Carboxylase small subunit (RBCS1A), Heat Shock protein 90-1 (Hsp90-1), Lipoxygenase 2 (LOX2) and Histone superfamily protein H3.3 (A8MRLO/At4G40030) revealing a pertinent role for these proteins in the host-pathogen interaction mechanism. This work represents the first SWATH-MS analysis performed in cork oak plants inoculated with P. cinnamomi and highlights host proteins that have a relevant action in the homeostatic states that emerge from the interaction between the oomycete and the host in the long term and in a distal organ.
Project description:This work aimed to characterize the molecular adaptations occurring in cork oak (Quercus suber) stems in adaptation to drought, and identify key genetic pathways regulating phellem development. One-year-old cork oak plants were grown for additional 6 months under well-watered (WW) or water-deficit (WD) conditions and main stems were targeted for transcriptomic analysis. WD had a negative impact on secondary growth, decreasing the activity of the vascular cambium and phellogen. Following a tissue-specific approach, we analyzed the transcriptional changes imposed by WD in phellem (outer bark), inner bark, and xylem, and found a global downregulation of genes related to cell division, cell wall biogenesis, lignin and/or suberin biosynthesis. Phellem and phloem showed a concerted upregulation of photosynthesis-related genes, suggesting a determinant role of stem photosynthesis in the adaptation of young plants to long-term drought. The data gathered will be important to further harness the diverse genetic background of this species for the development of optimized management practices.