2-DE proteomics analysis of drought treated seedlings of Quercus ilex supports a root active strategy for metabolic adaptation in response to water shortage

Abstract

Holm oak is a dominant tree in the western Mediterranean region. Despite being well adapted to dry hot climate, drought is the main cause of mortality post-transplanting in reforestation programs. An active response to drought is critical for tree establishment and survival. Applying a gel-based proteomic approach, dynamic changes in root proteins of drought treated Quercus ilex subsp. Ballota [Desf.] Samp. seedlings were followed. Water stress was applied on 20 day-old holm oak plantlets by water limitation for a period of 10 and 20 days, each followed by 10 days of recovery. Stress was monitored by changes in water status, plant growth, and electrolyte leakage. Contrary to leaves, holm oak roots responded readily to water shortage at physiological level by growth inhibition, changes in water status and membrane stability. Root proteins were extracted using trichloroacetate/acetone/phenol protocol and separated by two-dimensional electrophoresis. Coomassie colloidal stained gel images were analyzed and spot intensity data subjected to multivariate statistical analysis. Selected consistent spots in three biological replicas, presenting significant changes under stress, were subjected to MALDI-TOF mass spectrometry (peptide mass fingerprinting and MS/MS). For protein identification, combined search was performed with MASCOT search engine over NCBInr Viridiplantae and Uniprot databases. Data are available via ProteomeXchange with identifier PXD002484. Identified proteins were classified into functional groups: metabolism, protein biosynthesis and proteolysis, defense against biotic stress, cellular protection against abiotic stress, intracellular transport. Several enzymes of the carbohydrate metabolism decreased in abundance in roots under drought stress while some related to ATP synthesis and secondary metabolism increased. Results point at active metabolic adjustment and mobilization of the defense system in roots to actively counteract drought stress.

Elucidation of Complex Nature of PEG Induced Drought-Stress Response in Rice Root Using Comparative Proteomics Approach

“…Mitochondrial pyruvate dehydrogenase (OsC-4803) is an intermediate enzyme that links glycolysis to the citric acid cycle. The enzyme was downregulated under drought stress and results substantiate the earlier reports (Simova-Stoilova et al, 2015 ). Fructokinase-2 (OsC-3314) is mainly involved in carbohydrate metabolism, more specifically, sucrose and fructose metabolism (Odanaka et al, 2002 ).…”

Differences in the Response to Acute Drought and Phytophthora cinnamomi Rands Infection in Quercus ilex L. Seedlings

“…The plant responses detected in previous works as a result of P. cinnamomi inoculation [14], should be linked to changes in the secondary metabolism, agreeing with the suggestions of other authors about the involvement of secondary metabolites in stomatal closure or osmotic imbalance [16,46]. These changes might be related with the reduction of carbon compounds storage in roots under water stress [47]. However, when the normal metabolism of plants was only altered by pathogen infection, the responses detected in roots [14,48] could be considered as evidence of a set of physiological and morphological changes which led to a recovery of our seedlings after 15 days, time in which the first infection cycle is completed [14].…”

Drought stress and carbon assimilation in a warming climate: Reversible and irreversible impacts

“…Several key proteins involved in drought or heat stress tolerance were identified and studies including modern proteomics may allow a deeper insight into regulatory mechanisms and may allow to identify additional key players in plant stress responses (Priest et al, 2014 ;Song et al, 2014 ;Simova-Stoilova et al, 2015). Besides the identification of relevant genes, post-transcriptional processes must be borne in mind and may represent additional challenges for breeding programs focused on abiotic stress responses.…”

“…In the latter case, new enzyme molecules may be produced and become active already during the stress phase or during the recovery phase as long as compartmentation and basic cellular functions including gene expression and protein synthesis are maintained (Fu et al, 2008;Cartagena et al, 2015;Chen et al, 2014;Liu et al, 2014;Wang et al, 2015). During the stress phase, protein synthesis is important for the adaptation of the metabolism, especially for the formation of protective proteins such as dehydrins (Close, 1997;Volaire and Lelievre, 2001;Vaseva et al, 2014) or enzymes involved in the detoxification of reactive oxygen species (Ahmed et al, 2015;Jain et al, 2015) and in the production of compatible solutes and secondary metabolites (Jain et al, 2015;Simova-Stoilova et al, 2015).…”