Target proteins reprogrammed by As and As + Si treatments in Solanum lycopersicum L. fruit

Abstract

BackgroundArsenic is an important contaminant of many arable soils worldwide, while silicon, one of the most abundant elements in the earth’s crust, interacts with As in the context of plant metabolism. As toxicity results largely from its stimulation of reactive oxygen species, and it is believed that Si can mitigate this process through reduction of the level of oxidative stress. Experiments targeting the proteomic impact of exposure to As and Si have to date largely focused on analyses of root, shoot and seed of a range of mainly non-solanaceous species, thus it remains unclear whether oxidative stress is the most important manifestation of As toxicity in Solanum lycopersicum fruit which during ripening go through drastic physiological and molecular readjustments. The role of Si also needs to be re-evaluated.ResultsA comparison was drawn between the proteomic responses to As and As + Si treatments of the fruit of two tomato cultivars (cvs. Aragon and Gladis) known to contrast for their ability to take up these elements and to translocate them into fruits. Treatments were applied at the beginning of the red ripening stage, and the fruit proteomes were captured after a 14 day period of exposure. For each cultivar, a set of differentially abundant fruit proteins (from non-treated and treated plants) were isolated by 2DGE and identified using mass spectrometry. In the fruit of cv. Aragon, the As treatment reprogrammed proteins largely involved in transcription regulation (growth- regulating factor 9-like), and cell structure (actin-51), while in the cv. Gladis, the majority of differentially expressed proteins were associated with protein ubiquitination and proteolysis (E3 ubiquitin protein, and hormones (1-aminocyclopropane 1-carboxylase).ConclusionsThe present experiments were intended to establish whether Si supplementation can be used to reverse the proteomic disturbance induced by the As treatment; this reprogram was only partial and more effective in the fruit of cv. Gladis than in that of cv. Aragon. Proteins responsible for the protection of the fruits’ quality in the face of As-induced stress were identified. Moreover, supplementation with Si seemed to limit to a degree the accumulation of As in the tomato fruit of cv. Aragon.Electronic supplementary materialThe online version of this article (10.1186/s12870-017-1168-2) contains supplementary material, which is available to authorized users.

Abiotic Stress Response to As and As+Si, Composite Reprogramming of Fruit Metabolites in Tomato Cultivars

“…Calcium triggers a stress signaling molecular cascade through the expression of several protein kinases (CDPK genes, CBL-interacting protein kinase (CIPK), calcineurinB-like protein (CBL) through Calmodulin binding ( Das and Pandey, 2010 ; Truong and Carroll, 2013 ). Consistently, in a parallel study on proteome modulation in the same plants used in this study, we found for both cultivars a number of proteins involved in Ca signal transduction, such as Calmodulin, CBL-interacting protein kinase, and Calcium–dependent protein Kinase ( Marmiroli et al, 2017 ).…”

“…Arsenic affects negatively also mitochondria outer and inner membranes and causes a further damage to mitochondrial functions by substituting Pi thus leading to respiration impairment ( Finnegan and Chen, 2012 ). In our proteomic study of these same tomato fruit under As treatment, we found two reprogrammed proteins related to mitochondria: probable lipid-A-disaccharide synthase, mitochondrial (predicted); pentatricopeptide repeat-containing protein At1g80270, mitochondrial (predicted) involved in signal transduction, lipid biosynthesis and biogenesis/function respectively ( Marmiroli et al, 2017 ). It is therefore likely that in our case As damaged both mitochondria structural membranes and function.…”

“…Expression of specific stress-response genes was reported in tomato fruit when plants were treated with As ( Goupil et al, 2009 ). A detailed proteomic analysis on tomato fruit treated with As and As+Si showed a reprogramming of proteins from the abiotic stress family (Hsps, calmodulins, growth regulating factors, proteins ubiquitination), but also specific to oxidative stress response (sulfotrasferase, lipid metabolism proteins, and secondary metabolites biosynthetic enzymes) ( Marmiroli et al, 2017 ). In conclusion, within fruit distinctive molecular background, AsA and GSH redox state, total carotenoids, TP, and H 2 O 2 levels were optimal parameters to be considered as effective “phenotypic markers” of response to As-induced abiotic stress and of the Si alleviating role in ripening tomato fruit that, though complex to validate, would play a key role in studying phenomena where genetic markers alone should not suffice.…”

Get the Balance Right: ROS Homeostasis and Redox Signalling in Fruit

“…lycopene, carotenoids and phenolics), ASC and GSH redox states and lipid peroxidation (Marmiroli et al, 2017a). Alternatively, a detailed proteomic study on tomato fruit confirmed the implication of ASC- and GSH-related proteins in response to this abiotic stress (Marmiroli et al, 2017b). Some of these redox alterations (H 2 O 2 , ASC and GSH redox states, total carotenoids and phenolics) were proposed as reliable arsenic exposition biomarkers for further studies that could broaden our knowledge on arsenic-induced abiotic stress in fruit (Marmiroli et al, 2017a).…”

Proteomics of Reproductive Development, Fruit Ripening, and Stress Responses in Tomato

“…Tomato germplasms (cv. ‘Gladis’ and ‘Aragon’) displayed protein reprogramming to adjust to metal stress by expressing proteins such as growth regulating factor 9-like protein, a cellular housekeeping actin 1, and proteolytic degradation machinery such as E3 ubiquitin ligases …”