Tropical soils with high aluminum concentrations cause oxidative stress in two tomato genotypes

Abstract

Tropical and subtropical soils are usually acidic and have high concentrations of aluminum (Al). Aluminum toxicity in plants is caused by the high affinity of the Al cation for cell walls, membranes, and metabolites. In this study, the response of the antioxidant-enzymatic system to Al was examined in two tomato genotypes: Solanum lycopersicum var. esculentum (Calabash Rouge) and Solanum lycopersicum var. cerasiforme (CNPH 0082) grown in tropical soils with varying levels of Al. Plant growth; activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (GPOX), and glutathione reductase (GR) enzymes; stress-indicating compounds (malondialdehyde (MDA) and hydrogen peroxide); and morphology (root length and surface area) were analyzed. Increased levels of Al in soils were correlated with reduced shoot and root biomass and with reduced root length and surface area. Calabash Rouge exhibited low Al concentrations and increased growth in soils with the highest levels of Al. Plants grown in soils with high availability of Al exhibited higher levels of stress indicators (MDA and hydrogen peroxide) and higher enzyme activity (CAT, APX, GPOX, and GR). Calabash Rouge absorbed less Al from soils than CNPH 0082, which suggests that the genotype may possess mechanisms for Al tolerance.

Cadmium stress antioxidant responses and root-to-shoot communication in grafted tomato plants

“…The excessive production of H 2 O 2 may be detoxified to H 2 O by the action of a number of enzymes such as ascorbate peroxidase (APX, EC 1.11.1.11), catalase (CAT, 1.11.1.6), and guaiacol-type peroxidases (GPOX, EC 1.11.1.7) (Hippler et al 2015;Liu et al 2015;Roychoudhury et al 2012), as well as non-enzymatic mechanisms of ROS detoxification involving ascorbate (AsA), glutathione (GSH) (Foyer and Noctor 2013), organic acids , stress proteins, proline, flavonoids, alkaloids and carotenoids (Ahmad et al 2010;Gratão et al 2005). The regeneration of glutathione (GSH) from oxidized glutathione (GSSG) is catalyzed by glutathione reductase (GR, EC 1.6.4.2) using NAD(P)H as a reducing agent (Gratão et al 2012;Nogueirol et al 2015). Moreover, Cd can disrupt physiological signaling processes, amplifying cell response to the direct damage of enzymes and transporters, affecting cellular function and gene transcription and regulation (AlKhateeb and Al-Qwasemeh 2014; Gallego et al 2012;Zhou et al 2015).…”

Tropical soils cultivated with tomato: fractionation and speciation of Al

“…The genotype CNPH 0082 has previously been described as Al-tolerant and was selected in a region of Porte Firme, in the Brazilian state of Minas Gerais, where soils have high concentrations of Al. By contrast, the Calabash Rouge genotype is native to Chiapas, Mexico and is sensitive to toxic elements such as cadmium (Cd), as reported by Piotto (2012); see Piotto et al 2014 for heavy metals-tolerant screening methodology-see also Nogueirol et al 2015).…”

“…The data obtained and used in this report are the same published in the companion paper (Nogueirol et al 2015) in which the plant analyses for the same experiments were presented and discussed. Therefore, in order to avoid reproduction of the same data, please see Figs.…”

“…Aluminum phytotoxicity results in oxidative stress in plants (Gratão et al 2005), resulting in peroxidation of the cellular membrane, chromosomal aberration and even cell death, in addition to inhibiting root growth and development and consequently affecting both water and nutrient absorption (Yi et al 2010;Nogueirol et al 2015). At high concentrations, Al can be a serious threat to agricultural production because it inhibits growth and lengthening of the roots through various mechanisms, including interactions inside the symplast, plasmatic membrane, and cell wall (Yang et al 2008).…”

Evaluation of protein extraction methods for enhanced proteomic analysis of tomato leaves and roots

“…The tomato cultivar Micro-Tom (MT) has been successfully used as a model plant to explore several aspects of plant development due to important characteristics such as a short developmental cycle (Meissner et al 1997). Additionally, a MT mutant collection with other tomato lines are available at "HCPD-Lab Micro-Tom Mutants", which has been explored for different features, hormonal (Monteiro et al 2011, Carvalho et al 2013) and metal (Gratão et al 2009, 2014, Nogueirol et al 2015 responses and biochemical and histological characterization . However, since the complete tomato genome sequence was published (TGC 2012), reports have focused on genetic and genome features and little information with a focus on proteome is available.…”