Proteomic Analysis of Copper-Binding Proteins in Excess Copper-Stressed Roots of Two Rice (Oryza sativa L.) Varieties with Different Cu Tolerances

Abstract

To better understand the mechanisms involved in the heavy metal stress response and tolerance in plants, a proteomic approach was used to investigate the differences in Cu-binding protein expression in Cu-tolerant and Cu-sensitive rice varieties. Cu-binding proteins from Cu-treated rice roots were separated using a new IMAC method in which an IDA-sepharose column was applied prior to the Cu-IMAC column to remove metal ions from protein samples. More than 300 protein spots were reproducibly detected in the 2D gel. Thirty-five protein spots exhibited changes greater than 1.5-fold in intensity compared to the control. Twenty-four proteins contained one or more of nine putative metal-binding motifs reported by Smith et al., and 19 proteins (spots) contained one to three of the top six motifs reported by Kung et al. The intensities of seven protein spots were increased in the Cu-tolerant variety B1139 compared to the Cu-sensitive variety B1195 (p<0.05) and six protein spots were markedly up-regulated in B1139, but not detectable in B1195. Four protein spots were significantly up-regulated in B1139, but unchanged in B1195 under Cu stress. In contrast, two protein spots were significantly down-regulated in B1195, but unchanged in B1139. These Cu-responsive proteins included those involved in antioxidant defense and detoxification (spots 5, 16, 21, 22, 28, 29 and 33), pathogenesis (spots 5, 16, 21, 22, 28, 29 and 33), regulation of gene transcription (spots 8 and 34), amino acid synthesis (spots 8 and 34), protein synthesis, modification, transport and degradation (spots 1, 2, 4, 10, 15, 19, 30, 31, 32 and 35), cell wall synthesis (spot 14), molecular signaling (spot 3), and salt stress (spots 7, 9 and 27); together with other proteins, such as a putative glyoxylate induced protein, proteins containing dimeric alpha-beta barrel domains, and adenosine kinase-like proteins. Our results suggest that these proteins, together with related physiological processes, play an important role in the detoxification of excess Cu and in maintaining cellular homeostasis.

Genome-Wide Characterization and Expression Analysis of the Germin-Like Protein Family in Rice and Arabidopsis

“…For example, different expressions of GLP genes in response to salt in barley [37], cold in Arabidopsis [38], and heavy metals in rice [39] have been reported. It has been shown that GLPs possess SOD activity, this generates H 2 O 2 , which plays an important role in defending against various stresses [40].…”

“…For example, the overexpression of rice germin-like protein1 in tobacco hyper-accumulates H 2 O 2 and reinforces the cell wall components, and consequently increased tolerance against biotic and abiotic stresses [41]. Some GLPs involved in antioxidant defence and detoxification were identified as Cu-IMAC-binding proteins [39], and Cu stress could decrease the expression of certain GLP genes, such as a GLP subfamily with a three member precursor in the Cu-tolerant plant Elsholtzia splendens [42]. The present study showed that the larger cluster of OsGLP genes on chromosome 8 and the single OsGLP gene on chromosome 4 in rice may be involved in abiotic stresses, similar to the cluster of AtGLP genes on chromosome 5.…”

Metabolic adaptation of a Chlamydomonas acidophila strain isolated from acid mine drainage ponds with low eukaryotic diversity

“…Proteomic responses to Cu stress linked to Cu tolerance have previously been observed in other organisms. Cu exposure experiments in plants and fungi have observed increases in soluble protein that has been linked to induction of anti-oxidant enzymes (Cavalcanti Luna et al, 2015;Gao et al, 2008;Rout et al, 2013) while induction of Cu-binding proteins has been demonstrated in a Cu-tolerant variety of rice (Chen et al, 2015). Mechanisms of Cu tolerance in algae are not well understood, and may involve differential Cu uptake and internalisation in some cases (Levy et al, 2008).…”

Leaf proteome characterization in the context of physiological and morphological changes in response to copper stress in sorghum

“…Recently, copper has been frequently considered a deleterious heavy metal associated with different types of morphological, physiological (Adrees et al 2015) and proteomic alterations due to its toxic effects and molecular tolerance in plants (Chen et al 2015;Li et al 2013).…”

“…Using this approach, a number of studies have recently been conducted to identify Cu-responsive proteins in several plants and algal species (Ahsan et al 2007;Bona et al 2007;Chen et al 2015;Cuypers et al 2005;Ritter et al 2010;Song et al 2013Song et al , 2014Zhang et al 2009). More specifically, leaf proteome alterations in response to Cu have been investigated in the leaves of rice (Hajduch et al 2001;Rakwal et al 1999), the leaves and roots of wheat (Li et al 2013), Elsholtzia splendens (Li et al 2009), birch (Utriainen et al 1998), and the seedlings of Arabidopsis (Smith et al 2004).…”