Expression profile of oxidative and antioxidative stress enzymes based on ESTs approach of citrus

Abstract

Plants not only evolve but also reduce oxygen in photosynthesis. An inevitable consequence of this normal process is the production of reactive oxygen species (ROS). Plants are adequately protected by the presence of multiple antioxidative enzymes in the cytosol and also in the different cell organelles such as chloroplasts, mitochondria, and peroxisomes. Traditionally, ROS were considered to be only a toxic byproduct of aerobic metabolism. However, recently it has become apparent that plants actively produce these molecules which may control many different physiological processes such as abiotic and biotic stress response, pathogen defense and systemic signaling. The search results using the Citrus Genome Program in Brazil (CitEST) for oxidative stress and the antioxidant enzyme system in Citrus Sinensis variety 'Pera IAC' indicated that the multiple ROS-scavenging enzymes were expressed throughout all citrus tissues. The analyses demonstrated the ubiquitous expression of metallothioneins, probably indicating a constitutive expression pattern. Oxalate oxidase has been identified as the most abundant expressed gene in developing fruits, which suggests a specific function in the ripening of citrus fruit. Moreover, infected leaves with Xylella fastidiosa and Leprosis citri showed a massive change in their ROS gene expression profile which may indicate that the suppression of ROS detoxifying mechanisms may be involved in the induction of the diseases.

Changes in antioxidant gene expression and induction of oxidative stress in pea (Pisum sativum L.) under Al stress

“…1d) in both the Al concentrations for root and shoot which indicates accumulation of ROS in cells (Peroni et al 2007). On the other hand POX is also known to protect cells from oxidative injury by detoxifying H 2 O 2 (Peroni et al 2007;Smeets et al 2008). In our experiment we found that POX (Fig.…”

“…Basu et al (2001) overexpressed MnSOD in Brassica napus and found a modest Al-resistance. The gene expression pattern of oxidative stress related enzymes were also studied in Citrus sinensis (Peroni et al 2007). These genes encode peroxidase (POX), glutathione-Stransferase (GST), blue copperbinding protein (BCB) and Bowman-Birk protease inhibitor (Richards et al 1998), and some of them (POX, GST, BCB) have antioxidant functions.…”

“…(Noctor and Foyer 1998). The elimination of H 2 O 2 involves the conversion of H 2 O 2 to water molecule (Peroni et al 2007). Glutathione plays an important role in protecting plants from oxidative stress induced by some heavy metals (Xiang and Oliver 1998).…”

Citrus genomics

“…Genes related to reorganization of cell walls, ion transport and water stress were up-regulated in plants with CVC, supporting functions to allow plant survival. Up-regulated defense response genes associated with oxidative stress (Peroni et al 2007) and PR proteins (PR 7, PR 10) (Campos et al 2007) were found only in symptomatic plants, suggesting that although the defense machinery was activated, it was insufficient to block the disease completely. The processes of pathogen recognition may be triggered later, when the bacteria are already established within the plant, a common characteristic in susceptible responses to pathogens.…”

Deciphering key proteins of oil palm (Elaeis guineensis Jacq.) fruit mesocarp development by proteomics and chemometrics

“…Plant cells produce reactive oxygen species (ROS) especially hydrogen peroxide and superoxide which have been involved as second messengers in most of the plant growth and development processes and contribute to the lipid peroxidation and membrane deterioration and hence deleterious for cell metabolism . With regard to preventing the action of ROS, fruit synthesizes several antioxidant molecules during oxidative stress e.g.…”