Large-Scale Proteomics of the Cassava Storage Root and Identification of a Target Gene to Reduce Postharvest Deterioration

Abstract

ORCID IDs: 0000-0003-2102-9737 (H.V.); 0000-0002-1904-9440 (K.B.) Cassava (Manihot esculenta) is the most important root crop in the tropics, but rapid postharvest physiological deterioration (PPD) of the root is a major constraint to commercial cassava production. We established a reliable method for image-based PPD symptom quantification and used label-free quantitative proteomics to generate an extensive cassava root and PPD proteome. Over 2600 unique proteins were identified in the cassava root, and nearly 300 proteins showed significant abundance regulation during PPD. We identified protein abundance modulation in pathways associated with oxidative stress, phenylpropanoid biosynthesis (including scopoletin), the glutathione cycle, fatty acid a-oxidation, folate transformation, and the sulfate reduction II pathway. Increasing protein abundances and enzymatic activities of glutathione-associated enzymes, including glutathione reductases, glutaredoxins, and glutathione S-transferases, indicated a key role for ascorbate/glutathione cycles. Based on combined proteomics data, enzymatic activities, and lipid peroxidation assays, we identified glutathione peroxidase as a candidate for reducing PPD. Transgenic cassava overexpressing a cytosolic glutathione peroxidase in storage roots showed delayed PPD and reduced lipid peroxidation as well as decreased H 2 O 2 accumulation. Quantitative proteomics data from ethene and phenylpropanoid pathways indicate additional gene candidates to further delay PPD. Cassava root proteomics data are available at www.pep2pro.ethz.ch for easy access and comparison with other proteomics data.

Network Analysis of Postharvest Senescence Process in Citrus Fruits Revealed by Transcriptomic and Metabolomic Profiling

“…High-throughput molecular biological techniques like transcriptomic, proteomic, and metabolomic approaches have been widely used to explore aging-related mechanisms in fruits, as reported in tomato (Kok et al, 2008;Karlova et al, 2011;Osorio et al, 2011), pepper (Capsicum annuum; Osorio et al, 2012), grape (Fasoli et al, 2012), peach (Prunus persica; Jiang et al, 2014), apple (Zheng et al, 2013), melon (Cucumis melo; Bernillon et al, 2013), strawberry (Kang et al, 2013), and cassava (Manihot esculenta; Vanderschuren et al, 2014). The combination analysis of different omics data sets by network construction has been used to unravel the regulatory relationship or changes of metabolic pathways during the ripening and senescence process in strawberry (Fait et al, 2008), tomato (Enfissi et al, 2010;Lee et al, 2012), and peach (Lombardo et al, 2011).…”

Genomics approaches to unlock the high yield potential of cassava, a tropical model plant

“…Large-scale proteomic analyses indicated a key function for ascorbate/glutathione cycles, highlighting glutathione peroxidase as a candidate for reducing PPD. Transgenic cassava overexpressing a cytosolic glutathione peroxidase in storage roots showed delayed PPD and reduced lipid peroxidation, as well as decreased H 2 O 2 accumulation [54]. Overexpressing Cu-superoxide dismutase (SOD), Zn-SOD and acyl-CoA oxidase in cassava roots also could delay PPD 7-21 days of under greenhouse and field trial conditions [55,56].…”

Introductory Chapter: Cassava as a Staple Food

“…Upon examination of physiological and biochemical changes occurring after cassava root detachment, changes in the nature and type of volatile compounds emited, secondary metabolites accumulated, and changes in the expression of key genes in reactive oxygen species (ROS) turnover had been primarily observed [33,34]. Nevertheless, based on combined proteomics data, enzymatic activities, and lipid peroxidation assays, Vanderschuren et al for instance [35] have identiied glutathione peroxidase as a candidate for reducing PPD. Further, in this study, transgenic cassava overexpressing a cytosolic glutathione peroxidase in storage roots showed delayed PPD and reduced lipid peroxidation as well as decreased hydrogen peroxide accumulation [35].…”

“…Nevertheless, based on combined proteomics data, enzymatic activities, and lipid peroxidation assays, Vanderschuren et al for instance [35] have identiied glutathione peroxidase as a candidate for reducing PPD. Further, in this study, transgenic cassava overexpressing a cytosolic glutathione peroxidase in storage roots showed delayed PPD and reduced lipid peroxidation as well as decreased hydrogen peroxide accumulation [35].…”

“…This could be considered as a vital approach for promoting cassava as a means of preventing food security issues. To be successful, however, as highlighted by Vanderschuren et al [35], crop biofortiication programs must develop integrated management practices by which molecular biologists, breeders, agronomists, nutritionists, educators, economists, farmers and consumers are all engaged in product development and delivery.…”