Integrative “omic” analysis reveals distinctive cold responses in leaves and roots of strawberry, Fragaria × ananassa ‘Korona’

Abstract

To assess underlying metabolic processes and regulatory mechanisms during cold exposure of strawberry, integrative “omic” approaches were applied to Fragaria × ananassa Duch. ‘Korona.’ Both root and leaf tissues were examined for responses to the cold acclimation processes. Levels of metabolites, proteins, and transcripts in tissues from plants grown at 18°C were compared to those following 1–10 days of cold (2°C) exposure. When leaves and roots were subjected to GC/TOF-MS-based metabolite profiling, about 160 compounds comprising mostly structurally annotated primary and secondary metabolites, were found. Overall, ‘Korona’ showed a modest increase of protective metabolites such as amino acids (aspartic acid, leucine, isoleucine, and valine), pentoses, phosphorylated and non-phosphorylated hexoses, and distinct compounds of the raffinose pathway (galactinol and raffinose). Distinctive responses were observed in roots and leaves. By 2DE proteomics a total of 845 spots were observed in leaves; 4.6% changed significantly in response to cold. Twenty-one proteins were identified, many of which were associated with general metabolism or photosynthesis. Transcript levels in leaves were determined by microarray, where dozens of cold associated transcripts were quantitatively characterized, and levels of several potential key contributors (e.g., the dehydrin COR47 and GADb) to cold tolerance were confirmed by qRT-PCR. Cold responses are placed within the existing knowledge base of low temperature-induced changes in plants, allowing an evaluation of the uniqueness or generality of Fragaria responses in photosynthetic tissues. Overall, the cold response characteristics of ‘Korona’ are consistent with a moderately cold tolerant plant.

Cold-triggered induction of ROS- and raffinose-related metabolism in freezing-sensitive taproot tissue of sugar beet

“…4D ). These data suggest that survival of the pith tissue might be linked to high raffinose concentrations and are in line with previous reports, that showed that raffinose levels were elevated upon cold and freezing temperatures (Koehler et al, 2015; Yue et al, 2015). Such conditions induce the formation of reactive oxygen species (Gechev et al, 2006), which, when accumulating to high levels, can be harmful to the plant, as they can damage membranes (lipid peroxidation), proteins, RNA and DNA molecules (Choudhury et al, 2017).…”

Nitrogen Fertilization Influences the Quantity, Composition, and Tissue Association of Foliar Phenolics in Strawberries

“…Dihydroflavonols are utilized in the biosynthesis of not only flavonols but also leucoanthocyanidins, which are utilized for the biosynthesis of anthocyanins and flavan-3-ols. The anthocyanin content observed in our study was lower than the content previously reported under cold treatment in leaves and fruits (Koehler et al, 2015;Tanou et al, 2017). The reduction of anthocyanins to flavan-3ols by anthocyanin reductases (ANRs) has previously been reported to contribute a major share of the flavan-3-ols in tobacco (Luo et al, 2016), cotton (Zhu et al, 2015), white clover (Abeynayake et al, 2012), grape (Bogs et al, 2007), and strawberry (Fischer et al, 2014).…”

“…treatments (Supplementary Figure 1). These metabolites are known for their role as osmoprotectants, scavengers of ROS, and signaling molecules and are reported to be upregulated under cold, heat, and drought stress (Nishizawa et al, 2008;Koehler et al, 2015). Organic acids derived from the anaplerotic TCA cycle act as transient carbon substrates for amino acid synthesis and as regulators of redox and energy levels (Igamberdiev and Eprintsev, 2016).…”

Answering biological questions by analysis of the strawberry metabolome

“…To study the metabolic processes and regulatory mechanisms during cold exposure of strawberry, metabolite profiling approaches were applied to both root and leaf tissues (Koehler et al 2015; Rohloff et al 2012). About 160 substances comprising primary and secondary metabolites were quantitatively analysed.…”