Proteome dynamics of cold-acclimating Rhododendron species contrasting in their freezing tolerance and thermonasty behavior

Abstract

To gain a better understanding of cold acclimation in rhododendron and in woody perennials in general, we used the 2D-DIGE technique to analyze the rhododendron proteome during the seasonal development of freezing tolerance. We selected two species varying in their cold acclimation ability as well as their thermonasty response (folding of leaves in response to low temperature). Proteins were extracted from leaves of non-acclimated (NA) and cold acclimated (CA) plants of the hardier thermonastic species, R. catawbiense (Cata.), and from leaves of cold acclimated plants of the less hardy, non-thermonastic R. ponticum (Pont.). All three protein samples (Cata.NA, Cata.CA, and Pont.CA) were labeled with different CyDyes and separated together on a single gel. Triplicate gels were run and protein profiles were compared resulting in the identification of 72 protein spots that consistently had different abundances in at least one pair-wise comparison. From the 72 differential spots, we chose 56 spots to excise and characterize further by mass spectrometry (MS). Changes in the proteome associated with the seasonal development of cold acclimation were identified from the Cata.CA—Cata.NA comparisons. Differentially abundant proteins associated with the acquisition of superior freezing tolerance and with the thermonastic response were identified from the Cata.CA—Pont.CA comparisons. Our results indicate that cold acclimation in rhododendron involves increases in abundance of several proteins related to stress (freezing/desiccation tolerance), energy and carbohydrate metabolism, regulation/signaling, secondary metabolism (possibly involving cell wall remodeling), and permeability of the cell membrane. Cold acclimation also involves decreases in abundance of several proteins involved in photosynthesis. Differences in freezing tolerance between genotypes can probably be attributed to observed differences in levels of proteins involved in these functions. Also differences in freezing tolerance may be attributed to higher levels of some constitutive protective proteins in Cata. than in Pont. that may be required to overcome freeze damage, such as glutathione peroxidase, glutamine synthetase, and a plastid-lipid-associated protein.

Unveiling Kiwifruit Metabolite and Protein Changes in the Course of Postharvest Cold Storage

“…A similar quantitative profile was also verified for over-representation of cytosolic aldehyde dehydrogenase ALDH7B4 (AT1G54100) (Supplementary Table S3 and Supplementary Figure S5G), which is induced in plants as result of various abiotic stress conditions (Stiti et al, 2011). Measured level of specific proteins mentioned above was in good agreement with that observed in kiwifruit exposed to cold storage under different experimental conditions (Minas et al, 2016), in other climacteric fruits during ripening or cold storage (Nilo et al, 2010; Zhang et al, 2011; Giraldo et al, 2012; Zheng et al, 2013; Li et al, 2015; Du et al, 2016; Wu et al, 2016; Tanou et al, 2017) and in plants exposed to cold stress (Janmohammadi et al, 2015; Die et al, 2016, 2017). Some of the above-mentioned antioxidant proteins occurred in the interaction network shown in Figure 5.…”

“…In the whole, the quantitative behavior of specific proteins involved in glycolysis, the Krebs cycle, alcoholic fermentation, energy production and additional carbon metabolism pathways in kiwifruit well paralleled that observed in the same fruit exposed to low temperatures but in different experimental setup (Minas et al, 2016; Asiche et al, 2018), in other fruits during ripening (Borsani et al, 2009; Andrade et al, 2012; Huerta-Ocampo et al, 2012; Nogueira et al, 2012; Yun et al, 2013; Zheng et al, 2013; Du et al, 2016; Xiao et al, 2018) or cold-based postharvest management (Nilo et al, 2010; Li et al, 2015; Wu et al, 2016; Tanou et al, 2017; Wang et al, 2017), or in other plants experiencing cold stress conditions (Janmohammadi et al, 2015; Die et al, 2016, 2017), suggesting the existence of common regulation mechanisms of these metabolic pathways in above-mentioned organisms. Most of the proteins reported above constitute two functional subnetworks linked to each other and to additional ones related to stress response and protein destination/storage (Figure 5).…”

“…In particular, isoforms of HSP 70 kDa protein C (BIP2), HSP 90-2 (HSP81.4), 70 kDa HSP (HSC70-1), chaperone ClpB (CLPB3 and HSP101), and T-complex protein 1 subunits α (TCP-1), β (AT5G20890), γ (AT5G26360), ε (AT1G24510), η (AT3G11830), and ζ (AT3G02530) always showed augmented levels at T1, T2, and/or T3, whereas chaperone ClpB1 (CLPC1) was over-represented for the whole period of investigation. Some of the proteins reported above have already been referred as highly represented in banana, papaya and peach exposed to cold-based storage conditions (Huerta-Ocampo et al, 2012; Li et al, 2015; Wu et al, 2016) or in different plants following various abiotic stresses, including the cold one (Somer et al, 2002; Renaut et al, 2006; Timperio et al, 2008; Janmohammadi et al, 2015; Die et al, 2016, 2017; Muthusamy et al, 2016). They are known to assist polypeptide synthesis and macromolecular structures assembly, and to prevent corresponding misfolding in environmental conditions hampering their function.…”

iTRAQ-Based Quantitative Proteome Revealed Metabolic Changes in Winter Turnip Rape (Brassica rapa L.) under Cold Stress

“…Overexpression of the GCSH gene resulted in an increase in photosynthesis and biomass in Arabidopsis thaliana [ 56 ]. A previous study reported that the abundance of GS in cold-tolerant rhododendrons was higher than in cold-sensitive varieties [ 57 ]. A study on rice anthers found that GCSH was up-accumulated in the cold-sensitive variety, but did not significantly change in the cold-tolerant cultivar after cold stress [ 58 ].…”

Land Cover and Climate Change May Limit Invasiveness of Rhododendron ponticum in Wales

“…A genetic analysis of the British population of R. ponticum has confirmed the presence of genes from R. catawbiense (Michx), suggesting past hybridization between the two species. R. catawbiense is a species native to North America and characterized by greater cold tolerance (Erfmeier et al, 2011 ; Snowdonia Rhododendron Partnership, 2015 ; Die et al, 2017 ), a trait that may increase invasiveness of R. ponticum in the UK. However, an in-depth analysis is still required to identify the other key environmental factors responsible for colonization and spread of this species.…”