Potato skin proteome is enriched with plant defence components

Abstract

Periderm is a tissue of secondary origin that replaces damaged epidermis. It can be found in underground plant organs, as an above-ground tissue of woody species (cork), and as a wound-healing tissue. Its outer layers are composed of phellem cells with suberized walls that constitute a protective barrier, preventing pathogen invasion and fluid loss. In potato, a model for periderm studies, periderm tissue replaces the epidermis early in tuber development and the suberized phellems constitute the tuber's skin. To identify factors involved in phellem/skin development and that play a role in its defensive characteristics, two-dimensional gel electrophoresis was used to compare the skin and parenchymatic flesh proteomes of young developing tubers. Proteins exhibiting differentially high signal intensity in the skin were sorted by functional categories. As expected, the differential skin proteome was enriched in proteins whose activity is characteristic of actively dividing tissues such as cell proliferation, C1 metabolism, and the oxidative respiratory chain. Interestingly, the major functional category consisted of proteins (63%) involved in plant defence responses to biotic and abiotic stresses. This group included three isozymes of caffeoyl-CoA O-methyltransferase and five isozymes of peroxidase that may play a role in suberization processes. The differential expression of these proteins in the skin was further verified by RT-PCR of their corresponding transcripts in skin and tuber flesh samples. The results presented here shed light on the early events in skin development and further expand the concept of the periderm as a protective tissue containing an array of plant defence components.

A potato skin SSH library yields new candidate genes for suberin biosynthesis and periderm formation

“…What is more, at harvesting, potato periderm is highly exposed to dehydration, since in new potatoes, tubers with the periderm not yet mature pass from soil to atmosphere. In agreement with the results hereby presented, a proteomic approach of native periderm showed that 63% of the skin proteins identified were related to stress responses (Barel and Ginzberg 2008).…”

“…Moreover, the suberization-associated anionic peroxidase, long been proposed in the oxidative crosslinking of suberin aromatics (Bernards et al 1999), is also present in the library. Accordingly, this peroxidase is present in both native and wounded potato periderm proteomes (Barel and Ginzberg 2008;Chaves et al 2009) and Kloosterman et al 2008). a Factor loadings of the six developmental stages for the two PCA axes.…”

“…However, data concerning regulatory networks and the molecular events triggering periderm formation and deposition of suberin are scarce (Lulai et al 2008). Recently, two proteomic approaches identified the most abundant proteins expressed in both the native and the wound-healing periderm (Barel and Ginzberg 2008;Chaves et al 2009). In addition, Ginzberg et al (2009) performed transcriptomic profiling of potato periderm under heat-shock treatment.…”

A comparative transcriptomic approach to understanding the formation of cork

“…However, it is also possible that insulation against environmental factors provided by holm oak outer bark could be less efficient than in cork oak. Thus, the significant enrichment in abiotic stress transcripts may also be due to a greater exposure of holm oak outer bark to the environment, as was also described for potato tuber periderm (Barel and Ginzberg 2008;Soler et al 2011). Similarly, the overrepresentation in holm oak external bark of GO terms related to chromatin and translation could be linked to cell damage caused by abiotic stresses such as UV radiation and the need to maintain cellular homeostasis and ensure correct gene regulation (Teixeira et al 2014).…”

miRNA profiling in leaf and cork tissues of Quercus suber reveals novel miRNAs and tissue-specific expression patterns

“…In that work, a list of candidate genes isolated from cork tissues were identified including genes for the synthesis, transport, and polymerization of suberin monomers as well as a number of regulatory genes including members of the NO APICAL MERISTEM (NAM), MYB and WRKY transcription factor families with putative functions in meristem identity and cork differentiation. Since then, a number of studies have been published characterizing the role of a few selected candidate orthologues in potato tuber suberin formation by reverse genetics approaches (Serra et al 2010a;Serra et al 2010b;Serra et al 2009a;Serra et al 2009b) and identifying additional candidates in potato tuber periderm (Barel and Ginzberg 2008;Chaves et al 2009;Ginzberg et al 2009;Soler et al 2011). Despite the remarkable ability of cork oak to produce cork, potato has been the preferred model to study these processes since it is more amenable to in vitro manipulation and transformation having, in addition, its genome fully sequenced (Xu et al 2011).…”