Location: Sugarbeet and Potato ResearchTitle: Wound healing: some of what we have discovered about this critical and complex process
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/6/2017
Publication Date: N/A
Technical Abstract: The development of suberized layers in native and wound periderm is essential in protecting the organ from a range of pathogens, dehydration, oxidation, mild mechanical contact and other environmental dangers. Interestingly, suberized layers are also formed without the stimulus of a mechanical wound; these occurrences include the development of the periderm disorder syndrome (aka pink eye), suberization of cells surrounding tuber vessel elements challenged by Verticillium dahlia, and other natural processes. Consequently the induction and development of a suberized barrier, the mechanism of action and associated regulation is of huge agricultural and economic importance. The development of suberized layers in native and wound-periderm is essential in protecting the tuber from pathogens, dehydration, oxidation, and other deleterious effects. Despite chronic wound-related losses (>$320 M/yr.) and other suberization associated problems including the periderm disorder syndrome (idiom- pink eye), wound healing (WH) is poorly understood and often incorrectly described as a single event. This communication discusses the coordinate induction of the two stages of wound-induced suberization and biological processes that distinguish these two stages. During the first stage, closing layer formation (CLF), one or two layers of existing cells located at the wound surface are suberized (ca. 0 to 5/6 d WH). Although CLF does not involve cell division, early induction of DNA synthesis (S-phase) for cell division occurs at this time; anomalously, ca. 5 days prior to cell division. Cell division is the hall mark of the second stage, wound periderm formation (WPF), whereby organized stacks of protective suberized cells (wound phellem) are formed beneath the closing layer (ca. 7 to 28 d WH). Passage from CLF to WPF is marked by a transient decrease in the expression of genes specifically required for suberin biosynthesis. Cytokinins (CK) and indole acetic acid (IAA) are known to be required for cell division. However, wounding does not induce formation of biologically active CKs in quantifiable amounts, but precursor and catabolic breakdown products of bioactive CKs are present indicating that trace amounts of biologically active CKs were produced; this occurred in conjunction with increased IAA content to collectively provide the necessary signals for cell division during WPF. These results provide evidence for separate signals and biological processes that distinguish the two stages of WH; all are important in the development of new technologies to hasten WH and in turn reduce associated economic and nutritional losses.