Identification of Genes Involved During Healing in Response to Skinning Injury in Sweetpotato [Ipomoea batatas (L.) Lam.]

Skinning is inevitable due to the rigors of bulk harvesting in sweetpotato, and thus skinning resistance is a prerequisite to developing sweetpotato that can withstand subsequent postharvest loss caused by storage disease and insect predicament.  Understanding the genetics of wound healing through detail analysis of specific genes in different regulatory/signalling pathway of sweetpotato will help breeding for storage roots with tough skin acquiescent to mechanized harvesting.  A differential mRNA display approach was undertaken to identify the genes (and their expression profile) in different physiological processes that are involved in critical healing process of the storage root of sweetpotato cv ‘07-146’.  Using 20 annealing control primers 70 differentially expressing genes (DEGs) were identified.  Functional annotation of the DEGs revealed that genes/transcription factors known in dehydration stress network, in addition to those involved in wounding and lignin/suberin biosynthesis pathway, were induced in response to skinning during the healing process.  (Semi)quantitative measurement of the transcripts indicated that all DEGs involved in lignin/suberin pathway responded late and were upregulated in storage roots only at 8 and 12 h of skinning.  Genes involved in wounding/dehydration response were upregulated as early as 2 h after skinning and maintained their expression through 12 h.  Other genes showed up- or down-regulation in their transcript abundance depending on the time storage root was exposed after artificial skinning.  Further research will underscore the key process that leads to rapid deposition of wound periderm at the injury site, which is critical to healing.