Immunocytological comparison of native and wound periderm maturation in potato tuber

Abstract

The maturation of potato (Solanum tuberosum L.) tuber native periderm and wound periderm, which develops to replace the native periderm when it is damaged, are agriculturally important processes that are poorly understood. While both types of periderm form from a phellogen layer that serves as a lateral meristem, there has been little research done on comparing the biochemical processes and steps involved in the maturation of the two types of periderm. Here, we use immunological techniques to compare some of the cell wall changes during wound and native periderm maturation. Consistent with our recent work on native periderm, we demonstrate that toluidine blue O is also useful for distinguishing between suberized and non-suberized cells in wound periderm. More importantly, we use the immunological probes JIM5 and JIM7 to show that there is no increase in either un-esterified or esterified homogalacturonan pectin epitopes in phellogen walls accompanying wound periderm maturation. In contrast, as we previously described, native periderm maturation and resistance to excoriation (skinning) is accompanied by an increase in relatively un-esterified and esterified homogalacturonan pectin epitopes in the walls of phellogen cells. These results demonstrate that the biochemical processes responsible for maturation and resistance to excoriation differ between native and wound periderm. This dissimilarity between wound and native periderm maturation demonstrates the potential limitations in applying the wound periderm model to research on native periderm.