title: Kinetics and localization of wound-induced DNA biosynthesis in potato tuber.
abstract: Tuber wounding induces a cascade of biological responses that are involved in processes required to heal and protect surviving plant tissues. Little is known about the coordination of these processes, including essential wound-induced DNA synthesis, yet they play critical roles in maintaining marketability of the harvested crop and tubers cut for seed. A sensitive "Click-iT EdU Assay" employing incorporation of the thymidine analog, 5-ethynyl-2'-deoxyuridine (EdU), in conjunction with 4',6-diamindino-2-phenylindole (DAPI) counter labeling, was employed to objectively identify and determine the time course and spatial distribution of tuber nuclei that were wound-induced to enter S-phase of the cell cycle. Both labeling procedures are rapid and sensitive in situ. Following wounding, EdU incorporation (indicating DNA synthesis) was not detectable until after 12h, rapidly reached a maximum at about 18h and then declined to near zero at 48h. About 28% of the nuclei were EdU labeled at 18h reflecting the proportion of cells in S-phase of the cell cycle. During the ∼30h in which induced cells were progressing through S-phase, de novo DNA synthesis extended 7-8 cell layers below the wound surface. Cessation of nuclear DNA synthesis occurred about 4 d prior to completion of wound closing layer formation. Initiation of wound periderm development followed at 7 d, i.e. about 5 d after cessation of nuclear DNA biosynthesis; at this time the phellogen developed and meristematic activity was detected via the production of new phellem cells. Collectively, these results provide new insight into the coordination of wound-induced nucleic acid synthesis with associated tuber wound-healing processes.
authors.affiliation: United States Department of Agriculture, Agricultural Research Service, Sugarbeet and Potato Unit, Northern Crop Science Laboratory, Fargo, ND 58102-2765, United States. Electronic address: Ed.Lulai@ars.usda.gov.
authors.forename: Edward C
authors.initials: EC
authors.lastname: Lulai
authors.affiliation: United States Department of Agriculture, Agricultural Research Service, Sugarbeet and Potato Unit, Northern Crop Science Laboratory, Fargo, ND 58102-2765, United States.
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Neubauer
authors.affiliation: United States Department of Agriculture, Agricultural Research Service, Sugarbeet and Potato Unit, Northern Crop Science Laboratory, Fargo, ND 58102-2765, United States.
authors.forename: Jeffrey C
authors.initials: JC
authors.lastname: Suttle
mesh_terms: D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism; D018744:DNA, Plant / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D007211:Indoles; D007700:Kinetics; D008954:Models, Biological; D009928:Organ Specificity; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D035281:Plant Tubers / Q000166:cytology / Q000235:genetics / Q000502:physiology*; D016196:S Phase; D011198:Solanum tuberosum / Q000166:cytology / Q000235:genetics / Q000502:physiology*; D013194:Staining and Labeling; D013997:Time Factors; D014947:Wounds and Injuries
chemical_list: D018744:DNA, Plant; D007211:Indoles; D010940:Plant Proteins; C007293:DAPI
keywords: Phellogen; Potato; S-phase; Suberization; Wound- periderm; Wound-heal