title: Rootstock effects on gene expression patterns in apple tree scions.
abstract: Like many fruit trees, apple trees (Malus pumila) do not reproduce true-to-type from seed. Desirable cultivars are clonally propagated by grafting onto rootstocks that can alter the characteristics of the scion. For example, the M.7 EMLA rootstock is semi-dwarfing and reduces the susceptibility of the scion to Erwinia amylovora, the causal agent of fire blight disease. In contrast, the M.9 T337 rootstock is dwarfing and does not alter fire blight susceptibility of the scion. This study represents a comprehensive comparison of gene expression patterns in scions of the 'Gala' apple cultivar grafted to either M.7 EMLA or M.9 T337. Expression was determined by cDNA-AFLP coupled with silver staining of the gels. Scions grafted to the M.9 T337 rootstock showed higher expression of a number of photosynthesis-related, transcription/translation-related, and cell division-related genes, while scions grafted to the M.7 EMLA rootstock showed increased stress-related gene expression. The observed differences in gene expression showed a remarkable correlation with physiological differences between the two graft combinations. The roles that the differentially expressed genes might play in tree stature, stress tolerance, photosynthetic activity, fire blight resistance, and other differences conferred by the two rootstocks are discussed.
authors.affiliation: Department of Plant Pathology, 210 Buckhout Lab, Pennsylvania State University, University Park, PA 16802, USA.
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Jensen
authors.forename: Jo
authors.initials: J
authors.lastname: Rytter
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Detwiler
authors.forename: James W
authors.initials: JW
authors.lastname: Travis
authors.forename: Timothy W
authors.initials: TW
authors.lastname: McNellis
mesh_terms: D000595:Amino Acid Sequence; D002453:Cell Cycle / Q000235:genetics; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D044084:Erwinia amylovora / Q000254:growth & development; D020869:Gene Expression Profiling / Q000379:methods; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D027845:Malus / Q000235:genetics* / Q000254:growth & development* / Q000382:microbiology; D008969:Molecular Sequence Data; D010788:Photosynthesis / Q000235:genetics; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction / Q000235:genetics; D013696:Temperature; D014867:Water / Q000494:pharmacology
chemical_list: D018076:DNA, Complementary; D010940:Plant Proteins; D014867:Water