title: Profiling Gene Expression in GerminatingBrassicaRoots.
abstract: Based on previously developed solid-phase gene extraction (SPGE) we examined the mRNA profile in primary roots ofBrassica rapaseedlings for highly expressed genes likeACT7(actin7),TUB(tubulin1),UBQ(ubiquitin), and low expressedGLK(glucokinase) during the first day post-germination. The assessment was based on the mRNA load of the SPGE probe of about 2.1 ng. The number of copies of the investigated genes changed spatially along the length of primary roots. The expression level of all genes differed significantly at each sample position. Among the examined genesACT7expression was most even along the root.UBQwas highest at the tip and root-shoot junction (RS).TUBandGLKshowed a basipetal gradient. The temporal expression ofUBQwas highest in the MZ 9 h after primary root emergence and higher than at any other sample position. Expressions ofGLKin EZ and RS increased gradually over time. SPGE extraction is the result of oligo-dT and oligo-dA hybridization and the results illustrate that SPGE can be used for gene expression profiling at high spatial and temporal resolution. SPGE needles can be used within two weeks when stored at 4 °C. Our data indicate that gene expression studies that are based on the entire root miss important differences in gene expression that SPGE is able to resolve for example growth adjustments during gravitropism.
authors.forename: Myoung Ryoul
authors.initials: MR
authors.lastname: Park
authors.forename: Yi-Hong
authors.initials: YH
authors.lastname: Wang
authors.forename: Karl H
authors.initials: KH
authors.lastname: Hasenstein
keywords: Brassica; Gene expression profiling; Solid-phase gene extraction; mRNA quality