Abundant transcripts of malting barley identified by serial analysis of gene expression (SAGE)

Serial analysis of gene expression (SAGE) was applied to the major cereal crop barley (Hordeum vulgare) to characterize the transcriptional profile of grain during the malting process. Seven SAGE libraries were generated from seed at different time points during malting, in addition to one library from dry mature seed. A total of 155,206 LongSAGE tags, representing 41,909 unique sequences, was generated. This study reports an in-depth analysis of the most abundant transcripts from each of eight specific time points in a malting barley time course. The 100 most abundant tags from each library were analysed to identify the putative functional role of highly abundant transcripts. The largest functional groups included transcripts coding for stress response and cell defence, ribosomal proteins and storage proteins. The most abundant tag represented B22EL8, a barley metallothionein, which showed significant up-regulation across the malting time course. Considerable changes in the abundance profiles of some of the highly abundant tags occurred at 24 h post-steeping, indicating that it may be an important time point for gene expression changes associated with barley seed germination.

Genes associated with the end of dormancy in grapes

A grape bud EST library was constructed and 4270 ESTs sequenced. The library clones were arrayed for the purpose of investigating the level of gene expression over time, particularly leading up to the buds' release from dormancy. The arrays were hybridized with P(33)-labeled probes produced from samples of buds collected at weekly intervals. These probes covered the time from 9 weeks prior to bud burst until just after the emergence of the shoots. Expression patterns from these genes have been examined. It was found that 74% of the genes in the data set were homologous to known proteins. Genes were then assigned to functional categories according to their primary BLAST match. Of these 13% were involved with photosynthesis, 13% with disease resistance and defense, 5% energy, 12% metabolism, 20% protein production and processing, 25% cell structure and plant growth and the remaining 12% were unclassified The expression pattern of a selection of "candidate" genes retrieved from literature previously reporting an association with dormancy changes was assessed. On closer examination most of these genes relate to the oxidative processes and stress responses within the cell. The results of this study show that even in the dormant state, gene expression in the buds is high.

Single-nucleotide polymorphism detection in plants using a single-stranded pyrosequencing protocol with a universal biotinylated primer

Analysis of variations in plant genomes is increasingly focused on single-nucleotide polymorphism (SNP) analysis, increasing the need for fast yet reliable, simple, and cost-effective techniques to handle the large number of these polymorphisms within large plant genomes. Pyrosequencing technology offers a technique that takes advantage of the interaction of four enzymes in a single-tube assay to measure DNA synthesis in real time. Pyrosequencing provides a DNA sequence and an advantage over alternative techniques in poorly characterized genomes such as those of most plant species. Here we compare the use of both single-stranded and double-stranded template Pyrosequencing on plant tissue for SNP identification. Different enzymatic strategies for double-stranded template preparation were compared. Preparation of double-stranded template from plant tissue required labor-intensive purification to allow double-stranded Pyrosequencing. A more cost-effective and less labor-intensive alternative to double-stranded template preparation in plants has been developed using a universal biotinylated primer to improve the efficiency of single-stranded Pyrosequencing. This provides an efficient high-throughput method for SNP analysis by Pyrosequencing.