Barley N transporter from glumes, seeds and flag leaf from 454 transcriptome sequencing. Hordeum vulgare subsp. vulgare strain:Barke

Next generation sequencing (NGS) technologies offer new opportunities especially for the analysis of plants with not fully sequenced genomes. The presented 454-NGS approach was addressed to the tissues flag leaf, glumes and developing grains and to the processes remobilization/retranslocation and import of N-compounds taking place immediately before and after seed set. Data evaluation was focussed on two specific gene families responsible for the biological processes of interest, i. e. on cysteine-peptidase and N-transporter sequences. Combination of already known and 454 sequence information reduced redundancy, increased length of the gene-specific contigs and identified new members of the respective gene families. The deduced amino acid sequences were used to create phylogenetic trees of the different N-transporter gene families representing all known members from rice and Arabidopsis and including the new barley sequences. Sequence alignments result in establishment of 25 full-length genes encoding putative amino acid transporters (AATs). Based on temporal expression profiling we consider that the establishment of high N-sink strength in developing grains is registered in the ear-near tissues flag leaf and glumes. We postulate the presence of metabolic components that communicate increasing grain sink strength to remobilizing tissues by modulating transcript amounts as exemplified here for putative AAT genes.