Application of Single Molecule Sequencing to Facilitate de novo Sequencing of Wheat Chromosome Arm 7DL

De novo sequencing of wheat chromosome 7DL has been carried out using the Illumina Hiseq2000 sequencing platform. This process is essentially based on a BAC-by-BAC approach with 4457 minimal tiling path (MTP) clones derived from a physical map of 7DL. Single molecule sequencing technology developed by Pacific Bio is a promising tool for the genomic analysis of complex genomes with high repetitive sequence content such as wheat. Initially Pac Bio sequencing was performed using P4-C2 chemistry with 4 BAC clones, combined with Illumina sequencing data. A contig per each BAC clone was obtained and the result was validated with PCR fragments short than 2 kb, although long-range validation is still pending. Later on, we pooled 47 BAC clones for Pac Bio sequencing using P6-C4 chemistry with ~10x coverage. With the assistance the Illumina sequencing data, a single contig per BAC could be obtained with almost half of the clones. It appears that single molecule sequencing technology is useful for the analysis of wheat BACs and further study with pooling size and software improvement could make this a valuable tool.