Transcriptome Analysis of the Blueberry-Mummy Berry Pathosystem

Mummy berry disease of blueberry, casual agent Monilinia vaccinii-corymbosi, has two distinct phases- a blight stage of young foliage and flowers and a flower infection stage that leads to mummified fruit (pseudosclerotia). The flower infection stage requires conidia to germinate on the stigma and grow down the stylar canal into the ovary. The cultivar Berkeley is very susceptible to the mummy berry fruit infection stage while the cultivar Bluejay is resistant. We reasoned that the resistance/susceptibility reaction might be ‘expressed’ in the style. Open flowers of both cultivars were pollinated with ‘Bluecrop’ pollen and inoculated with mummy berry conidia. Total RNA was isolated from the styles two days post-pollination/inoculation. RNASeq libraries were prepared and sequenced using the Illumina HiSeqII platform. The resulting sequences were then quality- and adapter-trimmed with open-source software ‘cutadapt.’ Sequences were assembled using Velvet. This produced 37,354 contigs for ‘Bluejay and 36,202 for ‘Berkeley’ of at least 200 nucleotides in length. The sequences were then BLASTed against the NCBI’s nucleotide database (blastn), which yielded 33,184,648 and 21,143,803 ‘hits’ for the two varieties, respectively. The hits were then mapped to their respective taxonomies. The data generated will help determine the key genes involved in the plant-pathogen interaction.Paper presented at NABREW Conference, Paper Session I:Genetics and genomics, on June 24, 2014, Atlantic City, N.J