2019 ASHS Annual Conference

Gerbera daisy is one of the most popular flowers in the worldwide floricultural trade. Multiple fungal diseases can blight gerbera plants and flowers in natural and controlled environments, causing severe economic losses. Despite this, limited information on disease resistance in gerbera is known so far. In this study, we sequenced the leaf transcriptomes of two gerbera lines with contrasting traits for flower color, peduncle length, flower form and powdery mildew resistance. Transcriptome assembly using Trinity, TransAbyss, Velvet and Soapdenovo resulted in 145,348 contigs with an N50 of 1124 nucleotides and a mean contig length of 761 nucleotides. A total of 67,312 contigs contain open reading frames. Functional annotation of these contigs using Blast2Go identified 494 genes involved in disease resistance, including 382 genes containing the nucleotide-binding site (NBS) domain that is present in many cloned plant disease resistance genes. Among these NBS genes, 69 belong to the recognition of Peronospora parasitica (RPP) gene family. There were 306 genes containing the coiled-coil (CC) domain and 31 genes containing the Toll-like receptors (TIR) domain. Fifteen susceptibility genes were identified, belonging to the mildew resistance locus o (MLO) or the Long Vegetative Phase 1 (LOV1) gene family. Genes identified from this study may serves as candidate genes for over-expression to increase disease resistance in gerbera. The MLO and LOV1-like genes may be potential targets for CRISPR-mediated genome editing and gene knocking out to enhance disease resistance in gerbera.