Transcriptome analysis of colored calla lily (Zantedeschia rehmannii Engl.) by Illumina sequencing: de novo assembly, annotation and EST-SSR marker development

Colored calla lily is the short name for the species or hybrids in section Aestivae of genus Zantedeschia. It is currently one of the most popular flower plants in the world due to its beautiful flower spathe and long postharvest life. However, little genomic information and few molecular markers are available for its genetic improvement. Here, de novo transcriptome sequencing was performed to produce large transcript sequences for Z. rehmannii cv. 'Rehmannii' using an Illumina HiSeq 2000 instrument. More than 59.9 million cDNA sequence reads were obtained and assembled into 39,298 unigenes with an average length of 1,038 bp. Among these, 21,077 unigenes showed significant similarity to protein sequences in the non-redundant protein database (Nr) and in the Swiss-Prot, Gene Ontology (GO), Cluster of Orthologous Group (COG) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. Moreover, a total of 117 unique transcripts were then defined that might regulate the flower spathe development of colored calla lily. Additionally, 9,933 simple sequence repeats (SSRs) and 7,162 single nucleotide polymorphisms (SNPs) were identified as putative molecular markers. High-quality primers for 200 SSR loci were designed and selected, of which 58 amplified reproducible amplicons were polymorphic among 21 accessions of colored calla lily. The sequence information and molecular markers in the present study will provide valuable resources for genetic diversity analysis, germplasm characterization and marker-assisted selection in the genus Zantedeschia.