Hybrid Assembly Of Pomelo Genome Based On The Second And Third Generation Sequencing Technology

Emergence of the second and third generation sequencing technologies promotes the rapid developments of genome projects and high-throughput genomics researches.Whole-genome de novo assembly based on the second or third generation sequencing data is the first step for studying the genome of a species.As a world-wide fruit crop,Citrus has important values in breeding,genetic and genomics researches.Pomelo as an important citrus species has high edible and economic values as well as great significance in research.Previously,the pomolo genome has not been sequenced yet.In this study,we sequenced a pomelo genome(HWB)by utilizing the second generation(Illumina Hi-Seq)and third generation(Pacbio SMRT)whole-genome sequencing technologies simultaneously.Employing a hybrid de novo assembly method,we firstly assembled a genome based only on the second generation sequencing data and then improved it with the third generation sequencing data(the corrected SMRT long reads).Finally,we obtained a 332Mbp pomelo genome with Contig N50 of 187.5Kbp and Scaffold N50 of 1.77Mbp.Quality assessment showed that:the mapping rate of the original data to the genome is above 90%,the mapping rate of transcripts to the genome is 98.43%(45296/46018),and the annotation rate of the eukaryotic core conservative genes is 95.16%(236/248).Finally,we summarized our hybrid de novo genome assembly procedure and believe that it will be useful for studying the genomes of other species.