Korean Pear (Pyrus pyrifollia) Genome Sequence using Long Fragment Sequencing on the PacBio RSII Platform

Pear, the third most important temperature fruit species after grape and apple, belongs to the subfamily Pomoideae in the family Rosaceae. The cultivated pear (n=17) has been growing since antiquity from both Europe and China. In Korea, three basic species, P. pyrifolia, P. ussuriensis, and P. fauriei, are known as native. We selected ‘Wonwhang’ (P.  pyrifolia) for the whole genome sequencing material. Two distinguished different genus of Pear, Chines pear, ‘Dangshansuli” (P. brestchneideri) and ‘Bartlett’ (P. communis) are already published in the draft genome sequence with 527 Mb and in 577.3 Mb. By Illumina shot gun sequencing with 350bp targeting paired end library are analyzed and by De Bruiijin graph analysis (KmerGenie), the five different K-values with 69, 71, 73, 75, 77 used for genome assemble and the longest contig is 304Kb(N50=3.4kb) with total 525Mb size using K-value 71.

Long sequencing reads are allowing assembling and close larger genomes including many plant and animals even resolving complex repeats of extreme GC regions, we decide to sequencing only PacBio P6-C4 reads with 40 SMART cell analyses. Using the Celera Assembler PBcR pipeline with PacBio read self-correction and FALCON assembly. We generated 6,606 contigs and total assembled genome size is 584Mb. N50 contig length is 195Kb and longest contig is 3.99Mb. In order to generate chromosome-sized scaffolds, we will try to get Irys analysis and GBS studies on F2 mapping population to ‘Wonwhang’ and ‘Bartlett’.