华中农业大学药用植物学团队揭示皱皮木瓜药用成分生物合成途径

　　Chaenomeles speciosa �?n?=?34）， a medicinal and edible plant in the Rosaceae,is commo nly used in traditio nal Chinese medicine. To date, the lack of genomicsequence and genetic studies has impeded efforts to improve its medicinalvalue. Herein, we report the use of an integrative approach involving PacBioHiFi （third-generation� sequencing and Hi-C scaffolding to assemble ahigh-quality telomere-to-telomere genome of C. speciosa. Thegenome comprised 650.4 Mb with a co ntig N50 of 35.5 Mb. Of these, 632.3 Mb wereanchored to 17 pseudo-chromosomes, in which 12, 4, and 1 pseudo-chromosomeswere represented by a single contig, two contigs, and four contigs,respectively. Eleven pseudo-chromosomes had telomere repeats at both ends, andfour had telomere repeats at a single end. Repetitive sequences accounted for49.5% of the genome, while a total of 45,515 protein-coding genes have beenannotated. The genome size of C. speciosa wasrelatively similar to that of Malus domestica.Expanded or co ntracted gene families were identified and investigated for theirassociation with different plant me tabolisms or biological processes. Inparticular, functio nal annotation characterized gene families that wereassociated with the biosynthetic pathway of oleanolic and ursolic acids, twoabundant pentacyclic triterpenoids in the fruits of C. speciosa. Taken together, this telomere-to-telomereand chromosome-level genome of C. speciosa noto nly provides a valuable resource to enhance understanding of the biosynthesisof medicinal compounds in tissues, but also promotes understanding of theevolution of the Rosaceae.

　　论文链接：https://doi.org/10.1093/hr/uhad183