Cultivated hawthorn (Crataegus pinnatifida var. major) genome sheds light on the evolution of Maleae (apple tribe). Issue 8 (25th July 2022)

• Record Type: Journal Article
• Authors: Zhang, Ticao; Qiao, Qin; Du, Xiao; Zhang, Xiao; Hou, Yali; Wei, Xin; Sun, Chao; Zhang, Rengang; Yun, Quanzheng; Crabbe, M. James C.; Van de Peer, Yves; Dong, Wenxuan
• Is Part Of: Journal of integrative plant biology. Volume 64:Issue 8(2022)
• Page Start: 1487
• Page End: 1501
• Publication Date: 2022-07-25
• Subjects: ancestral chromosome reconstruction -- hawthorn (Crataegus spp.) -- long terminal repeat retrotransposons (LTR‐RTs) -- medicinal and edible plants -- sub‐genome; Plants -- Periodicals; Plants -- China -- Periodicals; Electronic journals; 580.5
• DOI: 10.1111/jipb.13318
• Languages: English
• ISSNs: 1672-9072

Abstract

Abstract: Cultivated hawthorn ( Crataegus pinnatifida var. major) is an important medicinal and edible plant with a long history of use for health protection in China. Herein, we provide a de novo chromosome‐level genome sequence of the hawthorn cultivar "Qiu Jinxing." We assembled an 823.41 Mb genome encoding 40 571 genes and further anchored the 779.24 Mb sequence into 17 pseudo‐chromosomes, which account for 94.64% of the assembled genome. Phylogenomic analyses revealed that cultivated hawthorn diverged from other species within the Maleae (apple tribe) at approximately 35.4 Mya. Notably, genes involved in the flavonoid and triterpenoid biosynthetic pathways have been significantly amplified in the hawthorn genome. In addition, our results indicated that the Maleae share a unique ancient tetraploidization event; however, no recent independent whole‐genome duplication event was specifically detected in hawthorn. The amplification of non‐specific long terminal repeat retrotransposons contributed the most to the expansion of the hawthorn genome. Furthermore, we identified two paleo‐sub‐genomes in extant species of Maleae and found that these two sub‐genomes showed different rearrangement mechanisms. We also reconstructed the ancestral chromosomes of Rosaceae and discussed two possible paleo‐polyploid origin patterns (autopolyploidization or allopolyploidization) of Maleae. Overall, our study provides an improved context for understanding the evolution of Maleae species, and this new high‐quality reference genome provides a useful resource for the horticultural improvement of hawthorn. Abstract : This report of a chromosome‐level genome of hawthorn ( Crataegus pinnatifida var. major ), an important medicinal and edible plant, reveals significant amplification of the genes in the flavonoid and triterpenoid biosynthetic pathways and allows reconstruction of the ancestral chromosomes of Rosaceae, thus improving understanding of apple tribe evolution.