Wei, Yongzan;Wang, Yi;Hu, Fuchu;Wang, Wei;Wei, Changbin;Xu, Bingqiang;Liu, Liqin;Li, Huayang;Wang, Can;Zhang, Hongna;Liang, Zhenchang;Xie, Jianghui

Chinese Acad Trop Agr Sci, Inst Trop Biosci & Biotechnol, State Key Lab Biol Breeding Trop Crops, Haikou 571101, Peoples R China;Hainan Univ, Sanya Inst Breeding & Multiplicat, Sch Trop Agr & Forestry, Haikou 570228, Peoples R China;Chinese Acad Sci, Beijing Key Lab Grape Sci & Enol, CAS Key Lab Plant Resources, Inst Bot, Beijing 100093, Peoples R China;Chinese Acad Trop Agr Sci, Sanya Res Acad, Sanya 572019, Peoples R China;Hainan Acad Agr Sci, Minist Agr & Rural Affairs, Inst Trop Fruit Trees, Key Lab Genet Resources Evaluat & Utilizat Trop Fr, Haikou 571100, Peoples R China;Chinese Acad Trop Agr Sci, South Subtrop Crops Res Inst, Key Lab Trop Fruit Biol, Minist Agr & Rural Affairs, Zhanjiang 524091, Peoples R China;Chinese Acad Trop Agr Sci, Haikou Expt Stn, Haikou 571101, Peoples R China

Clausena lansium;genome;evolution;methyltransferase activity;alkaloid biosynthesis;coumarin accumulation

Wampee (Clausena lansium) is an important evergreen fruit tree native to southern China that has a long history of use for medicinal purposes. Here, a chromosome-level genome of C. lansium was constructed with a genome size of 282.9 Mb and scaffold N50 of 30.75 Mb. The assembled genome contains 48.70% repetitive elements and 24,381 protein-coding genes. Comparative genomic analysis showed that C. lansium diverged from Aurantioideae 15.91-24.95 million years ago. Additionally, some expansive and specific gene families related to methyltransferase activity and S-adenosylmethionine-dependent methyltransferase activity were also identified. Further analysis indicated that N-methyltransferase (NMT) is mainly involved in alkaloid biosynthesis and O-methyltransferase (OMT) participates in the regulation of coumarin accumulation in wampee. This suggested that wampee's richness in alkaloids and coumarins might be due to the gene expansions of NMT and OMT. The tandem repeat event was one of the major reasons for the NMT expansion. Hence, the reference genome of C . lansium will facilitate the identification of some useful medicinal compounds from wampee resources and reveal their biosynthetic pathways.