The genome of Magnolia biondii Pamp. provides insights into the evolution of Magnoliales and biosynthesis of terpenoids

Magnolia biondii Pamp.(Magnoliaceae,magnoliids)is a phylogenetically,economically,and medicinally important ornamental tree species widely grown and cultivated in the north-temperate regions of China.Determining the genome sequence of M.biondii would help resolve the phylogenetic uncertainty of magnoliids and improve the understanding of individual trait evolution within the Magnolia genus.We assembled a chromosome-level reference genome of M.biondii using~67,~175,and~154Gb of raw DNA sequences generated via Pacific Biosciences single-molecule real-time sequencing,10X Genomics Chromium,and Hi-C scaffolding strategies,respectively.The final genome assembly was~2.22Gb,with a contig N50 value of 269.11 kb and a BUSCO complete gene percentage of 91.90%.Approximately 89.17%of the genome was organized into 19 chromosomes,resulting in a scaffold N50 of 92.86Mb.The genome contained 47,547 protein-coding genes,accounting for 23.47%of the genome length,whereas 66.48%of the genome length consisted of repetitive elements.We confirmed a WGD event that occurred very close to the time of the split between the Magnoliales and Laurales.Functional enrichment of the Magnolia-specific and expanded gene families highlighted genes involved in the biosynthesis of secondary metabolites,plant–pathogen interactions,and responses to stimuli,which may improve the ecological fitness and biological adaptability of the lineage.Phylogenomic analyses revealed a sister relationship of magnoliids and Chloranthaceae,which are sister to a clade comprising monocots and eudicots.The genome sequence of M.biondii could lead to trait improvement,germplasm conservation,and evolutionary studies on the rapid radiation of early angiosperms.

Genomic and transcriptomic analysis unveils population evolution and development of pesticide resistance in fall armyworm Spodoptera frugiperda

The fall armyworm(FAW),Spodoptera frugiperda,is a destructive pest native to America and has recently become an invasive insect pest in China.Because of its rapid spread and great risks in China,understanding of FAW genetic background and pesticide resistance is urgent and essential to develop effective management strategies.Here,we assembled a chromosome-level genome of a male FAW(SFynMstLFR)and compared re-sequencing results of the populations from America,Africa,and China.Strain identification of 163 individuals collected from America,Africa and China showed that both C and R strains were found in the American pop-ulations,while only C strain was found in the Chinese and African populations.Moreover,population geno-mics analysis showed that populations from Africa and China have close relationship with significantly genetic differentiation from American populations.Taken toge-ther,FAWs invaded into China were most likely origi-nated from Africa.Comparative genomics analysis displayed that the cytochrome p450 gene family is extremely expanded to 425 members in FAW,of which 283 genes are specific to FAW.Treatments of Chinese populations with twenty-three pesticides showed the variant patterns of transcriptome profiles,and several detoxification genes such as AOX,UGT and GST spe-cially responded to the pesticides.These findings will be useful in developing effective strategies for manage-ment of FAW in China and other invaded areas.