Chromosome-level genome assemblies of two cereal aphids, Metopolophium dirhodum and Schizaphis graminum, provides insights into wing dimorphism

ABSTRACT The rose-grain aphid Metopolophium dirhodum (Walker) and the greenbug Schizaphis graminum (Rondani) (Hemiptera: Aphididae), are two destructive aphid pests for cereals worldwide. Some studies have examined the biological and ecological characteristics of these two aphid species, however, the lack of genomic data limits in-depth studies of these two organisms. Here, we present the chromosome-level genome assemblies of M. dirhodum and S. graminum using PacBio long HiFi reads and Hi-C technology. The final genome assembly for M. dirhodum is 447.8 Mb, with 98.50% of the assembled sequences anchored to nine chromosomes. The contig and scaffold N50 values are 7.82 Mb and 37.54 Mb, respectively. A total of 18,003 protein-coding genes were predicted, of which 92.05% were functionally annotated. The final genome assembly for S. graminum is 476.1 Mb, with 99.08% of the assembled sequences anchored to six chromosomes. The contig and scaffold N50 values are 21.59 Mb and 99.65 Mb, respectively. A total of 24,368 protein-coding genes were predicted, of which 94.21% were functionally annotated. Comparative transcriptomic analyses identified a number of genes that might be related to wing dimorphism in M. dirhodum , including the insulin receptor, insulin receptor substrate, forkhead box protein O (Foxo), and ecdysone receptor. These results may provide important references for understanding the ecology, genetics, and evolution of these two organisms or even other aphid insects.