Data Availability
The raw reads generated in this study have been deposited in the NCBI Sequence Read Archive (https://www.ncbi.nlm.nih.gov/sra) under the BioProject accession PRJNA613008 (An et al., 2020a). The genome assembly and annotation of P. tomentosa has been deposited at DDBJ/ENA/GenBank under the accession JAAWWB000000000 (An et al., 2020b). The transcriptome assemblies have been deposited at DDBJ/EMBL/GenBank under the accessions GIKW00000000 (P. grandidentata), GILB00000000 (P. davidiana), GIKX00000000 (P. adenopoda) and GILC00000000 (P. alba) (An et al., 2020c). The chloroplast genome assemblies also have been deposited at GneBank under accessions MW537051 (P. alba × Populus glandulosa), MW537052 (P. glandulosa), MW537053 (P. tremuloides) and MK251149.1 (P. tomentosa ) (An et al., 2021).