主要研究：Here we generated and analyzed high quality genome sequences of diploid (E. haploclada), tetraploid (E. oryzicola) and hexaploid (E. crus-galli) Echinochloa species.

研究结果1-基因家族扩张：Gene family analysis showed that disease resistance genes such as those containing the NB-ARC domain have been significantly lost during Echinochloa polyploidization, which is contrary to significant expansion of those genes during wheat polyploidization. The result suggests that natural selection might favor reduced investment in resistance in the weed to maximize its growth and reproduction.

研究结果2-亚基因组演化：In contrast to the asymmetric patterns of genome evolution shown in wheat and other crops, no significant differences in selection pressure were detected between the subgenomes in E. oryzicola and E. crus-galli.

研究结果3-亚基因组表达偏性：Additionally, distinctive differences of transcriptomic dynamics in subgenome expression during hexaploidization were observed between E. crus-galli and bread wheat.

结论：This study documents genomic mechanisms for adaptation during polyploidization in a major agricultural weed and provides insights for crop breeding.