Molecular Plant: 科学家破解红薯古老起源和驯化之谜

解开红薯起源之谜:两祖先种杂交基因组加倍而来

重要粮食作物红薯,其驯化过程长期迷离。日前,来自中国、比利时和德国的科学家团队团队在《分子植物》发文揭示了红薯的祖先种和起源。

研究显示,红薯来源于两祖先种的杂交和基因组加倍。其二倍体祖先可能是二倍体番薯,四倍体祖先是四倍体红薯。红薯形成后,约半数基因发生重组。

利用红薯基因组中的天然转基因片段作为标记,研究准确识别出祖先种。还建立了适用于多倍体物种的新型系统发育方法。

明确红薯起源为改良红薯提供理论基础。例如可通过杂交或基因编辑,将优良基因导入红薯。这有助于克服目前红薯育种稳定性差、抗病性弱的困局。

The hexaploid sweetpotato (Ipomoea batatas (L.) Lam.) is one of the most important root crops worldwide. However, its genetic origin remains controversial, and its domestication history remains unknown. In this study, we employed a range of genetic evidence and a newly developed haplotype-based phylogenetic analysis to identify two probable progenitors of sweetpotato. The diploid progenitor is likely closely related to I. aequatoriensis and has contributed the B1 subgenome, the IbT-DNA2 and the lineage 1 type of chloroplast genome to sweetpotato. On the other hand, the tetraploid progenitor of sweetpotato is most likely I. batatas 4x, which has donated the B2 subgenome, IbT-DNA1 and the lineage 2 type of chloroplast genome. Sweetpotato most likely originated from reciprocal crosses between the diploid and the tetraploid progenitor, followed by a subsequent whole genome duplication. Additionally, we detected biased gene exchanges between subgenomes; the rate of B1 to B2 subgenome conversions was nearly three times higher than the B2 to B1 subgenome conversions. Our analyses reveal that the genes involved in storage root formation, maintenance of genome stability, biotic resistance, sugar transport, and potassium uptake have been selected during the speciation and domestication of sweetpotato. This study sheds lights on the evolution of sweetpotato and paves the way for the improvement of the crop

https://www.cell.com/molecular-plant/pdf/S1674-2052(23)00413-6.pdf

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