He Hai, Sadahisa Kumi, Yokoi Shuji, Tezuka Takahiro
Laboratory of Plant Breeding and Propagation, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Japan.
Laboratory of Breeding and Genetics, Graduate School of Agriculture, Osaka Metropolitan University, Sakai, Japan.
Front Plant Sci. 2022 May 19;13:899206. doi: 10.3389/fpls.2022.899206. eCollection 2022.
Enhanced ovary abscission after pollination and hybrid seed lethality result in post-zygotic reproductive isolation in plant interspecific crosses. However, the connection between these barriers remains unclear. Here, we report that an imbalance in parental genomes or endosperm balance number (EBN) causes hybrid seed lethality and ovary abscission in both interspecific and intraspecific-interploidy crosses in the genus . Auxin treatment suppressed ovary abscission, but not hybrid seed lethality, in an interspecific cross between and , suggesting that ovary abscission-related genes are located downstream of those involved in hybrid seed lethality. We performed interploidy crosses among tetraploids, octoploids, and neopolyploids and revealed hybrid seed lethality and ovary abscission in interploid crosses. Furthermore, a higher maternal EBN than paternal EBN caused these barriers, as previously observed in × crosses. Altogether, these results suggest that maternal excess of EBN causes hybrid seed lethality, which in turn leads to ovary abscission through the same mechanism in both interspecific and interploidy crosses.
授粉后增强的子房脱落和杂种种子致死导致植物种间杂交中的合子后生殖隔离。然而，这些障碍之间的联系仍不清楚。在这里，我们报告亲本基因组或胚乳平衡数（EBN）的不平衡在该属的种间和种内倍性间杂交中导致杂种种子致死和子房脱落。在[具体物种1]和[具体物种2]的种间杂交中，生长素处理抑制了子房脱落，但没有抑制杂种种子致死，这表明与子房脱落相关的基因位于参与杂种种子致死的基因下游。我们在[具体物种]的四倍体、八倍体和新多倍体之间进行了倍性间杂交，并揭示了倍性间杂交中的杂种种子致死和子房脱落。此外，正如先前在[具体杂交组合]杂交中所观察到的，母本EBN高于父本EBN会导致这些障碍。总之，这些结果表明母本EBN过量导致杂种种子致死，进而通过相同机制在种间和倍性间杂交中导致子房脱落。
