Klocko Amy L, Elorriaga Estefania, Ma Cathleen, Strauss Steven H
Department of Biology, University of Colorado Colorado Springs, Colorado Springs, CO 80918, USA.
Department of Forest Ecosystems and Society, Oregon State University, Corvallis, OR 97331, USA.
Hortic Res. 2023 Jun 29;10(8):uhad132. doi: 10.1093/hr/uhad132. eCollection 2023 Aug.
Plant migration and gene flow from genetically modified or exotic trees to nearby lands or by crossing with wild relatives is a major public and regulatory concern. Many genetic strategies exist to mitigate potential gene flow; however, the long delay in onset of flowering is a severe constraint to research progress. We used heat-induced FT overexpression to speed assessment of the expected floral phenotypes after CRISPR knockout of poplar homologs of the key floral genes, and . We selected events with previously characterized CRISPR-Cas9 induced biallelic changes then re-transformed them with the ) gene under control of either a strong constitutive promoter or a heat-inducible promoter. We successfully obtained flowering in both a male and female clones of poplar, observing a wide range of inflorescence and floral forms among flowers, ramets, and insertion events. Overall, flowers obtained from the selected and targeted events were consistent with what would be predicted for loss-of-function of these genes. -targeted events showed small catkins with leaf-like organs, -targeted events had nested floral organs consistent with reduction in floral determinacy and absence of well-formed carpels or anthers. These findings demonstrate the great developmental plasticity of flowers during genetically accelerated flowering, which may be of horticultural value. They also provide an informative early view of floral phenotypes and apparent sterility from knockouts of both these gene targets.
转基因或外来树种的植物迁移以及基因向附近土地的流动，或者通过与野生近缘种杂交而导致的基因流动，是一个主要的公众和监管问题。存在许多遗传策略来减轻潜在的基因流动；然而，开花起始的长期延迟严重限制了研究进展。我们利用热诱导的FT过表达来加速对杨树关键花基因同源物进行CRISPR敲除后预期花表型的评估。我们选择了具有先前表征的CRISPR-Cas9诱导的双等位基因变化的事件，然后用强组成型启动子或热诱导启动子控制下的（）基因对它们进行重新转化。我们成功地在杨树的雄性和雌性克隆中诱导出了开花，在花、分株和插入事件中观察到了广泛的花序和花形态。总体而言，从选定的和靶向事件中获得的花与这些基因功能丧失的预测结果一致。靶向事件显示出带有叶状器官的小花序，靶向事件具有嵌套的花器官，这与花确定性的降低以及没有发育良好的心皮或花药一致。这些发现证明了在基因加速开花过程中花具有巨大的发育可塑性，这可能具有园艺价值。它们还为这两个基因靶点敲除后的花表型和明显不育提供了一个有参考价值的早期观点。
