Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel
Plant Cell. 2019 Jul;31(7):1506-1519. doi: 10.1105/tpc.19.00235. Epub 2019 May 10.
The pleiotropic and complex gibberellin (GA) response relies on targeted proteolysis of DELLA proteins mediated by a GA-activated GIBBERELLIN-INSENSITIVE DWARF1 (GID1) receptor. The tomato () genome encodes for a single DELLA protein, PROCERA (PRO), and three receptors, SlGID1a (GID1a), GID1b1, and GID1b2, that may guide specific GA responses. In this work, clustered regularly interspaced short palindromic repeats (CRISPR) /CRISPR associated protein 9-derived mutants were generated and their effect on GA responses was studied. The triple mutant was extremely dwarf and fully insensitive to GA. Under optimal growth conditions, the three receptors function redundantly and the single mutants exhibited very mild phenotypic changes. Among the three receptors, GID1a had the strongest effects on germination and growth. Yeast two-hybrid assays suggested that GID1a has the highest affinity to PRO. Analysis of lines with a single active receptor demonstrated a unique role for GID1a in protracted response to GA that was saturated only at high doses. When the mutants were grown in the field under ambient changing environments, they showed phenotypic instability, the high redundancy was lost, and exhibited dwarfism that was strongly exacerbated by the loss of another receptor gene. These results suggest that multiple GA receptors contribute to phenotypic stability under environmental extremes.
多效且复杂的赤霉素（GA）反应依赖于 DELLA 蛋白的靶向蛋白水解，该过程由 GA 激活的 GIBBERELLIN-INSENSITIVE DWARF1（GID1）受体介导。番茄（）基因组编码一个单一的 DELLA 蛋白，PROCERA（PRO）和三个受体，SlGID1a（GID1a）、GID1b1 和 GID1b2，它们可能指导特定的 GA 反应。在这项工作中，产生了成簇的规律间隔的短回文重复（CRISPR）/CRISPR 相关蛋白 9 衍生的突变体，并研究了它们对 GA 反应的影响。三重突变体非常矮小，对 GA 完全不敏感。在最佳生长条件下，三个受体功能冗余，单个突变体表现出非常轻微的表型变化。在三个受体中，GID1a 对萌发和生长的影响最大。酵母双杂交试验表明，GID1a 与 PRO 具有最高的亲和力。对具有单个活性受体的系进行分析表明，GID1a 在 GA 的延长反应中具有独特的作用，只有在高剂量下才会饱和。当突变体在环境变化的野外生长时，它们表现出表型不稳定，高冗余性丧失，而当另一个受体基因丢失时，表现出强烈的矮小化。这些结果表明，多个 GA 受体有助于在环境极端条件下的表型稳定性。
