The 3-phosphoinositide-dependent protein kinase 1 (PDK1) is a conserved master regulator of AGC kinases in eukaryotic organisms. pdk1 loss of function causes a lethal phenotype in animals and yeasts, but only mild phenotypic defects in Arabidopsis thaliana (Arabidopsis). The Arabidopsis genome contains two PDK1-encoding genes, PDK1 and PDK2. Here, we used clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 9 (Cas9) to generate true loss-of-function pdk1 alleles, which, when combined with pdk2 alleles, showed severe developmental defects including fused cotyledons, a short primary root, dwarf stature and defects in male fertility. We obtained evidence that PDK1 is responsible for AGC1 kinase PROTEIN KINASE ASSOCIATED WITH BRX (PAX) activation by phosphorylation during vascular development, and that the PDK1 phospholipid-binding Pleckstrin Homology domain is not required for this process. Our data indicate that PDK1 regulates polar auxin transport by activating AGC1 clade kinases, resulting in PIN phosphorylation.

中文翻译：

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PDK1通过AGC1激酶PAX调节植物生长素的运输和拟南芥的血管发育。

3-磷酸​​肌醇依赖性蛋白激酶1（PDK1）是真核生物中保守的AGC激酶主调节剂。pdk1功能丧失会在动物和酵母中导致致命的表型，但只会在拟南芥（Arabidopsis）中产生轻微的表型缺陷。拟南芥基因组包含两个PDK1编码基因，PDK1和PDK2。在这里，我们使用成簇的规则间隔的短回文重复序列（CRISPR）/ CRISPR相关蛋白9（Cas9）生成真正的功能丧失的pdk1等位基因，当与pdk2等位基因结合使用时，显示出严重的发育缺陷，包括融合的子叶，初生根短，矮小和雄性育性缺陷。我们获得的证据表明，PDK1负责在血管发育过程中通过磷酸化使AGC1激酶与BRX（PAX）活化相关的蛋白激酶，并且该过程不需要PDK1磷脂结合的Pleckstrin同源域。我们的数据表明，PDK1通过激活AGC1进化枝激酶来调节极性植物生长素的运输，从而导致PIN磷酸化。