Phosphorus (P) is an essential element for plant growth often limiting agroecosystems. To identify genetic determinants of performance under variable phosphate (Pi) supply, we conducted genome-wide association studies on five highly predictive Pi starvation response traits in 200 Arabidopsis (Arabidopsis thaliana) accessions. Pi concentration in Pi-limited organs had the strongest, and primary root length had the weakest genetic component. Of 70 trait-associated candidate genes, 17 responded to Pi withdrawal. The PHOSPHATE TRANSPORTER1 gene cluster on chromosome 5 comprises PHT1;1, PHT1;2, and PHT1;3 with known impact on P status. A second locus featured uncharacterized endomembrane-associated auxin efflux carrier encoding PIN-LIKES7 (PILS7) which was more strongly suppressed in Pi-limited roots of Pi-starvation sensitive accessions. In the Col-0 background, Pi uptake and organ growth were impaired in both Pi-limited pht1;1 and two pils7 T-DNA insertion mutants, while Pi -limited pht1;2 had higher biomass and pht1;3 was indistinguishable from wild-type. Copy number variation at the PHT1 locus with loss of the PHT1;3 gene and smaller scale deletions in PHT1;1 and PHT1;2 predicted to alter both protein structure and function suggest diversification of PHT1 is a key driver for adaptation to P limitation. Haplogroup analysis revealed a phosphorylation site in the protein encoded by the PILS7 allele from stress-sensitive accessions as well as additional auxin-responsive elements in the promoter of the “stress tolerant” allele. The former allele’s inability to complement the pils7-1 mutant in the Col-0 background implies the presence of a kinase signaling loop controlling PILS7 activity in accessions from P-rich environments, while survival in P-poor environments requires fine-tuning of stress-responsive root auxin signaling.

中文翻译：

---

不同的磷酸盐和生长素转运基因座将耐磷酸盐与敏感的拟南芥种质区分开来

磷 (P) 是植物生长的基本元素，通常会限制农业生态系统。为了确定可变磷酸盐 (Pi) 供应下性能的遗传决定因素，我们对 200 个拟南芥 (Arabidopsis thaliana) 种质中的五个高度预测的 Pi 饥饿反应性状进行了全基因组关联研究。Pi限制器官中的Pi浓度最强，初生根长度的遗传成分最弱。在 70 个与性状相关的候选基因中，17 个对 Pi 退出有反应。5 号染色体上的 PHOSPHATE TRANSPORTER1 基因簇包括 PHT1;1、PHT1;2 和 PHT1;3，对 P 状态有已知影响。第二个基因座以编码 PIN-LIKES7 (PILS7) 的未表征的内膜相关生长素流出载体为特征，该载体在 Pi 饥饿敏感种质的 Pi 限制根中受到更强烈的抑制。在 Col-0 背景下，Pi 限制的 pht1;1 和两个 pils7 T-DNA 插入突变体中 Pi 摄取和器官生长受损，而 Pi 限制的 pht1;2 具有更高的生物量，而 pht1;3 与野生型无法区分-类型。PHT1 基因座的拷贝数变异与 PHT1;3 基因的丢失和 PHT1;1 和 PHT1;2 中较小规模的缺失预计会改变蛋白质结构和功能表明 PHT1 的多样化是适应 P 限制的关键驱动因素。单倍群分析揭示了来自应激敏感种质的 PILS7 等位基因编码的蛋白质中的磷酸化位点，以及“应激耐受”等位基因启动子中的额外生长素反应元件。