The phosphate transporters LpPHT1;1 and LpPHT1;4 have different roles in phosphate uptake and translocation in ryegrass under P stress condition. The phosphate transporter 1 (PHT1) family are integral membrane proteins that operate in phosphate uptake, distribution and remobilization within plants. In this study, we report on the functional characterization and expression of two PHT1 family members from ryegrass plants (Lolium perenne L.) and determine their roles in the specificity of Pi transport. The expression level of LpPHT1;4 was strongly influenced by phosphorus (P) status, being higher under P-starvation condition. In contrast, the expression level of LpPHT1;1 was not correlated with P supply. Yeast mutant complementation assays showed that LpPHT1;4 can complement the growth defect of the yeast mutant Δpho84 under Pi-deficient conditions, whereas the yeast mutant expressing LpPHT1;1 was not able to restore growth. Phylogenetic and molecular analyses indicated high sequence similarity to previously identified PHT1s from other species in the Poaceae. These results suggest that LpPHT1;1 may function as a low-affinity Pi transporter, whereas LpPHT1;4 could acts as a high-affinity Pi transporter to maintain Pi homeostasis under stress conditions in ryegrass plants. This study will form the basis for the long-term goal of improving the phosphate use efficiency of ryegrass plants.

中文翻译：

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黑麦草中两种 PHT1 家族磷酸转运蛋白的表达分析和功能表征

磷酸盐转运蛋白 LpPHT1;1 和 LpPHT1;4 在 P 胁迫条件下在黑麦草的磷酸盐吸收和转运中具有不同的作用。磷酸盐转运蛋白 1 (PHT1) 家族是完整的膜蛋白，在植物内参与磷酸盐的吸收、分布和再活化。在这项研究中，我们报告了来自黑麦草植物 (Lolium perenne L.) 的两个 PHT1 家族成员的功能表征和表达，并确定了它们在 Pi 转运特异性中的作用。LpPHT1;4的表达水平受磷（P）状态的强烈影响，在P饥饿条件下更高。相比之下，LpPHT1;1 的表达水平与磷供应无关。酵母突变体互补分析表明 LpPHT1;4 可以补充酵母突变体 Δpho84 在 Pi 缺陷条件下的生长缺陷，而表达 LpPHT1;1 的酵母突变体不能恢复生长。系统发育和分子分析表明与先前鉴定的来自禾本科其他物种的 PHT1 具有高度序列相似性。这些结果表明，LpPHT1;1 可能作为低亲和力的 Pi 转运蛋白发挥作用，而 LpPHT1;4 可以作为高亲和力的 Pi 转运蛋白在黑麦草植物的胁迫条件下维持 Pi 稳态。这项研究将为提高黑麦草植物磷酸盐利用效率的长期目标奠定基础。4 可以作为高亲和力的 Pi 转运蛋白，在黑麦草植物的胁迫条件下维持 Pi 稳态。这项研究将为提高黑麦草植物磷酸盐利用效率的长期目标奠定基础。4 可以作为高亲和力的 Pi 转运蛋白，在黑麦草植物的胁迫条件下维持 Pi 稳态。这项研究将为提高黑麦草植物磷酸盐利用效率的长期目标奠定基础。