Background and aims

Inorganic phosphate (Pi) deficiency is one of the major constraints on wheat growth and development. Identifying the genes conferring Pi efficiency is crucial for improving phosphorus (P) efficiency. Our previous studies showed that TaPHT1;9 is a high-affinity Pi transporter that functions in Pi absorption and transport in wheat seedlings under hydroponic conditions. However, its functions need to be evaluated in complex soil environments. In this study, we aimed to explore its role under soil conditions and reveal its potential for use in the breeding of Pi-efficient wheat cultivars.

Methods

CRISPR-edited TaPHT1;9 wheat mutants and TaPHT1;9 ectopic expression transgenic rice plants were cultivated in soils with different Pi supply treatments. The grain yield, biomass, P concentration and P utilization efficiency (PUE) were measured and calculated.

Results

CRISPR-edited homozygous TaPHT1;9-A/B/D wheat mutants were screened and identified. Under low Pi supplies (0 and 5 mg kg⁻¹ P/pot), the grain yields, P accumulations and PUEs were significantly lower than those in the wild-type (WT) control, and the reduced yields were primarily attributed to the decreases in both grain number per spike and 1000-grain weight. The TaPHT1;9-ectopic expression transgenic rice plants exhibited the opposite results, and their grain yields, P accumulations and PUEs were significantly greater than those of the WT plants under insufficient Pi supply conditions.

Conclusions

TaPHT1;9 plays a vital role in Pi utilization under soil conditions; thus, it is considered a candidate target gene for improving crop PUE.

中文翻译：

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在土壤条件下使用 CRISPR 编辑的突变体、异位转基因植物及其野生型对 TaPHT1;9 功能进行比较分析

 背景和目标

无机磷（Pi）缺乏是限制小麦生长发育的主要因素之一。识别赋予 Pi 效率的基因对于提高磷 (P) 效率至关重要。我们前期的研究表明，TaPHT1;9是一种高亲和力的Pi转运蛋白，在水培条件下的小麦幼苗中发挥Pi吸收和转运的作用。然而，其功能需要在复杂的土壤环境中进行评估。在本研究中，我们旨在探索其在土壤条件下的作用，并揭示其在育种高效 Pi 小麦品种中的潜力。

 方法

CRISPR 编辑的TaPHT1;9小麦突变体和TaPHT1;9异位表达转基因水稻植物在不同 Pi 供应处理的土壤中种植。测定并计算了籽粒产量、生物量、磷浓度和磷利用效率（PUE）。

 结果

筛选并鉴定了 CRISPR 编辑的纯合TaPHT1;9-A / B / D小麦突变体。低磷供应量（0和5 mg kg ^-1 P/盆）下，籽粒产量、磷积累量和PUE均显着低于野生型（WT）对照，产量下降的主要原因是每穗粒数和千粒重。 TaPHT1;9异位表达转基因水稻植株表现出相反的结果，在Pi供应不足的条件下，其籽粒产量、磷积累量和PUE显着高于WT植株。

 结论

TaPHT1;9在土壤条件下的 Pi 利用率中发挥着至关重要的作用；因此，它被认为是提高作物PUE的候选靶基因。