Lu Hong, Jin Kangming, Luo Yuelin, Wu Yunrong, Liu Yu, Xu Jiming, Mao Chuanzao
State Key Laboratory of Plant Environmental Resilience, College of Life Sciences, Zhejiang University, Hangzhou, China.
Hainan Institute of Zhejiang University, Yazhou Bay Science and Technology City, Sanya, Hainan, China.
Front Plant Sci. 2025 Aug 28;16:1654599. doi: 10.3389/fpls.2025.1654599. eCollection 2025.
Phosphorus (P), an essential macronutrient critical for plant growth and development, faces significant availability constraints in agricultural soils, substantially limiting crop yield potential. Transcription factors (TFs) play pivotal roles in phosphate (Pi) starvation responses in plants. In this study, we identified (), a homeobox domain TF in rice ( L.), which was strongly induced in roots under Pi starvation. Subcellular localization assays indicated that OSH45 is a nuclear localized protein. overexpression transgenic plants exhibited enhanced low-Pi tolerance, characterized by significantly higher Pi concentrations and increased shoot and root biomass compared to wild type (WT) under Pi-limited conditions. Whereas loss-of-function mutants displayed no significant difference in shoot and root biomass compared to WT under both Pi-sufficient and Pi-limited conditions, but showed lower Pi concentration under Pi-sufficient conditions. Through transcriptomic profiling, 2,406 differential expressed genes (DEGs) were identified in overexpression plants versus WT under Pi-sufficient conditions. About 38% of Pi starvation-induced (PSI) genes were upregulated and 25% of Pi starvation-suppressed (PSS) genes were downregulated in overexpression plants. The expression of phosphate transporters, such as , , , , and acid phosphatases was upregulated, while the expression of Pi signaling repressors was suppressed in overexpression plants. Conversely, displayed decreased expression of and compared to WT. Altogether, our findings demonstrated that OSH45 is a novel TF involved in Pi deficiency response, regulating a set of Pi starvation responsive (PSR) genes to optimize plant adaptation to Pi-limited environments. This mechanism provides a strategic target for engineering Pi-efficient crops.
磷（P）是植物生长发育所必需的大量元素，在农业土壤中磷的有效性受到显著限制，极大地制约了作物的产量潜力。转录因子（TFs）在植物对磷饥饿的响应中起关键作用。在本研究中，我们鉴定出水稻（Oryza sativa L.）中的一个同源异型盒结构域转录因子OSH45，它在磷饥饿条件下的根中被强烈诱导。亚细胞定位分析表明OSH45是一种定位于细胞核的蛋白。OSH45过表达转基因植株表现出增强的低磷耐受性，其特征是在低磷条件下与野生型（WT）相比，磷浓度显著更高，地上部和根部生物量增加。而功能缺失突变体在磷充足和磷限制条件下与WT相比，地上部和根部生物量均无显著差异，但在磷充足条件下磷浓度较低。通过转录组分析，在磷充足条件下，OSH45过表达植株与WT相比鉴定出2406个差异表达基因（DEGs）。在OSH45过表达植株中，约38%的磷饥饿诱导（PSI）基因上调，25%的磷饥饿抑制（PSS）基因下调。磷转运蛋白如PHT1;1、PHT1;2、PHT1;3、PHT1;4和酸性磷酸酶的表达上调，而磷信号抑制因子PHR2的表达在OSH45过表达植株中受到抑制。相反，与WT相比，OSH45功能缺失突变体中PHT1;1和PHT1;4的表达降低。总之，我们的研究结果表明OSH45是一个参与磷缺乏响应的新型转录因子，调控一组磷饥饿响应（PSR）基因以优化植物对磷限制环境的适应。这一机制为培育磷高效作物提供了一个战略靶点。
