Hu Hongmei, Wang Yikai, Zhong Haixu, Li Binyang, Qi Jingxiao, Wang Yarong, Liu Jin, Zhang Shuhao, Zhang Haiying, Luo Bowen, Zhang Xiao, Nie Zhi, Zhang Hongkai, Gao Duojiang, Gao Shiqiang, Liu Dan, Wu Ling, Gao Shibin
State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, Sichuan China.
Maize Research Institute, Sichuan Agricultural University, Chengdu, Sichuan China.
Mol Breed. 2024 Oct 1;44(10):69. doi: 10.1007/s11032-024-01508-2. eCollection 2024 Oct.
The PHOSPHATE STARVATION RESPONSE REGULATOR (PHR) plays a crucial regulatory role in plants during the process of responding to phosphate starvation. In this study, we combined reverse genetics and biotechnology to investigate the function of and , including proteins containing the Myb_DNA_banding and Myb_CC-LHEQLE structural domains, in maize seedlings. Phylogenetic analysis revealed that and have high homology with and , and share the characteristic features of nuclear localisation and transcriptional self-activation. Real-time quantitative PCR analysis showed that low phosphate (Pi) stress significantly induced the expression of and in maize seedling stage, and candidate gene association analysis further revealed the close association of these two genes with root traits under Pi stress conditions. Transgenic plants overexpressing and in show a significant increase in lateral root number, fresh weight and total phosphorus accumulation under low-Pi stress. Besides, CHIP-PCR experiments identified target genes involved in hormone regulation, metal ion transport and homeostasis, phosphatase encoding, and photosynthesis, providing new insights into the biological functions of and . Furthermore, our study showed that ZmPHR1 interacts with six SPX domain-only proteins (ZmSPXs) in maize, while ZmPHR2 interacts with five of these proteins. and expression was repressed in low Pi conditions, but was up-regulated in knockout material, according to our study of transgenic seedlings overexpressing in maize. We identified downstream target genes involved in the phosphorus signaling pathway, which are mainly involved in plant-pathogen interactions, ascorbic acid and arabinose metabolism, and ABC transporter proteins, by RNA-seq analysis of transgenic seedlings grown under low Pi stress for 7 days. Collectively, these results provide important clues to elucidate the role and functional significance of and under low Pi stress and also provide insights into understand the molecular mechanism of phosphorus homeostasis in maize.
The online version contains supplementary material available at 10.1007/s11032-024-01508-2.
磷饥饿响应调节因子（PHR）在植物对磷饥饿的响应过程中发挥着关键的调节作用。在本研究中，我们结合反向遗传学和生物技术来研究玉米幼苗中包含Myb_DNA结合和Myb_CC-LHEQLE结构域的蛋白质PHR1和PHR2的功能。系统发育分析表明，PHR1和PHR2与AtPHR1和AtPHR2具有高度同源性，并具有核定位和转录自激活的特征。实时定量PCR分析表明，低磷（Pi）胁迫显著诱导了玉米幼苗期PHR1和PHR2的表达，候选基因关联分析进一步揭示了这两个基因与Pi胁迫条件下根系性状的密切关联。在低磷胁迫下，过表达PHR1和PHR2的转基因拟南芥植株的侧根数、鲜重和总磷积累显著增加。此外，染色质免疫沉淀PCR实验确定了参与激素调节、金属离子运输和稳态、磷酸酶编码和光合作用的靶基因，为PHR1和PHR2的生物学功能提供了新的见解。此外，我们的研究表明，ZmPHR1与玉米中的六个仅含SPX结构域的蛋白质（ZmSPXs）相互作用，而ZmPHR2与其中五个蛋白质相互作用。根据我们对玉米中过表达PHR1的转基因幼苗的研究，PHR1和PHR2的表达在低磷条件下受到抑制，但在PHR1敲除材料中上调。通过对在低磷胁迫下生长7天的转基因幼苗进行RNA测序分析，我们确定了参与磷信号通路的下游靶基因，这些基因主要参与植物-病原体相互作用、抗坏血酸和阿拉伯糖代谢以及ABC转运蛋白。总的来说，这些结果为阐明PHR1和PHR2在低磷胁迫下的作用和功能意义提供了重要线索，也为理解玉米中磷稳态的分子机制提供了见解。
在线版本包含可在10.1007/s11032-024-01508-2获取的补充材料。
