Rai Vandna, Sanagala Raghavendrarao, Sinilal Bhaskaran, Yadav Sandeep, Sarkar Ananda K, Dantu Prem Kumar, Jain Ajay
National Research Centre on Plant Biotechnology, Lal Bahadur Shastri Building, Pusa Campus, New Delhi-110012, India These authors contributed equally to this work.
Department of Botany, Fatima Mata National College, Kollam, Kerala-691001, India.
Plant Cell Physiol. 2015 Jun;56(6):1107-23. doi: 10.1093/pcp/pcv035. Epub 2015 Mar 9.
Phosphate (Pi) is pivotal for plant growth and development. Pi deficiency triggers local and systemically regulated adaptive responses in Arabidopsis thaliana. Inhibition of primary root growth (PRG) and retarded development of lateral roots (LRs) are typical local Pi deficiency-mediated responses of the root system. Expression of Pi starvation-responsive (PSR) genes is regulated systemically. Here, we report the differential influence of iron (Fe) availability on local and systemic sensing of Pi by Arabidopsis. P-Fe- condition disrupted local Pi sensing, resulting in an elongated primary root (PR). Altered Fe homeostasis in the lpsi mutant with aberration in local Pi sensing provided circumstantial evidence towards the role of Fe in the maintenance of Pi homeostasis. Reporter gene assays, expression analysis of auxin-responsive genes (ARGs) and root phenotyping of the arf7arf19 mutant demonstrated the role of Fe availability on local Pi deficiency-mediated LR development. In addition, Fe availability also exerted a significant influence on PSR genes belonging to different functional categories. Together, these results demonstrated a substantial influence of Fe availability on Pi deficiency-mediated responses of ontogenetically distinct traits of the root system and PSR genes. The study also provided evidence of cross-talk between Pi, Fe and Zn, highlighting a complex tripartite interaction amongst them for maintaining Pi homeostasis.
磷（Pi）对植物生长发育至关重要。磷缺乏会引发拟南芥中局部和系统调节的适应性反应。主根生长受抑制（PRG）和侧根（LRs）发育迟缓是根系典型的局部磷缺乏介导的反应。磷饥饿响应（PSR）基因的表达受系统调节。在此，我们报告了铁（Fe）有效性对拟南芥局部和系统感知磷的不同影响。低磷高铁（P-Fe-）条件破坏了局部磷感知，导致主根伸长（PR）。局部磷感知异常的lpsi突变体中铁稳态的改变为铁在维持磷稳态中的作用提供了间接证据。报告基因分析、生长素响应基因（ARGs）的表达分析以及arf7arf19突变体的根表型分析证明了铁有效性对局部磷缺乏介导的侧根发育的作用。此外，铁有效性对属于不同功能类别的PSR基因也有显著影响。总之，这些结果表明铁有效性对根系个体发育不同性状的磷缺乏介导反应和PSR基因有重大影响。该研究还提供了磷、铁和锌之间相互作用的证据，突出了它们之间为维持磷稳态而进行的复杂三方相互作用。
