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<jats:title>Abstract</jats:title><jats:sec> <jats:title>Background</jats:title> <jats:p>The widespread presence of arsenic (As) and cadmium (Cd) in agricultural soils coupled with a problem of Al phytotoxicity threatens sustainability of agricultural production system as well as natural ecosystems.</jats:p> </jats:sec><jats:sec> <jats:title>Scope </jats:title> <jats:p>Understanding the role of membrane transporters responsible for uptake, translocation, and sequestration of above metal(oid)s and the modes of their regulation may be critical to tackle the above issue. In this review, we summarize the current knowledge of membrane transporters mediating As, Cd and Al homeostasis in plants, highlighting unanswered questions and offering potential solutions. Amongst these, the following topics may deserve a special attention in future studies: (1) uncoupling transport of As and inorganic phosphorous in plant roots focusing on PHT1;1 transporters; (2) revealing the modes of their post-translational regulation, especially under hypoxic conditions; (3) better understanding of structure–function relations of various transporters isoforms for Cd, to uncouple transport of toxic Cd metals from that for essential micronutrients such as Fe, Zn or Mn; (4) revealing the role of non-selective cation channels (NSCC) in Cd uptake and revealing mechanisms of their regulation; (5) elucidate the role of various aquaporins in Al<jats:sup>3+</jats:sup> uptake in plant roots; (6) understanding the role of slow vacuolar (SV) channels in Al sequestration in plant vacuoles; and (7) revealing the mechanistic basis of long-distant transport of toxic ions, with specific emphasis of phloem transport.</jats:p> </jats:sec><jats:sec> <jats:title>Conclusion</jats:title> <jats:p>These multidisciplinary efforts strive to ensure global food safety by mitigating the impact of heavy metal pollution on agriculture and human well-being.</jats:p> </jats:sec>

<jats:title>Abstract</jats:title><jats:sec> <jats:title>Background and aims</jats:title> <jats:p>Phosphorus (P) is an essential plant nutrient and integral for crop yield. However, plants adapted to P-impoverished environments, such as <jats:italic>Hakea prostrata</jats:italic> (Proteaceae), are often sensitive to P supplies that would be beneficial to other plants. The strategies for phosphate uptake and transport in P-sensitive species have received little attention.</jats:p> </jats:sec><jats:sec> <jats:title>Methods</jats:title> <jats:p>Using a recently-assembled transcriptome of <jats:italic>H. prostrata</jats:italic>, we identified 10 putative members of the <jats:italic>PHOSPHATE TRANSPORTER1</jats:italic> (<jats:italic>PHT1</jats:italic>) gene family, which is responsible for inorganic phosphate (Pi) uptake and transport in plants. We examined plant growth, organ P concentrations and the transcript levels for the eight <jats:italic>PHT1</jats:italic> members that were expressed in roots of <jats:italic>H. prostrata</jats:italic> at Pi supplies ranging from P-impoverished to P-excess.</jats:p> </jats:sec><jats:sec> <jats:title>Key results</jats:title> <jats:p><jats:italic>Hakea prostrata</jats:italic> plants suppressed cluster root growth above ecologically-relevant Pi supplies, whilst non-cluster root mass ratios were constant. Root P concentrations increased with increasing Pi supply. Of the eight <jats:italic>H. prostrata PHT1</jats:italic> genes tested, four had relatively high transcript amounts in young roots suggesting important roles in Pi uptake; however, a maximum five-fold difference in expression between P-impoverished and P-excess conditions indicated a low P-responsiveness for these genes. The <jats:italic>HpPHT1;8</jats:italic> and <jats:italic>HpPHT1;9</jats:italic> genes were paralogous to Pi-responsive <jats:italic>Arabidopsis thaliana PHT1;8</jats:italic> and <jats:italic>PHT1;9</jats:italic> orthologues involved in root-to-shoot translocation of P, but only <jats:italic>HpPHT1;9</jats:italic> was P responsive.</jats:p> </jats:sec><jats:sec> <jats:title>Conclusions</jats:title> <jats:p>An attenuated ability of <jats:italic>H. prostrata</jats:italic> to regulate <jats:italic>PHT1</jats:italic> expression in response to Pi supply is likely responsible for its low capacity to control P uptake and contributes to its high P sensitivity.</jats:p> </jats:sec>