Dealing with elemental toxicities in crops: hot topics and likely solutions

Abstract

Abstract Background 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. Scope  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 Al3+ 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. Conclusion These multidisciplinary efforts strive to ensure global food safety by mitigating the impact of heavy metal pollution on agriculture and human well-being.