Cation transporters in cell fate determination and plant adaptive responses to the low oxygen environment.

Soil flooding creates low-oxygen environments in root zones and thus severely affects plant growth and productivity. Plants adapt to low-oxygen environments by a suit of orchestrated metabolic and anatomical alterations. Of these, formation of aerenchyma and development of adventitious roots are considered very critical to enable plant performance in waterlogged soils. Both traits have been firmly associated with stress-induced increase in ethylene levels in root tissues that operate upstream of signalling pathways. Recently, we have used a bioinformatic approach to demonstrate that several Ca 2+ and K + -permeable channels from KCO, AKT and TPC families could also operate in low oxygen sensing in Arabidopsis (Wang et al., 2017b). Here we argue that low-oxygen-induced changes to cellular ion homeostasis and operation of membrane transporters may be critical for cell fate determination and formation of the lysigenous aerenchyma in plant roots and shaping the root architecture and adventitious roots development in grasses. We summarise the existing evidence for a causal link between tissue-specific changes in oxygen concentration, intracellular Ca 2+ and K + homeostasis, and reactive oxygen species levels, and their role in conferring those two major traits enabling plant adaptation to low-oxygen environment. We conclude that, for the efficient operation, plants may rely on several complementary signalling pathway mechanisms, that operate in concert and "fine-tune" each other. The better understanding of this interaction may open additional and previously unexplored opportunity to crop breeders to improve cereal crop yield losses to soil flooding.