In plants, flooding-induced
oxygen deficiency causes severe stress, leading to growth reduction and yield loss. It is therefore important to understand the molecular mechanisms for adaptation to
hypoxia.
Aquaporins at the plasma membrane play a crucial role in water uptake. However, their role during
hypoxia and membrane redox changes is still not fully understood. The influence of 24 h
hypoxia induction on hydroponically grown maize (Zea mays L.) was investigated using an oil-based setup. Analyses of physiological parameters revealed typical flooding symptoms such as increased
ethylene and H2O2 levels, an increased
alcohol dehydrogenase activity, and an increased redox activity at the plasma membrane along with decreased
oxygen of the medium. Transcriptomic analysis and shotgun proteomics of plasma membranes and soluble fractions were performed to determine alterations in maize roots.
RNA-sequencing data confirmed the upregulation of genes involved in anaerobic metabolism, biosynthesis of the
phytohormone ethylene, and its receptors. Transcripts of several antioxidative systems and other
oxidoreductases were regulated. Mass spectrometry analysis of the plasma membrane
proteome revealed alterations in redox systems and an increased abundance of
aquaporins. Here, we discuss the importance of plasma membrane
aquaporins and redox systems in
hypoxia stress response, including the regulation of plant growth and redox homeostasis.