Especially due to climate change, flooding represents a critical threat to agricultural production. Beside the reduced light harvesting and accumulation of toxic compounds in flooded soils, oxygen deficiency is one of the major consequences of submergence. To protect themselves from the damage associated with flooding, plants have evolved different stress responses, which involve strategies to reorganize their metabolism to ensure basal energy production even when aerobic respiration is not sustainable.
In spermatophytes, the molecular response to hypoxia is mediated by plant cysteine oxidases (PCOs), dioxygenases that use O2 as a co-substrate to initiate/engage the N-degron pathway-mediated degradation of signalling proteins, including the group VII of the Ethylene Response Factor (ERF-VII). Instead, little information is available about hypoxia stress perception in early diverging land plants.
To shed new light on this yet-unaddressed aspect of plant physiology, I exploited the bryophytes Marchantia polymorpha and Physcomitrium patens as model organisms to study the low oxygen sensing and its evolution in early land plants exploiting genome engineering technologies.
Firstly, I evaluated Marchantia phenotypic response exploiting tolerance assays to submergence and hypoxic conditions. Additionally, I introduced the spermatophyte oxygen sensing components in the moss P. patens for a further insight into the bryophyte low oxygen sensing.
From an evolutionary perspective, I exploited transgenic assay systems to functionally characterize the potential substitution of PCOs with oxygen-sensitive dioxygenase enzymes from different plant phyla and other eukaryotic kingdoms in Arabidopsis thaliana.