Plant responses to limited aeration: Advances and future challenges

Abstract

Limited aeration that is caused by tissue geometry, diffusion barriers, high elevation, or a flooding event poses major challenges to plants and is often, but not exclusively, associated with low oxygen. These processes span a broad interest in the research community ranging from whole plant and crop responses, post‐harvest physiology, plant morphology and anatomy, fermentative metabolism, plant developmental processes, oxygen sensing by ERF‐VIIs, gene expression profiles, the gaseous hormone ethylene, and O2 dynamics at cellular resolution. The International Society for Plant Anaerobiosis (ISPA) gathers researchers from all over the world contributing to understand the causes, responses, and consequences of limited aeration in plants. During the 14th ISPA meeting, major research progress was related to the evolution of O2 sensing mechanisms and the intricate network that balances low O2 signaling. Here, the work moved beyond flooding stress and emphasized novel underexplored roles of low O2 and limited aeration in altitude adaptation, fruit development and storage, and the vegetative development of growth apices. Regarding tolerance towards flooding, the meeting stressed the relevance and regulation of developmental plasticity, aerenchyma, and barrier formation to improve internal aeration. Additional newly explored flood tolerance traits concerned resource balance, senescence, and the exploration of natural genetic variation for novel tolerance loci. In this report, we summarize and synthesize the major progress and future challenges for low O2 and aeration research presented at the conference.

Phylotranscriptomics provides a treasure trove of flood tolerance mechanisms in the Cardamineae tribe

“…Autophagy is required to maintain cellular energy homeostasis when the substrate demand for glycolysis or respiration exceeds supply, which typically occurs during flooding (Dalle Carbonare et al 2023). The importance of autophagy for flood tolerance is apparent from the increased flood sensitivity observed in various autophagy mutants (Chen et al 2015).…”

“…However, such relationships are not universally found (Dalle Carbonare et al 2023). In contrast, starvation and defence responses seem more conserved transcriptomic responses to submergence.…”

Growth Responses and Adventitious Root Formation of Cucumber Hybrid Lines in a Waterlogged Condition

“…Another class of genes linked to hypoxia stress acclimation is plant cysteine oxidases (PCOs), whose products are known as O 2 -sensing enzymes. PCOs are capable of catalyzing the oxidation of cysteine to Cys-sulfinic acid in O 2 -availabilitydependent reactions, thereby activating Group VII ERFs [10,11]. Therefore, PCOs are considered to be important markers of plants' hypoxic conditions [12].…”

Overcoming constraints to measuring O2 diffusivity and consumption of intact roots

“…2D ). In addition, the development of genetically encoded O 2 biosensors responding to cellular changes in O 2 status, ATP levels, NAD redox dynamics or oxidative stress during plant acclimation to different concentrations of O 2 ( Panicucci et al 2020 ; Dalle Carbonare et al 2023 ) could provide higher resolution of pO 2 to organelle level. However, the main limitation remains in the translation of such O 2 profiles/signals into diffusive resistances and respiratory O 2 consumption by individual cell layers.…”