About this Research Topic
Plant cells are frequently challenged with varying degrees of oxygen shortage, the most common is complete or partial submergence in water, via flooding or waterlogging. During the course of evolution, plants have developed various adaptive mechanisms to withstand low oxygen (hypoxic) conditions. Most of these developmental responses are initiated by ethylene (ET) signaling. This gaseous plant hormone triggers the expression of Group VII of Ethylene Response Factors (ERFVII), transcription factors that target several hypoxia survival response genes, including loci encoding alcohol dehydrogenases (ADH), pyruvate decarboxylases (PDC), sucrose synthases (SuSy) or aspartate aminotransferases (AST). The ERFVIIs, in turn, are subjected to degradation via the N-degron pathway. Nitric oxide (NO) is also known to participate along with O2 in the stabilization of ERFVIIs and subsequent priming of plants to hypoxic stress.
Besides the pivotal roles of ET and NO, early work on plant soil flooding responses pointed towards an important role of abscisic acid (ABA) in the response and survival of plants to hypoxic conditions. Further research in the aquatic species Rumex palustris, characterized the interaction of ET signaling with ABA and other hormones during the induction of adaptive responses to submergence. An inhibitory role was assigned for ET on ABA metabolism. This effect has been confirmed in various experimental systems such as rice. A reduction in ABA levels during hypoxia in different plant species seems to be a pre-requisite for the induction of soil flooding acclimation responses including the formation of aerenchyma in soybean, adventitious root in tomato and maize, and stem elongation in watercress. Moreover, the N-degron pathway can interact with ABA signaling pathway in the regulation of different stress and developmental processes. Therefore, evidence points towards interaction of the ET and NO-oxygen sensing pathways in concert with ABA, to modulate plant physiological and metabolic responses to low oxygen environments.
Submissions of Original Research papers and Review articles are welcome that address the roles of ABA in regulating physiological, morphological, biochemical, and molecular responses of plants to hypoxia and anoxia alone. Additionally, the roles of ABA in crosstalk with other plant hormones to plant responses to low oxygen conditions are welcome. These responses could be restricted at the tissue or organ level in cases of root zone waterlogging or understanding how localized anoxic conditions might affect hormone regulation in distal tissues.
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