About this Research Topic
Aquaporins (AQPs) are channel-forming integral membrane proteins that facilitate movement of water and many other solutes. They play a vital role in solute transport systems of almost all living organisms including plants, animals and fungi. Aquaporins are encoded by very diverse gene families. Compared to animals, plants contain a much higher number of AQP genes, the likely consequence of genome duplication events and higher ploidy levels. As a result of duplication and subsequent diversification, plant AQPs have evolved very diverse functions.
Aquaporins in plants are highly selective for specific solutes because of their unique structural features. For instance, NPA domains and Ar/R selectivity filters have been found to play a major role in governing permeability of solutes through AQPs. Indeed, in many instances, it appears that a conserved combination of specific amino acids will dictate AQPs permeability for specific solutes such as water, urea, CO2, H2O2, boric acid, silicic acid and many more.
With the increasing availability of genomic and transcriptomic data, new plant AQPs are discovered on a regular basis. Identification of novel AQPs and their genetic variation provides opportunities to study the factors that influence nutritional uptake, and elemental balance. Several strategies like homology based search, protein structure modeling, and phylogenetic analysis are both developed and routinely employed for AQP identification. With the increasing number of known AQPs, more advanced research can be performed to understand transport mechanisms in plants. To decipher complex mechanisms of solute transport through AQPs, it is now possible to address these questions through different angles such as inter-dependency of AQPs, regulation through phosphorylation and reversible phosphorylation, networking with other transporters, structural features, pH gating system, trafficking and degradation.
Research on AQPs are very important for crop improvement programs, namely in the context of drought tolerance. Several studies have shown the role of AQPs in differential genotypic responses to abiotic stress in plants. Exploitation of genetic variation in AQPs for the development of stress tolerant cultivars is one of the promising approaches in different breeding programs. Other approaches involving transgenic technology have also been used to highlight the role of AQPs in alleviating abiotic and biotic stresses.
This Research Topic will provide a timely overview of the role and importance of AQPs in plant transport systems, and solute specificity and regulation. It will also cover endeavors including functional evaluation of AQPs through transgenic approaches, gene expression, protein structure prediction, and mutagenesis. Identification of candidate AQPs through QTL mapping and GWAS will also be addressed. We eagerly welcome reviews, mini-reviews, opinions and original articles related to AQPs in plants.
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