About this Research Topic
Heavy Metal Toxicity in Plants: Recent Insights on Physiological and Molecular Aspects
Being a natural resource, metals have been used by mankind since ancient times. However, urbanization and industrialization have deposited high levels of toxic metals in the environment, thus posing a severe threat to life on this planet. Heavy metals (HMs) are described as elements with metallic properties having an atomic number higher than 20. Being non-biodegradable, elevated levels of these metals may impart detrimental effects on the soil, as well as on crop productivity. Some metals, like Zinc (Zn), Copper (Cu), Manganese (Mn), Nickel (Ni), Cobalt (Co), and Selenium (Se), are regarded as micronutrients acting as co-enzymes and other functions, while others like Cadmium (Cd), Lead (Pb), Chromium (Cr) and Mercury (Hg) have an unknown biological function.
Plants have evolved diverse strategies to tolerate heavy metal toxicity. For example, some plant species limit HM absorption through avoidance. In other species, HMs may accumulate in roots, and much less is translocated to aerial parts like shoots, leaves, etc. However, some plant species can tolerate higher levels of toxic metals in their roots and shoots. Upon entry into plants, HMs can alter normal growth and development by distorting nutrient balances, physiological and metalloenzyme activities, and damage cell ultrastructure. At the molecular level, they can cause DNA damage, degradation of certain biomolecules, and alter gene expression. Subsequently, HM presence in plants (or in ecosystems) has raised alarming concerns regarding their contamination, as HMs could potentially accumulate in humans via the food chain. Different approaches have been adopted to decipher the regulatory pathways involved in response to HM tolerance in plants. Recently, various ‘omics approaches like transcriptomics, proteomics, and metabolomics, in combination with functional genomic approaches, have been used to develop improved varieties with enhanced metal tolerance and increased yield. Numerous studies have reported HM toxicity in plants. However, certain reports focused largely on physiological parameters and yield, and there is still a lack of understanding of the mechanisms surrounding plant-HM interactions.
The Research Topic aims to address these aspects related to plant-HM interaction in different plant species. We welcome Original Research, Reviews, and Mini-Reviews that fall within this area. Potential topics include, but are not limited to:
• Mechanistic insights into the effects of HM over-accumulation on cell biology and in turn on whole plant physiology
• Mechanistic studies on the roles of plant hormones in metal detoxification
• ‘Omics approaches to characterize HM stress, together with studies reporting physiological insights on metalloid(s) interactions in plant growth and development
• New plant varieties with enhanced metal tolerance/exclusion or remediation capacity.
Descriptive studies, including those using 'omics approaches, will not be considered for review unless they address further functional insights into a relevant physiological process.
Keywords: Heavy metal toxicity, Plant stress responses, Detoxification, Plant growth regulators, Signaling
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