Roles of Iron in Plant Defence and Fungal Virulence

Abstract

Iron is an essential component of various proteins and pigments for both plants and pathogenic fungi. However, redox cycling between the ferric and ferrous forms of iron can also catalyse the production of dangerous free radicals and iron homeostasis is therefore tightly regulated. our work has indicated that monocot plants challenged by pathogenic fungi redistribute cellular iron to the apoplast in a controlled manner to activate both intracellular and extracellular defences. In the apoplast, the accumulation of free, reactive ferric iron mediates defensive H 2 o 2 production. Inside the cell, this efflux of iron creates a state of iron depletion, which directs the transcription of pathogenesis-related genes in concert with H 2 o 2 . In this addendum, we describe differences between the roles of iron in mediation of the oxidative burst in cereal and Arabidopsis responses to fungal pathogens. Also, we discuss the implications of current work concerning fungal iron uptake on host defence strategies.

Pesticidal activity of metal oxide nanoparticles on plant pathogenic isolates of Pythium

“…Such effects of the NPs on Fe metabolism could have an additional effect on Pythium in the rhizosphere. Greenshields et al (2007) discussed how changes to siderophore levels or ferric reductase activities impaired the virulence of several fungal pathogens. Whether the NPs also modulate Pythium virulence, in addition to causing mycelial growth repression, awaits experimentation.…”

Regulation of lipid peroxidation and ferroptosis in diverse species

“…In particular, HR-induced cell death appears to have many overlapping features with ferroptosis as it was defined in mammalian cells. For example, high-affinity iron uptake mechanisms such as siderophore-mediated iron acquisition are known to be essential for the virulence of fungi and bacteria (Greenshields et al 2007;Dellagi et al 2009). Thus, iron-sequestering mechanisms that prevent cell death in the host may have conferred a selective advantage on plant pathogens during evolution, as it would allow them to overcome a barrier for infection; namely, ferroptosis during HR.…”

Iron and its complexation by phenolic cellular metabolites

“…15 Iron homeostasis is closely linked to redox homeostasis. 16 Iron ions participate in electron transfers, not only to reduce H 2 O 2 to • OH as in the Fenton reaction but also in the respiratory electron transport chains and, in plants, in photosynthesis and the biosynthesis of chlorophyll. 9,17…”