Oxidative Stress in Fungi: Its Function in Signal Transduction, Interaction with Plant Hosts, and Lignocellulose Degradation

Abstract

Abstract:In this review article, we want to present an overview of oxidative stress in fungal cells in relation to signal transduction, interaction of fungi with plant hosts, and lignocellulose degradation. We will discuss external oxidative stress which may occur through the interaction with other microorganisms or plant hosts as well as internally generated oxidative stress, which can for instance originate from NADPH oxidases or "leaky" mitochondria and may be modulated by the peroxiredoxin system or by protein disulfide isomerases thus contributing to redox signaling. Analyzing redox signaling in fungi with the tools of molecular genetics is presently only in its beginning. However, it is already clear that redox signaling in fungal cells often is linked to cell differentiation (like the formation of perithecia), virulence (in plant pathogens), hyphal growth and the successful passage through the stationary phase.

Gigaspora margarita with and without its endobacterium shows adaptive responses to oxidative stress

“…Our experiments reveal that G. margarita is highly sensitive to H2O2 treatment, leading to a consistent number of DEGs (5458 out of 35029 potential G. margarita genes) that respond to the treatment, irrespective of the presence of the endobacterium. G. margarita therefore is similar to yeast and many other filamentous fungi, where H2O2 treatment induces a strong detoxifying response with the activation of glutathione and thioredoxin metabolism, but can also trigger cellular differentiation and development (Breitenbach et al 2015). Some activated genes in the treated AM fungus were expected, such as the genes encoding ROS-detoxifying enzymes listed in Table 1, some of which have already been characterized in R.. irregularis (Tamayo et al 2016).…”

“…Eventually, the antioxidant status of the two fungal lines turns out to be very similar, demonstrating the unexpected capacity of the cured line to compensate for its original lower performance. We can speculate that for both the lines H2O2 also acts as a signal, as it does in dried seeds (Tommasi et al 2001, El-Maarouf-Bouteau andBailly 2008) and in fungal conidia also from pathogenic fungi, where changes in the cellular oxidative status trigger germination (Breitenbach et al 2015). Since H2O2 is a strong antibacterial molecule, the question remains whether CaGg is affected by the treatment, also considering that some of the key enzymes for glutathione biosynthesis were not found in its genome (Ghignone et al, 2012 Given the relevance of AM fungi in natural and agricultural ecosystems, we propose that the data set developed for G. margarita may be a starting point for studying environmental adaptation of AM fungi to the oxidative stress that originates from the application of fungicide or herbicide (Yang et al 2016;Angelova et al 2005).…”

“…Also DNA conformation/packaging GO categories were upregulated in the B+ treated line only. Given that H2O2 can act as a stimulus to activate some genomic areas (Breitenbach et al 2015), the fungalbacterial association could be more efficient in perceiving it.…”

“…Oxidative stresses can produce diverse responses in filamentous fungi, ranging from mitochondria-mediated ageing and programmed cell death (Osiewacz 2011) to signaling that may regulate mycelial development and sexual reproduction (Breitenbach et al 2015). Oxidative stresses can originate from endogenous or exogenous sources and may play different roles.…”

Metabolic comparison of aerial and submerged mycelia formed in the liquid surface culture of Cordyceps militaris

“…In this study, the expression of two peroxiredoxins, putative peroxiredoxin‐5 (CCM_03275), peroxiredoxin Osmc‐like protein (CCM_06109), four thioredoxins (thioredoxin‐like protein (CCM_03715), putative cytoplasmic thioredoxin (CCM_00029), thioredoxin (CCM_00331), M‐type thioredoxin (CCM_02074) and thioredoxin reductase (CCM_05420) was found as upregulated proteins in the submerged mycelia following 12 days of culture (Appendix Table A1, Supplementary Table S1). Organic peroxides are converted to alcohols by peroxiredoxins, which are conjugated with thioredoxins and thioredoxin reductase (Breitenbach et al, ).…”