Fusarium graminearum exploits ethylene signalling to colonize dicotyledonous and monocotyledonous plants

Abstract

Summary Ethylene signalling affects the resistance of dicotyledonous plant species to diverse pathogens but almost nothing is known about the role of this pathway in monocotyledonous crop species. Fusarium graminearum causes Fusarium head blight (FHB) of cereals, contaminating grain with mycotoxins such as deoxynivalenol (DON). Very little is known about the mechanisms of resistance/susceptibility to this disease. Genetic and chemical genetic studies were used to examine the influence of ethylene (ET) signalling and perception on infection of dicotyledonous (Arabidopsis) and monocotyledonous (wheat and barley) species by F. graminearum. Arabidopsis mutants with reduced ET signalling or perception were more resistant to F. graminearum than wild‐type, while mutants with enhanced ET production were more susceptible. These findings were confirmed by chemical genetic studies of Arabidopsis, wheat and barley. Attenuation of expression of EIN2 in wheat, a gene encoding a core component of ethylene signalling, reduced both disease symptoms and DON contamination of grain. Fusarium graminearum appears to exploit ethylene signalling in both monocotyledonous and dicotyledonous species. This demonstration of translation from model to crop species provides a foundation for improving resistance of cereal crops to FHB through identification of allelic variation for components of the ethylene‐signalling pathway.

Fusarium-plant interaction: state of the art - a review

“…Although ET signalling is involved in plant defence against necrotrophic pathogens, arabidopsis mutants impaired in ET signalling have demonstrated resistance to F. graminearum while mutants with ET overexpression were susceptible, confirming the ET participation in Fusarium interactions not only in arabidopsis but also in wheat and barley (Chen et al 2009). …”

The possible roles of <i>AtERF71</i> in the defense response against the <i>Fusarium graminearum</i>

“…In contrast, we showed that the knockout mutant of AtERF71 induced disease resistance to F. graminearum. As stated above, the SA signaling pathway positively regulates disease resistance against F. graminearum in both Arabidopsis and wheat plants (Makandar et al 2010), whereas the ET signaling pathway negatively regulates it (Chen et al 2009). Conversely, the aterf71 mutant contributed to its enhanced disease resistance against F. graminearum.…”

“…This resistance was positively controlled via the salicylic acid (SA)-dependent signaling pathway in Arabidopsis and wheat plants (Makandar et al 2010(Makandar et al , 2012. On the contrary, ethylene (ET) and jasmonic acid (JA) negatively regulated host plant resistance against F. graminearum (Chen et al 2009;Makandar et al 2010). Although ET is a simple gaseous hormone, it plays multiple roles in regulating plant growth and development, such as vegetative growth, the senescence of leaves, flowers, and fruits (Iqbal et al 2017), and adaptation to abiotic stresses, such as water-deficits (Gu et al 2007) and salinity stress (Tao et al 2015).…”

“…ET-insensitive mutants, such as ein2-1 and ein3-1, have been reported to show enhanced disease resistance against F. graminearum when wounded sites of detached leaves in aseptically grown plants were inoculated with conidia solutions containing 75 µM of DON (Chen et al 2009). In this study, the conidia solutions without trichothecenes were dropped onto the intact leaves of soil-grown wild type plants, as well as the ein2-1 and ein3-1 mutants.…”

Deoxynivalenol resistance as a component of FHB resistance

“…Doohan et al (2008) speculated that maintenance of hormone homeostasis plays an important role in DON tolerance. Chen et al (2009) demonstrated the role of ethylene signalling in DON-induced PCD. Silencing of a gene encoding Ethylene Insensitive 2 (EIN2) in wheat resulted in FHB resistance and reduced DON-induced PCD in leaves.…”