Silicon Reduces the Severity of Fusarium Infection on Young Wheat Parts In Vitro

Although silicon (Si) has been referred as an essential element for controlling destructive diseases of wheat, available data are limited about enhancing adult wheat resistance against Fusarium causing head blight. Also, no reports seem to exist on the use of Si to reduce Fusarium seedling blight (FSB) on young wheat parts in vitro. Under in vitro conditions, Fusarium infection happened at the seedling stage cannot be called Fusarium head blight, because it is not a “head” disease, instead it could be called “FSB”.

This research aimed to elucidate the bio-efficacy of soluble Si at 1.7 mM to increase wheat resistance to FSB measured by latent period (LP) of detached leaf inoculation, area under disease progress curve (AUDPC) of Petri-dish inoculation and coleoptile length reduction (CLR) of a coleoptile infection detected in vitro. Si treatments were applied to six bread and durum wheat cultivars of contrasting susceptibility to disease infected with four Fusarium species displaying a diverse pathogenicity.

Differences were observed on wheat detached leaves and seedlings in the resistance of Si-Fusarium-inoculated treatments relative to fungal-inoculated-controls, showing the beneficial role played by this element in decreasing head blight disease symptoms on young plant parts under in vitro conditions. In all wheat cultivars infected with different Fusarium species, the application of Si did increase host resistance measured in vitro; 1.7 mM Si resulted in significantly higher LP and lesser AUDPC and CLR compared with controls. More importantly, Si at 1.7 mM increased host resistance of susceptible to moderately susceptible cultivars measured by LP, AUDPC and CLR to the same level of resistance exhibited by a wheat cultivar high in quantitative resistance without Si.

This is the first report presenting the utility of three distinct in vitro bio-assays to investigate the effect of Si in the wheat- FSB pathosystem. The application of silicon to complement host resistance to head blight appears to be an effective strategy for disease management in wheat.