Silicon and Insect Pest Resistance

Abstract

In general, silicon (Si) is involved in plant resistance against insect pest damage via two major defence mechanisms: physical defence and induced biochemical (chemical) defence. Si deposited as opaline phytoliths within plants may act as an antiherbivore defence through increasing hardness and abrasiveness of tissues and wearing of herbivore mouthparts. In turn, this would create a feeding deterrent, which may reduce the palatability and digestibility of leaves, thereby potentially impacting on herbivore performance (physical defence). On the other hand, increasing evidence shows that biochemical changes and induced resistance, because of Si uptake by the plant, are also responsible for the alleviation of insect pest damage. More recently, it has been confi rmed that Si plays a positive role in priming plants for a better defence response against pest infestation (e.g. rice leaf roller). The primed state seems to be mediated via jasmonic acid signalling pathways.

Silicon-enhanced resistance of plants to biotic stresses review article

“…However, silicon is considered as essential due to abnormalities in growth, development and reproduction in silicon-deficient plants (Epstein and Bloom, 2005). In many plant species, it enhances plant resistance against abiotic and biotic stresses, and the resistance mechanisms are now beyond doubt because they may act in the soils, at the root surface and in planta (roots and shoots) (Ma, 2004;Liang et al, 2007Liang et al, , 2015a.…”

“…Enhanced plant silicon nutrition can be a potential strategy and an alternative environment-friendly approach to prevent or at least suppresses biotic and abiotic stresses, with a consequent increase in yield (Datnoff et al, 2007). Silicon-improved plant resistance has been reported to a wide range of fungal, bacterial and viral pathogens, and insect pests including borers and sap-feeding insects (Ma, 2004;Ma and Yamaji, 2006;Datnoff et al, 2007;Liang et al, 2007Liang et al, , 2015aVan Bockhaven et al, 2013;Sakr 2016aSakr ,b, 2017Reynolds et al, 2016).…”

“…In general, two mechanisms in which silicon can reduce the severity of diseases and insect pests have been reviewed: physical defense and induced biochemical defense (Fig. 1) (Ma, 2004;Liang et al, 2007Liang et al, , 2015aVan Bockhaven et al, 2013;Reynolds et al, 2016;Sakr, 2016aSakr, ,b, 2017. The first one is associated with an accumulation of absorbed silicon in the epidermal tissue, and the second one is related to an expression of metabolic or pathogenesis-mediated host defense responses.…”

“…To date, silicon application has been documented in controlling and reducing the incidence and severity of fungal, bacterial and viral diseases, and insect growth and reproduction in both monocotyledons and dicotyledons (Table 1). Under a range of abiotic and biotic stresses, the effect of silicon, its mode of action and its function are uncertain and presently a subject of debate (Ma, 2004;Liang et al, 2007Liang et al, , 2015a. However, silicon treatments induced physical and/or biochemical protection systems against all fungal, bacterial and insect feeding guilds: necrotrophic, hemibiotrophic and biotrophic fungal pathogens, epiphytic and endophytic bacterial pathogens, and lepidopteran borer and sap-feeding pest insects (Van Bockhaven et al, 2013;Liang et al, 2015a,b;Reynolds et al, 2016;Sakr, 2016aSakr, ,b, 2017.…”

Silicon-mediated and constitutive resistance to Rhopalosiphum maidis (Hemiptera: Aphididae) in corn hybrids

“…Plants have a sophisticated arsenal of defenses against herbivore attack, including toxic, anti-feedant, or repellant secondary substances and a variety of physical barriers (War et al, 2012). Plant defenses can be constitutive or induced by herbivore attack (War et al, 2012;Heidel-Fischer et al, 2014;Bruce, 2015) or by soil amendment with silicon (Liang et al, 2015;Hartley & DeGabriel, 2016;Reynolds et al, 2016). Constitutive resistance to R. maidis has been reported in different corn genotypes (Carena & Glogoza, 2004;Razmjou & Golizadeh, 2010;Betsiashvili et al, 2015); however, breeding programs have resulted in very few commercially available varieties resistant to corn leaf aphid (Carena & Glogoza, 2004;Moraes et al, 2005).…”