European Journal of Plant Pathology (2021) 159, 673-683

Lee Chuen Ng, Z. Nura Adila, Elham M. Shahrul Hafiz and A. Aziz (2021)
Foliar spray of silicon enhances resistance against Pyricularia oryzae by triggering phytoalexin responds in aerobic rice
European Journal of Plant Pathology 159 (3), 673-683
Abstract: Rice blast (caused by Pyricularia oryzae) is the most devastative disease threatening sustainability rice production. The role of silicon as a foliar application in biochemical defence involvement towards P. oryzae infection in aerobic rice remains unclear. The goal of this study was to explore the effectiveness of silicon (Si) as a foliar spray in triggering phytoalexin synthesis to increase resistance against P. oryzae infection on two aerobic rice cultivars MR219-4 (partially resistant to rice blast) and MARDI Aerob 1 (resistant). Three Si sources: calcium silicate, silica oxide and sodium metasilicate were tested at 3, 6, and 9 mg/L against P. oryzae infection. Foliar application of calcium silicate at 9 mg/L significantly reduced rice blast disease severity to 0.11% (MARDI Aerob 1) and 3.30% (MR219-4). In vitro screenings of phytoalexins (sakuranetin and momilactone A) against P. oryzae revealed that sakuranetin is more prominent to inhibit P. oryzae in both solid and liquid media. The expression of sakuranetin was further quantified from Si-mediated rice seedlings after challenge inoculated with P. oryzae. High-Performance Liquid Chromatography (HPLC) revealed that sakuranetin in both Si-mediated rice seedlings inoculated with P. oryzae significantly increased at 2nd DAI with 0.13 mg/mL in MARDI Aerob 1 and 0.48 mg/mL in MR219-4 compared with control (without Si foliar application). These results emphasized calcium silicate as foliar spray augmented resistance to P. oryzae infection by prolonging sakuranetin accumulation as one of the mechanisms that strengthening the rice plant health besides physiological barrier mechanism in the aerobic rice.
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Research topic(s) for pests/diseases/weeds:
control - general

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Pyricularia oryzae	Rice (Oryza)	Malaysia