Vietnam Journal of Agricultural Sciences, T. 1, S. 4 (2018)

Cỡ chữ:  Nhỏ  Vừa  Lớn

Herbal Extracts in Combination with Nanosilver Inhibit Blight Disease Caused by Xanthomonas oryzae pv. oryzae in Rice

NGUYEN THI XUAN, NGUYEN THANH HAI, DANG HOANG TRANG, NGUYEN THI THANH HA

Tóm tắt


    Bacterial rice leaf blight (BLB), caused by Xanthomonas oryzae pv. oryzae (Xoo), has a massive impact on the quality and productivity of rice. Besides BLB resistant rice cultivars, herbal extracts and nanosilver have increasingly demonstrated their important roles in controlling the disease as alternatives to synthetic chemical pesticides. Therefore, this research aimed to examine the Xoo antibacterial effects of several herbal extracts and nanosilver in vitro and in vivo. In the study, Wedelia chinensis Osbeck Merr., Clerodendrum fragrans Vent., Excoecaria cochinchinensis Lour., Polyathia longifolia var. Pendula, and Caesalpinia sappan L. were extracted by maceration with six types of solvents (distilled water, 70% ethanol, chloroform, n-hexane, and 100% acetonitrile), then used in an agar diffusion test to evaluate their Xoo antibacterial effects. The results showed that 70% ethanol was the best extracting solvent for the targeted plants. C. fragransE. Cochinchinensis, and C. sappan showed significant antibacterial effects with inhibition zone diameters of 28.50 cm, 21.00 cm, and 25.70 cm, respectively. Finally, the individual extract from C. fragransE. Cochinchinensis, and C. sappan were combined with nanosilver particles and used to access BLB inhibition capacity in vivo, using the rice cultivar IR24 as the target for Xoo infection. Application of the C. fragrans extract resulted in resistance of IR24 rice to BLB. Similar results were also observed in the infected rice when products combining nanosilver and E. cochinchinensis or C. sappan were applied to infected rice leaves.    

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