Study on Biological Control of Rice Blast by Fusarium solani

• Main Authors: Hsiu-Chuan Lin, 林秀娟
• Other Authors: Lih-Ling Chern
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/80903704763268275636

碩士 === 國立屏東科技大學 === 熱帶農業暨國際合作系所 === 99 === Rice blast caused by Pyricularia oryzae is one of the most destructive fungal diseases of cultivated rice worldwide, and could cause yield losses up to 90% when the environment is favorable. Although the disease can be managed by fungicide application, recent studies have focused on developing alternative control methods to reduce the negative impact on environment caused by overuse of chemicals and to increase food safety. In this study, we aimed to screen microorganisms from soil for biological control of rice blast. Seventy soil microorganisms capable of utilizing vegetable tissues for growth were isolated from KS soil, and liquid cultures of them were prepared using liquid medium containing the same vegetable tissues. Liquid cultures were individually spread on rice leaves to test their ability to control rice blast. Results showed that liquid cultures of 15 isolates completely inhibited rice blast on the leaf treated with liquid culture. Four of them inhibited the disease by effects on the growth of P. oryzae after germination. Two of them (KS-F14, KS-B23) could reduce rice blast on leaves adjacent to the treated leaf indicating an induced systemic resistance effect. Fungal isolate KS-F14 was identified as Fusarium solani and the substances in its liquid culture responsible for disease inhibition existed mainly in liquid phase, not in mycelium. The active substances could be extracted by water, methanol and ethanol, was heat stable, and functional in pH 4~10 but inactivated by pH 2 or 12 permanently, adsorbed partially or completely by ion exchange resins and activated charcoal. The liquid culture maintained its disease inhibitory effects for at least 14 days or at 2000-fold dilution, and application for two times was enough to inhibit disease, which showed great potential of F. solani KS-F14 as a biocontrol agent. This is the first report of F. solani inhibiting rice blast by induced systemic resistance in rice.