外源信号物质诱导广东高州普通野生稻抗稻瘟病的生理生化机理

The Physiological and Biochemical Mechanisms of Disease Resistance of Oryza rufipogon Griff. Indigenous to Gaozhou,Guangdong against Pyricularia grisea Induced by Exogenously Applied Plant Signal Compounds

分别用两个浓度(25和50μmol/L)的植物防御信号物质茉莉酸甲酯(MeJA)和水杨酸甲酯(MeSA)喷雾处理挺立型广东高州普通野生稻幼苗植株,发现25和50μmol/L的MeSA能有效提高野生稻幼苗对稻瘟病的抗性,且提高叶片内保护酶POD的活性。25μmol/L的MeSA在3 d内提高叶片内保护酶SOD的活性。MeJA只有在低浓度下提高野生稻的抗病性,MeJA在1 d内迅速提高SOD酶活性,而后下降。25μmol/L水杨酸甲酯处理显著提高叶片内香草酸和咖啡酸的含量,分别约是对照的3.6倍和3.2倍。研究表明,外源信号物质提高普通野生稻对稻瘟病的抗性可能与其诱导植物体内保护酶活性提高及酚酸合成有关。

Rice blast caused by Pyricularia grisea is one of the most important diseases of rice world- wide. Plant induced disease resistance is important for prevention of disease. The plant signaling molecules Methyl salicylate （MESA） and jasmonate（MeJA） play an important role in induced disease resistance. Exogenously applied MeSA （25 and 50 μmol/L） and MeJA （25 μmol/L） significantly increased disease resistance of wild rice （Oryza rufipogon） against blast disease caused by P. grisea. MeSA （25 μmol/L and 50 μmol/L） in leaves of O. rufipogon significantly enhanced the activity of peroxidase （POD） after inoculation with P. grisea. MeSA at 25 μmol/L also increased the activities of superoxide dismutase （SOD） within 3 d. SOD activities were increased 1 d after treatment with MeJA （25 and 50 μmol/L）, and then gradually decreased. The concentrations of 4-hydroxy -3 -methoxybenzoic acid and 3,4-dihydroxy benzoic acid in leaves of O. rufipogon were increased by 2600//00 and 218%, respectively after treatment with MeSA and. MeJA and 2 d later inoculation with Pyricularia grisea. These results suggest that induction of activity of protective enzymes and increase in phenolic compound biosynthesis may be important mechanisms of disease resistance of O. rufipogon inducedby exogenously applied plant signal compounds MeSA and MeJA.