Physiological Macro-lesions Enhanced Resistance to Blast （Magnaporthe grisea） in Rice Near-isogenic Lines

Roll-leaf-1 （rl-1） and spot-leaf-1 （spl-1） were two near-isogenic lines, which were obtained after 3 to 4 backcrosses with early season indica rice Zhefu 802 as recurrent parent. Henna macro-lesions, referred as physiological or morphological markers, began to appear on leaves at 4.5- to 6.0-leaf stage. The rice seedlings were inoculated at 3.5-, 5.0- and 7.0-leaf stages with high pathogenic races Zhong A1 and Zhong B1 of Magnaporthe grisea, respectively. The resistance of rl-1, spl-1 and Zhefu 802 against blast was significantly different. The seedlings of Zhefu 802 at 3.5- to 7.0-leaf stage were susceptible to races Zhong A1 and Zhong B1 of M. grisea, whereas those of rl-1 and spl-1 at 3.5-, 5.0- and 7.0-leaf stages were susceptible, moderately resistant and resistant, respectively. These results suggested that the enhanced resistance of rl-1 and spl-1 related to the appearance of their morphological marker lesions. The experiment provided a basis for studying lesion mimic and hypersensitive response in association with disease resistance.