稻瘟菌糖蛋白激发子诱导的水稻叶片膜脂过氧化及过敏性反应

将稻瘟菌细胞壁来源的专化性糖蛋白激发子接种于一套水稻抗稻瘟病近等基因系后,非亲和性互作水稻超氧阴离子(O-.2)积累在互作早期明显高于亲和性互作水稻;超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性均趋于下降,不同亲和性互作水稻间的差异不明显;脂氧合酶(LOX)活性在水稻/激发子非亲和互作早期增加明显、速度快;这些指标的变化进而导致非亲和性互作水稻的膜脂过氧化,其相对电导率及丙二醛(MDA)含量的高峰期和强度也明显早于和高于亲和性互作水稻.非亲和性互作水稻过氧化物酶(POD)活性在互作早期明显高于亲和性互作水稻,可能与其参与其它抗性有关.研究同时表明,激发子可专化性诱导完全和高度非亲和性互作水稻的过敏性坏死反应;而中度非亲和性互作和亲和性互作水稻则未发生过敏性(HR)坏死反应.这些结果表明,膜脂过氧化和HR反应的发生是激发子诱导水稻抗性的主要生理机制之一.

Membrane Lipid Peroxidation and Hypersensitive Reaction Induced by a Glycoprotein Elicitor from Magnaporthe grisea in Rice Leaves

With a series of four near-isogenic lines (NIL) of rice, studies were carried out in the interaction between rice and a specific gly-coprotein elicitor from Magnaporthe grisea. After treatment with the elicitor, O2- generation rate (Fig.l) increased more remarkably on the leaves of incompatible interaction of rice, than compatible interaction of rice. Change in SOD activity (Fig.2) and CAT activity (Fig.3) was similar in leaves of rice with different resistance after inoculation with the elicitor. On the contrary, POD activity (Fig.4) was positive relative to rice resistance. And changes in LOX activity (Fig.5) were increased more remarkably and rapidly on the leaves of incompatibly interacting rice. These changes led to lipid peroxidation in the leaves of incompatibly interacting rice. Relative conductance rate and MDA content were also in- creased more remarkably and rapidly in leaves of incompatibly interacting rice (Fig.6 and Fig. 7). Our results (Fig.8) also showed that elicitor could induce hypersensitive reaction (HR reaction) in leaves of completely or highly incompatible interacting rice, but not in the two NIL rice varieties (one with moderately incompatible interactions and another with compatible ones). The results suggest that lipid peroxidation and HR reaction in rice leaves induced by the elicitor may play an important role in the resistance of rice seedlings.