双核丝核菌诱导水稻增强广谱抗病性和防卫酶系活性

 用无致病性的双核丝核菌(Binucleate Rhizoctonia species,简称BNR)菌株2 32-CG预接种处理水稻品种IR2 6苗期植株根茎基部,可以诱导水稻增强对纹枯病(R.solani Kühn)的抗性。与未处理对照相比,BNR处理水稻植株的纹枯病害严重度明显降低。2 4 h以上的BNR处理,可以彻底保护幼苗不受立枯丝核菌侵染的危害。经BNR诱导的水稻也表现对白叶枯病(Xanthomonas oryzae pv.oryzae)和条斑病(X.oryzae pv.oryzicola)的抗性。BNR可以显著地诱导水稻防卫反应中的2类关键酶——苯丙氨酸解氨酶(PAL)和过氧化物酶(POX)活性提高。受BNR诱导的抗病性与PAL和POX活性呈正相关。对BNR在水稻病害生物防治中的作用进行了讨论。

INDUCTION OF ENHANCED BROAD-SPECTRUM RESISTANCE ANDDEFENSE ENZYME ACTIVITIES IN RICE BY BINUCLEATE Rhizoctonia SPECIES

Preinoculation of roots and foot of rice seedling,cultivar IR26 with a nonpathogenic binucleate Rhizoctonia (BNR) species isolate(232 CG)induced resistance to rice sheath blight caused by R.solani. A significant reduction of disease severity was observed on plant with BNR treatment compared with the non treat seedlings.Treatment with BNR at least 24 h prior to pathogen challenge resulted in significant protection of rice seedlings from R.solani infection.Protected rice seedlings showed enhanced resistance to bacterial blight caused by Xanthomonas oryzae pv. oryzae (OS 14) and bacterial streak caused by X.oryzae pv. oryzicola (RS 105) as well.Remarkable increases in activities of phenylalanine ammonia lyase(PAL) and peroxidases(POX),the key enzymes in plant defense responses,were observed in BNR treated rice seedlings.The elevated levels of PAL and POX were positively correlated with the increase in disease resistance in rice induced by BNR.