接触识别导误与烟草抗赤星病诱导的关系

用非病原细菌、病毒和赤星菌弱毒株先对烟草作预处理,后在未诱导叶片上接种赤星菌毒性菌株,发现诱导处理可引起病菌7类侵染前行为失误:①孢子萌发延迟;②持续产孢;③孢子、芽管产生粘联物(adhesin)的能力降低或丧失;④芽管背离叶片生长;⑤芽管顶端膨大、侵染能力降低或丧失;③芽管盘附在叶面上,但侵染能力降低或丧失;⑦芽管弯曲生长,顶部液泡化或原生质流空.这些行为导误与赤星菌致病力的诱导减弱有关,使烟草发病程度减轻55—94%.分析认为,病菌侵染前行为导误取决于接触识别导误,是烟草抗赤星病诱导的一种有效反应.

INDUCTION OF MISTAKES OF CONTACT RECOGNITION AS RELATED TO HOST INDUCED RESISTANCE IN TOBACCO BROWN SPOT

On leaf surfaces of tobacco which had been pretreated respectively withnopathogenic bacteria, virus, and hypovirulent strains of brown spot pathogen(Alternaria alternata), virulent strain of A. alternata showed 7 types of mistakes ofpreinfection behaviors: (1) delayed germination of spore; (2) continuous sporulation;(3) reduced or defective production of adhesin; (4) germ tube growth away from leafsurfaces; (5) swollen tip part of germ tube with defective or reduced infection; (6) tightanchoring of germ tube on leaf surfaces, with defective or reduced infection, and (7)zigzag germ tuber, vasculated or emptied tip part of germ tube. The induced mistakeswere related to decrease in pathogenicity of the pathogen, indicating by 55%-94%reduction of brown spot in the induced tobacco. It was suggested that the mistakeinduction is the expression of mistake induction of the host-pathogen contactrecognition and contributes to induced resistance of tobacco to brown spot.