Plant Infectin Mechanisms of Alternaria Pathogens : Non-Host Defense Peactions and Their Regulation by Host-Specific Toxins

主机识别和初始殖民化在主机细胞中的基本概念是由备用病原体产生的主机特定毒素（s） （HST）对孢子养殖已被确定为后续：1）从病原体中提取出的信号HST， 2）宿主细胞中的便携式接收器对病原体信号的识别，（3）通过信号的转换，对宿主细胞的无障碍渗透进行了检测。一条证据线，以支持已被收集的催眠。新的宿主特定毒素， ACT-Toxins I和II，在结构中作为环氧十烯酸的聚羟基戊二烯酸的多羟基乙烯醇酯的孢子凝胶流体中被孤立。这种三酸是AK-和AF-毒素的常见动力。In addition， ACT-toxin II is 5"-deoxyderivative of toxin I ; hence， a structure-activity correlation study was possible。HST受体的候选蛋白被检测到。毒素操作过程进行了比较好的分析，结果显示，细胞本身死亡并不是必要的条件，以使宿主细胞的可访问状态成为非法入侵。Rather， HST suppresses general defense reactions such as production and/or accumulation of infection-inhibiting factor or lignification in infection sites that was elicited by“Inducer”， 40000 daltons sugars released by fungal spores。我们的实验认为，HST依赖的替代性感染的绝对差异来自非循环性寄生虫的机制。

The basic concept of the host recognition and initial colonization in host cells by Alternaria pathogens that produce host-specific toxin (s) (HST) on spore germination have been established as follows :1) Release of a signal HST from germinating spores of the pathogen, 2) recognition of pathogen's signal by putative receptors in host cells, and 3) foment of accessibility to attempted fungal penetration in host cells through transduction of the signal. Lines of evidence for supporting this hypothesis have been collected. New host-specific toxins, ACT-toxins I and II, were isolated from spore germination fluids of the tangerine pathotype of Alternaria alternata and elucidated in structure as poly-hydroxyoctenoylvalyl esters of epoxy-decatrienoic acid. This trienoic acid is the common moiety of AK- and AF- toxins. In addition, ACT-toxin II is 5"-deoxy derivative of toxin I ; hence, a structure-activity correlation study was possible. A candidate protein for HST receptor was detected. Toxin action processes were comparatively analyzed, and the results showed that cell death itself is not necessary for conditioning the accessible state of host cells to fungal invasion. Rather, HST suppresses general defense reactions such as production and/or accumulation of infectionーinhibiting factors or lignification in infection sites that was elicited by "Inducer", 40000 daltons sugars released by fungal spores. Our experiments suggest that HST-depending Alternaria infection definitely differs from the mechanism of necrotrophic parasitism.