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Immunoelectron microscopic analysis of callose secretion and nuclear condensation associated with defense responses of plant pathogen-stressed plant cells

与植物病原体胁迫植物细胞防御反应相关的胼胝质分泌和核凝结的免疫电子显微镜分析

基本信息

批准号：
13660051
负责人：
PARK Pyoyun
金额：
$ 0.77万
依托单位：
Graduate School of Science and Technology, Kobe University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

项目摘要

Spores of Alternaria alternata Japanese pear pathotype germinated and formed appressoria at tips of germ tubes on surfaces of the susceptible and resistant pear leaves. Penetration pegs emerged from appressorial bottom made an attempt to invade cell walls of susceptible epidermal cells. The pegs penetrated into the cuticular layers and then were grown as infection hyphae along the pectin layers, but didn't invade directly the epidermal cytoplasm except for the completely disrupted cells. AK-toxin-induced plasma membrane modifications, associated with callose secretion, appeared at plasmodesmata of susceptible leaf cells before the fungal invasion in tissues, suggesting the hypothesis that the toxin was produced from germ tubes was also supported. On the contrary, the pathogen inoculated in resistant leaves was able to penetrate into cuticles, but fungal invasion was not limited after the cuticular penetration. These results indicated that resistant mechanism to black spot disease was e … More xpressed at the stage of cuticular invasion during pathogenesis. Papilla formation was found at the spaces between cell walls and plasma membranes irrespective of susceptible and resistant leaves against pathogen inoculation, but penetration pegs were observed, but not involved in the papillae themselves. This suggests that papillae are non-specific plant responses against cuticular wounding, but didn't contribute directly to disease resistance in black spot disease. Immunoelectron microscopic study showed that β-l,3-D-glucan accumulated both at papillae in the pathogen-infected susceptible and resistant leaves, and at callose in the toxin-treated susceptible ones. The glucan was shown to be be secreted from Golgi bodies of susceptible leaves via Golgi vesicles to damaged sites of plasma membranes, plasma membrane modifications. The generation of reactive oxygen species (ROS) wsa found at the membrane fragments of plasma modifications in the toxin-treated susceptible leaves, but not at the papillae. This results showed that ROS generation was associated with the toxin-induced plasma membrane modifications which were damaged plasmalemma which were spatially consistent with cellular ion-leakage sites. ROS generation also was recognized at the cell walls of penetration pegs during infection process in the pathogen-inoculated susceptible and resistant leaves. ROS might cause hardening cell walls by cross-reaction of cell wall proteins with ROS, suggesting increased aggressiveness of penetration pegs. Although nuclear condensation was observed in the toxin-treated and spore-inoculated susceptible leaves, the nuclear changes were not evaluated as one of apoptotic events. The changes were compatible with pknosis seen in necrotic tissues because of no laddering of DNA. Less

梨赤星病菌致病型孢子在感病和抗病梨叶片表面的芽管顶端萌发形成附着胞。附着胞底部出现的穿透钉试图侵入敏感表皮细胞的细胞壁。这些栓钉穿透表皮层，然后作为侵染菌丝沿着果胶层生长，但不直接侵入表皮细胞质，只有细胞完全破裂。AK-毒素诱导的质膜修饰，与胼胝质分泌，出现在感病叶细胞的胞间连丝真菌入侵组织之前，这表明毒素产生的芽管的假设也得到了支持。接种在抗病叶片上的病原菌能够穿透表皮，但真菌侵入表皮后并不受限制。这些结果表明，玉米对黑斑病的抗性机制是： ...更多信息在发病过程中表皮浸润阶段表达。乳头形成被发现在细胞壁和质膜之间的空间，无论对病原体接种的敏感和抗性叶，但观察到渗透钉，但不参与乳头本身。这表明乳突是植物对表皮损伤的非特异性反应，但对黑斑病的抗病性没有直接贡献。免疫电镜观察表明，β-1，3-D-葡聚糖在感病和抗病叶片的乳突和毒素处理的感病叶片的胼胝质中都有积累。结果表明，感病叶片的高尔基体分泌的葡聚糖通过高尔基囊泡到达质膜损伤部位，质膜修饰。活性氧（ROS）的产生在毒素处理的感病叶片中的血浆修饰的膜片段，而不是在乳头。这一结果表明，活性氧的产生与毒素诱导的质膜修饰有关，这些修饰是在空间上与细胞离子泄漏位点一致的质膜损伤。在感病和抗病叶片中，侵染过程中渗透栓细胞壁也产生了活性氧。ROS可能通过细胞壁蛋白与ROS的交叉反应导致细胞壁硬化，这表明渗透钉的攻击性增加。虽然在毒素处理和孢子接种的感病叶片中观察到核浓缩，但核变化未被评估为凋亡事件之一。这些变化与坏死组织中观察到的固缩一致，因为没有DNA梯状化。少