Scanning electron Microscopy reveals different response pattern of four Vitis genotypes to Xylella fastidiosa infection
Scanning electron Microscopy reveals different response pattern of four Vitis genotypes to Xylella fastidiosa infection
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DOI：
10.1094/pdis-92-2-0276
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发表时间：
2008-02-01
期刊：
影响因子：
4.5
通讯作者：
Walker, M. Andrew
中科院分区：
文献类型：
--
作者：
Fritschi, Felix B.;Lin, Hong;Walker, M. Andrew
木质部限制的细菌苛养木杆菌 (Xylella fastidiosa) 会引起皮尔斯病 (PD)，其疾病症状主要是易感葡萄藤木质部血管堵塞的结果。使用扫描电子显微镜 (SEM) 检查了 PD 敏感性不同的四种葡萄基因型（Vitis vinifera、V. rufotomentosa、V. Smalliana 和 V. arizonica/candicans）的感染和未感染对照植物的 Stein 节间和叶柄组织。在水接种的对照植物和所有基因型的 X. fastidiosa 接种的植物的叶柄和节间的气管元件的内腔中观察到柱丝、纤维状网络和胶塞。在对照植物中未观察到细菌。在叶柄和节间组织中，V. vinifera 中观察到的闭塞木质部导管数量最多，而 V. arizonica/candicans 中的闭塞木质部导管数量最少。 V vinifera 中被 X. fastidiosa 侵染的木质部导管数量最多，并且在其他三种基因型之间没有差异。所有基因型均发现全身感染。使用 SEM 观察到 X. fastidiosa 侵染血管的频率与通过酶联免疫吸附测定估计的细菌水平非常一致。在受感染的植物中，V. arizonica/candicans 节间的tylose 形成最低，并且在其他三种基因型之间没有差异。 X. fastidiosa 的感染强烈诱导V. vinifera 和V. Smalliana 中的tylose 形成，但不诱导V. arizonica/candicans 中的tylose 形成。跨组织和基因型的分析表明，针对 X. fastidiosa 感染，诱导了纤维网络和牙龈闭塞，而除 V. vinifera 叶柄外，基因型内的治疗比较并不显着。通过木质部导管闭塞来限制难养细菌感染的传播似乎并不是赋予对亚利桑那弧菌/念珠菌、小叶弧菌或红毛弧菌的 PD 抗性或耐受性的机制。相反，在 X. fastidiosa 感染后，强烈诱导 tyloses 对于 V. vinifera 的存活可能是有害的，而不是有益的。
The xylem-limited bacterium Xylella fastidiosa causes Pierce's disease (PD), whose disease symptoms are primarily the result of xylem vessel blockage in susceptible grapevines. Stein internode and petiole tissues from infected and uninfected control plants of four grape genotypes (Vitis vinifera, V. rufotomentosa, V. smalliana, and V. arizonica/candicans) differing in PD susceptibility were examined using scanning electron microscopy (SEM). Tyloses, fibrillar networks, and gum plugs were observed in lumens of tracheary elements in petioles and internodes of both water-inoculated control plants and X. fastidiosa-inoculated plants of all genotypes. Bacteria were not observed in control plants. In both petiole and internode tissues, the greatest number of occluded xylem vessels were observed in V. vinifera and the smallest number in V arizonica/candicans. The number of xylem vessels infested with X. fastidiosa was greatest in V vinifera and did not differ among the other three genotypes. Systemic infection was found in all genotypes. The frequency with which X. fastidiosa infested vessels were observed using SEM corresponded well with bacterial levels estimated by enzyme-linked immunosorbent assay. Among infected plants, tylose formation in internodes was lowest in V. arizonica/candicans and did not differ among the other three genotypes. Infection with X. fastidiosa strongly induced tylose formation in V. vinifera and V. smalliana but not in V. arizonica/candicans. Analysis across tissues and genotypes indicated an induction of fibrillar networks and gum occlusions in response to X. fastidiosa infection, whereas treatment comparisons within genotypes were not significant except for V. vinifera petioles. Limiting the spread of X. fastidiosa infection by xylem conduit occlusions does not appear to be the mechanism conferring PD resistance or tolerance to V. arizonica/candicans, V smalliana, or V. rufotomentosa. In contrast, the strong induction of tyloses may be detrimental rather than beneficial for V. vinifera survival after X. fastidiosa infection.