Yishay Moran, Burdman Saul, Valverde Angel, Luzzatto Tal, Ophir Ron, Yedidia Iris
Department of Plant Sciences, Agricultural Research Organization, The Volcani Center, PO Box 6, Bet-Dagan 50250, Israel.
Environ Microbiol. 2008 Oct;10(10):2746-59. doi: 10.1111/j.1462-2920.2008.01694.x. Epub 2008 Aug 3.
The capability of Pectobacterium carotovorum isolates to infect monocotyledonous plants has been previously reported; however, no full consideration was given to characterize the association between such isolates and their monocot hosts. To assess differences in aggressiveness among P. carotovorum ssp. carotovorum isolates originating from monocotyledonous or dicotyledonous plants, we used as model plants two susceptible monocot hosts, the ornamentals Zantedeschia aethiopica and Ornithogalum dubium, as well as two common dicot hosts, Solanum tuberosum and Brassica oleracea. Using virulence assays and different genetic analyses we characterized P. carotovorum ssp. carotovorum isolates from diverse geographical locations which originated from plants belonging to four unrelated orders of monocots and five orders of dicots. Invariably, isolates originating from monocots exhibited higher virulence towards the tested monocot plants than dicot isolates, independently of their geographical source. Moreover, monocot and dicot isolates were clearly differentiated by various genetic analyses, such as 16S rRNA sequence clustering, intergenic transcribed spacer-PCR (ITS-PCR) banding pattern and amplified fragment length polymorphism (AFLP). We propose that the observed relationship between pathogenicity and genetic diversity among P. carotovorum ssp. carotovorum isolates reveals a co-evolutionary specialization trend in the interaction between this pathogen and its hosts.
胡萝卜软腐果胶杆菌分离株感染单子叶植物的能力此前已有报道；然而，对于此类分离株与其单子叶宿主之间的关联特征并未进行充分研究。为了评估源自单子叶植物或双子叶植物的胡萝卜软腐果胶杆菌亚种胡萝卜软腐果胶杆菌分离株在致病性上的差异，我们选用了两种易感单子叶宿主植物——观赏植物马蹄莲和虎眼万年青，以及两种常见双子叶宿主植物——马铃薯和甘蓝作为模式植物。通过致病性测定和不同的遗传分析，我们对来自不同地理位置、源自属于四个不相关单子叶目和五个双子叶目的植物的胡萝卜软腐果胶杆菌亚种胡萝卜软腐果胶杆菌分离株进行了特征分析。无一例外，源自单子叶植物的分离株对所测试的单子叶植物表现出比对双子叶植物分离株更高的致病性，且与它们的地理来源无关。此外，通过各种遗传分析，如16S rRNA序列聚类、基因间转录间隔区PCR（ITS-PCR）条带模式和扩增片段长度多态性（AFLP），单子叶和双子叶分离株能够被清楚地区分。我们认为，在胡萝卜软腐果胶杆菌亚种胡萝卜软腐果胶杆菌分离株中观察到的致病性与遗传多样性之间的关系揭示了该病原体与其宿主相互作用中的一种协同进化专业化趋势。
