Erwinia psidii is an airborne bacterium that is the causal agent of eucalyptus bacterial blight in Brazil. However, there are no studies on the survival of the bacterial pathogen under epiphytic, soil and eucalyptus leaf debris conditions. We investigated the survival of E. psidii on the phylloplane and in leaf debris from two eucalyptus genotypes, and within eucalyptus forest soil. A rifampicin-resistant mutant (CR01R) was obtained from the wild type by the gradient plate method and chosen for the study because it showed the same morphological, growth, pathogenic and aggressive properties as the parental strain. On the phylloplane of Eucalyptus urophylla × Eucalyptus globulus and E. saligna, the plant–pathogenic bacterium was recovered for up to 40 and 60 days, respectively. Under non-sterile eucalyptus forest soil, E. psidii survived for 15 days post–soil infestation. In leaf debris from the eucalyptus genotypes, the bacterial pathogen was detected for up to 90 days in debris placed on the soil surface. However, under non-sterile soil, 5 or 15 cm deep, the bacterium was detected for up to 45 and 60 days in leaf debris from E. saligna and E. urophylla × E. globulus, respectively. In this study, we showed that E. psidii can survive as an epiphyte or saprophyte in diseased leaves on the soil. However, the pathogen was a poor survivor in natural eucalyptus forest soil. The pathogen's survival period in leaf debris buried in the soil was drastically reduced. This information shows that the phylloplane or leaf debris is putative reservoirs for the bacterium and may serve as a primary inoculum source.

中文翻译：

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Erwinia psidii 在附生植物、土壤和桉树叶碎片条件下的存活

Erwinia psidii是一种空气传播细菌，是巴西桉树细菌性枯萎病的病原体。然而，没有关于细菌病原体在附生植物、土壤和桉树叶碎片条件下存活的研究。我们调查了E的存活情况。psidii的叶面和叶碎片从两个桉树种基因型，并在桉树林土壤。通过梯度平板法从野生型中获得利福平抗性突变体 (CR01R) 并选择用于研究，因为它显示出与亲本菌株相同的形态、生长、致病性和侵袭性特性。在Eucalyptus urophylla  ×  Eucalyptus globulus和E的叶面。saligna，植物病原菌分别回收长达 40 天和 60 天。在非无菌桉树森林土壤下，E . psidii在土壤侵染后存活了 15 天。在桉树基因型的叶碎片中，在放置在土壤表面的碎片中检测到细菌病原体长达 90 天。然而，在 5 或 15 厘米深的非无菌土壤中，细菌在来自大肠杆菌的叶碎片中被检测到长达 45 天和 60 天。柳桉和Ë。尾叶 ×  E . 球状，分别。在这项研究中，我们表明E . 西迪可以在土壤上的病叶中作为附生植物或腐生植物存活。然而，该病原体在天然桉树林土壤中存活率很低。病原体在埋在土壤中的叶屑中的存活期大大缩短。该信息表明，叶面或叶片碎片是细菌的假定储存库，可作为主要接种源。