Department of Agricultural Microbiology, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India.
Department of Human and Molecular Genetics, Herbert Wertheim College of Medicine, Florida International University, Miami, Florida, USA.
J Med Microbiol. 2022 Aug;71(8). doi: 10.1099/jmm.0.001493.
causes fatal infections in immunocompromised individuals and patients with pulmonary disorders. Agricultural ecosystems are the vast reservoirs of this dreaded pathogen. However, there are limited attempts to analyse the pathogenicity of strains associated with edible plants. This study aims to (i) elucidate the virulence attributes of strains isolated from the rhizosphere and endophytic niches of cucumber, tomato, eggplant and chili;and (ii) compare these phenotypes with that of previously characterized clinical isolates. Crystal-violet microtitre assay, swarm plate experiment, gravimetric quantification and sheep blood lysis were performed to estimate the biofilm formation, swarming motility, rhamnolipid production and haemolytic activity, respectively, of strains. In addition, their pathogenicity was also assessed based on their ability to antagonize plant pathogens ( and ) and kill a select nematode (). Nearly 80 % of the plant-associated strains produced rhamnolipid and exhibited at least one type of lytic activity (haemolysis, proteolysis and lipolysis). Almost 50 % of these strains formed significant levels of biofilm and exhibited swarming motility. The agricultural strains showed significantly higher and lower virulence against the bacterial and fungal pathogens, respectively, compared to the clinical strains. In a maximum of 40 and 100% mortality were induced by the agricultural and clinical strains, respectively. This investigation shows that in edible plants isolated directly from the farm express virulence and pathogenicity. Furthermore, clinical and agricultural strains antagonized the tested fungal phytopathogens, and . Thus, we recommend using these fungi as simple eukaryotic model systems to test pathogenicity.
该病原体可导致免疫功能低下个体和肺部疾病患者发生致命感染。农业生态系统是这种可怕病原体的巨大储存库。然而,目前对与食用植物相关的 菌株的致病性进行分析的尝试有限。本研究旨在:(i)阐明从黄瓜、番茄、茄子和辣椒的根际和内生菌区系中分离出的 菌株的毒力特征;(ii)将这些表型与先前表征的临床分离株进行比较。采用结晶紫微量滴定法、菌苔实验、重量法定量和绵羊血溶血实验分别估计菌株的生物膜形成、菌苔运动、鼠李糖脂产生和溶血活性。此外,还根据其拮抗植物病原体( 和 )和杀死选择线虫()的能力来评估其致病性。近 80%的植物相关菌株产生鼠李糖脂,并表现出至少一种裂解活性(溶血、蛋白水解和脂肪水解)。这些菌株中有近 50%形成了显著水平的生物膜,并表现出菌苔运动。与临床菌株相比,农业菌株对细菌和真菌病原体的毒力分别显著更高和更低。在 中,农业和临床菌株分别导致高达 40%和 100%的死亡率。这项研究表明,直接从农场分离出的食用植物中的 表达了毒力和致病性。此外,临床和农业 菌株拮抗了测试的真菌植物病原体 和 。因此,我们建议使用这些真菌作为简单的真核模型系统来测试 的致病性。