USDA Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, Parlier, California, USA.
Electron Microscopy Facility, Oregon State Universitygrid.4391.f, Corvallis, Oregon, USA.
Microbiol Spectr. 2021 Dec 22;9(3):e0159121. doi: 10.1128/Spectrum.01591-21. Epub 2021 Nov 17.
Bacterial cold shock-domain proteins are conserved nucleic acid binding chaperones that play important roles in stress adaptation and pathogenesis. Csp1 is a temperature-independent cold shock protein homolog in Xylella fastidiosa, a bacterial plant pathogen of grapevine and other economically important crops. Csp1 contributes to stress tolerance and virulence in X. fastidiosa. However, besides general single-stranded nucleic acid binding activity, little is known about the specific function(s) of Csp1. To further investigate the role(s) of Csp1, we compared phenotypic differences and transcriptome profiles between the wild type and a deletion mutant (Δ). Csp1 contributes to attachment and long-term survival and influences gene expression. We observed reduced cell-to-cell attachment and reduced attachment to surfaces with the Δ strain compared to those with the wild type. Transmission electron microscopy imaging revealed that Δ was deficient in pili formation compared to the wild type and complemented strains. The Δ strain also showed reduced survival after long-term growth . Long-read nanopore transcriptome sequencing (RNA-Seq) analysis revealed changes in expression of several genes important for attachment and biofilm formation in Δ compared to that in the wild type. One gene of interest, , which encodes a type IV pili subunit protein, was upregulated in Δ. Deleting in X. fastidiosa strain Stag's Leap increased surface attachment and reduced virulence in grapevines. X. fastidiosa virulence depends on bacterial attachment to host tissue and movement within and between xylem vessels. Our results show that the impact of Csp1 on virulence may be due to changes in expression of attachment genes. Xylella fastidiosa is a major threat to the worldwide agriculture industry. Despite its global importance, many aspects of X. fastidiosa biology and pathogenicity are poorly understood. There are currently few effective solutions to suppress X. fastidiosa disease development or eliminate bacteria from infected plants. Recently, disease epidemics due to X. fastidiosa have greatly expanded, increasing the need for better disease prevention and control strategies. Our studies show a novel connection between cold shock protein Csp1 and pili abundance and attachment, which have not been reported for X. fastidiosa. Understanding how pathogenesis-related gene expression is regulated can aid in developing novel pathogen and disease control strategies. We also streamlined a bioinformatics protocol to process and analyze long-read nanopore bacterial RNA-Seq data, which will benefit the research community, particularly those working with non-model bacterial species.
细菌冷休克结构域蛋白是保守的核酸结合伴侣，在应激适应和发病机制中发挥重要作用。Csp1 是葡萄座腔菌（Xylella fastidiosa）的一种与温度无关的冷休克蛋白同源物，葡萄座腔菌是一种植物病原体，可感染葡萄和其他具有重要经济价值的作物。Csp1 有助于葡萄座腔菌耐受压力和毒力。然而，除了一般的单链核酸结合活性外，对于 Csp1 的特定功能知之甚少。为了进一步研究 Csp1 的作用，我们比较了野生型和缺失突变体（Δ）之间的表型差异和转录组谱。Csp1 有助于附着和长期存活，并影响基因表达。与野生型相比，我们观察到用Δ菌株附着细胞和附着到表面的能力降低。透射电子显微镜成像显示，与野生型和互补菌株相比，Δ 菌株的菌毛形成能力不足。Δ 菌株在长期生长后存活能力也降低。长读长纳米孔转录组测序（RNA-Seq）分析显示，与野生型相比，Δ 菌株中几个与附着和生物膜形成相关的基因的表达发生变化。一个感兴趣的基因 ，其编码 IV 型菌毛亚基蛋白，在Δ 中上调。在葡萄座腔菌 Stag's Leap 菌株中删除 增加了表面附着 并降低了对葡萄的毒力。葡萄座腔菌的毒力取决于细菌对宿主组织的附着以及在木质部导管内和之间的运动。我们的结果表明，Csp1 对毒力的影响可能是由于附着基因表达的变化。葡萄座腔菌是全球农业产业的主要威胁。尽管其具有全球重要性，但对葡萄座腔菌的生物学和致病性的许多方面仍了解甚少。目前，抑制葡萄座腔菌疾病发展或从感染植物中消除细菌的有效方法很少。最近，由于葡萄座腔菌引起的疾病流行范围大大扩大，这增加了对更好的疾病预防和控制策略的需求。我们的研究表明，冷休克蛋白 Csp1 与菌毛丰度和附着之间存在新的联系，这在葡萄座腔菌中尚未报道。了解与发病机制相关的基因表达如何受到调控，可以帮助开发新的病原体和疾病控制策略。我们还简化了一种生物信息学协议，以处理和分析长读长纳米孔细菌 RNA-Seq 数据，这将使研究界受益，特别是那些从事非模式细菌物种研究的人员。
