Fuentes-Romero Francisco, Moyano-Bravo Isamar, Ayala-García Paula, Rodríguez-Carvajal Miguel Ángel, Pérez-Montaño Francisco, Acosta-Jurado Sebastián, Ollero Francisco Javier, Vinardell José-María
Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain.
Departamento de Química Orgánica, Facultad de Química, Universidad de Sevilla, 41012 Seville, Spain.
Biology (Basel). 2023 Jan 18;12(2):148. doi: 10.3390/biology12020148.
(1) Background: Some rhizobia, such as CIAT 899, activate nodulation genes when grown under osmotic stress. This work aims to determine whether this phenomenon also takes place in HH103. (2) Methods: HH103 was grown with and without 400 mM mannitol. β-galactosidase assays, nodulation factor extraction, purification and identification by mass spectrometry, transcriptomics by RNA sequencing, motility assays, analysis of acyl-homoserine lactones, and indole acetic acid quantification were performed. (3) Results: Non-ionic osmotic stress induced the production of nodulation factors. Forty-two different factors were detected, compared to 14 found in the absence of mannitol. Transcriptomics indicated that hundreds of genes were either activated or repressed upon non-ionic osmotic stress. The presence of 400 mM mannitol induced the production of indole acetic acid and acyl homoserine lactones, abolished swimming, and promoted surface motility. (4) Conclusions: In this work, we show that non-ionic stress in HH103, caused by growth in the presence of 400 mM mannitol, provokes notable changes not only in gene expression but also in various bacterial traits, including the production of nodulation factors and other symbiotic signals.
(1) 背景：一些根瘤菌，如CIAT 899，在渗透胁迫下生长时会激活结瘤基因。本研究旨在确定这种现象是否也发生在HH103中。(2) 方法：将HH103分别在含有和不含有400 mM甘露醇的条件下培养。进行了β-半乳糖苷酶测定、结瘤因子提取、质谱纯化与鉴定、RNA测序转录组学分析、运动性测定、酰基高丝氨酸内酯分析以及吲哚乙酸定量分析。(3) 结果：非离子渗透胁迫诱导了结瘤因子的产生。检测到42种不同的因子，而在无甘露醇条件下仅发现14种。转录组学表明，数百个基因在非离子渗透胁迫下被激活或抑制。400 mM甘露醇的存在诱导了吲哚乙酸和酰基高丝氨酸内酯的产生，消除了游动性，并促进了表面运动性。(4) 结论：在本研究中，我们表明，在400 mM甘露醇存在下生长导致的HH103中的非离子胁迫，不仅引起基因表达的显著变化，还引起各种细菌性状的变化，包括结瘤因子和其他共生信号的产生。
