Centro de Investigaciones en Ciencias Microbiológicas, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Apdo, Postal 1622, C. P. 72000, Puebla, Mexico.
Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo, Postal 510-3, C. P. 62250, Cuernavaca, Mexico.
Arch Microbiol. 2020 Apr;202(3):579-589. doi: 10.1007/s00203-019-01769-y. Epub 2019 Nov 19.
Azotobacter vineladii is a Gram-negative bacterium that produces alginate and poly-hydroxybutyrate (PHB), two polymers of biotechnological interest. This bacterium has the ability to form desiccation-resistant cysts. In the cyst the membrane phospholipids are replaced with a family of phenolic lipids called alkylresorcinols (ARs). The alginate, PHB, and ARs are controlled by the GacS/A two-component system and the small regulatory RNA (sRNA) RsmZ1, belonging to the Rsm (Csr) regulatory system. The Rsm (Csr) systems usually possess two or more sRNAs, in this regard A. vinelandii is the bacterium with the highest number of rsm-sRNAs. Originally, the presence of two sRNAs of the RsmY family (RsmY1 and RsmY2) was reported, but in a subsequent work it was suggested that they conformed to a single sRNA. In this work we provide genetic evidence confirming that rsmY1 and rsmY2 constitute a single gene. Also, it was established that rsmY mutation decreased alginate and ARs production, but did not affect the PHB synthesis. Transcriptional studies showed that rsmY has its higher expression during the stationary growth phase, and in the absence of RsmZ1, rsmY increases its transcription. Interestingly, rsmY expression was influenced by the carbon source, but its expression did not correlate with alginate production.
威氏固氮菌是一种革兰氏阴性细菌，能够产生海藻酸盐和聚-β-羟基丁酸酯（PHB），这两种聚合物都具有生物技术应用价值。该细菌具有形成抗干燥的芽孢的能力。在芽孢中，膜磷脂被称为烷基间苯二酚（ARs）的酚类脂质家族所取代。海藻酸盐、PHB 和 ARs 受到 GacS/A 双组分系统和小调控 RNA（sRNA）RsmZ1 的控制，该 sRNA 属于 Rsm（Csr）调控系统。Rsm（Csr）系统通常拥有两个或更多个 sRNA，就这方面而言，威氏固氮菌是具有最多 rsm-sRNA 的细菌。最初，报道了 RsmY 家族的两个 sRNA（RsmY1 和 RsmY2）的存在，但在随后的一项工作中表明，它们符合单个 sRNA。在这项工作中，我们提供了遗传证据，证实 rsmY1 和 rsmY2 构成一个单一基因。此外，还确定了 rsmY 突变会降低海藻酸盐和 ARs 的产生，但不会影响 PHB 的合成。转录研究表明，rsmY 在静止生长阶段的表达水平更高，并且在没有 RsmZ1 的情况下，rsmY 会增加其转录。有趣的是，rsmY 的表达受到碳源的影响，但它的表达与海藻酸盐的产生没有相关性。
