Bejarano Ana, Perazzolli Michele, Pertot Ilaria, Puopolo Gerardo
Center of Agriculture, Food, Environment, University of Trento, San Michele all'Adige, Italy.
Department of Sustainable Agro-Ecosystems and Bioresources, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all'Adige, Italy.
Front Microbiol. 2021 Aug 18;12:725403. doi: 10.3389/fmicb.2021.725403. eCollection 2021.
The rhizosphere is a dynamic region governed by complex microbial interactions where diffusible communication signals produced by bacteria continuously shape the gene expression patterns of individual species and regulate fundamental traits for adaptation to the rhizosphere environment. spp. are common bacterial inhabitants of the rhizosphere and have been frequently associated with soil disease suppressiveness. However, little is known about their ecology and how diffusible communication signals might affect their behavior in the rhizosphere. To shed light on the aspects determining rhizosphere competence and functioning of spp., we carried out a functional and transcriptome analysis on the plant beneficial bacterium AZ78 (AZ78) grown in the presence of the most common diffusible communication signals released by rhizosphere bacteria. Mining the genome of AZ78 and other spp. showed that spp. share genes involved in the production and perception of diffusible signal factors, indole, diffusible factors, and -acyl-homoserine lactones. Most of the tested diffusible communication signals (i.e., indole and glyoxylic acid) influenced the ability of AZ78 to inhibit the growth of the phytopathogenic oomycete and the Gram-positive bacterium . Moreover, RNA-Seq analysis revealed that nearly 21% of all genes in AZ78 genome were modulated by diffusible communication signals. 13-Methyltetradecanoic acid, glyoxylic acid, and 2,3-butanedione positively influenced the expression of genes related to type IV pilus, which might enable AZ78 to rapidly colonize the rhizosphere. Moreover, glyoxylic acid and 2,3-butanedione downregulated tRNA genes, possibly as a result of the elicitation of biological stress responses. On its behalf, indole downregulated genes related to type IV pilus and the heat-stable antifungal factor, which might result in impairment of twitching motility and antibiotic production in AZ78. These results show that diffusible communication signals may affect the ecology of spp. in the rhizosphere and suggest that diffusible communication signals might be used to foster rhizosphere colonization and functioning of plant beneficial bacteria belonging to the genus .
根际是一个由复杂微生物相互作用所支配的动态区域，细菌产生的可扩散通讯信号不断塑造着各个物种的基因表达模式，并调节适应根际环境的基本性状。[具体细菌名称]属细菌是根际常见的细菌居民，并且经常与土壤病害抑制相关。然而，关于它们的生态学以及可扩散通讯信号如何影响它们在根际的行为却知之甚少。为了阐明决定[具体细菌名称]属细菌根际能力和功能的各个方面，我们对在根际细菌释放的最常见可扩散通讯信号存在的情况下生长的植物有益细菌AZ78进行了功能和转录组分析。挖掘AZ78和其他[具体细菌名称]属细菌的基因组表明，[具体细菌名称]属细菌共享参与可扩散信号因子、吲哚、可扩散因子和N-酰基高丝氨酸内酯的产生和感知的基因。大多数测试的可扩散通讯信号（即吲哚和乙醛酸）影响了AZ78抑制植物病原卵菌和革兰氏阳性细菌生长的能力。此外，RNA测序分析表明，AZ78基因组中近21%的基因受到可扩散通讯信号的调节。13-甲基十四烷酸、乙醛酸和2,3-丁二酮对与IV型菌毛相关的基因表达产生了积极影响，这可能使AZ78能够快速定殖于根际。此外，乙醛酸和2,3-丁二酮下调了tRNA基因，这可能是引发生物应激反应的结果。就其本身而言，吲哚下调了与IV型菌毛和热稳定抗真菌因子相关的基因，这可能导致AZ78的颤动运动和抗生素产生受损。这些结果表明，可扩散通讯信号可能会影响[具体细菌名称]属细菌在根际的生态学，并表明可扩散通讯信号可用于促进属于[具体细菌名称]属的植物有益细菌的根际定殖和功能。
