Astafyeva Yekaterina, Gurschke Marno, Streit Wolfgang R, Krohn Ines
Department of Microbiology and Biotechnology, Biocenter Klein Flottbek, University of Hamburg, Hamburg, Germany.
Front Microbiol. 2022 Oct 13;13:1006609. doi: 10.3389/fmicb.2022.1006609. eCollection 2022.
Based on previous research, related to detailed insight into mutualistic collaboration of microalga and its microbiome, we established an artificial plant-bacteria system of the microalga MZCH 672 and the bacterial isolate sp. HH091. The bacteria, affiliated with the phylum Bacteroidota, strongly stimulated growth of the microalga when it was added to axenic algal cultures. For further advances, we studied the isolate HH091 and its interaction with the microalga using transcriptome and extensive genome analyses. The genome of HH091 contains predicted polysaccharide utilizing gene clusters co-working with the type IX secretion system (T9SS) and conceivably involved in the algae-bacteria liaison. Here, we focus on characterizing the mechanism of T9SS, implementing the attachment and invasion of microalga by sp. HH091. Omics analysis exposed T9SS genes: , , , , , , , , and . Besides, genes not considered as the T9SS components but required for gliding motility and protein secretion (, , , , , , , , were also identified at this analysis. A first model of T9SS apparatus of was proposed in a course of this research. Using the combination of fluorescence labeling of sp. HH091, we examined the bacterial colonisation and penetration into the cell wall of the algal host MZCH 672.
基于之前有关深入洞察微藻与其微生物群落共生协作的研究，我们建立了微藻MZCH 672与细菌分离株sp. HH091的人工植物-细菌系统。该细菌隶属于拟杆菌门，当添加到无菌藻类培养物中时，能强烈刺激微藻生长。为了进一步深入研究，我们利用转录组和广泛的基因组分析，对分离株HH091及其与微藻的相互作用进行了研究。HH091的基因组包含预测的多糖利用基因簇，这些基因簇与IX型分泌系统（T9SS）协同工作，可能参与藻类与细菌的联系。在此，我们着重于表征T9SS的机制，该机制实现了sp. HH091对微藻的附着和入侵。组学分析揭示了T9SS基因： 、 、 、 、 、 、 、 和 。此外，在此次分析中还鉴定出了一些虽不被视为T9SS组分但对滑行运动和蛋白质分泌所必需的基因（ 、 、 、 、 、 、 、 ）。在本研究过程中，提出了 的T9SS装置的首个模型。通过结合sp. HH091的荧光标记，我们研究了细菌在藻类宿主MZCH 672细胞壁上的定殖和渗透情况。
