College of Ocean and Earth Science of Xiamen University, Xiamen, 361005, China.
Xiamen City Key Laboratory of Urban Sea Ecological Conservation and Restoration (USER), Xiamen University, Xiamen, 361005, China.
Commun Biol. 2024 Aug 6;7(1):952. doi: 10.1038/s42003-024-06622-7.
The transition from the swimming larval stage to the settlement stage represents a significant node in the marine sponge developmental process. Previous research has shown that the outer membrane vesicles (OMVs) from the bacterial species Tenacibaculum mesophilum associated with the sponge Tedania sp. influence larval settlement: low concentrations of OMVs increase the attachment rate, whereas high concentrations decrease the attachment rate. Here, by comparing the transcriptomes of sponge larvae in filtered seawater (FSW group) and in FSW supplemented with OMVs (FSW-OMV group), the results indicated that bacterial OMVs affected larval settlement by modulating the expression levels of apoptosis-inducing factor (AIF) in the host. Subsequently, quantitative real-time PCR revealed a decrease in aif expression near the time of settlement (SE) compared to that in the control group. RNA interference (RNAi) was used to target the aif gene, and the rate of larval settlement was significantly reduced, confirming the inhibitory effect of high concentrations of OMVs. Moreover, small RNA (sRNA) sequencing of OMVs revealed the existence of abundant AIF-sRNAs of 30 nt, further suggesting that one pathway for the involvement of sponge-associated bacteria in host development is the transport of OMVs and the direct function of cargo loading.
从游泳幼虫阶段到定居阶段的转变代表了海洋海绵发育过程中的一个重要节点。先前的研究表明，与海绵 Tedania sp. 相关的细菌物种 Tenacibaculum mesophilum 的外膜囊泡（OMVs）影响幼虫定居：低浓度的 OMVs 增加附着率，而高浓度则降低附着率。在这里，通过比较过滤海水（FSW 组）和添加 OMVs 的 FSW（FSW-OMV 组）中海绵幼虫的转录组，结果表明细菌 OMVs 通过调节宿主中凋亡诱导因子（AIF）的表达水平来影响幼虫定居。随后，定量实时 PCR 显示，与对照组相比，在定居（SE）附近，aif 的表达减少。针对 aif 基因的 RNA 干扰（RNAi）用于靶向该基因，并且幼虫定居率显著降低，证实了高浓度 OMVs 的抑制作用。此外，对 OMVs 的小 RNA（sRNA）测序揭示了大量 30nt 的 AIF-sRNAs 的存在，这进一步表明，海绵相关细菌参与宿主发育的一种途径是 OMVs 的运输和货物装载的直接功能。
