Ocean School, Yantai University, Yantai, 264005, China.
CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China.
BMC Genomics. 2024 Sep 6;25(1):840. doi: 10.1186/s12864-024-10742-z.
Coral reefs experience frequent and severe disturbances that can overwhelm their natural resilience. In such cases, ecological restoration is essential for coral reef recovery. Sexual reproduction has been reported to present the simplest and most cost-effective means for coral reef restoration. However, larval settlement and post-settlement survival represent bottlenecks for coral recruitment in sexual reproduction. While bacteria play a significant role in triggering coral metamorphosis and settlement in many coral species, the underlying molecular mechanisms remain largely unknown. In this study, we employed a transcriptome-level analysis to elucidate the intricate interactions between bacteria and coral larvae that are crucial for the settlement process.
High Metabacillus indicus strain cB07 inoculation densities resulted in the successful induction of metamorphosis and settlement of coral Pocillopora damicoris larvae. Compared with controls, inoculated coral larvae exhibited a pronounced increase in the abundance of strain cB07 during metamorphosis and settlement, followed by a significant decrease in total lipid contents during the settled stage. The differentially expressed genes (DEGs) during metamorphosis were significantly enriched in amino acid, protein, fatty acid, and glucose related metabolic pathways. In settled coral larvae induced by strain cB07, there was a significant enrichment of DEGs with essential roles in the establishment of a symbiotic relationship between coral larvae and their symbiotic partners. The photosynthetic efficiency of strain cB07 induced primary polyp holobionts was improved compared to those of the negative controls. In addition, coral primary polyps induced by strain cB07 showed significant improvements in energy storage and survival.
Our findings revealed that strain cB07 can promote coral larval settlement and enhance post-settlement survival and fitness. Manipulating coral sexual reproduction with strain cB07 can overcome the current recruitment bottleneck. This innovative approach holds promise for future coral reef restoration efforts.
珊瑚礁经常遭受频繁且剧烈的干扰，这些干扰可能会超出其自然恢复力。在这种情况下，生态恢复对于珊瑚礁的恢复至关重要。有报道称，有性繁殖是珊瑚礁恢复最简单、最具成本效益的方法。然而，幼虫附着和附着后生存是珊瑚有性繁殖中招募的瓶颈。虽然细菌在许多珊瑚物种中触发珊瑚变态和附着中起着重要作用，但潜在的分子机制在很大程度上仍然未知。在这项研究中，我们采用转录组水平分析来阐明细菌和珊瑚幼虫之间对附着过程至关重要的复杂相互作用。
高浓度的指示梅奇氏菌（Metabacillus indicus）cB07 菌株接种可成功诱导珊瑚虫 Pocillopora damicoris 幼虫变态和附着。与对照组相比，接种珊瑚幼虫在变态和附着过程中显著增加了 cB07 菌株的丰度，随后在附着阶段总脂质含量显著下降。在 cB07 菌株诱导的变态过程中，差异表达基因（DEGs）显著富集在氨基酸、蛋白质、脂肪酸和葡萄糖相关代谢途径中。在 cB07 菌株诱导的附着珊瑚幼虫中，有一组 DEGs 显著富集，这些基因在建立珊瑚幼虫与其共生伙伴之间的共生关系中起着至关重要的作用。与阴性对照相比，cB07 菌株诱导的原珊瑚息肉的光合作用效率得到了提高。此外，cB07 菌株诱导的珊瑚原息肉在能量储存和生存方面表现出显著的改善。
我们的研究结果表明，cB07 菌株可以促进珊瑚幼虫附着，并提高附着后的生存和适应能力。用 cB07 菌株操纵珊瑚有性繁殖可以克服当前的繁殖瓶颈。这种创新方法为未来的珊瑚礁恢复工作带来了希望。
