Veenhof Reina J, McGrath Alexander H, Champion Curtis, Dworjanyn Symon A, Marzinelli Ezequiel M, Coleman Melinda A
Faculty of Science and Engineering, National Marine Science Centre, Southern Cross University, Coffs Harbour, New South Wales, Australia.
School of Life and Environmental Sciences, The University of Sydney, Sydney, New South Wales, Australia.
J Phycol. 2025 Jun;61(3):633-649. doi: 10.1111/jpy.70018. Epub 2025 Apr 29.
Ocean warming is driving profound changes in the ecology of marine habitat formers such as kelps, with negative implications for the biodiversity and ecosystem services they support. Thermal stress can disturb associated microbiota that are essential to the healthy functioning of kelp, but little is known about how this process influences early-life stages. Because kelps have a biphasic life cycle, thermal stress dynamics of adult sporophyte microbiota may not reflect those of the free-living haploid gametophyte. We investigated the role of microbial disruption under thermal stress on gametophytes of the kelp Ecklonia radiata and compared sporophyte and gametophyte microbiota. The microbiota of gametophytes changed significantly when the microbiome was disrupted and under increased temperature (26°C), in which putative generalist bacterial taxa proliferated and bacterial families associated with nitrogen fixation decreased. Concurrently, the survival of gametophytes decreased to <10%, and surviving gametophytes did not become fertile when the microbiome was disrupted. The length of gametophytes decreased under both microbial disruption and thermal stress. Taken together, this suggests that the associated microbiota of Ecklonia gametophytes is important for their survival, fertility, and response to warming. Gametophyte and parental sporophyte microbiota were also distinct from the water column but not each other, suggesting vertical transmission of microbiota from one life stage to the next. This study furthers our understanding of the role of microbiota in gametophyte stress tolerance as well as the acquisition of microbiota, which may prove vital in protecting and increasing the stress resilience of these foundation species.
海洋变暖正在推动海带等海洋栖息地形成者的生态发生深刻变化，对它们所支持的生物多样性和生态系统服务产生负面影响。热应激会干扰对海带健康功能至关重要的相关微生物群，但对于这一过程如何影响早期生命阶段却知之甚少。由于海带具有双相生命周期，成年孢子体微生物群的热应激动态可能无法反映自由生活的单倍体配子体的情况。我们研究了热应激下微生物破坏对海带辐射昆布配子体的作用，并比较了孢子体和配子体的微生物群。当微生物群落受到破坏且温度升高（26°C）时，配子体的微生物群发生了显著变化，其中假定的泛化细菌类群增殖，与固氮相关的细菌科减少。同时，配子体的存活率降至<10%，当微生物群落受到破坏时，存活的配子体无法受精。在微生物破坏和热应激下，配子体的长度均减少。综上所述，这表明辐射昆布配子体的相关微生物群对其存活、繁殖力和对变暖的反应很重要。配子体和亲本孢子体的微生物群也与水柱不同，但彼此之间没有差异，这表明微生物群从一个生命阶段垂直传递到下一个阶段。这项研究进一步加深了我们对微生物群在配子体胁迫耐受性中的作用以及微生物群获取的理解，这可能对保护和提高这些基础物种的胁迫恢复力至关重要。
