In this study we report for the first time the appearance of an endophytic filamentous red alga, living associated with the edible red seaweed Chondracanthus chamissoi. Molecular identification, growth, and reproduction of this endophyte are described under different conditions: photoperiod (8:16, 12:12, and 16:08 L:D), temperature (10 and 15 °C), and photon flux density (40 and 20 μmol photons m⁻² s⁻¹). Filaments of this endophyte were isolated and cultured, and the growth was recorded according to the number of branches and its reproduction, by quantifying the emergence of monosporangia. By sequencing the COI gene and through phylogeny reconstruction using maximum likelihood, we determined that this endophyte corresponded to Colaconema daviesii. The highest growth was recorded under the treatment 16:08 (L:D), 10 °C, and 20 μmol photons m⁻² s⁻¹, reaching up to 100 branches after 18 days. On the other hand, over 80% of filaments with monosporangia were observed at 12:12 (L:D), 10 °C, and 20 μmol photons m⁻² s⁻¹. This is the first record of C. daviesii on the South-eastern Pacific as an endophyte on thalli of C. chamissoi. The results of the in vitro cultures showed that once C. daviesii is isolated, the filaments are able to grow and reproduce independently of C. chamissoi. This suggests that there may not be a strict relationship between both algae and reveals the possibility of finding C. daviesii living without a host or associated with other species.

在这项研究中，我们首次报告了一种内生的丝状红藻的出现，该藻类与可食用的红海藻软骨鱼chamissoi有关。在不同条件下描述了该内生菌的分子鉴定，生长和繁殖：光周期（8：16、12：12和16:08 L：D），温度（10和15°C）和光子通量密度（40和20μmol光子m ^-2  s ^-1）。分离并培养该内生菌的细丝，并通过定量单孢子囊的出现，根据分支的数目及其繁殖记录生长。通过对COI基因进行测序并通过使用最大可能性的系统发育重建，我们确定该内生菌对应于lac鱼 在16:08（L：D），10°C和20μmol光子m ^-2  s ^-1下记录到最高的生长，在18天后达到100个分支。另一方面，在12:12（L：D），10°C和20μmol光子m ^-2  s ^-1处观察到超过80％的单孢子囊丝。这是东南太平洋首次将戴维斯球藻（C. daviesii）记录为chamissoi球藻的内生菌。在体外培养物的结果表明，一旦C. daviesii被隔离，细丝能够独立生长和繁殖C. chamissoi。这表明这两种藻类之间可能没有严格的联系，并揭示了找到无宿主或与其他物种没有联系的戴维梭菌的可能性。