Mycorrhizal fungi are critical components of terrestrial habitats and agroecosystems. Recently, Mucoromycotina fine root endophyte fungi (MucFRE) were found to engage in nutritional mutualism with Lycopodiella inundata, which belongs to one of the earliest vascular plant lineages known to associate with MucFRE. The extent to which this mutualism plays a role in resilient plant populations can only be understood by examining its occurrence rate and phenological patterns. To test for prevalence and seasonality in colonization, we examined 1305 individual L. inundata roots from 275 plants collected during spring and autumn 2019 across 11 semi-natural heathlands in Britain and the Netherlands. We quantified presence/absence of fine root endophyte (FRE) hyphae and vesicles and explored possible relationships between temperature and precipitation in the months immediately before sampling. Fine root endophyte hyphae were dominant in all of the examined heathlands, and every colonized root had FRE in both cortical cells and root hairs. However, we found significant differences in colonization between the two seasons at every site. Overall, 14% of L. inundata roots were colonized in spring (2.4% with vesicles) compared with 86% in autumn (7.6% with vesicles). Colonization levels between populations were also significantly different, correlating with temperature and precipitation, suggesting some local environments may be more conducive to root and related hyphal growth. These marked seasonal differences in host-plant colonization suggest that results about FRE from single time point collections should be carefully interpreted. Our findings are relevant to habitat restoration, species conservation plans, agricultural bio-inoculation treatments, and microbial diversity studies.

中文翻译：

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石松种群中细根内生菌定植的流行率和物候学。


菌根真菌是陆地生境和农业生态系统的重要组成部分。最近，人们发现毛霉菌亚门细根内生真菌（MucFRE）与石松菌（Lycopodiella inundata ）存在营养互利关系，后者属于已知与 MucFRE 相关的最早的维管植物谱系之一。这种互利共生在植物种群恢复力中发挥作用的程度只能通过检查其发生率和物候模式来了解。为了测试定植的流行率和季节性，我们检查了 2019 年春季和秋季在英国和荷兰 11 个半自然石南地收集的 275 种植物的 1305 个单独的L. inundata根。我们量化了细根内生菌 (FRE) 菌丝和囊泡的存在/不存在，并探讨了采样前几个月温度和降水之间可能的关系。在所有检查的石南地中，细根内生菌菌丝占主导地位，并且每个定殖根的皮层细胞和根毛均具有 FRE。然而，我们发现每个地点两个季节之间的定殖存在显着差异。总体而言，春季有 14% 的L. inundata根定植（2.4% 有囊泡），而秋季则有 86%（7.6% 有囊泡）。种群之间的定植水平也存在显着差异，与温度和降水相关，这表明一些当地环境可能更有利于根和相关菌丝的生长。寄主植物定植的这些显着的季节性差异表明，应仔细解释单时间点收集的 FRE 结果。 我们的研究结果与栖息地恢复、物种保护计划、农业生物接种处理和微生物多样性研究相关。