Supplementary Dataset for 'The “Trojan horse” strategy: seed fungal endophyte symbiosis helps to explain the invasion success of Poa annua in Maritime Antarctica'

Supplementary tables 1-3 for the paper: <strong>The “Trojan horse” strategy: seed fungal endophyte symbiosis helps to explain the invasion success of </strong><em><strong>Poa annua</strong></em><strong> in Maritime Antarctica</strong> Although <em>Poa annua</em> L. (annual bluegrass) is presently the sole invasive vascular plant species to have successfully established in Maritime Antarctica, the reasons for its success in the region have yet to be established. Here, we determined whether the invasiveness of <em>P. annua</em>, and its competitiveness with the native Antarctic hairgrass <em>Deschampsia antarctica</em>, is influenced by symbioses formed with seed fungal endophytes, and whether plants derived from seeds from four global macro-regions differ in their performance (Maritime Antarctica, sub-Antarctica, South America and Europe) <br> Endophyte frequency was measured in <em>P. annua</em> seeds collected from the four macro-regions. The germination, survival, biomass accumulation, flower production and competitiveness with <em>D. antarctica</em> of <em>P. annua</em> plants grown from uncolonised and colonised seeds was determined in the laboratory. The effects of endophytes on <em>P. annua</em> seed germination and survival and seedling osmoprotection was also assessed in the Maritime Antarctic natural environment using locally-sourced seeds. <br> Endophytes were at least twice as frequent in seeds from Maritime Antarctica than in those from South America, Europe and sub-Antarctica. A higher proportion of endophyte-colonised seeds germinated and survived than did uncolonised seeds, but only when they originated from Maritime Antarctica. The presence of seed endophytes in <em>P. annua</em> increased the competitiveness of the species with <em>D. antarctica</em>, but only for <em>P. annua</em> plants grown from Maritime Antarctic seeds. In the field, endophyte-colonised seeds from Maritime Antarctica germinated and survived more frequently than uncolonised seeds, and osmoprotection was higher in seedlings grown from colonised seed. <br> The findings indicate beneficial effects of seed endophytes on invasion-related traits of <em>P. annua</em>, such as survival, germination success and flower production. Together with vegetative and reproductive traits facilitating the colonization process, the seed-fungal endophyte symbiosis can be invoked as an important factor explaining the invasiveness of <em>P. annua</em> in Maritime Antarctica.本论文的补充表1至3：《“特洛伊木马”策略：种子真菌内生菌（seed fungal endophyte）共生助力解释一年生早熟禾（Poa annua）在南极海洋性区域（Maritime Antarctica）的入侵成功》 尽管目前一年生早熟禾（Poa annua L.，annual bluegrass）是唯一成功在南极海洋性区域定殖的入侵维管植物，但其在该区域成功入侵的机制尚未阐明。本研究旨在探究一年生早熟禾的入侵性及其与本土南极发草（Deschampsia antarctica）的竞争力是否受种子真菌内生菌共生关系的影响，同时比较来自全球四大宏观区域（南极海洋性区域、亚南极区域（sub-Antarctica）、南美洲及欧洲）的种子繁育的植株在生长表现上是否存在差异。 研究测定了从上述四大宏观区域采集的一年生早熟禾种子中的内生菌定殖频率；在实验室条件下，分别检测了未被内生菌定殖和已被定殖的种子繁育出的一年生早熟禾植株的萌发率、存活率、生物量积累、开花量，以及其与南极发草的竞争力；此外，本研究还利用当地采集的种子，在南极海洋性区域的自然环境中评估了内生菌对一年生早熟禾种子萌发、存活率及幼苗渗透保护能力的影响。 结果显示，南极海洋性区域种子中的内生菌定殖频率至少是南美洲、欧洲及亚南极区域种子的两倍。仅当种子来源于南极海洋性区域时，被内生菌定殖的种子的萌发率和存活率均高于未被定殖的种子；种子内生菌的存在可提升一年生早熟禾与南极发草的竞争力，但该效应仅体现在由南极海洋性区域种子繁育的植株中。野外实验结果表明，来自南极海洋性区域的被内生菌定殖的种子，其萌发率和存活率均高于未被定殖的种子，且由定殖种子繁育的幼苗的渗透保护能力更强。 本研究结果表明，种子真菌内生菌可对一年生早熟禾的入侵相关性状产生有益影响，包括存活率、萌发成功率及开花量。结合助力定殖过程的营养生长与生殖性状，种子-真菌内生菌共生可作为解释一年生早熟禾在南极海洋性区域入侵性的重要因素。