Genetic and ecological drivers of successful bioinvasion by Gracilaria vermiculophylla

自20世纪80年代以来，亚洲特有的红藻虎尾藻（Gracilaria vermiculophylla）入侵大西洋和东太平洋沿岸，对群落结构和生态系统功能造成了严重影响。尽管生态生理和化学研究表明，某些生态性状和对捕食者的化学防御对其快速的全球入侵有重要贡献，但尚未有研究揭示遗传和/或表观遗传变异以及对新环境条件的驯化/适应速度是否解释了大规模入侵的成功。我们建议阐明蛭状芽孢菌入侵的生态遗传机制。中方的目标将包括：(1)通过转录组学鉴定本地和入侵种群中具有不同表达谱的基因，并分析这些基因如何促进对各种新环境的生态适应；(2)使用AFLP基因分型评估本地和入侵种群及其之间的遗传多样性；(3)检测特定线粒体单倍型G. vermiculophylla （H6）内的表观遗传变异；(4)在种群水平上检测遗传转移，表明健壮基因型在入侵胁迫条件下的选择性生存。在德国方面，目标将是(1)确定本地种群和入侵种群对环境压力是否表现出不同的耐受宽度，(2)评估本地种群和入侵种群之间压力敏感性（适应的基础）的种内变异量。(3)比较本地种群和入侵种群对新环境条件的驯化/适应速率（即速度）；(4)研究相关微生物在调节宿主对应激反应中的作用。该联合项目不仅将全面了解海藻成功入侵的遗传和生态机制，还将有助于开发更有效的候选入侵海藻监测管理，从而减轻和预防全球范围内的海藻入侵。

The Asia-endemic red alga Gracilaria vermiculophylla invaded the Atlantic and Eastern Pacific coasts since the 1980s and has imposed drastic impacts on community structure and ecosystem function. Although eco-physiological and chemical studies revealed that some ecological traits and chemical defense to predators made considerable contribution to its rapid global invasion, no studies were conducted to reveal whether genetic and/or epigenetic variations and the rate of acclimation/adaptation to new environmental conditions account for the large-scale invasion success of G. vermiculophylla. We propose to elucidate the eco-genetic mechanisms behind the invasion of G. vermiculophylla. The aims of the Chinese side will include (1) the identification of genes with distinct expression profiles in native and invasive populations by transcriptomics and the analysis of how these genes contribute to the ecological adaptation to a wide range of novel environments, (2) the assessment of genetic diversity in and between native and invasive populations using AFLP genotyping, (3) the detection of epigenetic variation within the specific mitochondrial haplotype G. vermiculophylla (H6), which dominated the invasion of Atlantic and E Pacific coasts using MS-AFLP, and (4) the detection of genetic shifts at the population level that indicate selective survival of robust genotypes under stressful conditions during invasion. On the German side the aims will be (1) to determine whether native and invasive populations exhibit different tolerance widths towards environmental stress, (2) to assess the amount of intraspecific variance of stress sensitivity (the basis for adaptation) between native and invasive populations, (3) to compare the rate (i.e. speed) of acclimation/adaptation of native and invasive populations to new environmental conditions and (4) to investigate the role of associated microorganisms in the modulation of host responses to stress. The joint project will not only provide a comprehensive understanding of genetic and ecological mechanisms underlying successful seaweed invasion, but also help to develop a more effective monitoring management for candidate invasive seaweeds, which will mitigate and prevent seaweed invasions worldwide.