Multiple horizontal mini-chromosome transfers drive genome evolution of clonal blast fungus lineages
Multiple horizontal mini-chromosome transfers drive genome evolution of clonal blast fungus lineages
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DOI：
10.1101/2024.02.13.580079
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发表时间：
2024-02
期刊：
影响因子：
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通讯作者：
A. C. Barragan;Sergio M. Latorre;Angus Malmgren;A. Harant;J. Win;Yu Sugihara;Hernán A. Burbano;S. Kamoun;Thorsten Langner
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作者：
A. C. Barragan;Sergio M. Latorre;Angus Malmgren;A. Harant;J. Win;Yu Sugihara;Hernán A. Burbano;S. Kamoun;Thorsten Langner
农作物疾病的大流行往往是由无性繁殖的植物病原体的克隆谱系驱动的。这些克隆病原体如何持续适应它们的宿主，尽管具有有限的遗传变异，并且在没有有性重组的情况下仍然是难以捉摸的。在这里，我们揭示了水平染色体转移的流行性克隆谱系内的稻瘟病菌（Syn。梨孢属（Pyricularia）我们发现了一条水平转移的1.2Mb的额外小染色体，它在M.稻瘟病菌分离物来自稻瘟病菌谱系和感染印度牛筋草（Eleusine indica）的谱系，印度牛筋草是一种通常生长在栽培谷类作物附近的野生草。此外，我们表明，这个迷你染色体水平获得的克隆稻瘟病分离物通过至少9个不同的转移事件在过去的三个世纪。这些研究结果建立了水平微染色体转移作为一种机制，促进不同的主机相关的稻瘟病菌谱系之间的遗传交换。我们认为，感染野草的稻瘟菌种群作为遗传水库，驱动困扰谷类作物的大流行性克隆谱系的基因组进化。
Crop disease pandemics are often driven by clonal lineages of plant pathogens that reproduce asexually. How these clonal pathogens continuously adapt to their hosts despite harboring limited genetic variation, and in absence of sexual recombination remains elusive. Here, we reveal multiple instances of horizontal chromosome transfer within pandemic clonal lineages of the blast fungus Magnaporthe (Syn. Pyricularia) oryzae. We identified a horizontally transferred 1.2Mb supernumerary mini-chromosome which is remarkably conserved between M. oryzae isolates from both the rice blast fungus lineage and the lineage infecting Indian goosegrass (Eleusine indica), a wild grass that often grows in the proximity of cultivated cereal crops. Furthermore, we show that this mini-chromosome was horizontally acquired by clonal rice blast isolates through at least nine distinct transfer events over the past three centuries. These findings establish horizontal mini-chromosome transfer as a mechanism facilitating genetic exchange among different host-associated blast fungus lineages. We propose that blast fungus populations infecting wild grasses act as genetic reservoirs that drive genome evolution of pandemic clonal lineages that afflict cereal crops.