Transposon-mediated telomere destabilization: a driver of genome evolution in the blast fungus

We hypothesize that the subtelomere regions are the main factories of fungal genome evolution, where recurrent bouts of telomere crisis provide the fuel for raw materials recruitment and telomere rescue pathways act to generate novel sequences. Furthermore, we suspect that enhanced rates of nucleotide substitution/indel polymorphism in the subtelomeric regions may further accelerate the neo-functionalization of captured sequences.The overall goal of this project is to gain an improved understanding of subtelomere-internal genome sequence exchange, as it relates to fungal genome structure and niche adaptation. Specific objectives include: 1. Characterize the structural and genic diversity of Pyricularia (syn. Magnaporthe) oryzae chromosome ends; 2. Assess the impact of telomere dynamics on genome evolution; 3. Examine genome reorganization following spontaneous or experimentally-induced telomere crisis events.

我们提出假说：亚端粒区（subtelomere regions）是真菌基因组演化的核心场所，周期性发生的端粒危机为原始遗传素材的招募提供动力，端粒拯救通路则负责生成全新序列。此外，我们推测亚端粒区中升高的核苷酸替换/插入缺失（indel）多态性速率，可进一步加速所捕获序列的新功能化进程。本项目的总体目标是深化对亚端粒区与基因组内部之间序列交换的认知，该过程与真菌基因组结构及生态位适应密切相关。具体研究目标包括：1. 解析稻瘟病菌（Pyricularia oryzae，异名Magnaporthe oryzae）染色体末端的结构与基因多样性；2. 评估端粒动态变化对基因组演化的影响；3. 探究自然发生或实验诱导的端粒危机事件后，基因组的重组模式。