Comparative mechanistic elucidation of adaptation of Sporisorium reilianum to its host plants maize and sorghum

植物定殖真菌对新寄主的适应是新出现的植物病原真菌的主要来源之一。虽然已知活体营养真菌紧密适应其宿主，并且通常对特定的宿主植物具有特异性，但在黑穗病真菌的进化过程中，宿主跳跃是相当常见的。允许宿主植物适应菌株交换宿主的机制尚不清楚。阐明适应性寄主定殖的机制对于制定保护作物免受未来威胁的策略是必要的。转基因黑穗病菌Sporisorium reilianum最近将宿主从高粱换成了玉米。今天，两个特殊的形式已经被确认，S。瑞利安湖sp.reilianum（SRS）和高粱高致病力病原菌S.瑞利安湖sp. zeae（SRZ）是一种中等致病力的玉米病原菌。在实验室中，SRS和SRZ菌株可以形成对两种宿主植物都具有弱感染性的杂交种。我们想利用实验进化，通过植物反复对自然和杂交菌株施加选择压力。进化菌株将使用基因组、转录组和染色质免疫沉淀测序与起始菌株进行比较，以探索对新宿主植物的适应是否涉及缓慢但稳定的遗传变化、适应性表观遗传变化，或者是杂交的结果。

Adaptation of plant-colonizing fungi to novel hosts is one of the major sources of newly emerging fungal plant pathogens. Although biotrophic fungi are known to tightly adapt to their hosts and often are specific to one particular host plant, host jumps were quite common during evolution of the smut fungi. The mechanisms allowing host-plant adapted strains to swap hosts are unclear. Mechanistic elucidation underlying adaptive host colonization is necessary for the development of protection strategies of our crop plants from tomorrows threats. The genetically amenable smut fungus Sporisorium reilianum has recently swapped host from sorghum to maize. Today, two formae speciales have been recognized, S. reilianum f. sp. reilianum (SRS), a highly virulent pathogen of sorghum, and S. reilianum f. sp. zeae (SRZ), a moderately virulent pathogen of maize. In the laboratory, strains of SRS and SRZ can form hybrids that are weakly infectious on both host plants. We want to use Experimental Evolution by repeatedly subjecting natural and hybrid strains to selection pressure by the plant. Evolved strains will be compared to starting strains using genome, transcriptome and chromatin immunoprecipitation sequencing to explore whether adaptation to a new host plant involves slow but stable genetic changes, adaptive epigenetic changes, or is the result of hybridization.