紫色紫孢菌营养胁迫诱导产孢的表观遗传机制研究

Asexual sporulation is the most common form of fungal reproduction. Starvation induced sporulation is also an important strategy of environmental adaptation. the nematophagous fungus Purpureocillium lavendulum (formally Paecilomyces lilacinus) is an important biocontrol agent of plant-parasitic nematodes. Our research showed that this fungus can produce asexual spores very early when the colony is very small when grown on PDA media. When we added the substance from the minimal media (MM) to PDA, or the histone H3K9 or H3K14 were mutated into alanine, the fungal colony were became bigger, while the spores produced were reduced. We proposed that the fungus may be stressed by starvation to some extent and produce spores when grown on PDA media, and this process of sporulation would be regulated epigenetically via histone modification. To confirm this proposal, we want to firstly confirm which substance were lacked in PDA, and then study the molecular function of its metabolism pathway in sporulation. Then we continue mutate H3K9 and H3K14 to simulate several epigenetic marks, such as methylation or acetylation. The histone modification enzymes were also studied to confirm which epigenetic mark were used by starvation to induce sporulation. The transcriptome analysis, ChIP - Seq, and mutation library screening will be also carried out to find more genes involved in regulating this sporulation process. The results of this project will help us more comprehensively understanding the molecular mechanism of lifestyle switching induced by starvation via epigenetic regulation and make a solid base for better bio-control of plant-parasitic nematodes.

分生孢子是丝状真菌普遍的繁殖方式，营养胁迫诱导的产孢是真菌适应环境的重要生存策略。线虫生防真菌紫色紫孢菌在PDA培养基上菌落生长受限并产孢，当在PDA中添加真菌基本培养基营养物质后菌落增大；突变组蛋白H3K9/K14后在PDA上菌落同样增大，产孢量降低。推测紫色紫孢菌在PDA上受一定程度的营养胁迫导致产孢且该过程依赖于表观遗传调控。为了研究该调控的分子机制，本项目首先筛选PDA中缺少的营养物质并研究其代谢通路的功能。对H3K9/K14进行突变以模拟甲基化或乙酰化等修饰，比较其与野生型菌株在不同培养基上的表型差异，同时对相应组蛋白修饰酶进行基因敲除，确定何种表观遗传修饰调控该产孢过程。通过转录组，ChIP-Seq和突变体库筛选，获得该调控通路的上下游基因。通过本项目的研究初步阐明营养胁迫如何通过表观遗传调控诱导真菌产孢，为深入理解食线虫真菌生活史转化的分子机制及线虫的生物防治奠定基础。

分生孢子是丝状真菌普遍的繁殖方式，营养胁迫诱导的产孢是真菌适应环境的重要生存策略。线虫生防真菌紫色紫孢菌在PDA培养基上菌落生长受限并产孢，当在PDA中添加真菌基本培养基营养物质后菌落增大；突变组蛋白H3K9/K14后在PDA上菌落同样增大，产孢量降低。推测紫色紫孢菌在PDA上受一定程度的营养胁迫导致产孢且该过程依赖于表观遗传调控。本项目首先筛选PDA中缺少的营养物质并研究其代谢通路的功能。对H3K9/K14进行突变以模拟甲基化或乙酰化等修饰，比较其与野生型菌株在不同培养基上的表型差异。通过转录组，ChIP-Seq和突变体库筛选，获得该调控通路的上下游基因。通过本项目的研究初步阐明营养胁迫如何通过表观遗传调控诱导真菌产孢，为深入理解食线虫真菌生活史转化的分子机制及线虫的生物防治奠定基础。通过项目的顺利实施，对紫色紫孢菌营养胁迫诱导产孢的表观遗传机制进行了深入的研究，对照预期研究目标以全部或超额完成既定任务。确定了PDA中缺少导致产孢的营养物质为氮源物质，硝酸铵，其它一些氮源物质的加入也可以影响紫色紫孢菌的生长和产孢。确定了紫色紫孢菌产孢过程中的关键表观遗传修饰为组蛋白H3K9甲基化，乙酰化和H3K14乙酰化，通过组学和分子生物学的研究初步阐明了调控机制。相关研究结果目前已发表SCI论文3篇，中文核心期刊论文1篇，待发表论文3篇。获授权国家发明专利2项，培养硕士研究生8名。