LaeA转录因子调控层出镰刀菌中伏马毒素生物合成的分子机理研究

Fumonisins, as one of the major mycotoxins, are not only considered to be a carcinogen and tumor activator in animal and human, but also involved with fungal infection. Therefore, clarifying its biological formation and regulation mechanism has theoretical and practical significance in reducing fungal disease and mycotoxin contamination risk and ensuring food safety. LaeA transcription factors (TFs) have been proven to play an essential role in the regulation of secondary metabolism and virulence of filamentous fungi. Our previous research have found that different carbon sources could regulate fumonisin biosynthesis and expressions of some LaeA genes. The project is to investigate transcriptional regulation of FUM by LaeA during fumonisin biosynthesis using Fusarium proliferatum, the most serious pathogenic fungi of banana fruit. The following issues will be studied: 1) identification of LaeA which possibly regulate the transcription of fumonisin biosynthesis related genes; 2) analysis of the regulation properties and regulation network of the identified LaeA; 3) verification of the role of LaeA using gene knock-out technology; 4) confirming the relationship between fumonisin production and infection ability of Fusarium proliferatum. The results will contribute to illuminate the molecular mechanism of fumonisin biosynthesis from the viewpoint of transcriptional regulation and provide some basic information for the biological role of fumonisin. Meanwhile, the results will improve our understanding of the regulation mechanism of fumonisin biosynthesis and infection mechanism of Fusarium proliferatum. In all, the results are useful in providing theoretical basis for the proposed new control strategies of mycotoxin contamination and fungal infection.

伏马毒素作为主要的真菌毒素之一，不仅能导致许多人畜疾病，还与真菌侵染相关。因此，探索伏马毒素生物合成的分子调控机制对减少真菌病害和真菌毒素污染，确保食品安全具有很重要的理论和实际意义。LaeA转录因子在丝状真菌次生代谢物生物合成和侵染过程中发挥重要的调控作用。申请人前期研究发现，不同碳源处理能够影响层出镰刀菌伏马毒素产量和LaeA的表达。本项目以香蕉采后重要致病菌层出镰刀菌为材料，研究LaeA对伏马毒素生物合成的转录调控作用，主要内容包括：1）鉴定对伏马毒素生物合成起转录调控的LaeA；2）分析层出镰刀菌LaeA的转录调控特性和调控网络；3）LaeA的功能验证；4）确定伏马毒素与层出镰刀菌侵染的关系。研究结果有望从转录调控角度阐明伏马毒素生物合成的分子调控机制，并初步明确伏马毒素的生物学功能，完善伏马毒素生物合成的调控机制和层出镰刀菌的侵染机制，为提出控制毒素残留和真菌侵染提供理论依据。

伏马毒素作为主要的真菌毒素之一，不仅能导致许多人畜疾病，还与真菌侵染相关。因此，探索伏马毒素生物合成的分子调控机制对减少真菌病害和真菌毒素污染，确保食品安全具有很重要的理论和实际意义。LaeA转录因子在丝状真菌次生代谢物生物合成和侵染过程中发挥重要的调控作用。本项目以香蕉采后重要致病菌层出镰刀菌为材料，筛选层出镰刀菌中调控伏马毒素生物合成的关键LaeA转录因子，分析LaeA的转录调控方式及调控网络，揭示LaeA调控伏马毒素生物合成的分子机制；通过分析层出镰刀菌伏马毒素产量与致病力的关系，并通过外源伏马毒素处理香蕉果实后接种层出镰刀菌，确定伏马毒素与层出镰刀菌侵染的关系，并探究伏马毒素介导层出镰刀菌侵染香蕉果实的可能机制。获得主要研究结果包括：1）筛选到了潜在的与伏马毒素生物合成相关的LaeA转录因子；2）发现缺乏碳源促进层出镰刀菌伏马毒素的生物合成，香蕉果皮不同细胞壁成分或不同成熟度的香蕉果皮多糖提取物做为碳源也能调控伏马毒素的生物合成，推测伏马毒素的产生是真菌响应外界逆境环境的一种重要策略，同时伏马毒素也是层出镰刀菌应对宿主细胞壁防御时的重要响应物质，而在此过程中，LaeA转录因子可能参与其中；3）成功构建层出镰刀菌酵母双杂文库，初步筛选LaeA互作蛋白，主要包括F-box and WD-40 domain-containing protein，nuclear localization protein NPL6，helix-loop-helix protein；同时利用蛋白组学，筛选出与LaeA表达趋势一致的关键蛋白，进一步分析层出镰刀菌LaeA的调控网络；4）获得LaeA的抗体，有助于进一步研究LaeA的转录调控特性；5）伏马毒素与胞外分泌蛋白可能存在互补的作用；6）通过伏马毒素处理香蕉果实，确定伏马毒素处理能够促进层出镰刀菌对香蕉果实的侵染，初步明确伏马毒素的生物学意义；7）发表SCI论文8篇，获得一项国际发明专利，培养研究生2名。本项目研究结果进一步阐明伏马毒素生物合成的分子调控机制，明确伏马毒素的生物学功能，完善层出镰刀菌的侵染机制，为提出控制毒素残留和真菌侵染提供理论依据。