意大利青霉（Penicillium itallicum，PI）是导致柑桔采后损失的最重要致病真菌之一，当前针对柑橘青霉病的防腐保鲜剂因耐药性、安全性、防腐效果等问题在使用逐渐受到限制，从生物源中寻找安全、高效、低毒和低残留的新型抑菌成分并解析其作用机理是柑桔采后保鲜领域的重要发展方向。前期研究中，项目申请者从落羽杉内生真菌代谢产物中发现了一类能高效抑制柑橘青绿霉病的新三糖酯（6-O-β-L-甘露糖基海藻糖酯，MTE)，它们骨架新，易降解。本项目拟采用植物化学、生物化学和分子生物学方法，主要从细胞壁和细胞膜代谢调控角度研究MTE抑制PI的机理。主要研究内容包括：MTE对PI抑菌效果和安全性评价；MTE抑制PI的形态学基础；抑制PI生长的调控网络解析；抑制PI细胞壁合成和细胞膜合成的作用机制。研究结果可为新型寡糖酯抗青霉药物研发和MTE后续结构优化提供理论依据，具有重要的科学意义和应用价值。

Citrus blue and green mold caused by of Penicillium pathogenic fungi is one of the most common and serious citrus diseases during postharvest storage and transportation. The challenge of drug-resistance and public concern of pesticide residue requires an immediate development of antifungal agents with novel structure, novel mechanism of action, high efficiency, low toxicity and low residue. Historical records of fighting against pathogenic fungi suggest the need for effective development in novel antifungal agents with new targets and new mechanism of action to address the challenges of fungal drug-resistance. .In previous research, applicant has identified eight novel 6-O-β-L-mannopyranosyltrehalose esters, MTE-I~VIII, from an endophytic fungi, Pezicula sp. SC1337. Structures of these compounds are simple but unique, with carbon scaffolds completely different from existing antifungal drugs. In vitro and in vivo experiments showed that they had significant antagonistic activity against three main pathogenic fungi of citrus, citrus blue mold, citrus green mold, and citrus sour rot, caused by P. italicum, P. digitatum and Geotrichum citri-aurantii respectively. These compounds display similar or even improved antifungal activities to the existing pesticide antifungal agents. This project aims to unravel the underlying molecular mechanisms of action for these novel antifungal compounds, and to find the potential targets of MTE against P. itallicum by using micro technology, proteomics and molecular biology methods. Accomplishment of this project will clearly aid in the development of structure optimization of MTE and its analogues, and will help with the development of novel biological antifungal oligosaccharide ester agents against Penicillium.