真菌与超过80%的植物之间存在共生关系。病原真菌可通过直接从植物获取蔗糖作为有效避开植物免疫的途径之一，而有益真菌直接获取蔗糖的目的暂不清楚。另一方面，蔗糖转运蛋白参与共生真菌细胞的蔗糖获取，在不同进化类群真菌中发挥不同功能。目前，对早期分歧进化有益真菌的蔗糖代谢及蔗糖转运蛋白的功能研究未见报道。球托霉菌w5属于早期分歧进化的Mucoromycotina亚门真菌。我们前期研究显示，w5可促进植物生长，其在侵染和定植植物根系时，可能通过功能未知的2个新型蔗糖转运蛋白，转运植物来源蔗糖进入细胞质并代谢利用。在此基础上，本项目拟采用分子生物学方法，结合生物信息学及多组学分析，明晰w5菌株细胞内2个蔗糖转运蛋白基因在与植物互作过程中的转录规律，以及各蛋白成员性质，揭示它们在w5侵染植物根系及与植物互作中发挥的生物学功能，为共生真菌-植物互作研究提供新证据，也为推进w5在农业生产中的应用奠定基础。

Fungi form symbiosis with more than 80% of living plant species. Pathogenic fungi usually directly uptake photosynthetic carbon sucrose to avoid eliciting apparent host defense responses. However, the purpose of direct sucrose uptake by the beneficial fungi is still unknown. On the other hand, sucrose transporters are involved in sucrose uptake and transport in fungal cells. They play different roles in fungi from different Eumycotina. Till now, little knowledge has gained on early diverging fungi regarding to their sucrose utilization and the function of their sucrose transporters. Gongronella sp. w5 is an early diverging fungus that belongs to Mucoromycotina. Previously, our results showed that w5 promotes plant growth. It may directly uptake sucrose from plant during root penetration by using two sucrose transporters that are functionally different from the known fungal sucrose transporters. Based on these results, in this proposal, we plan to identify and characterize the sucrose transporters in w5. Furthermore, we plan to verify the functions and significance of these sucrose transporters during plant-fungal symbiosis. Our results will provide new evidences for plant-fungal symbiosis and will facilitate the further application of w5 in agriculture industries.