植物益生解淀粉芽孢杆菌VII型分泌系统影响根际定殖的机理研究

有效根际定殖是根际益生菌发挥促生和生防等作用的前提，而根际益生菌的根际定殖主要受根系分泌物和植物免疫等宿主环境因素的影响。细菌的独特分泌系统是增强其环境生存定殖的重要工具，前期研究发现根际益生解淀粉芽孢杆菌SQR9的VII型分泌系统缺失会导致其根际定殖显著降低，然而，VII型分泌系统对芽孢杆菌根际定殖的作用机理还不清楚。初步研究表明VII型分泌系统与SQR9对植物根系分泌物的利用有关，并且参与影响植物免疫，因此，本研究将深入探究解淀粉芽孢杆菌SQR9中T7SS影响根系分泌物利用和植物免疫的机制，并进而阐明VII型分泌系统影响解淀粉芽孢杆菌SQR9根际定殖的机制。本研究结果将首次揭示芽孢杆菌中VII型分泌系统的生理功能，并能够在农业生产上为芽孢杆菌的合理应用提供理论技术依据。

Efficient rhizosphere colonization of beneficial rhizobacteria is prerequisite to exert their function of growth promotion and biocontrol. The rhizosphere colonization of the beneficial bacteria is mainly affected by the surrounding environment factors, such as root exudates and host plant immunity. The unique secretion systems of bacteria are important tools for survival and colonization, preliminary study showed that deletion of the type VII secretion system in the rhizospheric beneficial Bacillus amyloliquefaciens SQR9 led to significant decreasing of colonization in rhizosphere, however, the mechanism that type VII secretion system affects colonization of B. amyloliquefaciens SQR9 is not clear. Previous study showed that type VII secretion system is involved in root exudates utilization by SQR9 and affecting plant immunity. In this study, the mechanisms of type VII secretion system affecting utilization of root exudates and regulation of plant immunity will be investigated, and then the mechanisms that type VII secretion system affecting the colonization of SQR9 will be clarified. This study will reveal the physiological function of type VII secretion system in Bacillus for the first time and technically support the application of Bacillus in agriculture.