Fic蛋白催化的单磷酸核苷化修饰是现代生物科学中蛋白翻译后加工的研究热点，但除了少数致病性相关的Fic蛋白作用机制和靶标蛋白已知外，大量Fic蛋白的功能和其发挥功能的解阻遏条件尚无研究报道。前期研究发现生防假单胞菌2P24中的fic-1基因影响菌株防病效果，在大肠杆菌和假单胞菌中表达都会造成质粒拷贝数下降和细胞形态丝状化改变。本项目拟通过遗传和生化手段阐明Fic-1的互作靶标及对靶蛋白修饰的生化机制，初步明确Fic-1调控的下游基因及其影响菌株环境适应能力和生防效果的可能途径。通过构建新的遗传筛选体系，找到可激活Fic-1功能的环境因子和调控基因。上述研究结果一方面可帮助我们明确Fic-1蛋白在菌株2P24生防功能表达和调控中的作用，加深对生防菌适应复杂环境策略的理解；另一方面，研究结果还对基础生物学中诸如细菌的形态变化机制、DNA的复制调控等研究有重要参考意义。

Protein modification after translation by Fic (Filamentation induced by cyclic AMP)-mediated NMPylation is a research hotspot in modern life sciences. Despite of a few Fic proteins involved in bacterial virulence, our understanding of Fic proteins, particularly the “housekeeping” Fic proteins that appear to conserve among diverse bacteria, is still very limited. Our previous study on disease-suppressive bacterium Pseudomonas fluorescens 2P24 revealed a Fic family member gene, fic-1, which is involved in the regulation of bacterial cell filamentation, plasmid DNA duplication and biocontrol activities against pathogenic microbes on plants. This project focuses on identification of target proteins of Fic-1, elucidation of the biochemical mechanism of Fic-1 action on its target, and discovery of downstream genes which regulated by Fic-1 and contribute to bacterial adaption and disease suppression in the changing environments. We will further establish highly efficient strategies to identify the environmental and genetic components of the signaling cascade responsible for the activation of Fic-1 protein. The predicted results not only help us to understand the Fic-1-mediated pathway that enhances the bacterial adaptive capacity upon environmental stresses, but also provide us novel cues to understand the important cell processes in basic biology, such as cell morphological changes and regulation of DNA replication.