Agrobacterium tumefaciens, a soil-born phytopathogenic bacterium, is well known as a nature's engineer due to its ability to genetically transform the host by transferring a DNA fragment (called T-DNA) from its Ti plasmid to host-cell genome. To combat the harsh soil environment and seek the appropriate host, A. tumefaciens can sense and be attracted by a large number of chemical compounds released by wounded host. As a member of α-proteobacterium, A. tumefaciens has a chemotaxis system different from that found in Escherichia coli, since many chemoattractants for A. tumefaciens chemotaxis are virulence (vir) inducers. However, advances in the study of the chemotaxis paradigm, E. coli chemotaxis system, have provided enough information to analyze the A. tumefaciens chemotaxis. At low concentration, chemoattractants elicit A. tumefaciens chemotaxis and attract the species to the wound sites of the host. At high concentration, chemoattractants induce the expression of virulence genes and trigger T-DNA transfer. Recent studies on the VirA and ChvE of the vir-induction system provide some evidences to support the crosstalk between chemotaxis and vir-induction. This review compares the core components of chemotaxis signaling system of A. tumefaciens with those observed in other species, discusses the connection between chemotaxis and vir-induction in A. tumefaciens, and proposes a model depicting the signaling crosstalk between chemotaxis and vir-induction.

根癌土壤杆菌（Agrobacterium tumefaciens）是一种土壤致病的植物病原细菌，由于其能够通过将其Ti质粒中的DNA片段（称为T-DNA）转移至宿主细胞基因组而对宿主进行遗传转化的能力，因此被公认为自然界的工程师。为了对抗恶劣的土壤环境并寻找合适的宿主，根癌农杆菌可以感觉到并被受伤宿主释放的大量化学化合物所吸引。作为α-变形杆菌的成员，根癌农杆菌的趋化性系统不同于大肠杆菌，因为许多根癌农杆菌的趋化性趋化因子都是毒力（vir）诱导剂。然而，化学趋化范式的研究进展，大肠杆菌趋化系统已经提供了足够的信息来分析根癌农杆菌的趋化性。在低浓度下，化学吸引剂引起根癌农杆菌趋化性并将该种吸引至宿主的伤口部位。在高浓度下，化学吸引剂诱导毒性基因的表达并触发T-DNA转移。关于vir诱导系统的VirA和ChvE的最新研究提供了一些证据来支持趋化性和vir诱导之间的串扰。这篇综述比较了根癌农杆菌的趋化信号系统的核心组件与其他物种中观察到的那些，讨论了趋化与病毒之间的联系。-induction在根癌农杆菌，并提出一个模型描绘趋化之间的信号串扰VIR -induction。