共生根瘤菌在豆科植物宿主根瘤中的固氮是农业生产中使用化学合成肥料的另一种重要选择。因此通过研究这些植物-细菌互作可为一个具有经济竞争力且环境友好的可持续农业作出贡献。然而共生固氮有宿主特异性限制了其的普遍应用。由此对根瘤共生相关分子机制的了解是农业应用的基础。本项目我们拟对与花生结瘤的慢生型根瘤菌菌株SYSU49的两个III型效应因子进行研究。我们计划：(a)分析效应因子进入植物细胞里的分泌和转运；(b)确定效应因子在植物细胞内的亚细胞定位；(c)在植物细胞中表达效应因子并分析宿主总转录组；(d) 体外研究效应因子的活性；(e)研究不同效应因子突变株的因子活性；(f) 鉴定因子靶标蛋白；(g) 研究效应因子在与豆科植物共生中的功能。所获得的结果将有助于加深我们对细菌是如何感染植物并模仿宿主蛋白操纵宿主细胞从而有利于对病原体这方面的了解。

Nitrogen fixation of symbiotic rhizobial bacteria in root nodules of legume host plants is an important alternative for the use of synthetic fertilizers in agriculture. Enhancing these plant-bacteria interactions through research will contribute to an economically competitive and environmental friendly agriculture. Hence, the understanding of molecular mechanisms underlying the nodule symbiosis forms a basis for improvement of biological nitrogen fixation in agriculture. Here, we propose research on two type 3 effector proteins of the peanut-nodulating strain Bradyrhizobium sp. strain SYSU49. We plan: (a) to analyze effector secretion and translocation into plant cells, (b) to determine subcellular localization of the effectors within plant cells, (c) to express the effectors within plants and analyze the host trancriptome, (d) to identify effector activities in vitro, (e) to study effector activities of mutated effector variants, (f) to identify plant target proteins, and (g) to study effector function during symbiosis with host legumes. The obtained results will contribute to our general understanding of how bacteria infect plants and mimic host proteins to manipulate the host cell for the pathogen's benefit.