A novel 3-oxoacyl-ACP reductase (FabG3) is involved in the xanthomonadin biosynthesis of Xanthomonas campestris pv. campestris
A novel 3-oxoacyl-ACP reductase (FabG3) is involved in the xanthomonadin biosynthesis of Xanthomonas campestris pv. campestris
复制标题
一种新型 3-氧代酰基-ACP 还原酶 (FabG3) 参与 Xanthomonas Campestris pv. 的黄单胞菌素生物合成。
DOI：
10.1111/mpp.12871
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发表时间：
2019
影响因子：
4.9
通讯作者：
Wang Haihong
中科院分区：
文献类型：
--
作者：
Yu Yonghong;Ma Jianrong;Guo Qiaoqiao;Ma Jincheng;Wang Haihong
野油菜黄单胞菌（Xanthomonascampestrispv.campestris，Xcc）是十字花科植物黑腐病的病原菌，它产生一种膜结合的黄色色素，称为黄单胞菌素（xanthomonadin），以防止光生物学和过氧化损伤，并利用由扩散信号因子（DSF）家族信号介导的群体感应机制来调节毒力因子的产生。Xcc基因XCC 4003（Xcc fabG 3）位于猪簇中，可能与黄单胞菌素的合成有关。我们报道了在非允许条件下，FabG 3的表达恢复了大肠杆菌FabG温度敏感突变株CL 104的生长。体外试验表明，FabG 3催化脂肪酸合成反应中3-氧代酰基-酰基载体蛋白（ACP）中间体的还原，尽管FabG 3的活性低于FabG 1。此外，fabG 3缺失不影响生长或脂肪酸组成。这些结果表明，Xcc fabG 3编码3-氧代酰基-ACP还原酶，但不是生长或脂肪酸合成所必需的。然而，Xcc fabG 3敲除突变体消除了黄单胞菌素的产生，这只能由野生型fabG 3恢复，而不能由其他3-氧代酰基-ACP还原酶编码基因恢复，表明Xcc FabG 3特异性地参与黄单胞菌素的生物合成。此外，我们的研究还表明，Xcc fabG 3-破坏突变体影响Xcc在宿主植物中的毒力。
Xanthomonas campestrispv.campestris(Xcc), the causal agent of black rot in crucifers, produces a membrane‐bound yellow pigment called xanthomonadin to protect against photobiological and peroxidative damage, and uses a quorum‐sensing mechanism mediated by the diffusible signal factor (DSF) family signals to regulate virulence factors production. TheXccgene XCC4003, annotated asXcc fabG3, is located in thepigcluster, which may be responsible for xanthomonadin synthesis. We report thatfabG3expression restored the growth of theEscherichia coli fabGtemperature‐sensitive mutant CL104 under non‐permissive conditions.In vitroassays demonstrated that FabG3 catalyses the reduction of 3‐oxoacyl‐acyl carrier protein (ACP) intermediates in fatty acid synthetic reactions, although FabG3 had a lower activity than FabG1. Moreover, thefabG3deletion did not affect growth or fatty acid composition. These results indicate thatXcc fabG3encodes a 3‐oxoacyl‐ACP reductase, but is not essential for growth or fatty acid synthesis. However, theXcc fabG3knock‐out mutant abolished xanthomonadin production, which could be only restored by wild‐typefabG3, but not by other 3‐oxoacyl‐ACP reductase‐encoding genes, indicating thatXccFabG3 is specifically involved in xanthomonadin biosynthesis. Additionally, our study also shows that theXcc fabG3‐disrupted mutant affectsXccvirulence in host plants.