Centro de Investigación La Libertad, Corporación Colombiana de Investigación Agropecuaria - Agrosavia, Villavicencio, Meta, Colombia.
Facultad de Ciencias Agrarias, Universidad Nacional de Colombia, Bogotá, Colombia.
World J Microbiol Biotechnol. 2023 Sep 2;39(11):297. doi: 10.1007/s11274-023-03719-9.
Tomato vascular wilt caused by Fusarium oxysporum f. sp. lycopersici (Fol) is one of the most limiting diseases of this crop. The use of fungicides and varieties resistant to the pathogen has not provided adequate control of the disease. In this study, siderophore-producing bacteria isolated from wild cocoa trees from the Colombian Amazon were characterized to identify prominent strategies for plant protection. The isolates were taxonomically classified into five different genera. Eight of the fourteen were identified as bacteria of the Acinetobacter baumannii complex. Isolates CBIO024, CBIO086, CBIO117, CBIO123, and CBIO159 belonging to this complex showed the highest efficiency in siderophore synthesis, producing these molecules in a range of 91-129 µmol/L deferoxamine mesylate equivalents. A reduction in disease severity of up to 45% was obtained when plants were pretreated with CBIO117 siderophore-rich cell-free supernatant (SodSid). Regarding the mechanism of action that caused antagonistic activity against Fol, it was found that plants infected only with Fol and plants pretreated with SodSid CBIO117 and infected with Fol showed higher levels of PR1 and ERF1 gene expression than control plants. In contrast, MYC2 gene expression was not induced by the SodSid CBIO117 application. However, it was upregulated in plants infected with Fol and plants pretreated with SodSid CBIO117 and infected with the pathogen. In addition to the disease suppression exerted by SodSid CBIO117, the results suggest that the mechanism underlying this effect is related to an induction of systemic defense through the salicylic acid, ethylene, and priming defense via the jasmonic acid pathway.
番茄黄萎病由尖孢镰刀菌番茄专化型（Fol）引起，是这种作物最具限制的病害之一。杀菌剂的使用和对病原体具有抗性的品种并没有为该疾病的防治提供充分的控制。在这项研究中，从哥伦比亚亚马逊地区的野生可可树中分离出的产铁载体细菌被用来鉴定具有保护植物的突出策略。分离物被分类为五个不同的属。其中 14 个分离物中有 8 个被鉴定为鲍曼不动杆菌复合体的细菌。属于该复合体的 CBIO024、CBIO086、CBIO117、CBIO123 和 CBIO159 这四个分离物在铁载体合成方面表现出最高的效率，产生这些分子的范围为 91-129 µmol/L 去铁胺甲磺酸盐当量。当用富含 CBIO117 铁载体的无细胞上清液（SodSid）预处理植物时，可获得高达 45%的疾病严重程度降低。关于对 Fol 产生拮抗活性的作用机制，发现仅感染 Fol 的植物和用 SodSid CBIO117 预处理并用 Fol 感染的植物与对照植物相比，PR1 和 ERF1 基因的表达水平更高。相比之下，SodSid CBIO117 的应用没有诱导 MYC2 基因的表达。然而，在感染 Fol 的植物和用 SodSid CBIO117 预处理并用病原体感染的植物中，该基因的表达上调。除了 SodSid CBIO117 发挥的疾病抑制作用外，这些结果表明，这种效应的作用机制与通过水杨酸、乙烯和茉莉酸途径的启动防御来诱导系统防御有关。
