Rojas-Solis Daniel, Rodríguez Yolanda Magdalena García, Larsen John, Santoyo Gustavo, Lindig-Cisneros Roberto
Laboratorio Nacional de Innovación Ecotecnológica para la Sustentabilidad, Instituto de Investigaciones en Ecosistemas y Sustentabilidad, Universidad Nacional Autónoma de México, Morelia, Michoacán, Mexico.
Laboratorio de Diversidad Genómica, Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edifcio A1', Ciudad Universitaria, 58063, Morelia, Michoacán, Mexico.
Curr Microbiol. 2025 Aug 6;82(9):438. doi: 10.1007/s00284-025-04393-w.
In this study we evaluated plant growth promotion (PGP) traits of bacteria associated with maize (Zea mays L.) including Pseudomonas sp. (TL36), Staphylococcus sp. (TL49), Gottfriedia sp. (TL52), and Bacillus sp. (TL80), isolated from mining tailings, when exposed to mercury and arsenic. Initially, the response of the bacteria to the heavy metals studied were evaluated in in vitro assays, showing regular-moderate tolerance to arsenic and low tolerance to mercury. Also plant growth promotion traits of the bacteria were studied in in vitro assays in terms of production of indole-3-acetic acid (IAA), phosphate solubilization, siderophores and biofilm when exposed to arsenic and mercury. In addition, production of volatile organic compounds by the four bacteria were measured. In general, bacterial PGP traits were maintained when exposed to arsenic though some differences were observed between bacteria and individual PGP trait. On the other hand, all the PGP traits were strongly reduced when exposed to mercury for all bacteria. Also, the compatibility between the four bacteria was examined in vitro. From the abovementioned results two consortia were established based on the TL36 and TL80 (consortium 1) and, TL49 and TL52 consortium 2, which were tested for plant growth promotion after single or multiple inoculations in maize exposed to arsenic and mercury. Single and multiple inoculation, with consortium 1 with Pseudomonas sp. and Bacillus sp. increased maize plant growth similarly, while on the other hand, consortium 2 with Staphylococcus sp. and Gottfriedia sp. had no effect on maize plant growth. Despite the observed moderate tolerance to arsenic of bacteria in consortium 1, the observed plant growth promotion was mitigated in the presence of arsenic.
在本研究中，我们评估了从采矿尾矿中分离出的与玉米（Zea mays L.）相关的细菌的植物生长促进（PGP）特性，这些细菌包括假单胞菌属（TL36）、葡萄球菌属（TL49）、戈特弗里德菌属（TL52）和芽孢杆菌属（TL80），研究了它们在接触汞和砷时的情况。最初，在体外试验中评估了这些细菌对所研究重金属的反应，结果显示它们对砷具有中等耐受性，对汞耐受性较低。此外，还在体外试验中研究了这些细菌在接触砷和汞时的吲哚 - 3 - 乙酸（IAA）产生、磷溶解、铁载体和生物膜等植物生长促进特性。另外，还测定了这四种细菌产生挥发性有机化合物的情况。总体而言，当接触砷时，细菌的PGP特性得以保持，不过在细菌和个别PGP特性之间观察到了一些差异。另一方面，当所有细菌接触汞时，所有PGP特性都大幅降低。此外，还在体外检测了这四种细菌之间的兼容性。根据上述结果，基于TL36和TL80组建了一个组合（组合1），基于TL49和TL52组建了组合2，在接触砷和汞的玉米中进行单次或多次接种后，对它们促进植物生长的能力进行了测试。组合1中的假单胞菌属和芽孢杆菌属进行单次和多次接种对玉米植株生长的促进作用相似，而另一方面，组合2中的葡萄球菌属和戈特弗里德菌属对玉米植株生长没有影响。尽管观察到组合1中的细菌对砷具有中等耐受性，但在有砷存在的情况下，观察到的植物生长促进作用有所减弱。
