Instituto Superior de Investigaciones Biológicas (INSIBIO, CONICET-UNT) and Instituto de Química Biológica "Dr. Bernabé Bloj", Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, Chacabuco 461, T4000ILI, San Miguel de Tucumán, Tucumán, Argentina.
Department of Environmental Protection, Estación Experimental del Zaidín, CSIC, Granada, Spain.
Appl Microbiol Biotechnol. 2020 May;104(10):4577-4592. doi: 10.1007/s00253-020-10516-z. Epub 2020 Mar 27.
New strategies to improve crop yield include the incorporation of plant growth-promoting bacteria in agricultural practices. The non-pathogenic bacterium Pseudomonas putida KT2440 is an excellent root colonizer of crops of agronomical importance and has been shown to activate the induced systemic resistance of plants in response to certain foliar pathogens. In this work, we have analyzed additional plant growth promotion features of this strain. We show it can tolerate high NaCl concentrations and determine how salinity influences traits such as the production of indole compounds, siderophore synthesis, and phosphate solubilization. Inoculation with P. putida KT2440 significantly improved seed germination and root and stem length of soybean and corn plants under saline conditions compared to uninoculated plants, whereas the effects were minor under non-saline conditions. Also, random transposon mutagenesis was used for preliminary identification of KT2440 genes involved in bacterial tolerance to saline stress. One of the obtained mutants was analyzed in detail. The disrupted gene encodes a predicted phosphoethanolamine-lipid A transferase (EptA), an enzyme described to be involved in the modification of lipid A during lipopolysaccharide (LPS) biosynthesis. This mutant showed changes in exopolysaccharide (EPS) production, low salinity tolerance, and reduced competitive fitness in the rhizosphere.
提高作物产量的新策略包括将植物促生细菌纳入农业实践中。非致病性细菌恶臭假单胞菌 KT2440 是一种优秀的农业重要作物根际定殖菌，已被证明可以激活植物对某些叶部病原体的诱导系统抗性。在这项工作中，我们分析了该菌株的其他植物生长促进特性。我们表明它可以耐受高浓度的 NaCl，并确定盐度如何影响吲哚化合物的产生、铁载体合成和磷酸盐溶解等特性。与未接种的植物相比，在盐胁迫条件下，接种恶臭假单胞菌 KT2440 显著提高了大豆和玉米种子的萌发以及根和茎的长度，而在非盐胁迫条件下，这种影响较小。此外，还使用随机转座子诱变初步鉴定了 KT2440 基因参与细菌对盐胁迫的耐受。对获得的一个突变体进行了详细分析。该突变体破坏的基因编码一种预测的磷酸乙醇胺-脂 A 转移酶（EptA），该酶被描述为参与脂多糖（LPS）生物合成过程中脂 A 的修饰。该突变体表现出胞外多糖（EPS）产量的变化、低耐盐性和根际竞争能力下降。
