Pseudomonas spp., a ubiquitous biocontrol agent, protects the plants from phytopathogens by suppressing them directly by reinforcing the plant’s intrinsic defense mechanism. Root exudated phenolics play an important role in establishing the rhizobacteria population and cross the host boundaries in beneficial plant–microbe interaction. In this study, Pseudomonas spp. HU-8 & HU-9 antagonized the sugarcane red rot pathogen (C. falcatum) and showed a positive chemotactic response against different concentrations (10–30 µM) of synthetic phenolic acids like p-coumaric, vanillic, and 3,4 di-hydroxybenzoic acid. In a pot experiment, they effectively colonized the sugarcane rhizosphere and mediated defense response in sugarcane plants challenged with red rot pathogen C. falcatum by regulating the exudation of root phenolics under hydroponic conditions. They significantly induced the activity of the antioxidant enzymes CAT (1.24–1.64 fold), PO (0.78–1.61 fold), PAL (0.77–0.97 fold), and PPO (3.67–3.73 fold) over untreated plants in sugarcane. They also induced the total phenolic contents (TPC) in sugarcane in the presence (6.56–10.29 mg/g GAE) and absence (2.89–4.16 mg/g GAE) of the pathogen quantified through the Folin-Ciocalteu (FC) method. However, their effect was lower than that of the pathogen (4.34–8 mg/g GAE). The Pseudomonas spp. significantly colonized the sugarcane rhizosphere by maintaining a cell population of (1.0E + 07–1.3E + 08 CFU/mL). A significant positive Pearson’s correlation was observed between the root exudated total phenolic contents, antioxidant enzymatic activities, and rhizospheric population of inoculated bacteria. The 16S rRNA and rpoD gene analysis showed sequence conservation (C: 0.707), average number of nucleotide differences (k: 199.816), nucleotide diversity, (Pi): 0.09819), average number of informative nucleotide sites per site (Psi: 0.01275), GC content (0.57), and polymorphic sites (n = 656). These diverse Pseudomonas spp. could be an ideal bio-inoculants for a broad range of hosts especially graminaceous crops.

假单胞菌属（Pseudomonas spp.）是一种普遍存在的生物防治剂，通过加强植物的内在防御机制直接抑制植物病原体，从而保护植物免受植物病原体的侵害。根系分泌出的酚类物质在建立根际细菌种群和跨越有益植物 - 微生物相互作用的宿主边界方面发挥着重要作用。在这项研究中，假单胞菌属。HU-8 和 HU-9 拮抗甘蔗红腐病菌 ( C. falcatum ) 并对不同浓度 (10–30 µM) 的合成酚酸如p-香豆酸、香草酸和 3,4 二羟基苯甲酸。在盆栽实验中，他们通过调节水培条件下根部酚类物质的渗出，有效地在甘蔗根际定植并介导了受到红腐病病原体C. falcatum攻击的甘蔗植物的防御反应。与未经处理的甘蔗植物相比，它们显着诱导抗氧化酶 CAT（1.24-1.64 倍）、PO（0.78-1.61 倍）、PAL（0.77-0.97 倍）和 PPO（3.67-3.73 倍）的活性。他们还在通过 Folin-Ciocalteu (FC) 方法量化的病原体存在 (6.56–10.29 mg/g GAE) 和不存在 (2.89–4.16 mg/g GAE) 的情况下诱导甘蔗中的总酚含量 (TPC)。然而，它们的作用低于病原体（4.34-8 mg/g GAE）。该假单胞菌属 通过维持 (1.0E + 07–1.3E + 08 CFU/mL) 的细胞群，显着定植甘蔗根际。在根系分泌的总酚含量、抗氧化酶活性和接种细菌的根际种群之间观察到显着的正 Pearson 相关性。16S rRNA 和rpoD基因分析显示序列保守性 (C: 0.707)、平均核苷酸差异数 (k: 199.816)、核苷酸多样性 (Pi): 0.09819)、每个位点的信息性核苷酸位点平均数 (Psi: 0.01275) 、GC 含量 (0.57) 和多态位点 (n = 656)。这些不同的假单胞菌属。可能是一种理想的生物接种剂，适用于广泛的宿主，尤其是禾本科作物。