Streptomyces pratensis S10 Promotes Wheat Plant Growth and Induces Resistance in Wheat Seedlings against Fusarium graminearum

<i>Fusarium graminearum</i>, a devastating fungal pathogen, causes great economic losses to crop yields worldwide. The present study investigated the potential of <i>Streptomyces pratensis</i> S10 to alleviate <i>F. graminearum</i> stress in wheat seedlings based on plant growth-promoting and resistance-inducing assays. The bioassays revealed that S10 exhibited multiple plant growth-promoting properties, including the production of siderophores, 1-aminocyclopropane-1-carboxylic acid deaminase (ACC), and indole-3-acetic acid (IAA), phosphate solubilization, and nitrogen fixation. Meanwhile, the pot experiment demonstrated that S10 improved wheat plant development, substantially enhancing wheat height, weight, root activity, and chlorophyll content. Consistently, genome mining identified abundant genes associated with plant growth promotion. S10 induced resistance against <i>F. graminearum</i> in wheat seedlings. The disease incidence and disease index reduced by nearly 52% and 65% in S10 pretreated wheat seedlings, respectively, compared with those infected with <i>F. graminearum</i> only in the non-contact inoculation assay. Moreover, S10 enhanced callose deposition and reactive oxygen species (ROS) accumulation and induced the activities of CAT, SOD, POD, PAL, and PPO. Furthermore, the quantitative real-time PCR (qRT-PCR) results indicated that S10 pretreatment increased the expression of SA- (<i>PR1.1</i>, <i>PR2</i>, <i>PR5</i>, and <i>PAL1</i>) and JA/ET-related genes (<i>PR3</i>, <i>PR4a</i>, <i>PR9</i>, and <i>PDF1.2</i>) in wheat seedlings upon <i>F. graminearum</i> infection. In summary, <i>S. pratensis</i> S10 could be an integrated biological agent and biofertilizer in wheat seedling blight management and plant productivity enhancement.