This study aims to evaluate the use of Bacillus velezensis strain XT1 as a plant growth-promoting rhizobacterium (PGPR) and biocontrol agent against B. cinerea in tomato and strawberry plants. Foliar and radicular applications of strain XT1 increased plant total biomass as compared to the control and B. cinerea-infected plants, with root applications being, on the whole, the most effective mode of treatment. Applications of the bacterium were found to reduce infection parameters such as disease incidence and severity by 50% and 60%, respectively. We analyzed stress parameters and phytohormone content in order to evaluate the capacity of XT1 to activate the defense system through phytohormonal regulation. Overall, the application of XT1 reduced oxidative damage, while the H₂O₂ and malondialdehyde (MDA) content was lower in XT1-treated and B. cinerea-infected plants as compared to non-XT1-treated plants. Moreover, treatment with XT1 induced callose deposition, thus boosting the response to pathogenic infection. The results of this study suggest that the signaling and activation pathways involved in defense mechanisms are mediated by jasmonic acid (JA) and ethylene hormones, which are induced by preventive treatment with XT1. The study also highlights the potential of preventive applications of strain XT1 to activate defense mechanisms in strawberry and tomato plants through hormone regulation.

中文翻译：

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根际生物防治剂芽孢杆菌Bacillus velezensis XT1对灰葡萄孢的农作物保护。

这项研究旨在评估使用芽孢杆菌XT1菌株作为促进植物生长的根瘤菌（PGPR）和针对番茄和草莓植物中灰葡萄孢的生物防治剂的用途。叶面和根系施用XT1菌株与对照和灰葡萄孢相比增加了植物总生物量感染的植物，从根本上讲，根部施用是最有效的治疗方式。发现使用该细菌可将感染参数（例如疾病发生率和严重性）分别降低50％和60％。我们分析了压力参数和植物激素含量，以评估XT1通过植物激素调节激活防御系统的能力。总体而言，XT1的使用减少了氧化损伤，而XT1处理和灰葡萄孢的H ₂ O ₂和丙二醛（MDA）含量较低。与未经XT1处理的植物相比 此外，用XT1进行处理可诱导ose质沉积，从而增强对病原体感染的反应。这项研究的结果表明，防御机制中涉及的信号传导和激活途径是由茉莉酸（JA）和乙烯激素介导的，而茉莉酸和乙烯激素是由XT1的预防性治疗诱导的。该研究还强调了预防性应用XT1菌株通过激素调节激活草莓和番茄植物防御机制的潜力。