Bacterial leaf blight (BLB) disease caused by Xanthomonas oryzae pv. oryzae (Xoo) is one of the most destructive pathogens responsible for severe yield losses in rice. Application of bacterial biocontrol agent (BCA) with plant growth promotion (PGP) abilities is a promising method that alternates current conventional practices to manage BLB disease and increase crop yield. Hence, this study aimed to isolate and identify BCA with PGP abilities from internal plant tissues and rhizosphere soil of healthy and Xoo-infected rice and evaluate their antagonistic and PGP properties under greenhouse and field conditions. A total of 14 bacterial isolates were isolated and presented in vitro antagonistic ability against the Xoo. The rice endophytic bacterium strain Bacillius velezensis (BTR11) had the highest antagonistic activity against the Xoo, produced indole acetic acid (IAA), and mineralized nutrients (K and P). The greenhouse experiment revealed that culture broth of strain BTR11 had a high protective effect (72.1%) against the BLB when applied at the protective-fighting mode, i.e., before and after the Xoo infection. Preliminary results of the field experiment showed that a protective effect against the bacterial blight disease was obtained as high as 75–85%, if the strain was used as an additive to the soil for the seedlings in combination with spraying when the disease began in the field. In addition, using the strain BTR11 also increased the rice yield to about 12% more than the un-treatment control. The study showed a significant potential for the application of endophytic bacteria in controlling BLB disease, while stimulating plant growth, thus reducing the use of agrochemicals in rice cultivation.

中文翻译：

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内生细菌贝莱斯芽孢杆菌BTR11在防治白叶枯病促进水稻生长中的应用

由米黄单胞菌 (Xanthomonas oryzae pv.) 引起的细菌性叶枯病 (BLB) 病。米曲霉 (Xoo) 是最具破坏性的病原体之一，导致水稻严重减产。应用具有植物生长促进（PGP）能力的细菌生物防治剂（BCA）是一种很有前景的方法，可以替代目前的传统做法来控制BLB病害并提高作物产量。因此，本研究旨在从健康和 Xoo 感染水稻的内部植物组织和根际土壤中分离和鉴定具有 PGP 能力的 BCA，并评估其在温室和田间条件下的拮抗和 PGP 特性。共分离出14株细菌，并表现出对Xoo的体外拮抗能力。水稻内生菌株 Bacillius velezensis (BTR11) 对 Xoo 的拮抗活性最高，产生吲哚乙酸（IAA）和矿化营养素（K和P）。温室实验表明，在保护性战斗模式下，即Xoo感染前后，菌株BTR11的培养液对BLB具有较高的保护效果（72.1％）。田间试验的初步结果表明，如果将该菌株作为幼苗土壤的添加剂，并在病害发生时喷洒，对白叶枯病的防护效果高达75%~85%。场地。此外，使用菌株BTR11还使水稻产量比未处理对照增加约12%。该研究表明内生细菌在控制 BLB 病害方面具有巨大潜力，同时刺激植物生长，