Meloidogyne incognita is among the most detrimental parasitic nematodes with a wide host range causing huge economic losses annually. Biological control of M. incognita has emerged as a promising alternative in sustainable agriculture. In our previous study, Bacillus velezensis TA-1 effectively controlled M. incognita in vitro and in the field trials through direct nematocidal activities. However, it remains poorly understood for the underlying mechanisms including whether TA-1 could induce host resistance against M. incognita. In the present study, the effects of TA-1 induced resistance against M. incognita in tomato were determined. Results showed that TA-1 colonized tomato roots, with 1.23 × 10⁸ colony forming units (CFU)/g root tissues attached within 36 h, significantly reduced the number of galls in the local and systemic root systems in the split-root experiments by 44.0% and 28.1%, respectively. The bacteria also increased the basic defense responses of tomato plants, such as lignin accumulation and hydrogen peroxide (H₂O₂) content, which was associated with the enhanced activities of enzymes related to plant defense [e.g. phenylalanine ammonia-lyase (PAL), peroxidase (POD) and polyphenol oxidase (PPO)]. Moreover, TA-1 enhanced the expressions of tomato defense response genes in the salicylic acid (PR1a and PR-P6) and jasmonic acid (PI II and MC) pathways and induced resistance against M. incognita. These results suggested that TA-1 could effectively control M. incognita through induction of tomato resistance, therefore it could be used as a promising biocontrol agent to be incorporated in the integrated management programs in tomato production.

南方根结线虫是危害最严重的寄生线虫之一，其寄主范围广泛，每年造成巨大的经济损失。南方根结线虫的生物防治已成为可持续农业中一种有前景的替代方案。在我们之前的研究中，贝莱斯芽孢杆菌TA-1通过直接杀线虫活性在体外和田间试验中有效控制南方根结线虫。然而，对于潜在的机制仍然知之甚少，包括TA-1是否可以诱导宿主对南方根结线虫的抗性。在本研究中，确定了 TA-1 诱导番茄对南方根结线虫抗性的影响。结果表明，TA-1在番茄根部定殖，36小时内附着的菌落形成单位（CFU）/克根组织达到1.23×10 ⁸，在分根实验中显着减少了局部和全身根系的虫瘿数量。分别为 44.0% 和 28.1%。这些细菌还增加了番茄植株的基本防御反应，例如木质素积累和过氧化氢（H ₂ O ₂）含量，这与植物防御相关酶活性的增强有关[例如苯丙氨酸解氨酶（PAL）、过氧化物酶（POD）和多酚氧化酶（PPO）]。此外，TA-1增强了水杨酸（PR1a和PR-P6）和茉莉酸（PI II和MC ）途径中番茄防御反应基因的表达，并诱导对南方根结线虫的抗性。这些结果表明TA-1可以通过诱导番茄抗性来有效控制南方根结线虫，因此它可以作为一种有前景的生物防治剂纳入番茄生产的综合管理计划中。