Alternaria blight causes significant losses in tomato. High disease severity during fruiting stage restricts the applicability of chemicals. Chemical pesticides can be substituted by resistance inducing agents. In present investigation, two resistance inducing agents namely Salicylic acid and Abscisic acid and a plant growth promoting rhizobacteria Pseudomonas fluorescens strain PBAT-2 (Psf) were used to assess their effect on Alternaria blight disease severity through the activity of defense-related compounds i.e. Peroxidase (POD), Polyphenol oxidase (PPO), Phenyl ammonia lyase (PAL), total phenolic content along with pathogenesis-related gene PR-1 and β-1,3-glucanase (GLU) gene expression in tomato. SA, ABA and Psf reduced disease severity significantly as compared to control. A significant increase in the activity of POD, PPO, PAL and total phenol content was recorded in all the three treatments over control. POD, PPO, PAL levels were significantly high at 24 h and 48 h post Alternaria solani inoculation, whereas total phenolic content increased up to 72 h. The expression of PR-1 and GLU gene was upregulated at 24 h post A. solani inoculation in SA and ABA treated leaves. However, these genes were unexpressed in Psf treated plants which confirms the role of SA and ABA in systemic acquired resistance. These findings suggest that SA, ABA and Psf can be used in early blight management in tomato without affecting the quality of the fruit.

交链孢霉病导致番茄大量损失。结果期的高病害严重程度限制了化学品的适用性。化学农药可用抗性诱导剂代替。在本研究中，使用了两种抗性诱导剂，即水杨酸和脱落酸和一种促进植物生长的根瘤菌荧光假单胞菌菌株PBAT-2（Psf），通过防御相关化合物即过氧化物酶的活性来评估其对枯萎病严重程度的影响。 （POD），多酚氧化酶（PPO），苯基氨裂解酶（PAL），总酚含量以及发病相关基因PR-1和β-1,3-葡聚糖酶（GLU）在番茄中的表达。SA，ABA和Psf与对照组相比，显着降低了疾病严重程度 在所有三种处理中，与对照相比，POD，PPO，PAL和总酚含量的活性均显着增加。Solnaria solani接种后24 h和48 h POD，PPO，PAL水平显着升高，而总酚含量增加到72 h。在SA和ABA处理的叶片中，sol。A . solani接种后24小时，PR-1和GLU基因的表达上调。然而，这些基因在经Psf处理的植物中未表达，这证实了SA和ABA在系统获得性抗性中的作用。这些发现表明，SA，ABA和Psf可用于番茄的早疫病处理，而不会影响果实的品质。