Tomato is a major horticulture crop and a rich source of antioxidants and vitamins. Early blight, late blight, bacterial spot, bacterial wilt, and Fusarium wilt are among the bacterial and fungal diseases that damage tomato plants. Early blight is more prevalent among these diseases in areas with more dew, rain, and humidity. Defoliation is the most serious stage of early blight disease since it affects the fruit quality and yield, resulting in a severe yield reduction (Adhikari et al. 2017). Efficient strategies for disease prophylaxis are limited due to inadequate knowledge about the interaction mechanism between the host (tomato) and pathogen Alternaria solani. Therefore, understanding defence-associated signals, and the corresponding genes and pathways need thorough attention.Genes belonging to the NBS-LRR family, including members of the TIR-NBS-LRR (TNL) family, are considered one of the most effective defence mechanisms against pathogens (Chen et al. 2016). The NBS-LRR genes encode proteins with nucleotide binding sites (NBSs) and leucine-rich repeat (LRR) domains, often present in large numbers in the plant genome (Zhao et al. 2016). NBS-LRR genes reported in plant defence include both CC-NBS-LRR (CNL) and TNLs. The CNL members include wheat powdery mildew resist-