Reactive oxygen species production and signal transduction in response to stress triggered by Alternaria elicitors in Brassicaceae.

The redox-dependent modulation of redox-sensitive proteins and transcription factors serves as a central mechanism to regulate plant defense responses against necrotrophic fungal pathogens. This process is interconnected with hormone signaling pathways involving salicylic acid (SA) or jasmonic acid (JA)/ethylene (ET), resulting in a coordinated holistic defense response to combat pathogen infection. In response to Alternaria infection, additional reactive oxygen species (ROS) production triggers an appropriate response to the invasive hyphae, acting as a primary defense mechanism in Brassicaceae. This ROS signaling pathway, involving receptors, kinases, transcriptional activators, and downstream genes such as ATR7 and ERF102/MACD1, among others, is critical for the well-coordinated plant response to Alternaria disease. These pathways can lead to either tolerance or programmed cell death (PCD), depending on the balance of signaling events. Despite the significant contribution of redox-mediated pathways, Alternaria blight continues to infect crops in the Brassicaceae family, leading to yield losses in Brassica species, especially oilseed crops, exerting a substantial economic impact. Given the importance of this pathogen, the current review provides an in-depth understanding of the oxidative stress and associated signaling networks triggered by Alternaria blight. Special emphasis is given to the interaction of Alternaria with oilseed Brassica crops, highlighting key molecular pathways involved in disease progression and plant response. Understanding these complex interactions provides valuable clues into the plant’s adaptations to stress. Thus, opening avenues for identifying novel solutions in producing resilience against the Alternaria pathogen, ensuring sustainable productivity in Brassica crops.