Evaluation of salicylic acid (SA) signaling pathways and molecular markers in Trichoderma-treated plants under salinity and Fusarium stresses. A Review

Plants are exposed to a range of biotic and abiotic stresses, including fungal infections and soil salinity. These stresses have negative impacts on plant growth and productivity, resulting in reduced yields and economic losses. To mitigate these effects, researchers have explored the use of biocontrol agents, such as Trichoderma, which can enhance plant growth and protect plants against various stresses. Salicylic acid (SA) is a key signaling molecule in plant defense against pathogens and plays a crucial role in activating the plant defense response. SA signaling pathways are known to be involved in the regulation of pathogenesis-related (PR) proteins, reactive oxygen species (ROS) production, and the synthesis of phytohormones, such as jasmonic acid (JA) and ethylene (ET). In this review, we evaluated the effect of Trichoderma treatment on SA signaling pathways and molecular markers in plants under salinity and Fusarium stresses. The findings showed that Trichoderma-treated plants exhibited enhanced SA signaling, as evidenced by the upregulation of SA-related genes. This was associated with improved disease resistance, as Trichoderma-treated plants showed lower disease severity and increased survival rates when exposed to Fusarium infection. Moreover, Trichoderma-treated plants also exhibited increased tolerance to salinity stress, as evidenced by improved physiological parameters, such as chlorophyll content and root growth. Molecular markers such as PR proteins and ROS-scavenging enzymes were upregulated in Trichoderma-treated plants, further indicating the activation of plant defense mechanisms. Overall, these findings suggest that Trichoderma-induced SA signaling and molecular markers contribute to the enhanced stress tolerance in plants, highlighting the potential of Trichoderma as a biocontrol agent for sustainable agriculture. Further studies are needed to elucidate the mechanisms underlying these effects and to optimize the use of Trichoderma in crop production.