Tomato Aphid () Secreted Saliva Can Enhance Aphid Resistance by Upregulating Signaling Molecules in Tomato ().

This study investigated the impact of watery saliva on the induction of tomato () plant resistance. To examine the role of saliva, we collected watery saliva from after a 48 h feeding period on an artificial diet. SDS-PAGE resolving gel 12% was used to separate the salivary proteins. Relative expression of gene analysis revealed that the intrusion of saliva dripping onto leaves triggered robust defense responses mediated by a signaling molecule, i.e., salicylic acid, while the signaling molecule's jasmonic acid-dependent defense responses were moderately activated. Aphid saliva infiltrated leaves slowed the intrinsic rate of population growth of and significantly reduced the number of nymphs produced daily, compared to untreated leaves. During a choice test with untreated , aphids showed a repellent response towards saliva-infiltrated . Moreover, the (EPG) electrical penetration graph analysis demonstrated that the eating pattern of compared to untreated , that had been exposed to saliva was negatively impacted. These results provide compelling evidence for the involvement of salivary components of in inducing resistance against aphids in plants. Furthermore, the study underscores the crucial role of watery saliva in the intricate interactions between aphids and plants. The activation of pathways was also part of the defensive response (jasmonic acid (JA), salicylic acid (SA) signaling molecules). The findings of this research deliver valuable insights into the potential of watery aphid saliva as a natural defense mechanism against aphid infestations in crops.