Advancing tomato crop protection: Green leaf volatile-mediated defense mechanisms against Nesidiocoris tenuis plant damage

Although Nesidiocoris tenuis is highly effective as a biological control agent, it can also damage tomato plants due to its zoophytophagous behavior. When N. tenuis pierces the stems and petioles of tomato plants with its stylets, it triggers callose deposition and subsequent cell death, resulting in blocked nutrient transport, floral abortions, or wilting of tender shoots. Recently, it has been shown that exposure of tomato plants to the green leaf volatile (Z)-3-hexenyl propanoate [(Z)-3-HP] activates defensive mechanisms, including the regulation of genes involved in the synthesis and degradation of callose. In this study, conducted under greenhouse conditions, we tested the hypothesis that damage caused by N. tenuis could be reduced by exposing tomato plants to (Z)-3-HP through polymeric dispensers. Tomato plants exposed to (Z)-3-HP and non-exposed control plants were inoculated with N. tenuis. Nesidiocoris tenuis established in both groups with no significant differences between the two treatments. However, as hypothesized, the damage caused by N. tenuis was significantly lower in the plants exposed to (Z)-3-HP. Gene expression analysis of salicylic, jasmonic, and abscisic acids, along with histochemical staining methods, was used to compare the defensive responses of tomato plants infested solely with N. tenuis versus those infested with N. tenuis and exposed to (Z)-3-HP. Our findings confirm the influence of (Z)-3-HP exposure on differential defensive activation between treatments and reduced callose deposition in (Z)-3-HP-exposed plants. These results pave the way for improved management of N. tenuis by enhancing the plant's defenses based on inter-plant communication.