Targeted Manipulation of a Tomato Terpene Synthase Enhances TMTT-Mediated Attraction of <i>Eretmocerus corni</i> for Sustainable Whitefly Control

The whitefly <i>Bemisia tabaci</i> (Hemiptera: Aleyrodidae) is a globally destructive pest of tomato. We elucidated the chemical and molecular basis of the key herbivore-induced volatile TMTT in mediating tomato-whitefly-parasitoid interactions and its potential for augmenting biological control. Gas chromatography-mass spectrometry profiling identified 13 differentially emitted volatiles from whitefly infested plants, with four terpenoids─(<i>Z</i>)-3-hexen-1-ol, β-ocimene, 4,8-dimethyl-1,3,7-nonatriene (DMNT), and (<i>E</i>,<i>E</i>)-4,8,12-trimethyltrideca-1,3,7,11-tetraene (TMTT)─significantly upregulated. Behavioral assays revealed that DMNT and, more strongly, TMTT attracted <i>Eretmocerus corni</i>, a whitefly specific parasitoid. Transcriptome and RT-qPCR analyses identified <i>SlTPS46</i> as the key terpene synthase for TMTT biosynthesis, showing a 9.9-fold induction upon herbivory. Overexpression of <i>SlTPS46</i> significantly enhanced the TMTT emission. This elevated emission increased parasitoid recruitment by 40% and significantly boosted parasitism rates, without adversely affecting whitefly life-history traits. This study provides the first mechanistic link between a specific terpene synthase, HIPV emission, and parasitoid attraction in tomato, establishing TMTT as a pivotal semiochemical and demonstrating that targeted terpenoid pathway manipulation can enhance HIPV-mediated biological control in this system.