Direct defense of Solanum lycopersicum L. to Tetranychus urticae Koch (Acari: Tetranychidae) mediated by plant morphological and chemical traits

Abstract

Tetranychus urticae is an economically important pest in many crops, such as cotton, soybean, beans, and tomato. The polyphagous behavior of this mite allows it to adapt to resistant hosts within a few generations. Here, we evaluated the resistance of tomato accessions to T. urticae through choice and no-choice trials, identified traits linked to resistance, and found candidate accessions for gene introgression in susceptible plants. In the choice trial, sixty-two accessions of S. lycopersicon from the Horticultural Germplasm Bank (HGB) were assessed together with ‘Santa Clara’ (susceptible control) and PI-134417 (resistant control) in a circular arena made of foam (50 cm diameter), followed by counting of mites on each accession. In the no-choice trial, four less preferred accessions from the choice trial plus the susceptible and resistant control were tested using 2-cm-diameter leaflets circles. Daily mortality was evaluated until the life cycle was completed. The content of zingiberene, 2-tridecanone, the number of idioblasts containing calcium oxalate crystals (COC), and the thickness of the lower and upper leaf epidermis, palisade parenchyma, lacunous parenchyma, and leaf blade were determined. The zingiberene, 2-tridecanone, number of idioblasts containing COC, lower and upper leaf epidermis thickness, palisade parenchyma, lacunous parenchyma, and leaf blade differed among treatments. In most situations, the accessions HGBs-2119 and 2123 had the highest thickness of the anatomical tissue components measured. The highest number of idioblasts containing COC was found in PI-134417 and HGB-2119. The zingeberene content was maximum in the HGB-2119 access and minimum in the resistant control PI-134417. Two-tridecanone was detected only in the resistant control PI-134417. The female survival rate and the number of eggs decreased significantly as the number of idioblasts containing COC increased. The overall analysis of the data shows that the accessions HGBs-2119, 813, 2123, and 327 have the greatest potential to serve as resistant sources for the introgression of resistant genes in tomato lines for processing industries.

Graphical abstract