title: Drought stress in tomato increases the performance of adapted and non-adapted strains of Tetranychus urticae.
abstract: The performance of the two-spotted spider mite, Tetranychus urticae Koch, on plants depends on the rate of adaptation of mite populations to each particular host and can be influenced by environmental conditions. We have tested the effects of drought stress, caused by water deficiency, in the interaction of tomato plants with tomato adapted (TA) and tomato non-adapted (TNA) strains of T. urticae. Our data revealed that mite performance was enhanced for the TA strain when reared on drought-stressed tomato plants, rising population growth and leaf damage. Population growth in the case of the TNA strain was negative, but they laid more eggs and the number of mobile forms was higher on drought-stressed tomato plants than on control plants. Water stress resulted in tomato plants with increased concentrations of essential amino acids and free sugars, improving the nutritional value of drought-stressed tomato plants for T. urticae. Mite infestation alone had almost no effect on the nutritional composition of tomato leaves, with the exception of an increase of free sugars. Tomato plant defense proteins were induced by both drought stress and mite infestation. However, the induction of protease inhibitors was higher in tomatoes exposed to mites from the TNA strain than in tomatoes that were fed upon by mites from the TA strain. The better performance of the TA strain could be associated to both changes in the digestive (cysteine and aspartyl protease and α-amylase activities) and detoxification (esterase activity) physiology of the mites and the attenuation of some of the plant defenses (protease inhibitors). Taken together, our results suggest that drought stress might favor outbreaks of T. urticae on tomato, by enhancing population growth of adapted populations and increasing the suitability of tomato as a host for non-adapted ones.
authors: Centro de Investigaciones Biológicas, CSIC, Departamento de Biología Medioambiental, Ramiro de Maeztu 9, 28040 Madrid, Spain.
authors: Miguel G
authors: MG
authors: Ximénez-Embún
authors: Centro de Investigaciones Biológicas, CSIC, Departamento de Biología Medioambiental, Ramiro de Maeztu 9, 28040 Madrid, Spain.
authors: Pedro
authors: P
authors: Castañera
authors: Centro de Investigaciones Biológicas, CSIC, Departamento de Biología Medioambiental, Ramiro de Maeztu 9, 28040 Madrid, Spain. Electronic address: ortego@cib.csic.es.
authors: Félix
authors: F
authors: Ortego
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D055864:Droughts; D005260:Female; D060434:Herbivory; D007814:Larva / Q000254:growth & development / Q000502:physiology; D018551:Solanum lycopersicum / Q000502:physiology*; D009758:Nymph / Q000254:growth & development / Q000502:physiology; D018521:Plant Physiological Phenomena; D040102:Tetranychidae / Q000254:growth & development / Q000502:physiology*
keywords: Climate change; Detoxification; Digestion; Nutrition; Plant-mite interaction; Spider mite