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Salivary proteins of spider mites suppress defenses in Nicotiana benthamiana and promote mite reproduction
Author(s) -
Villarroel Carlos A.,
Jonckheere Wim,
Alba Juan M.,
Glas Joris J.,
Dermauw Wannes,
Haring Michel A.,
Van Leeuwen Thomas,
Schuurink Robert C.,
Kant Merijn R.
Publication year - 2016
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.13152
Subject(s) - tetranychus urticae , nicotiana benthamiana , biology , spider mite , effector , jasmonic acid , plant defense against herbivory , botany , solanum , salicylic acid , microbiology and biotechnology , mite , genetics , gene
Summary Spider mites ( Tetranychidae sp.) are widely occurring arthropod pests on cultivated plants. Feeding by the two‐spotted spider mite T. urticae , a generalist herbivore, induces a defense response in plants that mainly depends on the phytohormones jasmonic acid and salicylic acid ( SA ). On tomato ( Solanum lycopersicum ), however, certain genotypes of T. urticae and the specialist species T. evansi were found to suppress these defenses. This phenomenon occurs downstream of phytohormone accumulation via an unknown mechanism. We investigated if spider mites possess effector‐like proteins in their saliva that can account for this defense suppression. First we performed an in silico prediction of the T. urticae and the T. evansi secretomes, and subsequently generated a short list of candidate effectors based on additional selection criteria such as life stage‐specific expression and salivary gland expression via whole mount in situ hybridization. We picked the top five most promising protein families and then expressed representatives in Nicotiana benthamiana using Agrobacterium tumefaciens transient expression assays to assess their effect on plant defenses. Four proteins from two families suppressed defenses downstream of the phytohormone SA . Furthermore, T. urticae performance on N. benthamiana improved in response to transient expression of three of these proteins and this improvement was similar to that of mites feeding on the tomato SA accumulation mutant nahG . Our results suggest that both generalist and specialist plant‐eating mite species are sensitive to SA defenses but secrete proteins via their saliva to reduce the negative effects of these defenses.