Methyl salicylate production in tomato affects biotic interactions.
The role of methyl salicylate (MeSA) production was studied in indirect and direct defence responses of tomato (Solanum lycopersicum) to the spider mite Tetranychus urticae and the root-invading fungus Fusarium oxysporum f. sp. lycopersici, respectively. To this end, we silenced the tomato gene encoding salicylic acid methyl transferase (SAMT). Silencing of SAMT led to a major reduction in SAMT expression and MeSA emission upon herbivory by spider mites, without affecting the induced emission of other volatiles (terpenoids). The predatory mite Phytoseiulus persimilis, which preys on T. urticae, could not discriminate between infested and non-infested SAMT-silenced lines, as it could for wild-type tomato plants. Moreover, when given the choice between infested SAMT-silenced and infested wild-type plants, they preferred the latter. These findings are supportive of a major role for MeSA in this indirect defence response of tomato. SAMT-silenced tomato plants were less susceptible to a virulent strain of F. oxysporum f. sp. lycopersici, indicating that the direct defense responses in the roots are also affected in these plants. Our studies show that the conversion of SA to MeSA can affect both direct and indirect plant defence responses.
Ament
Kai
K
Department of Plant Physiology, Swammerdam Institute for Life Sciences, Science Park 904, 1098 XH, Amsterdam, the Netherlands.
Krasikov
Vladimir
V
Allmann
Silke
S
Rep
Martijn
M
Takken
Frank L W
FL
Schuurink
Robert C
RC
D000818:Animals; D005670:Fusarium / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D020868:Gene Silencing; D054884:Host-Pathogen Interactions; D018551:Solanum lycopersicum / Q000235:genetics / Q000378:metabolism*; D008780:Methyltransferases / Q000235:genetics / Q000378:metabolism*; D008924:Mite Infestations / Q000235:genetics; D009822:Oils, Volatile / Q000378:metabolism; D010935:Plant Diseases / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000235:genetics; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D011235:Predatory Behavior; D018749:RNA, Plant / Q000235:genetics; D012459:Salicylates / Q000378:metabolism*; D013729:Terpenes / Q000378:metabolism; D040102:Tetranychidae / Q000502:physiology*
D009822:Oils, Volatile; D010940:Plant Proteins; D018749:RNA, Plant; D012459:Salicylates; D013729:Terpenes; D008780:Methyltransferases; C110994:salicylic acid carboxyl methyltransferase; C033069:methyl salicylate