Article

Methyl salicylate production in tomato affects biotic interactions: Role of methyl salicylate in tomato defence

Department of Plant Physiology, Swammerdam Institute for Life Sciences, Science Park 904, 1098 XH, Amsterdam, the Netherlands.
The Plant Journal (Impact Factor: 6.82). 04/2010; 62(1):124-34. DOI: 10.1111/j.1365-313X.2010.04132.x
Source: PubMed

ABSTRACT 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.

Download full-text

Full-text

Available from: Frank Takken, Nov 25, 2014
1 Follower
 · 
153 Views
  • Source
    • "Salicylic acid methyltransferase from P. brassicae 357 Fusarium oxysporum (Ament et al., 2010). In accordance with a function for SA in defence against P. brassicae, treatment of Arabidopsis roots with 0.5 mM SA before inoculation completely reduced clubroot symptoms (Agarwal et al., 2011). "
    [Show abstract] [Hide abstract]
    ABSTRACT: The obligate biotrophic pathogen Plasmodiophora brassicae causes clubroot disease in Arabidopsis thaliana which is characterised by large root galls. Salicylic acid (SA) production is a defence response in plants, and its methyl ester is involved in systemic signalling. P. brassicae seems to suppress plant defence reactions, but knowledge of how this is achieved is scarce. Here, we profile the changes in SA metabolism during Arabidopsis clubroot disease. The accumulation of SA and emission of methylated SA (MeSA) were observed in P. brassicae-infected Arabidopsis 28 days after inoculation. There is evidence that MeSA is transported from infected roots to the upper plant. Analysis of the mutant Atbsmt1 deficient in methylation of SA, indicated that the Arabidopsis SA methyltransferase was not responsible for alterations in clubroot symptoms. We found that P. brassicae possesses a methyltransferase (PbBSMT) with homology to plant methyltransferases. The PbBSMT gene is maximally transcribed when SA production is highest. By heterologous expression and enzymatic analyses we showed that PbBSMT can methylate SA, benzoic and anthranilic acids.
    Molecular Plant Pathology 08/2014; 16(4). DOI:10.1111/mpp.12185 · 4.49 Impact Factor
  • Source
    • "RNAi silencing constructs were designed to silence simultaneously the genes of interest as well as a GUS reporter gene. The latter can be transiently expressed in leaves of stable transformants by agroinfiltration to simplify screening for plants exhibiting strong silencing (Wroblewski et al., 2007; Ament et al. 2010; Krasikov et al. 2010). For each gene two constructs were created that targetted either the 3# or the 5# end of the transcribed gene sequence. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Plant resistance proteins (R) are involved in pathogen recognition and subsequent initiation of defence responses. Their activity is regulated by inter- and intramolecular interactions. In a yeast two-hybrid screen two clones (I2I-1 and I2I-2) specifically interacting with I-2, a Fusarium oxysporum f. sp. lycopersici resistance protein of the CC-NB-LRR family, were identified. Sequence analysis revealed that I2I-1 belongs to the Formin gene family (SlFormin) whereas I2I-2 has homology to translin-associated protein X (SlTrax). SlFormin required only the N-terminal CC I-2 domain for binding, whereas SlTrax required both I-2 CC and part of the NB-ARC domain. Tomato plants stably silenced for these interactors were not compromised in I-2-mediated disease resistance. When extended or mutated forms of I-2 were used as baits, distinct and often opposite, interaction patterns with the two interactors were observed. These interaction patterns correlated with the proposed activation state of I-2 implying that active and inactive R proteins adopt distinct conformations. It is concluded that the yeast two hybrid system can be used as a proxy to monitor these different conformational states.
    Journal of Experimental Botany 02/2012; 63(8):3047-60. DOI:10.1093/jxb/ers021 · 5.79 Impact Factor
  • Source
    • "This supports its purported role as a universal lure for beneficial insects used in the biocontrol of agricultural pests (e.g., PredaLure). It also substantiates the outcomes from laboratory preference assays, which document that natural enemies frequently orient toward this volatile when offered a choice in foraging arenas (De Boer and Dicke, 2004, 2005; Ishiwari et al., 2007; Sasso et al., 2009; Ament et al., 2010; Shimoda, 2010). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Methyl salicylate (MeSA) is a herbivore-induced plant volatile that has shown potential in attracting natural enemies. Here, we conducted a meta-analysis to evaluate the magnitude of natural enemy response to MeSA in the field, and tested its attractiveness to insect predators in commercial cranberry bogs. Eighteen experiments from 14 publications were used in the meta-analysis, resulting in 91 total observations. Of these, 41 documented significant attraction and the magnitude of this attraction response was not significantly different across predator and parasitoid taxa. Insect predators were monitored in cranberries using MeSA (PredaLure)-baited and unbaited yellow sticky traps. MeSA-baited traps caught greater numbers of adult hoverfly, Toxomerus marginatus, lady beetles, and green lacewings compared with unbaited traps. In another field experiment, predator abundance was monitored using traps placed near the MeSA lure (0m), as well as at 2.5, 5, and 10m away from the lure. Adult T. marginatus, the dominant predator species, showed a clear attraction to the point source but not to the other distances. In complementary studies we showed that MeSA emissions from PredaLures dropped quickly soon after deployment in the field but remained relatively high for over 4weeks; flowering, but not vegetative, vines were a primary source of MeSA in cranberries; and, exposure to PredaLures triggered elevated MeSA emissions from vegetative vines. In conclusion, we find strong evidence that insect predators are broadly attracted to MeSA in agricultural fields, including cranberries; yet, whether this behavior can be manipulated to improve biological control needs further investigation.
    Biological Control 11/2011; 59(2):294-303. DOI:10.1016/j.biocontrol.2011.06.017 · 1.87 Impact Factor
Show more