Aphid-Induced Defense Responses in Mi-1-Mediated Compatible and Incompatible Tomato Interactions

Abstract

The tomato Mi-1 gene confers resistance to three species of root-knot nematode and potato aphid. We studied changes in expression of jasmonic acid (JA)- and salicylic acid (SA)-dependent defense genes in response to potato and green peach aphids. We determined changes in three PR proteins, lipoxygenase and proteinase inhibitors I and II transcripts, locally and systemically in both compatible and incompatible interactions in tomato. Transcripts for PR-1 were detected earlier and accumulated to higher levels in the incompatible than in the compatible potato aphid/tomato interactions. The transcript profiles of the other genes were similar in compatible compared with incompatible interactions. Pin1 and Pin2 RNAs were detected early and transiently in both compatible and incompatible interactions. In tomato plants containing Mi-1, systemic expression of PR-1 and GluB was detected in both compatible and incompatible interactions at 48 h after infestations with either aphid. These results suggest that aphid feeding involves both SA and JA/ethylene plant defense signaling pathways and that Mi-1-mediated resistance might involve a SA-dependent signaling pathway. Potato aphid feeding generated reactive oxygen species in both compatible and incompatible interactions. However, a hypersensitive response was absent in the Mi-1-mediated resistance response to potato aphids. Reciprocal grafting experiments revealed that resistance is cell autonomous, and local expression of Mi-1 is required for Mi-1-mediated resistance against the potato aphid.

Loss of Function of FATTY ACID DESATURASE7 in Tomato Enhances Basal Aphid Resistance in a Salicylate-Dependent Manner

“…S1). This is consistent with prior reports that the induction of PI-II by aphids is relatively weak and transient compared with the induction of P4 (Fidantsef et al, 1999;Martinez de Ilarduya et al, 2003). As predicted by previous observations , PI-II expression was negligible in spr2 (Fig.…”

Regulation of tradeoffs between plant defenses against pathogens with different lifestyles

“…This may be explained by the fact that R protein-mediated resistance is associated with the concomitant engagement of both SA and JA signaling pathways (45). In tomato, R proteinmediated resistance to aphids induced simultaneous expression of SA-and JA-dependent defenses (46). Moreover, avirulent Pst DC3000 strains robustly activated the expression of JA biosynthesis enzymes and induced high levels of both SA and JA in Arabidopsis (16,47).…”

The Coiled-Coil and Nucleotide Binding Domains of BROWN PLANTHOPPER RESISTANCE14 Function in Signaling and Resistance against Planthopper in Rice

“…Support for this hypothesis comes from studies on Rx (Slootweg et al, 2010), RPS4 (Heidrich et al, 2011), and N (Bhattacharjee et al, 2009). Moreover, cell death appears to be uncoupled from the defense mechanisms induced by plant disease resistance genes encoding R proteins such as Rdg2a (Bulgarelli et al, 2010), Rrs1 (Lehnackers and Knogge, 1990), Mla1 (Freialdenhoven et al, 1994), Rx (Bendahmane et al, 1999), RPS4, RPS6 (Gassmann, 2005), and Mi-1 (Martinez de Ilarduya et al, 2003). These findings indicate that plant immunity can be effective without programmed host cell death.…”