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. 2021 Aug 26;187(3):1762–1778. doi: 10.1093/plphys/kiab368

Figure 8.

Figure 8

Schematic representation of systemic responses induced by Ma. sexta herbivory and their impact on M. incognita root-induced responses. A, Root infection by M. incognita leads to an early and transient local downregulation of the 13-LOX branch of the oxylipin pathway and the repression of defense-related metabolites in tomato roots. The yellow boxes show specific gene markers for the 13-LOX pathway and defense metabolites that are repressed in the roots upon M. incognita infection. B, Ma. sexta leaf herbivory triggers a systemic activation of the 13-LOX and 9-LOX branches of the oxylipin pathway, and the accumulation of defense-related metabolites in tomato roots. The green boxes show specific genes markers for the 13-LOX and 9-LOX branches of the oxylipin pathway, and defense metabolites that are enhanced by Ma. sexta leaf herbivory in the roots. C, Ma. sexta leaf herbivory antagonizes the M. incognita-triggered repression of the 13-LOX branch of oxylipin pathway and defense-related metabolites in tomato roots, and leads to a higher nematode resistance. When plants are co-infected with M. incognita and Ma. sexta, the root responses to M. incognita shift from the yellow box to the green box (D). The shoot jasmonate signaling pathway mediates the negative effect of Ma. sexta leaf herbivory on M. incognita performance. LOXD: LIPOXYGENASE D; AOS1: ALLENE OXIDE SYNTHASE 1; AOS2: ALLENE OXIDE SYNTHASE 2; AOC: ALLENE OXIDE CYCLASE; and OPR3; 12-OXOPHYTODIENOIC ACID REDUCTASE 3; LOXA: LIPOXYGENASE A; AOS3: ALLENE OXIDE SYNTHASE; DES: DIVINYL ETHER SYNTHASE.