Brassinosteroids interact negatively with jasmonates in the formation of anti-herbivory traits in tomato

Abstract

Given the susceptibility of tomato plants to pests, the aim of the present study was to understand how hormones are involved in the formation of tomato natural defences against insect herbivory. Tomato hormone mutants, previously introgressed into the same genetic background of reference, were screened for alterations in trichome densities and allelochemical content. Ethylene, gibberellin, and auxin mutants indirectly showed alteration in trichome density, through effects on epidermal cell area. However, brassinosteroids (BRs) and jasmonates (JAs) directly affected trichome density and allelochemical content, and in an opposite fashion. The BR-deficient mutant dpy showed enhanced pubescence, zingiberene biosynthesis, and proteinase inhibitor expression; the opposite was observed for the JA-insensitive jai1-1 mutant. The dpy x jai1-1 double mutant showed that jai1-1 is epistatic to dpy, indicating that BR acts upstream of the JA signalling pathway. Herbivory tests with the poliphagous insect Spodoptera frugiperda and the tomato pest Tuta absoluta clearly confirmed the importance of the JA-BR interaction in defence against herbivory. The study underscores the importance of hormonal interactions on relevant agricultural traits and raises a novel biological mechanism in tomato that may differ from the BR and JA interaction already suggested for Arabidopsis.

Biological invasion of European tomato crops by Tuta absoluta: ecology, geographic expansion and prospects for biological control

“…However, mass trapping would likely be most effective when used in conjunction with recommended insecticides. Other pest control approaches have been studied and documented, notably the potential use of biological control agents (predators, parasitoids and entomopathogens which are described in ''Biological control of T. absoluta in South America'' section), resistant plants (de Resende et al 2006;Pereira et al 2008;Campos et al 2009;Oliveira et al 2009;Maluf et al 2010) and botanical insecticides (Moreira et al 2004;da Cunha et al 2005da Cunha et al , 2006GoncalvesGervasio and Vendramim 2007;da Cunha et al 2008). However, despite increasing interest in such control approach options (notably because smaller populations of T. absoluta are usually observed in organic vs. conventional systems, Medeiros 2007;Medeiros et al 2009b) they are only scarcely used.…”

Canopy Light and Plant Health

“…BRs were recently found to participate in the orchestration of the SAS phenotype induced by low R:FR values in Arabidopsis (Kozuka et al, 2010). Interestingly, BRs have also been shown to antagonize JA-mediated growth and antiherbivore responses (Campos et al, 2009;Ren et al, 2009) and to modulate the efficiency of plant immune responses elicited by microbe-associated molecular patterns (Albrecht et al, 2012;Belkhadir et al, 2012;Wang, 2012). BRI1-ASSOCIATED KINASE1 (BAK1) is a BR coreceptor and also physically interacts with the flg22 receptor FLS2, positively regulating FLS2-mediated innate immunity in Arabidopsis (Chinchilla et al, 2009).…”

Ocorrência De Nanismo Em Planta De Tomateiro Do Tipo Grape

“…Além do importante aspecto socioeconômico, a referida espécie é rotineiramente utilizada em pesquisas na área de genética vegetal em função da disponibilidade de mutantes (ZSOGON et al, 2008;CAMPOS et al, 2009;LIMA et al, 2009). As variações genéticas naturais em tomateiros assumem grande importância e vêm sendo usadas intensivamente, como é o caso das mutações jointless (MAO et al, 2000) e self-pruning (PIOTTO; PERES, 2012).…”