Brassinosteroids interact negatively with jasmonates in the formation of anti-herbivory traits in tomato.
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.
Campos
Marcelo Lattarulo
ML
Departamento de Ciências Biológicas, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Piracicaba-SP, Brazil.
de Almeida
Marcílio
M
Rossi
Mônica Lanzoni
ML
Martinelli
Adriana Pinheiro
AP
Litholdo Junior
Celso Gaspar
CG
Figueira
Antonio
A
Rampelotti-Ferreira
Fátima Teresinha
FT
Vendramim
José Djair
JD
Benedito
Vagner Augusto
VA
Peres
Lázaro Eustáquio Pereira
LE
D000818:Animals; D003517:Cyclopentanes / Q000378:metabolism*; D004435:Eating; D018506:Gene Expression Regulation, Plant; D007313:Insecta / Q000502:physiology*; D018551:Solanum lycopersicum / Q000235:genetics* / Q000378:metabolism*; D054883:Oxylipins / Q000378:metabolism*; D010937:Plant Growth Regulators / Q000378:metabolism*; D019655:Quantitative Trait, Heritable
D003517:Cyclopentanes; D054883:Oxylipins; D010937:Plant Growth Regulators; C011006:jasmonic acid