INVESTIGADORES
ZAVALA Jorge Alberto
congresos y reuniones científicas
Título:
Stink bugs (Nezara viridula) induce soybean MAPKs activation and expression of genes related with cell wall proteins in developing seeds modulating chemical defenses.
Autor/es:
GIACOMETTI, R; ILINA, N.; ZAVALA, J.A.
Lugar:
Bogota
Reunión:
Congreso; III Congress of the Latin American Association of Chemical Ecology (ALAEQ); 2014
Institución organizadora:
Latin American Association of Chemical Ecology (ALAEQ)
Resumen:
Stink bugs (Nezara
viridula) are a key pest in soybean (Glycine
max), which attack decreases yield crop. Plant response begins
with the recognition of cell injury and oral secretions, triggering mitogen
activated protein kinases (MAPK) pathway and inducing defenses against
herbivores. Stink bugs preferentially feed on young developing seeds and inject
toxic saliva that causes further tissue damage. Soybean MAPK?s role in
mediating responses to insects attack remains largely unexplored. In this work we examined in developing
seeds under attack of stink bugs the transcription of genes involved in cell
wall modification, as well as early and late MAPKs involvement in defense modulation. We
found that MPK3, MPK4 and MPK6 as well as a MPKK are differentially transcribed
in time after insect perception. We analyzed the phosphorylation status and
identified soybean MPK6 as an herbivore and wound-induced kinase, while MPK3
and MPK4 were found to be activated after SA and JA treatments. Although two
critical genes involved in flavonoid synthesis, Phe-ammonia lyase (PAL2) and chalcone synthase (CHS7) were up-regulated under all
treatments, only stink bug attack induced isoflavone synthase (IFS), an enzyme responsible for the
synthesis of daidzein and genistein, which are the main chemical defenses
against these insects. We also analyzed
the cell wall transcriptional response and found that 72h after stink bugs
attack increased the expression of expansine (EXP), xyloglucan endo-transferase (EXT), pectate lyase (PL)
y polygalacturonase (PG). Our results
suggest that stink bug attack not only increases the expression of cell wall
genes causing a re-arrangement of the wall, but also triggers JA and
SA-mediated defenses through a tightly regulated induction of MAPKs
transcription and phosphorylation of particular MAPKs in a time-dependent
fashion.