Maize Resistance to Stem Borers can be modulated by Systemic Maize
Responses to Long-term Stem Tunneling
Abstract
Scarce attention has been paid to maize (Zea mays L.) resistance induced
by corn borer damage although evidence shows that induced defenses have
lower resource allocation costs than constitutive defenses. The maize
responses to short and long-term attacks by the Mediterranean corn borer
(MCB, Sesamia nionagrioides) have been previously studied but suggested
differences between responses could be due to experimental differences.
Therefore, in the current study, a direct comparison between short and
long-term responses has been made. The objectives were (i) to determine
changes in the level of antibiosis of the stems induced by feeding of
Sesamia nonagrioides (Mediterranean Corn Borer; MCB) larvae for two days
(short-term feeding) and nine days (long-term feeding), (ii) to
characterize the metabolome of the stem short and long-term responses to
borer attack and (iii) to look for metabolic pathways that could
modulate plant resistance to MCB. Adjustment of plant performance under
subsequent conspecific attack due to previous insect damage was
genotype-dependent; defenses were progressively induced in the resistant
inbred and constitutive defenses were broken down in the susceptible
inbred. Results suggest that the different resistance of the two inbreds
to stem tunneling by MCB could depend on their ability to stablish a
systemic response.