Maize Hybrids Exhibit Reduction in an Elicitor-Triggered Defense Response Compared to Their Inbred Parents

Heterosis is the increased performance of hybrids relative to their parental genotypes. Heterosis for growth may be mediated by underlying traits, including traits affecting host-microbe interactions. A trade-off between growth and defense is often observed in plant disease studies, such that a stronger defense response is often associated with slower growth and lower yield. We investigated the production of reactive oxygen species (ROS) following treatment with microbial elicitors, an early component of the pattern-triggered immunity (PTI) response, in maize hybrids and their inbred parents. ROS production was often reduced in hybrids compared to inbred parents, and this effect was dependent on genotype, elicitor used, and time of day. These results identify PTI as a response displaying heterosis whose regulation might contribute to heterosis in other traits such as growth and yield.