This collaborative and interdisciplinary project is focused on understanding the biosynthetic pathways and genetic networks responsible for the accumulation of surface lipids on aerial portions of land plants.These surface lipids provide a hydrophobic layer that is a primary line of defense against numerous biological and environmental stresses. We are using the surface lipid metabolome on the silks of maize as the model to study how the organism adapts and protects plant surfaces from environmental stresses.
In this objective we are constructing genetic and metabolic network models for surface lipid accumulation on maize silks using a premier genetic resource in maize, a series of intermated B73xMo17 (IBM) mapping populations. These populations consist of 660 individual isolines, each of which carry a unique set of highly mosaic chromosomes derived from recombining the B73 and Mo17 genomes. The genetic factors controlling quantitative traits (termed QTLs) can be precisely mapped in these populations, which we have shown to exhibit a dynamic range of surface lipid metabolomes.
It is generally understood that the non-polar nature of the surface lipids that are infused within and coat the cuticle of plant surfaces provide a hydrophobic layer that acts as a protective water barrier between the plant and its environment. This Objective will test both the impact of water status on surface lipid accumulation as well as the protective capacities of these lipids on maize silks.
In addition to protecting against abiotic stresses, surface lipids are also thought to protect plants against insects (i.e. biotic stress). In the southern United States, annual yield losses from corn earworm (CEW; Helicoverpa zea [Boddie]) damage range between 1.5 and 16.7% for field corn and up to 50% for sweet corn (http://ipm.illinois.edu/fieldcrops/insects/corn_earworm/). Although the chemistry and ultrastructure of the cuticle is thought to have a major impact on resistance to both biotic and abiotic stresses, little is understood about the precise components of the surface lipid metabolome that are necessary to provide resistance against these stresses.